Examples

Get started

Styles

Size styles

C code  

 GitHub
#include "../lv_examples.h"
#if LV_BUILD_EXAMPLES && LV_USE_IMG

/**
 * Using the Size, Position and Padding style properties
 */
void lv_example_style_1(void)
{
     static lv_style_t style;
     lv_style_init(&style);
     lv_style_set_radius(&style, 5);

     /*Make a gradient*/
     lv_style_set_width(&style, 150);
     lv_style_set_height(&style, LV_SIZE_CONTENT);

     lv_style_set_pad_ver(&style, 20);
     lv_style_set_pad_left(&style, 5);

     lv_style_set_x(&style, lv_pct(50));
     lv_style_set_y(&style, 80);

     /*Create an object with the new style*/
     lv_obj_t * obj = lv_obj_create(lv_scr_act());
     lv_obj_add_style(obj, &style, 0);

     lv_obj_t * label = lv_label_create(obj);
     lv_label_set_text(label, "Hello");
}

#endif

MicroPython code  

 GitHub Simulator
#
# Using the Size, Position and Padding style properties
#
style = lv.style_t()
style.init()
style.set_radius(5)

# Make a gradient
style.set_width(150)
style.set_height(lv.SIZE.CONTENT)

style.set_pad_ver(20)
style.set_pad_left(5)

style.set_x(lv.pct(50))
style.set_y(80)

# Create an object with the new style
obj = lv.obj(lv.scr_act())
obj.add_style(style, 0)

label = lv.label(obj)
label.set_text("Hello")


Background styles

C code  

 GitHub
#include "../lv_examples.h"
#if LV_BUILD_EXAMPLES

/**
 * Using the background style properties
 */
void lv_example_style_2(void)
{
    static lv_style_t style;
    lv_style_init(&style);
    lv_style_set_radius(&style, 5);

    /*Make a gradient*/
    lv_style_set_bg_opa(&style, LV_OPA_COVER);
    lv_style_set_bg_color(&style, lv_palette_lighten(LV_PALETTE_GREY, 1));
    lv_style_set_bg_grad_color(&style, lv_palette_main(LV_PALETTE_BLUE));
    lv_style_set_bg_grad_dir(&style, LV_GRAD_DIR_VER);

    /*Shift the gradient to the bottom*/
    lv_style_set_bg_main_stop(&style, 128);
    lv_style_set_bg_grad_stop(&style, 192);

    /*Create an object with the new style*/
    lv_obj_t * obj = lv_obj_create(lv_scr_act());
    lv_obj_add_style(obj, &style, 0);
    lv_obj_center(obj);
}

#endif

MicroPython code  

 GitHub Simulator
#
# Using the background style properties
#
style = lv.style_t()
style.init()
style.set_radius(5)

# Make a gradient
style.set_bg_opa(lv.OPA.COVER)
style.set_bg_color(lv.palette_lighten(lv.PALETTE.GREY, 1))
style.set_bg_grad_color(lv.palette_main(lv.PALETTE.BLUE))
style.set_bg_grad_dir(lv.GRAD_DIR.VER)

# Shift the gradient to the bottom
style.set_bg_main_stop(128)
style.set_bg_grad_stop(192)

# Create an object with the new style
obj = lv.obj(lv.scr_act())
obj.add_style(style, 0)
obj.center()

Border styles

C code  

 GitHub
#include "../lv_examples.h"
#if LV_BUILD_EXAMPLES

/**
 * Using the border style properties
 */
void lv_example_style_3(void)
{
    static lv_style_t style;
    lv_style_init(&style);

    /*Set a background color and a radius*/
    lv_style_set_radius(&style, 10);
    lv_style_set_bg_opa(&style, LV_OPA_COVER);
    lv_style_set_bg_color(&style, lv_palette_lighten(LV_PALETTE_GREY, 1));

    /*Add border to the bottom+right*/
    lv_style_set_border_color(&style, lv_palette_main(LV_PALETTE_BLUE));
    lv_style_set_border_width(&style, 5);
    lv_style_set_border_opa(&style, LV_OPA_50);
    lv_style_set_border_side(&style, LV_BORDER_SIDE_BOTTOM | LV_BORDER_SIDE_RIGHT);

    /*Create an object with the new style*/
    lv_obj_t * obj = lv_obj_create(lv_scr_act());
    lv_obj_add_style(obj, &style, 0);
    lv_obj_center(obj);
}

#endif

MicroPython code  

 GitHub Simulator
#
# Using the border style properties
#
style = lv.style_t()
style.init()

# Set a background color and a radius
style.set_radius(10)
style.set_bg_opa(lv.OPA.COVER)
style.set_bg_color(lv.palette_lighten(lv.PALETTE.GREY, 1))

# Add border to the bottom+right
style.set_border_color(lv.palette_main(lv.PALETTE.BLUE))
style.set_border_width(5)
style.set_border_opa(lv.OPA._50)
style.set_border_side(lv.BORDER_SIDE.BOTTOM | lv.BORDER_SIDE.RIGHT)

# Create an object with the new style
obj = lv.obj(lv.scr_act())
obj.add_style(style, 0)
obj.center()

Outline styles

C code  

 GitHub
#include "../lv_examples.h"
#if LV_BUILD_EXAMPLES

/**
 * Using the outline style properties
 */
void lv_example_style_4(void)
{
    static lv_style_t style;
    lv_style_init(&style);

    /*Set a background color and a radius*/
    lv_style_set_radius(&style, 5);
    lv_style_set_bg_opa(&style, LV_OPA_COVER);
    lv_style_set_bg_color(&style, lv_palette_lighten(LV_PALETTE_GREY, 1));

    /*Add outline*/
    lv_style_set_outline_width(&style, 2);
    lv_style_set_outline_color(&style, lv_palette_main(LV_PALETTE_BLUE));
    lv_style_set_outline_pad(&style, 8);

    /*Create an object with the new style*/
    lv_obj_t * obj = lv_obj_create(lv_scr_act());
    lv_obj_add_style(obj, &style, 0);
    lv_obj_center(obj);
}

#endif

MicroPython code  

 GitHub Simulator
#
# Using the outline style properties
#

style = lv.style_t()
style.init()

# Set a background color and a radius
style.set_radius(5)
style.set_bg_opa(lv.OPA.COVER)
style.set_bg_color(lv.palette_lighten(lv.PALETTE.GREY, 1))

# Add outline
style.set_outline_width(2)
style.set_outline_color(lv.palette_main(lv.PALETTE.BLUE))
style.set_outline_pad(8)

# Create an object with the new style
obj = lv.obj(lv.scr_act())
obj.add_style(style, 0)
obj.center()

Shadow styles

C code  

 GitHub
#include "../lv_examples.h"
#if LV_BUILD_EXAMPLES

/**
 * Using the Shadow style properties
 */
void lv_example_style_5(void)
{
    static lv_style_t style;
    lv_style_init(&style);

    /*Set a background color and a radius*/
    lv_style_set_radius(&style, 5);
    lv_style_set_bg_opa(&style, LV_OPA_COVER);
    lv_style_set_bg_color(&style, lv_palette_lighten(LV_PALETTE_GREY, 1));

    /*Add a shadow*/
    lv_style_set_shadow_width(&style, 55);
    lv_style_set_shadow_color(&style, lv_palette_main(LV_PALETTE_BLUE));
//    lv_style_set_shadow_ofs_x(&style, 10);
//    lv_style_set_shadow_ofs_y(&style, 20);

    /*Create an object with the new style*/
    lv_obj_t * obj = lv_obj_create(lv_scr_act());
    lv_obj_add_style(obj, &style, 0);
    lv_obj_center(obj);
}

#endif

MicroPython code  

 GitHub Simulator
#
# Using the Shadow style properties
#

style = lv.style_t()
style.init()

# Set a background color and a radius
style.set_radius(5)
style.set_bg_opa(lv.OPA.COVER)
style.set_bg_color(lv.palette_lighten(lv.PALETTE.GREY, 1))

# Add a shadow
style.set_shadow_width(8)
style.set_shadow_color(lv.palette_main(lv.PALETTE.BLUE))
style.set_shadow_ofs_x(10)
style.set_shadow_ofs_y(20)

# Create an object with the new style
obj = lv.obj(lv.scr_act())
obj.add_style(style, 0)
obj.center()

Image styles

C code  

 GitHub
#include "../lv_examples.h"
#if LV_BUILD_EXAMPLES && LV_USE_IMG

/**
 * Using the Image style properties
 */
void lv_example_style_6(void)
{
    static lv_style_t style;
    lv_style_init(&style);

    /*Set a background color and a radius*/
    lv_style_set_radius(&style, 5);
    lv_style_set_bg_opa(&style, LV_OPA_COVER);
    lv_style_set_bg_color(&style, lv_palette_lighten(LV_PALETTE_GREY, 3));
    lv_style_set_border_width(&style, 2);
    lv_style_set_border_color(&style, lv_palette_main(LV_PALETTE_BLUE));

    lv_style_set_img_recolor(&style, lv_palette_main(LV_PALETTE_BLUE));
    lv_style_set_img_recolor_opa(&style, LV_OPA_50);
    lv_style_set_transform_angle(&style, 300);

    /*Create an object with the new style*/
    lv_obj_t * obj = lv_img_create(lv_scr_act());
    lv_obj_add_style(obj, &style, 0);

    LV_IMG_DECLARE(img_cogwheel_argb);
    lv_img_set_src(obj, &img_cogwheel_argb);

    lv_obj_center(obj);
}

#endif

MicroPython code  

 GitHub Simulator
from imagetools import get_png_info, open_png
# Register PNG image decoder
decoder = lv.img.decoder_create()
decoder.info_cb = get_png_info
decoder.open_cb = open_png

# Create an image from the png file
try:
    with open('../assets/img_cogwheel_argb.png', 'rb') as f:
        png_data = f.read()
except:
    print("Could not find img_cogwheel_argb.png")
    sys.exit()
    
img_cogwheel_argb = lv.img_dsc_t({
  'data_size': len(png_data),
  'data': png_data 
})

#
# Using the Image style properties
#
style = lv.style_t()
style.init()

# Set a background color and a radius
style.set_radius(5)
style.set_bg_opa(lv.OPA.COVER)
style.set_bg_color(lv.palette_lighten(lv.PALETTE.GREY, 3))
style.set_border_width(2)
style.set_border_color(lv.palette_main(lv.PALETTE.BLUE))

style.set_img_recolor(lv.palette_main(lv.PALETTE.BLUE))
style.set_img_recolor_opa(lv.OPA._50)
# style.set_transform_angle(300)

# Create an object with the new style
obj = lv.img(lv.scr_act())
obj.add_style(style, 0)

obj.set_src(img_cogwheel_argb)

obj.center()

Text styles

C code  

 GitHub
#include "../lv_examples.h"
#if LV_BUILD_EXAMPLES && LV_USE_LABEL

/**
 * Using the text style properties
 */
void lv_example_style_8(void)
{
    static lv_style_t style;
    lv_style_init(&style);

    lv_style_set_radius(&style, 5);
    lv_style_set_bg_opa(&style, LV_OPA_COVER);
    lv_style_set_bg_color(&style, lv_palette_lighten(LV_PALETTE_GREY, 2));
    lv_style_set_border_width(&style, 2);
    lv_style_set_border_color(&style, lv_palette_main(LV_PALETTE_BLUE));
    lv_style_set_pad_all(&style, 10);

    lv_style_set_text_color(&style, lv_palette_main(LV_PALETTE_BLUE));
    lv_style_set_text_letter_space(&style, 5);
    lv_style_set_text_line_space(&style, 20);
    lv_style_set_text_decor(&style, LV_TEXT_DECOR_UNDERLINE);

    /*Create an object with the new style*/
    lv_obj_t * obj = lv_label_create(lv_scr_act());
    lv_obj_add_style(obj, &style, 0);
    lv_label_set_text(obj, "Text of\n"
                            "a label");

    lv_obj_center(obj);
}

#endif

MicroPython code  

 GitHub Simulator
#
# Using the text style properties
#

style = lv.style_t()
style.init()

style.set_radius(5)
style.set_bg_opa(lv.OPA.COVER)
style.set_bg_color(lv.palette_lighten(lv.PALETTE.GREY, 3))
style.set_border_width(2)
style.set_border_color(lv.palette_main(lv.PALETTE.BLUE))
style.set_pad_all(10)

style.set_text_color(lv.palette_main(lv.PALETTE.BLUE))
style.set_text_letter_space(5)
style.set_text_line_space(20)
style.set_text_decor(lv.TEXT_DECOR.UNDERLINE)

# Create an object with the new style
obj = lv.label(lv.scr_act())
obj.add_style(style, 0)
obj.set_text("Text of\n"
             "a label")

obj.center()


Line styles

C code  

 GitHub
#include "../lv_examples.h"
#if LV_BUILD_EXAMPLES && LV_USE_LINE

/**
 * Using the line style properties
 */
void lv_example_style_9(void)
{
    static lv_style_t style;
    lv_style_init(&style);

    lv_style_set_line_color(&style, lv_palette_main(LV_PALETTE_GREY));
    lv_style_set_line_width(&style, 6);
    lv_style_set_line_rounded(&style, true);

    /*Create an object with the new style*/
    lv_obj_t * obj = lv_line_create(lv_scr_act());
    lv_obj_add_style(obj, &style, 0);

    static lv_point_t p[] = {{10, 30}, {30, 50}, {100, 0}};
    lv_line_set_points(obj, p, 3);

    lv_obj_center(obj);
}

#endif

MicroPython code  

 GitHub Simulator
#
# Using the line style properties
#

style = lv.style_t()
style.init()

style.set_line_color(lv.palette_main(lv.PALETTE.GREY))
style.set_line_width(6)
style.set_line_rounded(True)

# Create an object with the new style
obj = lv.line(lv.scr_act())
obj.add_style(style, 0)
p =  [ {"x":10, "y":30}, 
       {"x":30, "y":50}, 
       {"x":100, "y":0}]

obj.set_points(p, 3)

obj.center()

Transition

C code  

 GitHub
#include "../lv_examples.h"
#if LV_BUILD_EXAMPLES && LV_USE_IMG

/**
 * Creating a transition
 */
void lv_example_style_10(void)
{
    static const lv_style_prop_t props[] = {LV_STYLE_BG_COLOR, LV_STYLE_BORDER_COLOR, LV_STYLE_BORDER_WIDTH, 0};

    /* A default transition
     * Make it fast (100ms) and start with some delay (200 ms)*/
    static lv_style_transition_dsc_t trans_def;
    lv_style_transition_dsc_init(&trans_def, props, lv_anim_path_linear, 100, 200, NULL);

    /* A special transition when going to pressed state
     * Make it slow (500 ms) but start  without delay*/
    static lv_style_transition_dsc_t trans_pr;
    lv_style_transition_dsc_init(&trans_pr, props, lv_anim_path_linear, 500, 0, NULL);

    static lv_style_t style_def;
    lv_style_init(&style_def);
    lv_style_set_transition(&style_def, &trans_def);

    static lv_style_t style_pr;
    lv_style_init(&style_pr);
    lv_style_set_bg_color(&style_pr, lv_palette_main(LV_PALETTE_RED));
    lv_style_set_border_width(&style_pr, 6);
    lv_style_set_border_color(&style_pr, lv_palette_darken(LV_PALETTE_RED, 3));
    lv_style_set_transition(&style_pr, &trans_pr);

    /*Create an object with the new style_pr*/
    lv_obj_t * obj = lv_obj_create(lv_scr_act());
    lv_obj_add_style(obj, &style_def, 0);
    lv_obj_add_style(obj, &style_pr, LV_STATE_PRESSED);

    lv_obj_center(obj);
}

#endif

MicroPython code  

 GitHub Simulator
#
# Creating a transition
#

props = [lv.STYLE.BG_COLOR, lv.STYLE.BORDER_COLOR, lv.STYLE.BORDER_WIDTH, 0]

# A default transition
# Make it fast (100ms) and start with some delay (200 ms)

trans_def =  lv.style_transition_dsc_t()
trans_def.init(props, lv.anim_t.path_linear, 100, 200, None)

# A special transition when going to pressed state
# Make it slow (500 ms) but start  without delay

trans_pr = lv.style_transition_dsc_t()
trans_pr.init(props, lv.anim_t.path_linear, 500, 0, None)

style_def = lv.style_t()
style_def.init()
style_def.set_transition(trans_def)

style_pr = lv.style_t()
style_pr.init()
style_pr.set_bg_color(lv.palette_main(lv.PALETTE.RED))
style_pr.set_border_width(6)
style_pr.set_border_color(lv.palette_darken(lv.PALETTE.RED, 3))
style_pr.set_transition(trans_pr)

# Create an object with the new style_pr
obj = lv.obj(lv.scr_act())
obj.add_style(style_def, 0)
obj.add_style(style_pr, lv.STATE.PRESSED)

obj.center()

Using multiple styles

C code  

 GitHub
#include "../lv_examples.h"
#if LV_BUILD_EXAMPLES && LV_USE_IMG

/**
 * Using multiple styles
 */
void lv_example_style_11(void)
{
    /*A base style*/
    static lv_style_t style_base;
    lv_style_init(&style_base);
    lv_style_set_bg_color(&style_base, lv_palette_main(LV_PALETTE_LIGHT_BLUE));
    lv_style_set_border_color(&style_base, lv_palette_darken(LV_PALETTE_LIGHT_BLUE, 3));
    lv_style_set_border_width(&style_base, 2);
    lv_style_set_radius(&style_base, 10);
    lv_style_set_shadow_width(&style_base, 10);
    lv_style_set_shadow_ofs_y(&style_base, 5);
    lv_style_set_shadow_opa(&style_base, LV_OPA_50);
    lv_style_set_text_color(&style_base, lv_color_white());
    lv_style_set_width(&style_base, 100);
    lv_style_set_height(&style_base, LV_SIZE_CONTENT);

    /*Set only the properties that should be different*/
    static lv_style_t style_warning;
    lv_style_init(&style_warning);
    lv_style_set_bg_color(&style_warning, lv_palette_main(LV_PALETTE_YELLOW));
    lv_style_set_border_color(&style_warning, lv_palette_darken(LV_PALETTE_YELLOW, 3));
    lv_style_set_text_color(&style_warning, lv_palette_darken(LV_PALETTE_YELLOW, 4));

    /*Create an object with the base style only*/
    lv_obj_t * obj_base = lv_obj_create(lv_scr_act());
    lv_obj_add_style(obj_base, &style_base, 0);
    lv_obj_align(obj_base, LV_ALIGN_LEFT_MID, 20, 0);

    lv_obj_t * label = lv_label_create(obj_base);
    lv_label_set_text(label, "Base");
    lv_obj_center(label);

    /*Create an other object with the base style and earnings style too*/
    lv_obj_t * obj_warning = lv_obj_create(lv_scr_act());
    lv_obj_add_style(obj_warning, &style_base, 0);
    lv_obj_add_style(obj_warning, &style_warning, 0);
    lv_obj_align(obj_warning, LV_ALIGN_RIGHT_MID, -20, 0);

    label = lv_label_create(obj_warning);
    lv_label_set_text(label, "Warning");
    lv_obj_center(label);
}

#endif

MicroPython code  

 GitHub Simulator
#
# Using multiple styles
#
# A base style

style_base = lv.style_t()
style_base.init()
style_base.set_bg_color(lv.palette_main(lv.PALETTE.LIGHT_BLUE))
style_base.set_border_color(lv.palette_darken(lv.PALETTE.LIGHT_BLUE, 3))
style_base.set_border_width(2)
style_base.set_radius(10)
style_base.set_shadow_width(10)
style_base.set_shadow_ofs_y(5)
style_base.set_shadow_opa(lv.OPA._50)
style_base.set_text_color(lv.color_white())
style_base.set_width(100)
style_base.set_height(lv.SIZE.CONTENT)

# Set only the properties that should be different
style_warning = lv.style_t()
style_warning.init()
style_warning.set_bg_color(lv.palette_main(lv.PALETTE.YELLOW))
style_warning.set_border_color(lv.palette_darken(lv.PALETTE.YELLOW, 3))
style_warning.set_text_color(lv.palette_darken(lv.PALETTE.YELLOW, 4))

# Create an object with the base style only
obj_base = lv.obj(lv.scr_act())
obj_base.add_style(style_base, 0)
obj_base.align(lv.ALIGN.LEFT_MID, 20, 0)

label = lv.label(obj_base)
label.set_text("Base")
label.center()

# Create an other object with the base style and earnings style too
obj_warning = lv.obj(lv.scr_act())
obj_warning.add_style(style_base, 0)
obj_warning.add_style(style_warning, 0)
obj_warning.align(lv.ALIGN.RIGHT_MID, -20, 0)

label = lv.label(obj_warning)
label.set_text("Warning")
label.center()

Local styles

C code  

 GitHub
#include "../lv_examples.h"
#if LV_BUILD_EXAMPLES && LV_USE_IMG

/**
 * Local styles
 */
void lv_example_style_12(void)
{
    static lv_style_t style;
    lv_style_init(&style);
    lv_style_set_bg_color(&style, lv_palette_main(LV_PALETTE_GREEN));
    lv_style_set_border_color(&style, lv_palette_lighten(LV_PALETTE_GREEN, 3));
    lv_style_set_border_width(&style, 3);

    lv_obj_t * obj = lv_obj_create(lv_scr_act());
    lv_obj_add_style(obj, &style, 0);

    /*Overwrite the background color locally*/
    lv_obj_set_style_bg_color(obj,lv_palette_main(LV_PALETTE_ORANGE), LV_PART_MAIN);

    lv_obj_center(obj);
}

#endif

MicroPython code  

 GitHub Simulator
#
# Local styles
#

style = lv.style_t()
style.init()
style.set_bg_color(lv.palette_main(lv.PALETTE.GREEN))
style.set_border_color(lv.palette_lighten(lv.PALETTE.GREEN, 3))
style.set_border_width(3)

obj = lv.obj(lv.scr_act())
obj.add_style(style, 0)

# Overwrite the background color locally
obj.set_style_bg_color(lv.palette_main(lv.PALETTE.ORANGE), lv.PART.MAIN)

obj.center()

Add styles to parts and states

C code  

 GitHub
#include "../lv_examples.h"
#if LV_BUILD_EXAMPLES && LV_USE_IMG

/**
 * Add styles to parts and states
 */
void lv_example_style_13(void)
{
    static lv_style_t style_indic;
    lv_style_init(&style_indic);
    lv_style_set_bg_color(&style_indic, lv_palette_lighten(LV_PALETTE_RED, 3));
    lv_style_set_bg_grad_color(&style_indic, lv_palette_main(LV_PALETTE_RED));
    lv_style_set_bg_grad_dir(&style_indic, LV_GRAD_DIR_HOR);

    static lv_style_t style_indic_pr;
    lv_style_init(&style_indic_pr);
    lv_style_set_shadow_color(&style_indic_pr, lv_palette_main(LV_PALETTE_RED));
    lv_style_set_shadow_width(&style_indic_pr, 10);
    lv_style_set_shadow_spread(&style_indic_pr, 3);

    /*Create an object with the new style_pr*/
    lv_obj_t * obj = lv_slider_create(lv_scr_act());
    lv_obj_add_style(obj, &style_indic, LV_PART_INDICATOR);
    lv_obj_add_style(obj, &style_indic_pr, LV_PART_INDICATOR | LV_STATE_PRESSED);
    lv_slider_set_value(obj, 70, LV_ANIM_OFF);
    lv_obj_center(obj);
}

#endif

MicroPython code  

 GitHub Simulator
#
# Add styles to parts and states
#

style_indic = lv.style_t()
style_indic.init()
style_indic.set_bg_color(lv.palette_lighten(lv.PALETTE.RED, 3))
style_indic.set_bg_grad_color(lv.palette_main(lv.PALETTE.RED))
style_indic.set_bg_grad_dir(lv.GRAD_DIR.HOR)

style_indic_pr = lv.style_t()
style_indic_pr.init()
style_indic_pr.set_shadow_color(lv.palette_main(lv.PALETTE.RED))
style_indic_pr.set_shadow_width(10)
style_indic_pr.set_shadow_spread(3)

# Create an object with the new style_pr
obj = lv.slider(lv.scr_act())
obj.add_style(style_indic, lv.PART.INDICATOR)
obj.add_style(style_indic_pr, lv.PART.INDICATOR | lv.STATE.PRESSED)
obj.set_value(70, lv.ANIM.OFF)
obj.center()

Extending the current theme

C code  

 GitHub
#include "../lv_examples.h"
#if LV_BUILD_EXAMPLES && LV_USE_IMG


static lv_style_t style_btn;

/*Will be called when the styles of the base theme are already added
  to add new styles*/
static void new_theme_apply_cb(lv_theme_t * th, lv_obj_t * obj)
{
    LV_UNUSED(th);

    if(lv_obj_check_type(obj, &lv_btn_class)) {
        lv_obj_add_style(obj, &style_btn, 0);
    }
}

static void new_theme_init_and_set(void)
{
    /*Initialize the styles*/
    lv_style_init(&style_btn);
    lv_style_set_bg_color(&style_btn, lv_palette_main(LV_PALETTE_GREEN));
    lv_style_set_border_color(&style_btn, lv_palette_darken(LV_PALETTE_GREEN, 3));
    lv_style_set_border_width(&style_btn, 3);

    /*Initialize the new theme from the current theme*/
    lv_theme_t * th_act = lv_disp_get_theme(NULL);
    static lv_theme_t th_new;
    th_new = *th_act;

    /*Set the parent theme and the style apply callback for the new theme*/
    lv_theme_set_parent(&th_new, th_act);
    lv_theme_set_apply_cb(&th_new, new_theme_apply_cb);

    /*Assign the new theme the the current display*/
    lv_disp_set_theme(NULL, &th_new);
}



/**
 * Extending the current theme
 */
void lv_example_style_14(void)
{
    lv_obj_t * btn;
    lv_obj_t * label;

    btn = lv_btn_create(lv_scr_act());
    lv_obj_align(btn, LV_ALIGN_TOP_MID, 0, 20);

    label = lv_label_create(btn);
    lv_label_set_text(label, "Original theme");

    new_theme_init_and_set();

    btn = lv_btn_create(lv_scr_act());
    lv_obj_align(btn, LV_ALIGN_BOTTOM_MID, 0, -20);

    label = lv_label_create(btn);
    lv_label_set_text(label, "New theme");
}

#endif

MicroPython code  

 GitHub Simulator
# Will be called when the styles of the base theme are already added
# to add new styles


class NewTheme(lv.theme_t):
    def __init__(self):
        super().__init__()
        # Initialize the styles
        self.style_btn = lv.style_t()
        self.style_btn.init()
        self.style_btn.set_bg_color(lv.palette_main(lv.PALETTE.GREEN))
        self.style_btn.set_border_color(lv.palette_darken(lv.PALETTE.GREEN, 3))
        self.style_btn.set_border_width(3)

        # This theme is based on active theme 
        th_act = lv.theme_get_from_obj(lv.scr_act())
        # This theme will be applied only after base theme is applied
        self.set_parent(th_act)        


class ExampleStyle_14:
    
    def __init__(self):
        # 
        # Extending the current theme
        #

        btn = lv.btn(lv.scr_act())
        btn.align(lv.ALIGN.TOP_MID, 0, 20)

        label = lv.label(btn)
        label.set_text("Original theme")
        
        self.new_theme_init_and_set()
        
        btn = lv.btn(lv.scr_act())
        btn.align(lv.ALIGN.BOTTOM_MID, 0, -20)
        
        label = lv.label(btn)
        label.set_text("New theme")
        
    def new_theme_apply_cb(self, th, obj):
        print(th,obj)
        if obj.get_class() == lv.btn_class:
            obj.add_style(self.th_new.style_btn, 0)
        
    def new_theme_init_and_set(self):
        print("new_theme_init_and_set")
        # Initialize the new theme from the current theme        
        self.th_new = NewTheme()
        self.th_new.set_apply_cb(self.new_theme_apply_cb)
        lv.disp_get_default().set_theme(self.th_new)


exampleStyle_14 = ExampleStyle_14()

Animations

Events

Button click event

C code  

 GitHub
#include "../lv_examples.h"
#if LV_BUILD_EXAMPLES && LV_USE_SWITCH

static void event_cb(lv_event_t * e)
{
    LV_LOG_USER("Clicked");

    static uint32_t cnt = 1;
    lv_obj_t * btn = lv_event_get_target(e);
    lv_obj_t * label = lv_obj_get_child(btn, 0);
    lv_label_set_text_fmt(label, "%"LV_PRIu32, cnt);
    cnt++;
}

/**
 * Add click event to a button
 */
void lv_example_event_1(void)
{
    lv_obj_t * btn = lv_btn_create(lv_scr_act());
    lv_obj_set_size(btn, 100, 50);
    lv_obj_center(btn);
    lv_obj_add_event_cb(btn, event_cb, LV_EVENT_CLICKED, NULL);

    lv_obj_t * label = lv_label_create(btn);
    lv_label_set_text(label, "Click me!");
    lv_obj_center(label);
}

#endif

MicroPython code  

 GitHub Simulator
class Event_1():
    def __init__(self):
        self.cnt = 1
        #
        # Add click event to a button
        #

        btn = lv.btn(lv.scr_act())
        btn.set_size(100, 50)
        btn.center()
        btn.add_event_cb(self.event_cb, lv.EVENT.CLICKED, None)
        
        label = lv.label(btn)
        label.set_text("Click me!")
        label.center()

    def event_cb(self,e):
        print("Clicked")
            
        btn = e.get_target()
        label = btn.get_child(0)
        label.set_text(str(self.cnt))
        self.cnt += 1

evt1 = Event_1()

Handle multiple events

C code  

 GitHub
#include "../lv_examples.h"
#if LV_BUILD_EXAMPLES && LV_USE_SWITCH

static void event_cb(lv_event_t * e)
{
    lv_event_code_t code = lv_event_get_code(e);
    lv_obj_t * label = lv_event_get_user_data(e);

    switch(code) {
    case LV_EVENT_PRESSED:
        lv_label_set_text(label, "The last button event:\nLV_EVENT_PRESSED");
        break;
    case LV_EVENT_CLICKED:
        lv_label_set_text(label, "The last button event:\nLV_EVENT_CLICKED");
        break;
    case LV_EVENT_LONG_PRESSED:
        lv_label_set_text(label, "The last button event:\nLV_EVENT_LONG_PRESSED");
        break;
    case LV_EVENT_LONG_PRESSED_REPEAT:
        lv_label_set_text(label, "The last button event:\nLV_EVENT_LONG_PRESSED_REPEAT");
        break;
    default:
        break;
    }
}

/**
 * Handle multiple events
 */
void lv_example_event_2(void)
{
    lv_obj_t * btn = lv_btn_create(lv_scr_act());
    lv_obj_set_size(btn, 100, 50);
    lv_obj_center(btn);

    lv_obj_t * btn_label = lv_label_create(btn);
    lv_label_set_text(btn_label, "Click me!");
    lv_obj_center(btn_label);

    lv_obj_t * info_label = lv_label_create(lv_scr_act());
    lv_label_set_text(info_label, "The last button event:\nNone");

    lv_obj_add_event_cb(btn, event_cb, LV_EVENT_ALL, info_label);
}

#endif

MicroPython code  

 GitHub Simulator
def event_cb(e,label):
    code = e.get_code()
    if code == lv.EVENT.PRESSED:
        label.set_text("The last button event:\nLV_EVENT_PRESSED")
    elif code == lv.EVENT.CLICKED:
        label.set_text("The last button event:\nLV_EVENT_CLICKED")
    elif code ==  lv.EVENT.LONG_PRESSED:
        label.set_text("The last button event:\nLV_EVENT_LONG_PRESSED")
    elif code == lv.EVENT.LONG_PRESSED_REPEAT:
        label.set_text("The last button event:\nLV_EVENT_LONG_PRESSED_REPEAT")        
btn = lv.btn(lv.scr_act())
btn.set_size(100, 50)
btn.center()

btn_label = lv.label(btn)
btn_label.set_text("Click me!")
btn_label.center()

info_label = lv.label(lv.scr_act())
info_label.set_text("The last button event:\nNone")

btn.add_event_cb(lambda e: event_cb(e,info_label), lv.EVENT.ALL, None)

Event bubbling

C code  

 GitHub
#include "../lv_examples.h"
#if LV_BUILD_EXAMPLES && LV_USE_FLEX

static void event_cb(lv_event_t * e)
{
    /*The original target of the event. Can be the buttons or the container*/
    lv_obj_t * target = lv_event_get_target(e);

    /*The current target is always the container as the event is added to it*/
    lv_obj_t * cont = lv_event_get_current_target(e);

    /*If container was clicked do nothing*/
    if(target == cont) return;

    /*Make the clicked buttons red*/
    lv_obj_set_style_bg_color(target, lv_palette_main(LV_PALETTE_RED), 0);
}

/**
 * Demonstrate event bubbling
 */
void lv_example_event_3(void)
{

    lv_obj_t * cont = lv_obj_create(lv_scr_act());
    lv_obj_set_size(cont, 290, 200);
    lv_obj_center(cont);
    lv_obj_set_flex_flow(cont, LV_FLEX_FLOW_ROW_WRAP);

    uint32_t i;
    for(i = 0; i < 30; i++) {
        lv_obj_t * btn = lv_btn_create(cont);
        lv_obj_set_size(btn, 80, 50);
        lv_obj_add_flag(btn, LV_OBJ_FLAG_EVENT_BUBBLE);

        lv_obj_t * label = lv_label_create(btn);
        lv_label_set_text_fmt(label, "%"LV_PRIu32, i);
        lv_obj_center(label);
    }

    lv_obj_add_event_cb(cont, event_cb, LV_EVENT_CLICKED, NULL);
}

#endif

MicroPython code  

 GitHub Simulator
def event_cb(e):

    # The original target of the event. Can be the buttons or the container
    target = e.get_target()
    # print(type(target))

    # If container was clicked do nothing
    if type(target) != type(lv.btn()):
        return

    # Make the clicked buttons red
    target.set_style_bg_color(lv.palette_main(lv.PALETTE.RED), 0)

#
# Demonstrate event bubbling
#

cont = lv.obj(lv.scr_act())
cont.set_size(320, 200)
cont.center()
cont.set_flex_flow(lv.FLEX_FLOW.ROW_WRAP)

for i in range(30):
    btn = lv.btn(cont)
    btn.set_size(80, 50)
    btn.add_flag(lv.obj.FLAG.EVENT_BUBBLE)

    label = lv.label(btn)
    label.set_text(str(i))
    label.center()
    cont.add_event_cb(event_cb, lv.EVENT.CLICKED, None)

Layouts

Flex

Grid

Scrolling

Widgets

Base object

Base objects with custom styles

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_BUILD_EXAMPLES

void lv_example_obj_1(void)
{
    lv_obj_t * obj1;
    obj1 = lv_obj_create(lv_scr_act());
    lv_obj_set_size(obj1, 100, 50);
    lv_obj_align(obj1, LV_ALIGN_CENTER, -60, -30);

    static lv_style_t style_shadow;
    lv_style_init(&style_shadow);
    lv_style_set_shadow_width(&style_shadow, 10);
    lv_style_set_shadow_spread(&style_shadow, 5);
    lv_style_set_shadow_color(&style_shadow, lv_palette_main(LV_PALETTE_BLUE));

    lv_obj_t * obj2;
    obj2 = lv_obj_create(lv_scr_act());
    lv_obj_add_style(obj2, &style_shadow, 0);
    lv_obj_align(obj2, LV_ALIGN_CENTER, 60, 30);
}
#endif

MicroPython code  

 GitHub Simulator
obj1 = lv.obj(lv.scr_act())
obj1.set_size(100, 50)
obj1.align(lv.ALIGN.CENTER, -60, -30)

style_shadow = lv.style_t()
style_shadow.init()
style_shadow.set_shadow_width(10)
style_shadow.set_shadow_spread(5)
style_shadow.set_shadow_color(lv.palette_main(lv.PALETTE.BLUE))

obj2 = lv.obj(lv.scr_act())
obj2.add_style(style_shadow, 0)
obj2.align(lv.ALIGN.CENTER, 60, 30)


Make an object draggable

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_BUILD_EXAMPLES

static void drag_event_handler(lv_event_t * e)
{
    lv_obj_t * obj = lv_event_get_target(e);

    lv_indev_t * indev = lv_indev_get_act();
    if(indev == NULL)  return;

    lv_point_t vect;
    lv_indev_get_vect(indev, &vect);

    lv_coord_t x = lv_obj_get_x(obj) + vect.x;
    lv_coord_t y = lv_obj_get_y(obj) + vect.y;
    lv_obj_set_pos(obj, x, y);
}


/**
 * Make an object dragable.
 */
void lv_example_obj_2(void)
{
    lv_obj_t * obj;
    obj = lv_obj_create(lv_scr_act());
    lv_obj_set_size(obj, 150, 100);
    lv_obj_add_event_cb(obj, drag_event_handler, LV_EVENT_PRESSING, NULL);

    lv_obj_t * label = lv_label_create(obj);
    lv_label_set_text(label, "Drag me");
    lv_obj_center(label);

}
#endif

MicroPython code  

 GitHub Simulator
def drag_event_handler(e):

    obj = e.get_target()

    indev = lv.indev_get_act()

    vect = lv.point_t()
    indev.get_vect(vect)
    x = obj.get_x() + vect.x
    y = obj.get_y() + vect.y
    obj.set_pos(x, y)


#
# Make an object dragable.
#

obj = lv.obj(lv.scr_act())
obj.set_size(150, 100)
obj.add_event_cb(drag_event_handler, lv.EVENT.PRESSING, None)

label = lv.label(obj)
label.set_text("Drag me")
label.center()


Arc

Simple Arc

C code  

 GitHub
#include "../../lv_examples.h"

#if LV_USE_ARC && LV_BUILD_EXAMPLES

void lv_example_arc_1(void)
{
  /*Create an Arc*/
  lv_obj_t * arc = lv_arc_create(lv_scr_act());
  lv_obj_set_size(arc, 150, 150);
  lv_arc_set_rotation(arc, 135);
  lv_arc_set_bg_angles(arc, 0, 270);
  lv_arc_set_value(arc, 40);
  lv_obj_center(arc);
}

#endif

MicroPython code  

 GitHub Simulator
# Create an Arc
arc = lv.arc(lv.scr_act())
arc.set_end_angle(200)
arc.set_size(150, 150)
arc.center()




Loader with Arc

C code  

 GitHub
#include "../../lv_examples.h"

#if LV_USE_ARC && LV_BUILD_EXAMPLES

static void set_angle(void * obj, int32_t v)
{
    lv_arc_set_value(obj, v);
}

/**
 * Create an arc which acts as a loader.
 */
void lv_example_arc_2(void)
{
  /*Create an Arc*/
  lv_obj_t * arc = lv_arc_create(lv_scr_act());
  lv_arc_set_rotation(arc, 270);
  lv_arc_set_bg_angles(arc, 0, 360);
  lv_obj_remove_style(arc, NULL, LV_PART_KNOB);   /*Be sure the knob is not displayed*/
  lv_obj_clear_flag(arc, LV_OBJ_FLAG_CLICKABLE);  /*To not allow adjusting by click*/
  lv_obj_center(arc);

  lv_anim_t a;
  lv_anim_init(&a);
  lv_anim_set_var(&a, arc);
  lv_anim_set_exec_cb(&a, set_angle);
  lv_anim_set_time(&a, 1000);
  lv_anim_set_repeat_count(&a, LV_ANIM_REPEAT_INFINITE);    /*Just for the demo*/
  lv_anim_set_repeat_delay(&a, 500);
  lv_anim_set_values(&a, 0, 100);
  lv_anim_start(&a);



}

#endif

MicroPython code  

 GitHub Simulator
#
# An `lv_timer` to call periodically to set the angles of the arc
#
class ArcLoader():
    def __init__(self):
        self.a = 270
        
    def arc_loader_cb(self,tim,arc):
        # print(tim,arc)
        self.a += 5

        arc.set_end_angle(self.a)

        if self.a >= 270 + 360:
            tim._del()


#
# Create an arc which acts as a loader.
#

# Create an Arc
arc = lv.arc(lv.scr_act())
arc.set_bg_angles(0, 360)
arc.set_angles(270, 270)
arc.center()

# create the loader
arc_loader = ArcLoader()

# Create an `lv_timer` to update the arc.

timer = lv.timer_create_basic()
timer.set_period(20)
timer.set_cb(lambda src: arc_loader.arc_loader_cb(timer,arc))
  


Bar

Simple Bar

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_BAR && LV_BUILD_EXAMPLES

void lv_example_bar_1(void)
{
    lv_obj_t * bar1 = lv_bar_create(lv_scr_act());
    lv_obj_set_size(bar1, 200, 20);
    lv_obj_center(bar1);
    lv_bar_set_value(bar1, 70, LV_ANIM_OFF);
}

#endif

MicroPython code  

 GitHub Simulator
bar1 = lv.bar(lv.scr_act())
bar1.set_size(200, 20)
bar1.center()
bar1.set_value(70, lv.ANIM.OFF)


Styling a bar

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_BAR && LV_BUILD_EXAMPLES

/**
 * Example of styling the bar
 */
void lv_example_bar_2(void)
{
    static lv_style_t style_bg;
    static lv_style_t style_indic;

    lv_style_init(&style_bg);
    lv_style_set_border_color(&style_bg, lv_palette_main(LV_PALETTE_BLUE));
    lv_style_set_border_width(&style_bg, 2);
    lv_style_set_pad_all(&style_bg, 6); /*To make the indicator smaller*/
    lv_style_set_radius(&style_bg, 6);
    lv_style_set_anim_time(&style_bg, 1000);

    lv_style_init(&style_indic);
    lv_style_set_bg_opa(&style_indic, LV_OPA_COVER);
    lv_style_set_bg_color(&style_indic, lv_palette_main(LV_PALETTE_BLUE));
    lv_style_set_radius(&style_indic, 3);

    lv_obj_t * bar = lv_bar_create(lv_scr_act());
    lv_obj_remove_style_all(bar);  /*To have a clean start*/
    lv_obj_add_style(bar, &style_bg, 0);
    lv_obj_add_style(bar, &style_indic, LV_PART_INDICATOR);

    lv_obj_set_size(bar, 200, 20);
    lv_obj_center(bar);
    lv_bar_set_value(bar, 100, LV_ANIM_ON);
}

#endif

MicroPython code  

 GitHub Simulator
#
# Example of styling the bar
#
style_bg = lv.style_t()
style_indic = lv.style_t()

style_bg.init()
style_bg.set_border_color(lv.palette_main(lv.PALETTE.BLUE))
style_bg.set_border_width(2)
style_bg.set_pad_all(6)            # To make the indicator smaller
style_bg.set_radius(6)
style_bg.set_anim_time(1000)

style_indic.init()
style_indic.set_bg_opa(lv.OPA.COVER)
style_indic.set_bg_color(lv.palette_main(lv.PALETTE.BLUE))
style_indic.set_radius(3)

bar = lv.bar(lv.scr_act())
bar.remove_style_all()   # To have a clean start
bar.add_style(style_bg, 0)
bar.add_style(style_indic, lv.PART.INDICATOR)

bar.set_size(200, 20)
bar.center()
bar.set_value(100, lv.ANIM.ON)


Temperature meter

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_BAR && LV_BUILD_EXAMPLES

static void set_temp(void * bar, int32_t temp)
{
    lv_bar_set_value(bar, temp, LV_ANIM_ON);
}

/**
 * A temperature meter example
 */
void lv_example_bar_3(void)
{
    static lv_style_t style_indic;

    lv_style_init(&style_indic);
    lv_style_set_bg_opa(&style_indic, LV_OPA_COVER);
    lv_style_set_bg_color(&style_indic, lv_palette_main(LV_PALETTE_RED));
    lv_style_set_bg_grad_color(&style_indic, lv_palette_main(LV_PALETTE_BLUE));
    lv_style_set_bg_grad_dir(&style_indic, LV_GRAD_DIR_VER);

    lv_obj_t * bar = lv_bar_create(lv_scr_act());
    lv_obj_add_style(bar, &style_indic, LV_PART_INDICATOR);
    lv_obj_set_size(bar, 20, 200);
    lv_obj_center(bar);
    lv_bar_set_range(bar, -20, 40);

    lv_anim_t a;
    lv_anim_init(&a);
    lv_anim_set_exec_cb(&a, set_temp);
    lv_anim_set_time(&a, 3000);
    lv_anim_set_playback_time(&a, 3000);
    lv_anim_set_var(&a, bar);
    lv_anim_set_values(&a, -20, 40);
    lv_anim_set_repeat_count(&a, LV_ANIM_REPEAT_INFINITE);
    lv_anim_start(&a);
}


#endif

MicroPython code  

 GitHub Simulator
def set_temp(bar, temp):
    bar.set_value(temp, lv.ANIM.ON)

#
# A temperature meter example
#


style_indic = lv.style_t()

style_indic.init()
style_indic.set_bg_opa(lv.OPA.COVER)
style_indic.set_bg_color(lv.palette_main(lv.PALETTE.RED))
style_indic.set_bg_grad_color(lv.palette_main(lv.PALETTE.BLUE))
style_indic.set_bg_grad_dir(lv.GRAD_DIR.VER)

bar = lv.bar(lv.scr_act())
bar.add_style(style_indic, lv.PART.INDICATOR)
bar.set_size(20, 200)
bar.center()
bar.set_range(-20, 40)

a = lv.anim_t()
a.init()
a.set_time(3000)
a.set_playback_time(3000)
a.set_var(bar)
a.set_values(-20, 40)
a.set_repeat_count(lv.ANIM_REPEAT.INFINITE)
a.set_custom_exec_cb(lambda a, val: set_temp(bar,val))
lv.anim_t.start(a)


Stripe pattern and range value

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_BAR && LV_BUILD_EXAMPLES

/**
 * Bar with stripe pattern and ranged value
 */
void lv_example_bar_4(void)
{
    LV_IMG_DECLARE(img_skew_strip);
    static lv_style_t style_indic;

    lv_style_init(&style_indic);
    lv_style_set_bg_img_src(&style_indic, &img_skew_strip);
    lv_style_set_bg_img_tiled(&style_indic, true);
    lv_style_set_bg_img_opa(&style_indic, LV_OPA_30);

    lv_obj_t * bar = lv_bar_create(lv_scr_act());
    lv_obj_add_style(bar, &style_indic, LV_PART_INDICATOR);

    lv_obj_set_size(bar, 260, 20);
    lv_obj_center(bar);
    lv_bar_set_mode(bar, LV_BAR_MODE_RANGE);
    lv_bar_set_value(bar, 90, LV_ANIM_OFF);
    lv_bar_set_start_value(bar, 20, LV_ANIM_OFF);
}

#endif

MicroPython code  

 GitHub Simulator
#
# get an icon
#
def get_icon(filename,xres,yres):
    try:
        sdl_filename = "../../assets/" + filename + "_" + str(xres) + "x" + str(yres) + "_argb8888.fnt"
        print("file name: ", sdl_filename)
        with open(sdl_filename,'rb') as f:
            icon_data = f.read()
    except:
        print("Could not find image file: " + filename) 
        return None
    
    icon_dsc = lv.img_dsc_t(
        {
            "header": {"always_zero": 0, "w": xres, "h": yres, "cf": lv.img.CF.TRUE_COLOR_ALPHA},
            "data": icon_data,
            "data_size": len(icon_data),
        }
    )
    return icon_dsc

#
# Bar with stripe pattern and ranged value
#

img_skew_strip_dsc = get_icon("img_skew_strip",80,20)
style_indic = lv.style_t()

style_indic.init()
style_indic.set_bg_img_src(img_skew_strip_dsc)
style_indic.set_bg_img_tiled(True)
style_indic.set_bg_img_opa(lv.OPA._30)

bar = lv.bar(lv.scr_act())
bar.add_style(style_indic, lv.PART.INDICATOR)

bar.set_size(260, 20)
bar.center()
bar.set_mode(lv.bar.MODE.RANGE)
bar.set_value(90, lv.ANIM.OFF)
bar.set_start_value(20, lv.ANIM.OFF)


    

Bar with LTR and RTL base direction

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_BAR && LV_BUILD_EXAMPLES

/**
 * Bar with LTR and RTL base direction
 */
void lv_example_bar_5(void)
{
    lv_obj_t * label;


    lv_obj_t * bar_ltr = lv_bar_create(lv_scr_act());
    lv_obj_set_size(bar_ltr, 200, 20);
    lv_bar_set_value(bar_ltr, 70, LV_ANIM_OFF);
    lv_obj_align(bar_ltr, LV_ALIGN_CENTER, 0, -30);

    label = lv_label_create(lv_scr_act());
    lv_label_set_text(label, "Left to Right base direction");
    lv_obj_align_to(label, bar_ltr, LV_ALIGN_OUT_TOP_MID, 0, -5);

    lv_obj_t * bar_rtl = lv_bar_create(lv_scr_act());
    lv_obj_set_style_base_dir(bar_rtl, LV_BASE_DIR_RTL, 0);
    lv_obj_set_size(bar_rtl, 200, 20);
    lv_bar_set_value(bar_rtl, 70, LV_ANIM_OFF);
    lv_obj_align(bar_rtl, LV_ALIGN_CENTER, 0, 30);

    label = lv_label_create(lv_scr_act());
    lv_label_set_text(label, "Right to Left base direction");
    lv_obj_align_to(label, bar_rtl, LV_ALIGN_OUT_TOP_MID, 0, -5);
}

#endif

MicroPython code  

 GitHub Simulator
#
# Bar with LTR and RTL base direction
#

bar_ltr = lv.bar(lv.scr_act())
bar_ltr.set_size(200, 20)
bar_ltr.set_value(70, lv.ANIM.OFF)
bar_ltr.align(lv.ALIGN.CENTER, 0, -30)

label = lv.label(lv.scr_act())
label.set_text("Left to Right base direction")
label.align_to(bar_ltr, lv.ALIGN.OUT_TOP_MID, 0, -5)

bar_rtl = lv.bar(lv.scr_act())
bar_rtl.set_style_base_dir(lv.BASE_DIR.RTL,0)
bar_rtl.set_size(200, 20)
bar_rtl.set_value(70, lv.ANIM.OFF)
bar_rtl.align(lv.ALIGN.CENTER, 0, 30)

label = lv.label(lv.scr_act())
label.set_text("Right to Left base direction")
label.align_to(bar_rtl, lv.ALIGN.OUT_TOP_MID, 0, -5)

Custom drawer to show the current value

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_BAR && LV_BUILD_EXAMPLES

static void set_value(void *bar, int32_t v)
{
    lv_bar_set_value(bar, v, LV_ANIM_OFF);
}

static void event_cb(lv_event_t * e)
{
    lv_obj_draw_part_dsc_t * dsc = lv_event_get_param(e);
    if(dsc->part != LV_PART_INDICATOR) return;

    lv_obj_t * obj= lv_event_get_target(e);

    lv_draw_label_dsc_t label_dsc;
    lv_draw_label_dsc_init(&label_dsc);
    label_dsc.font = LV_FONT_DEFAULT;

    char buf[8];
    lv_snprintf(buf, sizeof(buf), "%d", (int)lv_bar_get_value(obj));

    lv_point_t txt_size;
    lv_txt_get_size(&txt_size, buf, label_dsc.font, label_dsc.letter_space, label_dsc.line_space, LV_COORD_MAX, label_dsc.flag);

    lv_area_t txt_area;
    /*If the indicator is long enough put the text inside on the right*/
    if(lv_area_get_width(dsc->draw_area) > txt_size.x + 20) {
        txt_area.x2 = dsc->draw_area->x2 - 5;
        txt_area.x1 = txt_area.x2 - txt_size.x + 1;
        label_dsc.color = lv_color_white();
    }
    /*If the indicator is still short put the text out of it on the right*/
    else {
        txt_area.x1 = dsc->draw_area->x2 + 5;
        txt_area.x2 = txt_area.x1 + txt_size.x - 1;
        label_dsc.color = lv_color_black();
    }

    txt_area.y1 = dsc->draw_area->y1 + (lv_area_get_height(dsc->draw_area) - txt_size.y) / 2;
    txt_area.y2 = txt_area.y1 + txt_size.y - 1;

    lv_draw_label(dsc->draw_ctx, &label_dsc, &txt_area, buf, NULL);
}

/**
 * Custom drawer on the bar to display the current value
 */
void lv_example_bar_6(void)
{
    lv_obj_t * bar = lv_bar_create(lv_scr_act());
    lv_obj_add_event_cb(bar, event_cb, LV_EVENT_DRAW_PART_END, NULL);
    lv_obj_set_size(bar, 200, 20);
    lv_obj_center(bar);

    lv_anim_t a;
    lv_anim_init(&a);
    lv_anim_set_var(&a, bar);
    lv_anim_set_values(&a, 0, 100);
    lv_anim_set_exec_cb(&a, set_value);
    lv_anim_set_time(&a, 2000);
    lv_anim_set_playback_time(&a, 2000);
    lv_anim_set_repeat_count(&a, LV_ANIM_REPEAT_INFINITE);
    lv_anim_start(&a);

}

#endif

MicroPython code  

 GitHub Simulator
def set_value(bar, v):
    bar.set_value(v, lv.ANIM.OFF)

def event_cb(e):
    dsc = lv.obj_draw_part_dsc_t.__cast__(e.get_param())
    if dsc.part != lv.PART.INDICATOR:
        return

    obj= e.get_target()

    label_dsc = lv.draw_label_dsc_t()
    label_dsc.init()
    # label_dsc.font = LV_FONT_DEFAULT;

    value_txt = str(obj.get_value())
    txt_size = lv.point_t()
    lv.txt_get_size(txt_size, value_txt, label_dsc.font, label_dsc.letter_space, label_dsc.line_space, lv.COORD.MAX, label_dsc.flag)

    txt_area = lv.area_t()
    # If the indicator is long enough put the text inside on the right
    if dsc.draw_area.get_width() > txt_size.x + 20:
        txt_area.x2 = dsc.draw_area.x2 - 5
        txt_area.x1 = txt_area.x2 - txt_size.x + 1
        label_dsc.color = lv.color_white()
    # If the indicator is still short put the text out of it on the right*/
    else:
        txt_area.x1 = dsc.draw_area.x2 + 5
        txt_area.x2 = txt_area.x1 + txt_size.x - 1
        label_dsc.color = lv.color_black()

    txt_area.y1 = dsc.draw_area.y1 + (dsc.draw_area.get_height() - txt_size.y) // 2
    txt_area.y2 = txt_area.y1 + txt_size.y - 1

    dsc.draw_ctx.label(label_dsc, txt_area, value_txt, None)

#
# Custom drawer on the bar to display the current value
#

bar = lv.bar(lv.scr_act())
bar.add_event_cb(event_cb, lv.EVENT.DRAW_PART_END, None)
bar.set_size(200, 20)
bar.center()

a = lv.anim_t()
a.init()
a.set_var(bar)
a.set_values(0, 100)
a.set_custom_exec_cb(lambda a,val: set_value(bar,val))
a.set_time(2000)
a.set_playback_time(2000)
a.set_repeat_count(lv.ANIM_REPEAT.INFINITE)
lv.anim_t.start(a)


Button

Simple Buttons

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_BTN && LV_BUILD_EXAMPLES

static void event_handler(lv_event_t * e)
{
    lv_event_code_t code = lv_event_get_code(e);

    if(code == LV_EVENT_CLICKED) {
        LV_LOG_USER("Clicked");
    }
    else if(code == LV_EVENT_VALUE_CHANGED) {
        LV_LOG_USER("Toggled");
    }
}

void lv_example_btn_1(void)
{
    lv_obj_t * label;

    lv_obj_t * btn1 = lv_btn_create(lv_scr_act());
    lv_obj_add_event_cb(btn1, event_handler, LV_EVENT_ALL, NULL);
    lv_obj_align(btn1, LV_ALIGN_CENTER, 0, -40);

    label = lv_label_create(btn1);
    lv_label_set_text(label, "Button");
    lv_obj_center(label);

    lv_obj_t * btn2 = lv_btn_create(lv_scr_act());
    lv_obj_add_event_cb(btn2, event_handler, LV_EVENT_ALL, NULL);
    lv_obj_align(btn2, LV_ALIGN_CENTER, 0, 40);
    lv_obj_add_flag(btn2, LV_OBJ_FLAG_CHECKABLE);
    lv_obj_set_height(btn2, LV_SIZE_CONTENT);

    label = lv_label_create(btn2);
    lv_label_set_text(label, "Toggle");
    lv_obj_center(label);
}
#endif

MicroPython code  

 GitHub Simulator
def event_handler(evt):
    code = evt.get_code()

    if code == lv.EVENT.CLICKED:
            print("Clicked event seen")
    elif code == lv.EVENT.VALUE_CHANGED:
        print("Value changed seen")
        
# create a simple button
btn1 = lv.btn(lv.scr_act())

# attach the callback
btn1.add_event_cb(event_handler,lv.EVENT.ALL, None)

btn1.align(lv.ALIGN.CENTER,0,-40)
label=lv.label(btn1)
label.set_text("Button")

# create a toggle button
btn2 = lv.btn(lv.scr_act())

# attach the callback
#btn2.add_event_cb(event_handler,lv.EVENT.VALUE_CHANGED,None)
btn2.add_event_cb(event_handler,lv.EVENT.ALL, None)

btn2.align(lv.ALIGN.CENTER,0,40)
btn2.add_flag(lv.obj.FLAG.CHECKABLE)
btn2.set_height(lv.SIZE.CONTENT)

label=lv.label(btn2)
label.set_text("Toggle")
label.center()

Styling buttons

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_BTN && LV_BUILD_EXAMPLES

/**
 * Style a button from scratch
 */
void lv_example_btn_2(void)
{
    /*Init the style for the default state*/
    static lv_style_t style;
    lv_style_init(&style);

    lv_style_set_radius(&style, 3);

    lv_style_set_bg_opa(&style, LV_OPA_100);
    lv_style_set_bg_color(&style, lv_palette_main(LV_PALETTE_BLUE));
    lv_style_set_bg_grad_color(&style, lv_palette_darken(LV_PALETTE_BLUE, 2));
    lv_style_set_bg_grad_dir(&style, LV_GRAD_DIR_VER);

    lv_style_set_border_opa(&style, LV_OPA_40);
    lv_style_set_border_width(&style, 2);
    lv_style_set_border_color(&style, lv_palette_main(LV_PALETTE_GREY));

    lv_style_set_shadow_width(&style, 8);
    lv_style_set_shadow_color(&style, lv_palette_main(LV_PALETTE_GREY));
    lv_style_set_shadow_ofs_y(&style, 8);

    lv_style_set_outline_opa(&style, LV_OPA_COVER);
    lv_style_set_outline_color(&style, lv_palette_main(LV_PALETTE_BLUE));

    lv_style_set_text_color(&style, lv_color_white());
    lv_style_set_pad_all(&style, 10);

    /*Init the pressed style*/
    static lv_style_t style_pr;
    lv_style_init(&style_pr);

    /*Add a large outline when pressed*/
    lv_style_set_outline_width(&style_pr, 30);
    lv_style_set_outline_opa(&style_pr, LV_OPA_TRANSP);

    lv_style_set_translate_y(&style_pr, 5);
    lv_style_set_shadow_ofs_y(&style_pr, 3);
    lv_style_set_bg_color(&style_pr, lv_palette_darken(LV_PALETTE_BLUE, 2));
    lv_style_set_bg_grad_color(&style_pr, lv_palette_darken(LV_PALETTE_BLUE, 4));

    /*Add a transition to the outline*/
    static lv_style_transition_dsc_t trans;
    static lv_style_prop_t props[] = {LV_STYLE_OUTLINE_WIDTH, LV_STYLE_OUTLINE_OPA, 0};
    lv_style_transition_dsc_init(&trans, props, lv_anim_path_linear, 300, 0, NULL);

    lv_style_set_transition(&style_pr, &trans);

    lv_obj_t * btn1 = lv_btn_create(lv_scr_act());
    lv_obj_remove_style_all(btn1);                          /*Remove the style coming from the theme*/
    lv_obj_add_style(btn1, &style, 0);
    lv_obj_add_style(btn1, &style_pr, LV_STATE_PRESSED);
    lv_obj_set_size(btn1, LV_SIZE_CONTENT, LV_SIZE_CONTENT);
    lv_obj_center(btn1);

    lv_obj_t * label = lv_label_create(btn1);
    lv_label_set_text(label, "Button");
    lv_obj_center(label);
}
#endif

MicroPython code  

 GitHub Simulator
#
# Style a button from scratch
#

# Init the style for the default state
style = lv.style_t()
style.init()

style.set_radius(3)

style.set_bg_opa(lv.OPA.COVER)
style.set_bg_color(lv.palette_main(lv.PALETTE.BLUE))
style.set_bg_grad_color(lv.palette_darken(lv.PALETTE.BLUE, 2))
style.set_bg_grad_dir(lv.GRAD_DIR.VER)

style.set_border_opa(lv.OPA._40)
style.set_border_width(2)
style.set_border_color(lv.palette_main(lv.PALETTE.GREY))

style.set_shadow_width(8)
style.set_shadow_color(lv.palette_main(lv.PALETTE.GREY))
style.set_shadow_ofs_y(8)

style.set_outline_opa(lv.OPA.COVER)
style.set_outline_color(lv.palette_main(lv.PALETTE.BLUE))

style.set_text_color(lv.color_white())
style.set_pad_all(10)

# Init the pressed style
style_pr = lv.style_t()
style_pr.init()

# Add a large outline when pressed
style_pr.set_outline_width(30)
style_pr.set_outline_opa(lv.OPA.TRANSP)

style_pr.set_translate_y(5)
style_pr.set_shadow_ofs_y(3)
style_pr.set_bg_color(lv.palette_darken(lv.PALETTE.BLUE, 2))
style_pr.set_bg_grad_color(lv.palette_darken(lv.PALETTE.BLUE, 4))

# Add a transition to the outline
trans = lv.style_transition_dsc_t()
props = [lv.STYLE.OUTLINE_WIDTH, lv.STYLE.OUTLINE_OPA, 0]
trans.init(props, lv.anim_t.path_linear, 300, 0, None)

style_pr.set_transition(trans)

btn1 = lv.btn(lv.scr_act())
btn1.remove_style_all()                          # Remove the style coming from the theme
btn1.add_style(style, 0)
btn1.add_style(style_pr, lv.STATE.PRESSED)
btn1.set_size(lv.SIZE.CONTENT, lv.SIZE.CONTENT)
btn1.center()

label = lv.label(btn1)
label.set_text("Button")
label.center()


Gummy button

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_BUILD_EXAMPLES && LV_USE_BTN

/**
 * Create a style transition on a button to act like a gum when clicked
 */
void lv_example_btn_3(void)
{
    /*Properties to transition*/
    static lv_style_prop_t props[] = {
            LV_STYLE_TRANSFORM_WIDTH, LV_STYLE_TRANSFORM_HEIGHT, LV_STYLE_TEXT_LETTER_SPACE, 0
    };

    /*Transition descriptor when going back to the default state.
     *Add some delay to be sure the press transition is visible even if the press was very short*/
    static lv_style_transition_dsc_t transition_dsc_def;
    lv_style_transition_dsc_init(&transition_dsc_def, props, lv_anim_path_overshoot, 250, 100, NULL);

    /*Transition descriptor when going to pressed state.
     *No delay, go to presses state immediately*/
    static lv_style_transition_dsc_t transition_dsc_pr;
    lv_style_transition_dsc_init(&transition_dsc_pr, props, lv_anim_path_ease_in_out, 250, 0, NULL);

    /*Add only the new transition to he default state*/
    static lv_style_t style_def;
    lv_style_init(&style_def);
    lv_style_set_transition(&style_def, &transition_dsc_def);

    /*Add the transition and some transformation to the presses state.*/
    static lv_style_t style_pr;
    lv_style_init(&style_pr);
    lv_style_set_transform_width(&style_pr, 10);
    lv_style_set_transform_height(&style_pr, -10);
    lv_style_set_text_letter_space(&style_pr, 10);
    lv_style_set_transition(&style_pr, &transition_dsc_pr);

    lv_obj_t * btn1 = lv_btn_create(lv_scr_act());
    lv_obj_align(btn1, LV_ALIGN_CENTER, 0, -80);
    lv_obj_add_style(btn1, &style_pr, LV_STATE_PRESSED);
    lv_obj_add_style(btn1, &style_def, 0);

    lv_obj_t * label = lv_label_create(btn1);
    lv_label_set_text(label, "Gum");
}
#endif

MicroPython code  

 GitHub Simulator
#
# Create a style transition on a button to act like a gum when clicked
#

# Properties to transition
props = [lv.STYLE.TRANSFORM_WIDTH, lv.STYLE.TRANSFORM_HEIGHT, lv.STYLE.TEXT_LETTER_SPACE, 0]

# Transition descriptor when going back to the default state.
# Add some delay to be sure the press transition is visible even if the press was very short*/
transition_dsc_def = lv.style_transition_dsc_t()
transition_dsc_def.init(props, lv.anim_t.path_overshoot, 250, 100, None)

# Transition descriptor when going to pressed state.
# No delay, go to pressed state immediately
transition_dsc_pr = lv.style_transition_dsc_t()
transition_dsc_pr.init(props, lv.anim_t.path_ease_in_out, 250, 0, None)

# Add only the new transition to the default state
style_def = lv.style_t()
style_def.init()
style_def.set_transition(transition_dsc_def)

# Add the transition and some transformation to the presses state.
style_pr = lv.style_t()
style_pr.init()
style_pr.set_transform_width(10)
style_pr.set_transform_height(-10)
style_pr.set_text_letter_space(10)
style_pr.set_transition(transition_dsc_pr)

btn1 = lv.btn(lv.scr_act())
btn1.align(lv.ALIGN.CENTER, 0, -80)
btn1.add_style(style_pr, lv.STATE.PRESSED)
btn1.add_style(style_def, 0)

label = lv.label(btn1)
label.set_text("Gum")


Button matrix

Simple Button matrix

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_BTNMATRIX && LV_BUILD_EXAMPLES

static void event_handler(lv_event_t * e)
{
    lv_event_code_t code = lv_event_get_code(e);
    lv_obj_t * obj = lv_event_get_target(e);
    if(code == LV_EVENT_VALUE_CHANGED) {
        uint32_t id = lv_btnmatrix_get_selected_btn(obj);
        const char * txt = lv_btnmatrix_get_btn_text(obj, id);

        LV_LOG_USER("%s was pressed\n", txt);
    }
}


static const char * btnm_map[] = {"1", "2", "3", "4", "5", "\n",
                                  "6", "7", "8", "9", "0", "\n",
                                  "Action1", "Action2", ""};

void lv_example_btnmatrix_1(void)
{
    lv_obj_t * btnm1 = lv_btnmatrix_create(lv_scr_act());
    lv_btnmatrix_set_map(btnm1, btnm_map);
    lv_btnmatrix_set_btn_width(btnm1, 10, 2);        /*Make "Action1" twice as wide as "Action2"*/
    lv_btnmatrix_set_btn_ctrl(btnm1, 10, LV_BTNMATRIX_CTRL_CHECKABLE);
    lv_btnmatrix_set_btn_ctrl(btnm1, 11, LV_BTNMATRIX_CTRL_CHECKED);
    lv_obj_align(btnm1, LV_ALIGN_CENTER, 0, 0);
    lv_obj_add_event_cb(btnm1, event_handler, LV_EVENT_ALL, NULL);
}

#endif

MicroPython code  

 GitHub Simulator
def event_handler(evt):
    code = evt.get_code()
    obj  = evt.get_target()

    if code == lv.EVENT.VALUE_CHANGED :
        id = obj.get_selected_btn()
        txt = obj.get_btn_text(id)

        print("%s was pressed"%txt)

btnm_map = ["1", "2", "3", "4", "5", "\n",
            "6", "7", "8", "9", "0", "\n",
            "Action1", "Action2", ""]

btnm1 = lv.btnmatrix(lv.scr_act())
btnm1.set_map(btnm_map)
btnm1.set_btn_width(10, 2)        # Make "Action1" twice as wide as "Action2"
btnm1.set_btn_ctrl(10, lv.btnmatrix.CTRL.CHECKABLE)
btnm1.set_btn_ctrl(11, lv.btnmatrix.CTRL.CHECKED)
btnm1.align(lv.ALIGN.CENTER, 0, 0)
btnm1.add_event_cb(event_handler, lv.EVENT.ALL, None)


#endif

Custom buttons

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_BTNMATRIX && LV_BUILD_EXAMPLES


static void event_cb(lv_event_t * e)
{
    lv_event_code_t code = lv_event_get_code(e);
    lv_obj_t * obj = lv_event_get_target(e);
    if(code == LV_EVENT_DRAW_PART_BEGIN) {
        lv_obj_draw_part_dsc_t * dsc = lv_event_get_param(e);

        /*Change the draw descriptor the 2nd button*/
        if(dsc->id == 1) {
            dsc->rect_dsc->radius = 0;
            if(lv_btnmatrix_get_selected_btn(obj) == dsc->id)  dsc->rect_dsc->bg_color = lv_palette_darken(LV_PALETTE_BLUE, 3);
            else dsc->rect_dsc->bg_color = lv_palette_main(LV_PALETTE_BLUE);

            dsc->rect_dsc->shadow_width = 6;
            dsc->rect_dsc->shadow_ofs_x = 3;
            dsc->rect_dsc->shadow_ofs_y = 3;
            dsc->label_dsc->color = lv_color_white();
        }
        /*Change the draw descriptor the 3rd button*/
        else if(dsc->id == 2) {
            dsc->rect_dsc->radius = LV_RADIUS_CIRCLE;
            if(lv_btnmatrix_get_selected_btn(obj) == dsc->id)  dsc->rect_dsc->bg_color = lv_palette_darken(LV_PALETTE_RED, 3);
            else dsc->rect_dsc->bg_color = lv_palette_main(LV_PALETTE_RED);

            dsc->label_dsc->color = lv_color_white();
        }
        else if(dsc->id == 3) {
            dsc->label_dsc->opa = LV_OPA_TRANSP; /*Hide the text if any*/

        }
    }
    if(code == LV_EVENT_DRAW_PART_END) {
        lv_obj_draw_part_dsc_t * dsc = lv_event_get_param(e);

        /*Add custom content to the 4th button when the button itself was drawn*/
        if(dsc->id == 3) {
            LV_IMG_DECLARE(img_star);
            lv_img_header_t header;
            lv_res_t res = lv_img_decoder_get_info(&img_star, &header);
            if(res != LV_RES_OK) return;

            lv_area_t a;
            a.x1 = dsc->draw_area->x1 + (lv_area_get_width(dsc->draw_area) - header.w) / 2;
            a.x2 = a.x1 + header.w - 1;
            a.y1 = dsc->draw_area->y1 + (lv_area_get_height(dsc->draw_area) - header.h) / 2;
            a.y2 = a.y1 + header.h - 1;

            lv_draw_img_dsc_t img_draw_dsc;
            lv_draw_img_dsc_init(&img_draw_dsc);
            img_draw_dsc.recolor = lv_color_black();
            if(lv_btnmatrix_get_selected_btn(obj) == dsc->id)  img_draw_dsc.recolor_opa = LV_OPA_30;

            lv_draw_img(dsc->draw_ctx, &img_draw_dsc, &a, &img_star);
        }
    }
}

/**
 * Add custom drawer to the button matrix to customize buttons one by one
 */
void lv_example_btnmatrix_2(void)
{
    lv_obj_t * btnm = lv_btnmatrix_create(lv_scr_act());
    lv_obj_add_event_cb(btnm, event_cb, LV_EVENT_ALL, NULL);
    lv_obj_center(btnm);
}

#endif

MicroPython code  

 GitHub Simulator
from imagetools import get_png_info, open_png

# Register PNG image decoder
decoder = lv.img.decoder_create()
decoder.info_cb = get_png_info
decoder.open_cb = open_png

# Create an image from the png file
try:
    with open('../../assets/img_star.png','rb') as f:
        png_data = f.read()
except:
    print("Could not find star.png")
    sys.exit()
    
img_star_argb = lv.img_dsc_t({
  'data_size': len(png_data),
  'data': png_data 
})

def event_cb(e):
    code = e.get_code()
    obj = e.get_target()
    dsc = lv.obj_draw_part_dsc_t.__cast__(e.get_param())
    if code == lv.EVENT.DRAW_PART_BEGIN:
        # Change the draw descriptor the 2nd button
        if dsc.id == 1:
            dsc.rect_dsc.radius = 0
            if obj.get_selected_btn() == dsc.id:
                dsc.rect_dsc.bg_color = lv.palette_darken(lv.PALETTE.GREY, 3)
            else:
                dsc.rect_dsc.bg_color = lv.palette_main(lv.PALETTE.BLUE)

            dsc.rect_dsc.shadow_width = 6
            dsc.rect_dsc.shadow_ofs_x = 3
            dsc.rect_dsc.shadow_ofs_y = 3
            dsc.label_dsc.color = lv.color_white()

        # Change the draw descriptor the 3rd button

        elif dsc.id == 2:
            dsc.rect_dsc.radius = lv.RADIUS.CIRCLE
            if obj.get_selected_btn() == dsc.id:
                dsc.rect_dsc.bg_color = lv.palette_darken(lv.PALETTE.RED, 3)
            else:
                dsc.rect_dsc.bg_color = lv.palette_main(lv.PALETTE.RED)
                
                dsc.label_dsc.color = lv.color_white()
        elif dsc.id == 3:
            dsc.label_dsc.opa = lv.OPA.TRANSP  # Hide the text if any

    if code == lv.EVENT.DRAW_PART_END:
        # Add custom content to the 4th button when the button itself was drawn
        if dsc.id == 3:
            # LV_IMG_DECLARE(img_star)
            header = lv.img_header_t()
            res = lv.img.decoder_get_info(img_star_argb, header)
            if res != lv.RES.OK:
                print("error when getting image header")
                return
            else:
                a = lv.area_t()
                a.x1 = dsc.draw_area.x1 + (dsc.draw_area.get_width() - header.w) // 2
                a.x2 = a.x1 + header.w - 1
                a.y1 = dsc.draw_area.y1 + (dsc.draw_area.get_height() - header.h) // 2
                a.y2 = a.y1 + header.h - 1
                img_draw_dsc = lv.draw_img_dsc_t()
                img_draw_dsc.init()
                img_draw_dsc.recolor = lv.color_black()
                if obj.get_selected_btn() == dsc.id:
                    img_draw_dsc.recolor_opa = lv.OPA._30

                dsc.draw_ctx.img(img_draw_dsc, a, img_star_argb)

#
# Add custom drawer to the button matrix to c
#
btnm = lv.btnmatrix(lv.scr_act())
btnm.add_event_cb(event_cb, lv.EVENT.ALL, None)
btnm.center()


Calendar

Calendar with header

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_CALENDAR && LV_BUILD_EXAMPLES

static void event_handler(lv_event_t * e)
{
    lv_event_code_t code = lv_event_get_code(e);
    lv_obj_t * obj = lv_event_get_current_target(e);

    if(code == LV_EVENT_VALUE_CHANGED) {
        lv_calendar_date_t date;
        if(lv_calendar_get_pressed_date(obj, &date)) {
            LV_LOG_USER("Clicked date: %02d.%02d.%d", date.day, date.month, date.year);
        }
    }
}

void lv_example_calendar_1(void)
{
    lv_obj_t  * calendar = lv_calendar_create(lv_scr_act());
    lv_obj_set_size(calendar, 185, 185);
    lv_obj_align(calendar, LV_ALIGN_CENTER, 0, 27);
    lv_obj_add_event_cb(calendar, event_handler, LV_EVENT_ALL, NULL);

    lv_calendar_set_today_date(calendar, 2021, 02, 23);
    lv_calendar_set_showed_date(calendar, 2021, 02);

    /*Highlight a few days*/
    static lv_calendar_date_t highlighted_days[3];       /*Only its pointer will be saved so should be static*/
    highlighted_days[0].year = 2021;
    highlighted_days[0].month = 02;
    highlighted_days[0].day = 6;

    highlighted_days[1].year = 2021;
    highlighted_days[1].month = 02;
    highlighted_days[1].day = 11;

    highlighted_days[2].year = 2022;
    highlighted_days[2].month = 02;
    highlighted_days[2].day = 22;

    lv_calendar_set_highlighted_dates(calendar, highlighted_days, 3);

#if LV_USE_CALENDAR_HEADER_DROPDOWN
    lv_calendar_header_dropdown_create(calendar);
#elif LV_USE_CALENDAR_HEADER_ARROW
    lv_calendar_header_arrow_create(calendar);
#endif
    lv_calendar_set_showed_date(calendar, 2021, 10);
}

#endif

MicroPython code  

 GitHub Simulator

def event_handler(evt):
    code = evt.get_code()

    if code == lv.EVENT.VALUE_CHANGED:
        source = evt.get_current_target()
        date = lv.calendar_date_t()
        if source.get_pressed_date(date) == lv.RES.OK:        
            calendar.set_today_date(date.year, date.month, date.day)
            print("Clicked date: %02d.%02d.%02d"%(date.day, date.month, date.year))
                

calendar = lv.calendar(lv.scr_act())
calendar.set_size(200, 200)
calendar.align(lv.ALIGN.CENTER, 0, 20)
calendar.add_event_cb(event_handler, lv.EVENT.ALL, None)

calendar.set_today_date(2021, 02, 23)
calendar.set_showed_date(2021, 02)

# Highlight a few days
highlighted_days=[
    lv.calendar_date_t({'year':2021, 'month':2, 'day':6}),
    lv.calendar_date_t({'year':2021, 'month':2, 'day':11}),
    lv.calendar_date_t({'year':2021, 'month':2, 'day':22})
]

calendar.set_highlighted_dates(highlighted_days, len(highlighted_days))

lv.calendar_header_dropdown(calendar)

Canvas

Drawing on the Canvas and rotate

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_CANVAS && LV_BUILD_EXAMPLES


#define CANVAS_WIDTH  200
#define CANVAS_HEIGHT  150

void lv_example_canvas_1(void)
{
    lv_draw_rect_dsc_t rect_dsc;
    lv_draw_rect_dsc_init(&rect_dsc);
    rect_dsc.radius = 10;
    rect_dsc.bg_opa = LV_OPA_COVER;
    rect_dsc.bg_grad.dir = LV_GRAD_DIR_HOR;
    rect_dsc.bg_grad.stops[0].color = lv_palette_main(LV_PALETTE_RED);
    rect_dsc.bg_grad.stops[1].color = lv_palette_main(LV_PALETTE_BLUE);
    rect_dsc.border_width = 2;
    rect_dsc.border_opa = LV_OPA_90;
    rect_dsc.border_color = lv_color_white();
    rect_dsc.shadow_width = 5;
    rect_dsc.shadow_ofs_x = 5;
    rect_dsc.shadow_ofs_y = 5;

    lv_draw_label_dsc_t label_dsc;
    lv_draw_label_dsc_init(&label_dsc);
    label_dsc.color = lv_palette_main(LV_PALETTE_ORANGE);

    static lv_color_t cbuf[LV_CANVAS_BUF_SIZE_TRUE_COLOR(CANVAS_WIDTH, CANVAS_HEIGHT)];

    lv_obj_t * canvas = lv_canvas_create(lv_scr_act());
    lv_canvas_set_buffer(canvas, cbuf, CANVAS_WIDTH, CANVAS_HEIGHT, LV_IMG_CF_TRUE_COLOR);
    lv_obj_center(canvas);
    lv_canvas_fill_bg(canvas, lv_palette_lighten(LV_PALETTE_GREY, 3), LV_OPA_COVER);

    lv_canvas_draw_rect(canvas, 70, 60, 100, 70, &rect_dsc);

    lv_canvas_draw_text(canvas, 40, 20, 100, &label_dsc, "Some text on text canvas");

    /*Test the rotation. It requires another buffer where the original image is stored.
     *So copy the current image to buffer and rotate it to the canvas*/
    static lv_color_t cbuf_tmp[CANVAS_WIDTH * CANVAS_HEIGHT];
    memcpy(cbuf_tmp, cbuf, sizeof(cbuf_tmp));
    lv_img_dsc_t img;
    img.data = (void *)cbuf_tmp;
    img.header.cf = LV_IMG_CF_TRUE_COLOR;
    img.header.w = CANVAS_WIDTH;
    img.header.h = CANVAS_HEIGHT;

    lv_canvas_fill_bg(canvas, lv_palette_lighten(LV_PALETTE_GREY, 3), LV_OPA_COVER);
    lv_canvas_transform(canvas, &img, 120, LV_IMG_ZOOM_NONE, 0, 0, CANVAS_WIDTH / 2, CANVAS_HEIGHT / 2, true);
}

#endif

MicroPython code  

 GitHub Simulator
_CANVAS_WIDTH = 200
_CANVAS_HEIGHT = 150
LV_IMG_ZOOM_NONE = 256

rect_dsc = lv.draw_rect_dsc_t()
rect_dsc.init()
rect_dsc.radius = 10
rect_dsc.bg_opa = lv.OPA.COVER
rect_dsc.bg_grad.dir = lv.GRAD_DIR.HOR
rect_dsc.bg_grad.stops[0].color = lv.palette_main(lv.PALETTE.RED)
rect_dsc.bg_grad.stops[1].color = lv.palette_main(lv.PALETTE.BLUE)
rect_dsc.border_width = 2
rect_dsc.border_opa = lv.OPA._90
rect_dsc.border_color = lv.color_white()
rect_dsc.shadow_width = 5
rect_dsc.shadow_ofs_x = 5
rect_dsc.shadow_ofs_y = 5

label_dsc = lv.draw_label_dsc_t()
label_dsc.init()
label_dsc.color = lv.palette_main(lv.PALETTE.YELLOW)

cbuf = bytearray(_CANVAS_WIDTH * _CANVAS_HEIGHT * 4)

canvas = lv.canvas(lv.scr_act())
canvas.set_buffer(cbuf, _CANVAS_WIDTH, _CANVAS_HEIGHT, lv.img.CF.TRUE_COLOR)
canvas.center()
canvas.fill_bg(lv.palette_lighten(lv.PALETTE.GREY, 3), lv.OPA.COVER)

canvas.draw_rect(70, 60, 100, 70, rect_dsc)
canvas.draw_text(40, 20, 100, label_dsc, "Some text on text canvas")

# Test the rotation. It requires another buffer where the original image is stored.
# So copy the current image to buffer and rotate it to the canvas

img = lv.img_dsc_t()
img.data = cbuf[:]
img.header.cf = lv.img.CF.TRUE_COLOR
img.header.w = _CANVAS_WIDTH
img.header.h = _CANVAS_HEIGHT

canvas.fill_bg(lv.palette_lighten(lv.PALETTE.GREY, 3), lv.OPA.COVER)
canvas.transform(img, 30, LV_IMG_ZOOM_NONE, 0, 0, _CANVAS_WIDTH // 2, _CANVAS_HEIGHT // 2, True)

Transparent Canvas with chroma keying

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_CANVAS && LV_BUILD_EXAMPLES

#define CANVAS_WIDTH  50
#define CANVAS_HEIGHT  50

/**
 * Create a transparent canvas with Chroma keying and indexed color format (palette).
 */
void lv_example_canvas_2(void)
{
    /*Create a button to better see the transparency*/
    lv_btn_create(lv_scr_act());

    /*Create a buffer for the canvas*/
    static lv_color_t cbuf[LV_CANVAS_BUF_SIZE_INDEXED_1BIT(CANVAS_WIDTH, CANVAS_HEIGHT)];

    /*Create a canvas and initialize its palette*/
    lv_obj_t * canvas = lv_canvas_create(lv_scr_act());
    lv_canvas_set_buffer(canvas, cbuf, CANVAS_WIDTH, CANVAS_HEIGHT, LV_IMG_CF_INDEXED_1BIT);
    lv_canvas_set_palette(canvas, 0, LV_COLOR_CHROMA_KEY);
    lv_canvas_set_palette(canvas, 1, lv_palette_main(LV_PALETTE_RED));

    /*Create colors with the indices of the palette*/
    lv_color_t c0;
    lv_color_t c1;

    c0.full = 0;
    c1.full = 1;

    /*Red background (There is no dedicated alpha channel in indexed images so LV_OPA_COVER is ignored)*/
    lv_canvas_fill_bg(canvas, c1, LV_OPA_COVER);

    /*Create hole on the canvas*/
    uint32_t x;
    uint32_t y;
    for( y = 10; y < 30; y++) {
        for( x = 5; x < 20; x++) {
            lv_canvas_set_px_color(canvas, x, y, c0);
        }
    }

}
#endif

MicroPython code  

 GitHub Simulator
CANVAS_WIDTH   = 50
CANVAS_HEIGHT  = 50
LV_COLOR_CHROMA_KEY = lv.color_hex(0x00ff00) 

def LV_IMG_BUF_SIZE_ALPHA_1BIT(w, h):
    return int(((w / 8) + 1) * h)

def LV_IMG_BUF_SIZE_INDEXED_1BIT(w, h):
    return LV_IMG_BUF_SIZE_ALPHA_1BIT(w, h) + 4 * 2

def LV_CANVAS_BUF_SIZE_INDEXED_1BIT(w, h):
    return LV_IMG_BUF_SIZE_INDEXED_1BIT(w, h)

#
# Create a transparent canvas with Chroma keying and indexed color format (palette).
# 

# Create a button to better see the transparency
btn=lv.btn(lv.scr_act())

# Create a buffer for the canvas
cbuf= bytearray(LV_CANVAS_BUF_SIZE_INDEXED_1BIT(CANVAS_WIDTH, CANVAS_HEIGHT))

# Create a canvas and initialize its palette
canvas = lv.canvas(lv.scr_act())
canvas.set_buffer(cbuf, CANVAS_WIDTH, CANVAS_HEIGHT, lv.img.CF.INDEXED_1BIT)
canvas.set_palette(0, LV_COLOR_CHROMA_KEY)
canvas.set_palette(1, lv.palette_main(lv.PALETTE.RED))

# Create colors with the indices of the palette
c0 = lv.color_t()
c1 = lv.color_t()

c0.full = 0
c1.full = 1

# Red background (There is no dedicated alpha channel in indexed images so LV_OPA_COVER is ignored)
canvas.fill_bg(c1, lv.OPA.COVER)

# Create hole on the canvas
for y in range(10,30):
    for x in range(5,20):
        canvas.set_px(x, y, c0)

Chart

Line Chart

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_CHART && LV_BUILD_EXAMPLES

void lv_example_chart_1(void)
{
    /*Create a chart*/
    lv_obj_t * chart;
    chart = lv_chart_create(lv_scr_act());
    lv_obj_set_size(chart, 200, 150);
    lv_obj_center(chart);
    lv_chart_set_type(chart, LV_CHART_TYPE_LINE);   /*Show lines and points too*/

    /*Add two data series*/
    lv_chart_series_t * ser1 = lv_chart_add_series(chart, lv_palette_main(LV_PALETTE_RED), LV_CHART_AXIS_PRIMARY_Y);
    lv_chart_series_t * ser2 = lv_chart_add_series(chart, lv_palette_main(LV_PALETTE_GREEN), LV_CHART_AXIS_SECONDARY_Y);

    /*Set the next points on 'ser1'*/
    lv_chart_set_next_value(chart, ser1, 10);
    lv_chart_set_next_value(chart, ser1, 10);
    lv_chart_set_next_value(chart, ser1, 10);
    lv_chart_set_next_value(chart, ser1, 10);
    lv_chart_set_next_value(chart, ser1, 10);
    lv_chart_set_next_value(chart, ser1, 10);
    lv_chart_set_next_value(chart, ser1, 10);
    lv_chart_set_next_value(chart, ser1, 30);
    lv_chart_set_next_value(chart, ser1, 70);
    lv_chart_set_next_value(chart, ser1, 90);

    /*Directly set points on 'ser2'*/
    ser2->y_points[0] = 90;
    ser2->y_points[1] = 70;
    ser2->y_points[2] = 65;
    ser2->y_points[3] = 65;
    ser2->y_points[4] = 65;
    ser2->y_points[5] = 65;
    ser2->y_points[6] = 65;
    ser2->y_points[7] = 65;
    ser2->y_points[8] = 65;
    ser2->y_points[9] = 65;

    lv_chart_refresh(chart); /*Required after direct set*/
}

#endif

MicroPython code  

 GitHub Simulator
# Create a chart
chart = lv.chart(lv.scr_act())
chart.set_size(200, 150)
chart.center()
chart.set_type(lv.chart.TYPE.LINE)   # Show lines and points too

# Add two data series
ser1 = chart.add_series(lv.palette_main(lv.PALETTE.RED), lv.chart.AXIS.PRIMARY_Y)
ser2 = chart.add_series(lv.palette_main(lv.PALETTE.GREEN), lv.chart.AXIS.SECONDARY_Y)
print(ser2)
# Set next points on ser1
chart.set_next_value(ser1,10)
chart.set_next_value(ser1,10)
chart.set_next_value(ser1,10)
chart.set_next_value(ser1,10)
chart.set_next_value(ser1,10)
chart.set_next_value(ser1,10)
chart.set_next_value(ser1,10)
chart.set_next_value(ser1,30)
chart.set_next_value(ser1,70)
chart.set_next_value(ser1,90)

# Directly set points on 'ser2'
ser2.y_points = [90, 70, 65, 65, 65, 65, 65, 65, 65, 65]
chart.refresh()      #  Required after direct set


Faded area line chart with custom division lines

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_CHART && LV_DRAW_COMPLEX && LV_BUILD_EXAMPLES

static lv_obj_t * chart1;
static lv_chart_series_t * ser1;
static lv_chart_series_t * ser2;

static void draw_event_cb(lv_event_t * e)
{
    lv_obj_t * obj = lv_event_get_target(e);

    /*Add the faded area before the lines are drawn*/
    lv_obj_draw_part_dsc_t * dsc = lv_event_get_draw_part_dsc(e);
    if(dsc->part == LV_PART_ITEMS) {
        if(!dsc->p1 || !dsc->p2) return;

        /*Add a line mask that keeps the area below the line*/
        lv_draw_mask_line_param_t line_mask_param;
        lv_draw_mask_line_points_init(&line_mask_param, dsc->p1->x, dsc->p1->y, dsc->p2->x, dsc->p2->y, LV_DRAW_MASK_LINE_SIDE_BOTTOM);
        int16_t line_mask_id = lv_draw_mask_add(&line_mask_param, NULL);

        /*Add a fade effect: transparent bottom covering top*/
        lv_coord_t h = lv_obj_get_height(obj);
        lv_draw_mask_fade_param_t fade_mask_param;
        lv_draw_mask_fade_init(&fade_mask_param, &obj->coords, LV_OPA_COVER, obj->coords.y1 + h / 8, LV_OPA_TRANSP,obj->coords.y2);
        int16_t fade_mask_id = lv_draw_mask_add(&fade_mask_param, NULL);

        /*Draw a rectangle that will be affected by the mask*/
        lv_draw_rect_dsc_t draw_rect_dsc;
        lv_draw_rect_dsc_init(&draw_rect_dsc);
        draw_rect_dsc.bg_opa = LV_OPA_20;
        draw_rect_dsc.bg_color = dsc->line_dsc->color;

        lv_area_t a;
        a.x1 = dsc->p1->x;
        a.x2 = dsc->p2->x - 1;
        a.y1 = LV_MIN(dsc->p1->y, dsc->p2->y);
        a.y2 = obj->coords.y2;
        lv_draw_rect(dsc->draw_ctx, &draw_rect_dsc, &a);

        /*Remove the masks*/
        lv_draw_mask_free_param(&line_mask_param);
        lv_draw_mask_free_param(&fade_mask_param);
        lv_draw_mask_remove_id(line_mask_id);
        lv_draw_mask_remove_id(fade_mask_id);
    }
    /*Hook the division lines too*/
    else if(dsc->part == LV_PART_MAIN) {
        if(dsc->line_dsc == NULL || dsc->p1 == NULL || dsc->p2 == NULL) return;

        /*Vertical line*/
        if(dsc->p1->x == dsc->p2->x) {
            dsc->line_dsc->color  = lv_palette_lighten(LV_PALETTE_GREY, 1);
            if(dsc->id == 3) {
                dsc->line_dsc->width  = 2;
                dsc->line_dsc->dash_gap  = 0;
                dsc->line_dsc->dash_width  = 0;
            }
            else {
                dsc->line_dsc->width = 1;
                dsc->line_dsc->dash_gap  = 6;
                dsc->line_dsc->dash_width  = 6;
            }
        }
        /*Horizontal line*/
        else {
            if(dsc->id == 2) {
                dsc->line_dsc->width  = 2;
                dsc->line_dsc->dash_gap  = 0;
                dsc->line_dsc->dash_width  = 0;
            }
            else {
                dsc->line_dsc->width = 2;
                dsc->line_dsc->dash_gap  = 6;
                dsc->line_dsc->dash_width  = 6;
            }

            if(dsc->id == 1  || dsc->id == 3) {
                dsc->line_dsc->color  = lv_palette_main(LV_PALETTE_GREEN);
            } else {
                dsc->line_dsc->color  = lv_palette_lighten(LV_PALETTE_GREY, 1);
            }
        }
    }
}

static void add_data(lv_timer_t * timer)
{
    LV_UNUSED(timer);
    static uint32_t cnt = 0;
    lv_chart_set_next_value(chart1, ser1, lv_rand(20, 90));

    if(cnt % 4 == 0) lv_chart_set_next_value(chart1, ser2, lv_rand(40, 60));

    cnt++;
}

/**
 * Add a faded area effect to the line chart and make some division lines ticker
 */
void lv_example_chart_2(void)
{
    /*Create a chart1*/
    chart1 = lv_chart_create(lv_scr_act());
    lv_obj_set_size(chart1, 200, 150);
    lv_obj_center(chart1);
    lv_chart_set_type(chart1, LV_CHART_TYPE_LINE);   /*Show lines and points too*/

    lv_chart_set_div_line_count(chart1, 5, 7);

    lv_obj_add_event_cb(chart1, draw_event_cb, LV_EVENT_DRAW_PART_BEGIN, NULL);
    lv_chart_set_update_mode(chart1, LV_CHART_UPDATE_MODE_CIRCULAR);

    /*Add two data series*/
    ser1 = lv_chart_add_series(chart1, lv_palette_main(LV_PALETTE_RED), LV_CHART_AXIS_PRIMARY_Y);
    ser2 = lv_chart_add_series(chart1, lv_palette_main(LV_PALETTE_BLUE), LV_CHART_AXIS_SECONDARY_Y);

    uint32_t i;
    for(i = 0; i < 10; i++) {
        lv_chart_set_next_value(chart1, ser1, lv_rand(20, 90));
        lv_chart_set_next_value(chart1, ser2, lv_rand(30, 70));
    }

    lv_timer_create(add_data, 200, NULL);
}

#endif

MicroPython code  

 GitHub Simulator
def draw_event_cb(e):

    obj = e.get_target()

    # Add the faded area before the lines are drawn
    dsc = lv.obj_draw_part_dsc_t.__cast__(e.get_param())
    if dsc.part != lv.PART.ITEMS:
        return
    if not dsc.p1 or not dsc.p2:
        return

    # Add a line mask that keeps the area below the line
    line_mask_param = lv.draw_mask_line_param_t()
    line_mask_param.points_init(dsc.p1.x, dsc.p1.y, dsc.p2.x, dsc.p2.y, lv.DRAW_MASK_LINE_SIDE.BOTTOM)
    # line_mask_id = line_mask_param.draw_mask_add(None)
    line_mask_id = lv.draw_mask_add(line_mask_param, None)
    # Add a fade effect: transparent bottom covering top
    h = obj.get_height()
    fade_mask_param = lv.draw_mask_fade_param_t()
    coords = lv.area_t()
    obj.get_coords(coords)
    fade_mask_param.init(coords, lv.OPA.COVER, coords.y1 + h // 8, lv.OPA.TRANSP,coords.y2)
    fade_mask_id = lv.draw_mask_add(fade_mask_param,None)

    # Draw a rectangle that will be affected by the mask
    draw_rect_dsc = lv.draw_rect_dsc_t()
    draw_rect_dsc.init()
    draw_rect_dsc.bg_opa = lv.OPA._20
    draw_rect_dsc.bg_color = dsc.line_dsc.color

    a = lv.area_t()
    a.x1 = dsc.p1.x
    a.x2 = dsc.p2.x - 1
    a.y1 = min(dsc.p1.y, dsc.p2.y)
    coords = lv.area_t()
    obj.get_coords(coords)
    a.y2 = coords.y2
    dsc.draw_ctx.rect(draw_rect_dsc, a)

    # Remove the masks
    lv.draw_mask_remove_id(line_mask_id)
    lv.draw_mask_remove_id(fade_mask_id)


def add_data(timer):
    # LV_UNUSED(timer);
    cnt = 0
    chart1.set_next_value(ser1, lv.rand(20, 90))

    if cnt % 4 == 0:
        chart1.set_next_value(ser2, lv.rand(40, 60))

    cnt +=1

#
# Add a faded area effect to the line chart
#

# Create a chart1
chart1 = lv.chart(lv.scr_act())
chart1.set_size(200, 150)
chart1.center()
chart1.set_type(lv.chart.TYPE.LINE)    # Show lines and points too

chart1.add_event_cb(draw_event_cb, lv.EVENT.DRAW_PART_BEGIN, None)
chart1.set_update_mode(lv.chart.UPDATE_MODE.CIRCULAR)

# Add two data series
ser1 = chart1.add_series(lv.palette_main(lv.PALETTE.RED), lv.chart.AXIS.PRIMARY_Y)
ser2 = chart1.add_series(lv.palette_main(lv.PALETTE.BLUE), lv.chart.AXIS.SECONDARY_Y)

for i in range(10):
    chart1.set_next_value(ser1, lv.rand(20, 90))
    chart1.set_next_value(ser2, lv.rand(30, 70))

timer = lv.timer_create(add_data, 200, None)

Axis ticks and labels with scrolling

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_CHART && LV_BUILD_EXAMPLES

static void draw_event_cb(lv_event_t * e)
{
    lv_obj_draw_part_dsc_t * dsc = lv_event_get_draw_part_dsc(e);
    if(!lv_obj_draw_part_check_type(dsc, &lv_chart_class, LV_CHART_DRAW_PART_TICK_LABEL)) return;

    if(dsc->id == LV_CHART_AXIS_PRIMARY_X && dsc->text) {
        const char * month[] = {"Jan", "Febr", "March", "Apr", "May", "Jun", "July", "Aug", "Sept", "Oct", "Nov", "Dec"};
        lv_snprintf(dsc->text, dsc->text_length, "%s", month[dsc->value]);
    }
}

/**
 * Add ticks and labels to the axis and demonstrate scrolling
 */
void lv_example_chart_3(void)
{
    /*Create a chart*/
    lv_obj_t * chart;
    chart = lv_chart_create(lv_scr_act());
    lv_obj_set_size(chart, 200, 150);
    lv_obj_center(chart);
    lv_chart_set_type(chart, LV_CHART_TYPE_BAR);
    lv_chart_set_range(chart, LV_CHART_AXIS_PRIMARY_Y, 0, 100);
    lv_chart_set_range(chart, LV_CHART_AXIS_SECONDARY_Y, 0, 400);
    lv_chart_set_point_count(chart, 12);
    lv_obj_add_event_cb(chart, draw_event_cb, LV_EVENT_DRAW_PART_BEGIN, NULL);

    /*Add ticks and label to every axis*/
    lv_chart_set_axis_tick(chart, LV_CHART_AXIS_PRIMARY_X, 10, 5, 12, 3, true, 40);
    lv_chart_set_axis_tick(chart, LV_CHART_AXIS_PRIMARY_Y, 10, 5, 6, 2, true, 50);
    lv_chart_set_axis_tick(chart, LV_CHART_AXIS_SECONDARY_Y, 10, 5, 3, 4, true, 50);

    /*Zoom in a little in X*/
    lv_chart_set_zoom_x(chart, 800);

    /*Add two data series*/
    lv_chart_series_t * ser1 = lv_chart_add_series(chart, lv_palette_lighten(LV_PALETTE_GREEN, 2), LV_CHART_AXIS_PRIMARY_Y);
    lv_chart_series_t * ser2 = lv_chart_add_series(chart, lv_palette_darken(LV_PALETTE_GREEN, 2), LV_CHART_AXIS_SECONDARY_Y);

    /*Set the next points on 'ser1'*/
    lv_chart_set_next_value(chart, ser1, 31);
    lv_chart_set_next_value(chart, ser1, 66);
    lv_chart_set_next_value(chart, ser1, 10);
    lv_chart_set_next_value(chart, ser1, 89);
    lv_chart_set_next_value(chart, ser1, 63);
    lv_chart_set_next_value(chart, ser1, 56);
    lv_chart_set_next_value(chart, ser1, 32);
    lv_chart_set_next_value(chart, ser1, 35);
    lv_chart_set_next_value(chart, ser1, 57);
    lv_chart_set_next_value(chart, ser1, 85);
    lv_chart_set_next_value(chart, ser1, 22);
    lv_chart_set_next_value(chart, ser1, 58);

    lv_coord_t * ser2_array = lv_chart_get_y_array(chart, ser2);
    /*Directly set points on 'ser2'*/
    ser2_array[0] = 92;
    ser2_array[1] = 71;
    ser2_array[2] = 61;
    ser2_array[3] = 15;
    ser2_array[4] = 21;
    ser2_array[5] = 35;
    ser2_array[6] = 35;
    ser2_array[7] = 58;
    ser2_array[8] = 31;
    ser2_array[9] = 53;
    ser2_array[10] = 33;
    ser2_array[11] = 73;

    lv_chart_refresh(chart); /*Required after direct set*/
}

#endif

MicroPython code  

 GitHub Simulator
def draw_event_cb(e):

    dsc = lv.obj_draw_part_dsc_t.__cast__(e.get_param())
    if dsc.part == lv.PART.TICKS and dsc.id == lv.chart.AXIS.PRIMARY_X: 
        month = ["Jan", "Febr", "March", "Apr", "May", "Jun", "July", "Aug", "Sept", "Oct", "Nov", "Dec"]
        # dsc.text is defined char text[16], I must therefore convert the Python string to a byte_array
        dsc.text = bytes(month[dsc.value],"ascii") 
#
# Add ticks and labels to the axis and demonstrate scrolling
#

# Create a chart
chart = lv.chart(lv.scr_act())
chart.set_size(200, 150)
chart.center()
chart.set_type(lv.chart.TYPE.BAR)
chart.set_range(lv.chart.AXIS.PRIMARY_Y, 0, 100)
chart.set_range(lv.chart.AXIS.SECONDARY_Y, 0, 400)
chart.set_point_count(12)
chart.add_event_cb(draw_event_cb, lv.EVENT.DRAW_PART_BEGIN, None)

# Add ticks and label to every axis
chart.set_axis_tick(lv.chart.AXIS.PRIMARY_X, 10, 5, 12, 3, True, 40)
chart.set_axis_tick(lv.chart.AXIS.PRIMARY_Y, 10, 5, 6, 2, True, 50)
chart.set_axis_tick(lv.chart.AXIS.SECONDARY_Y, 10, 5, 3, 4,True, 50)

# Zoom in a little in X
chart.set_zoom_x(800)

# Add two data series
ser1 = lv.chart.add_series(chart, lv.palette_lighten(lv.PALETTE.GREEN, 2), lv.chart.AXIS.PRIMARY_Y)
ser2 = lv.chart.add_series(chart, lv.palette_darken(lv.PALETTE.GREEN, 2), lv.chart.AXIS.SECONDARY_Y)

# Set the next points on 'ser1'
chart.set_next_value(ser1, 31)
chart.set_next_value(ser1, 66)
chart.set_next_value(ser1, 10)
chart.set_next_value(ser1, 89)
chart.set_next_value(ser1, 63)
chart.set_next_value(ser1, 56)
chart.set_next_value(ser1, 32)
chart.set_next_value(ser1, 35)
chart.set_next_value(ser1, 57)
chart.set_next_value(ser1, 85)
chart.set_next_value(ser1, 22)
chart.set_next_value(ser1, 58)

# Directly set points on 'ser2'
ser2.y_points = [92,71,61,15,21,35,35,58,31,53,33,73]

chart.refresh()  # Required after direct set


Show the value of the pressed points

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_CHART && LV_BUILD_EXAMPLES


static void event_cb(lv_event_t * e)
{
    lv_event_code_t code = lv_event_get_code(e);
    lv_obj_t * chart = lv_event_get_target(e);

    if(code == LV_EVENT_VALUE_CHANGED) {
        lv_obj_invalidate(chart);
    }
    if(code == LV_EVENT_REFR_EXT_DRAW_SIZE) {
        lv_coord_t * s = lv_event_get_param(e);
        *s = LV_MAX(*s, 20);
    }
    else if(code == LV_EVENT_DRAW_POST_END) {
        int32_t id = lv_chart_get_pressed_point(chart);
        if(id == LV_CHART_POINT_NONE) return;

        LV_LOG_USER("Selected point %d", (int)id);

        lv_chart_series_t * ser = lv_chart_get_series_next(chart, NULL);
        while(ser) {
            lv_point_t p;
            lv_chart_get_point_pos_by_id(chart, ser, id, &p);

            lv_coord_t * y_array = lv_chart_get_y_array(chart, ser);
            lv_coord_t value = y_array[id];

            char buf[16];
            lv_snprintf(buf, sizeof(buf), LV_SYMBOL_DUMMY"$%d", value);

            lv_draw_rect_dsc_t draw_rect_dsc;
            lv_draw_rect_dsc_init(&draw_rect_dsc);
            draw_rect_dsc.bg_color = lv_color_black();
            draw_rect_dsc.bg_opa = LV_OPA_50;
            draw_rect_dsc.radius = 3;
            draw_rect_dsc.bg_img_src = buf;
            draw_rect_dsc.bg_img_recolor = lv_color_white();

            lv_area_t a;
            a.x1 = chart->coords.x1 + p.x - 20;
            a.x2 = chart->coords.x1 + p.x + 20;
            a.y1 = chart->coords.y1 + p.y - 30;
            a.y2 = chart->coords.y1 + p.y - 10;

            lv_draw_ctx_t * draw_ctx = lv_event_get_draw_ctx(e);
            lv_draw_rect(draw_ctx, &draw_rect_dsc, &a);

            ser = lv_chart_get_series_next(chart, ser);
        }
    }
    else if(code == LV_EVENT_RELEASED) {
        lv_obj_invalidate(chart);
    }
}

/**
 * Show the value of the pressed points
 */
void lv_example_chart_4(void)
{
    /*Create a chart*/
    lv_obj_t * chart;
    chart = lv_chart_create(lv_scr_act());
    lv_obj_set_size(chart, 200, 150);
    lv_obj_center(chart);

    lv_obj_add_event_cb(chart, event_cb, LV_EVENT_ALL, NULL);
    lv_obj_refresh_ext_draw_size(chart);

    /*Zoom in a little in X*/
    lv_chart_set_zoom_x(chart, 800);

    /*Add two data series*/
    lv_chart_series_t * ser1 = lv_chart_add_series(chart, lv_palette_main(LV_PALETTE_RED), LV_CHART_AXIS_PRIMARY_Y);
    lv_chart_series_t * ser2 = lv_chart_add_series(chart, lv_palette_main(LV_PALETTE_GREEN), LV_CHART_AXIS_PRIMARY_Y);
    uint32_t i;
    for(i = 0; i < 10; i++) {
        lv_chart_set_next_value(chart, ser1, lv_rand(60,90));
        lv_chart_set_next_value(chart, ser2, lv_rand(10,40));
    }
}

#endif

MicroPython code  

 GitHub Simulator
def event_cb(e):
    code = e.get_code()
    chart = e.get_target()

    if code == lv.EVENT.VALUE_CHANGED:
        chart.invalidate()

    if code == lv.EVENT.REFR_EXT_DRAW_SIZE:
        e.set_ext_draw_size(20)

    elif code == lv.EVENT.DRAW_POST_END:
        id = lv.chart.get_pressed_point(chart)
        if id == lv.CHART_POINT.NONE:
            return
        # print("Selected point ", id)
        for i in range(len(series)):
            p = lv.point_t()
            chart.get_point_pos_by_id(series[i], id, p)
            value = series_points[i][id]
            buf = lv.SYMBOL.DUMMY + "$" + str(value)
            
            draw_rect_dsc = lv.draw_rect_dsc_t()
            draw_rect_dsc.init()
            draw_rect_dsc.bg_color = lv.color_black()
            draw_rect_dsc.bg_opa = lv.OPA._50
            draw_rect_dsc.radius = 3
            draw_rect_dsc.bg_img_src = buf
            draw_rect_dsc.bg_img_recolor = lv.color_white()
            
            a = lv.area_t()
            coords = lv.area_t()
            chart.get_coords(coords)
            a.x1 = coords.x1 + p.x - 20
            a.x2 = coords.x1 + p.x + 20
            a.y1 = coords.y1 + p.y - 30
            a.y2 = coords.y1 + p.y - 10
            
            clip_area = lv.area_t.__cast__(e.get_param())
            lv.draw_rect(a, clip_area, draw_rect_dsc)
            
    elif code == lv.EVENT.RELEASED:
        chart.invalidate()
            
# 
# Add ticks and labels to the axis and demonstrate scrolling
#

# Create a chart
chart = lv.chart(lv.scr_act())
chart.set_size(200, 150)
chart.center()

chart.add_event_cb(event_cb, lv.EVENT.ALL, None)
chart.refresh_ext_draw_size()

# Zoom in a little in X
chart.set_zoom_x(800)

# Add two data series
ser1 = chart.add_series(lv.palette_main(lv.PALETTE.RED), lv.chart.AXIS.PRIMARY_Y)
ser2 = chart.add_series(lv.palette_main(lv.PALETTE.GREEN), lv.chart.AXIS.PRIMARY_Y)

ser1_p = []
ser2_p = []
for i in range(10):
    ser1_p.append(lv.rand(60,90))
    ser2_p.append(lv.rand(10,40))
ser1.y_points = ser1_p
ser2.y_points = ser2_p

series = [ser1,ser2]
series_points=[ser1_p,ser2_p]


Display 1000 data points with zooming and scrolling

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_CHART && LV_USE_SLIDER && LV_BUILD_EXAMPLES

static lv_obj_t * chart;
/* Source: https://github.com/ankur219/ECG-Arrhythmia-classification/blob/642230149583adfae1e4bd26c6f0e1fd8af2be0e/sample.csv*/
static const lv_coord_t ecg_sample[] = {
    -2, 2, 0, -15, -39, -63, -71, -68, -67, -69, -84, -95, -104, -107, -108, -107, -107, -107, -107, -114, -118, -117,
    -112, -100, -89, -83, -71, -64, -58, -58, -62, -62, -58, -51, -46, -39, -27, -10, 4, 7, 1, -3, 0, 14, 24, 30, 25, 19,
    13, 7, 12, 15, 18, 21, 13, 6, 9, 8, 17, 19, 13, 11, 11, 11, 23, 30, 37, 34, 25, 14, 15, 19, 28, 31, 26, 23, 25, 31,
    39, 37, 37, 34, 30, 32, 22, 29, 31, 33, 37, 23, 13, 7, 2, 4, -2, 2, 11, 22, 33, 19, -1, -27, -55, -67, -72, -71, -63,
    -49, -18, 35, 113, 230, 369, 525, 651, 722, 730, 667, 563, 454, 357, 305, 288, 274, 255, 212, 173, 143, 117, 82, 39,
    -13, -53, -78, -91, -101, -113, -124, -131, -131, -131, -129, -128, -129, -125, -123, -123, -129, -139, -148, -153,
    -159, -166, -183, -205, -227, -243, -248, -246, -254, -280, -327, -381, -429, -473, -517, -556, -592, -612, -620,
    -620, -614, -604, -591, -574, -540, -497, -441, -389, -358, -336, -313, -284, -222, -167, -114, -70, -47, -28, -4, 12,
    38, 52, 58, 56, 56, 57, 68, 77, 86, 86, 80, 69, 67, 70, 82, 85, 89, 90, 89, 89, 88, 91, 96, 97, 91, 83, 78, 82, 88, 95,
    96, 105, 106, 110, 102, 100, 96, 98, 97, 101, 98, 99, 100, 107, 113, 119, 115, 110, 96, 85, 73, 64, 69, 76, 79,
    78, 75, 85, 100, 114, 113, 105, 96, 84, 74, 66, 60, 75, 85, 89, 83, 67, 61, 67, 73, 79, 74, 63, 57, 56, 58, 61, 55,
    48, 45, 46, 55, 62, 55, 49, 43, 50, 59, 63, 57, 40, 31, 23, 25, 27, 31, 35, 34, 30, 36, 34, 42, 38, 36, 40, 46, 50,
    47, 32, 30, 32, 52, 67, 73, 71, 63, 54, 53, 45, 41, 28, 13, 3, 1, 4, 4, -8, -23, -32, -31, -19, -5, 3, 9, 13, 19,
    24, 27, 29, 25, 22, 26, 32, 42, 51, 56, 60, 57, 55, 53, 53, 54, 59, 54, 49, 26, -3, -11, -20, -47, -100, -194, -236,
    -212, -123, 8, 103, 142, 147, 120, 105, 98, 93, 81, 61, 40, 26, 28, 30, 30, 27, 19, 17, 21, 20, 19, 19, 22, 36, 40,
    35, 20, 7, 1, 10, 18, 27, 22, 6, -4, -2, 3, 6, -2, -13, -14, -10, -2, 3, 2, -1, -5, -10, -19, -32, -42, -55, -60,
    -68, -77, -86, -101, -110, -117, -115, -104, -92, -84, -85, -84, -73, -65, -52, -50, -45, -35, -20, -3, 12, 20, 25,
    26, 28, 28, 30, 28, 25, 28, 33, 42, 42, 36, 23, 9, 0, 1, -4, 1, -4, -4, 1, 5, 9, 9, -3, -1, -18, -50, -108, -190,
    -272, -340, -408, -446, -537, -643, -777, -894, -920, -853, -697, -461, -251, -60, 58, 103, 129, 139, 155, 170, 173,
    178, 185, 190, 193, 200, 208, 215, 225, 224, 232, 234, 240, 240, 236, 229, 226, 224, 232, 233, 232, 224, 219, 219,
    223, 231, 226, 223, 219, 218, 223, 223, 223, 233, 245, 268, 286, 296, 295, 283, 271, 263, 252, 243, 226, 210, 197,
    186, 171, 152, 133, 117, 114, 110, 107, 96, 80, 63, 48, 40, 38, 34, 28, 15, 2, -7, -11, -14, -18, -29, -37, -44, -50,
    -58, -63, -61, -52, -50, -48, -61, -59, -58, -54, -47, -52, -62, -61, -64, -54, -52, -59, -69, -76, -76, -69, -67,
    -74, -78, -81, -80, -73, -65, -57, -53, -51, -47, -35, -27, -22, -22, -24, -21, -17, -13, -10, -11, -13, -20, -20,
    -12, -2, 7, -1, -12, -16, -13, -2, 2, -4, -5, -2, 9, 19, 19, 14, 11, 13, 19, 21, 20, 18, 19, 19, 19, 16, 15, 13, 14,
    9, 3, -5, -9, -5, -3, -2, -3, -3, 2, 8, 9, 9, 5, 6, 8, 8, 7, 4, 3, 4, 5, 3, 5, 5, 13, 13, 12, 10, 10, 15, 22, 17,
    14, 7, 10, 15, 16, 11, 12, 10, 13, 9, -2, -4, -2, 7, 16, 16, 17, 16, 7, -1, -16, -18, -16, -9, -4, -5, -10, -9, -8,
    -3, -4, -10, -19, -20, -16, -9, -9, -23, -40, -48, -43, -33, -19, -21, -26, -31, -33, -19, 0, 17, 24, 9, -17, -47,
    -63, -67, -59, -52, -51, -50, -49, -42, -26, -21, -15, -20, -23, -22, -19, -12, -8, 5, 18, 27, 32, 26, 25, 26, 22,
    23, 17, 14, 17, 21, 25, 2, -45, -121, -196, -226, -200, -118, -9, 73, 126, 131, 114, 87, 60, 42, 29, 26, 34, 35, 34,
    25, 12, 9, 7, 3, 2, -8, -11, 2, 23, 38, 41, 23, 9, 10, 13, 16, 8, -8, -17, -23, -26, -25, -21, -15, -10, -13, -13,
    -19, -22, -29, -40, -48, -48, -54, -55, -66, -82, -85, -90, -92, -98, -114, -119, -124, -129, -132, -146, -146, -138,
    -124, -99, -85, -72, -65, -65, -65, -66, -63, -64, -64, -58, -46, -26, -9, 2, 2, 4, 0, 1, 4, 3, 10, 11, 10, 2, -4,
    0, 10, 18, 20, 6, 2, -9, -7, -3, -3, -2, -7, -12, -5, 5, 24, 36, 31, 25, 6, 3, 7, 12, 17, 11, 0, -6, -9, -8, -7, -5,
    -6, -2, -2, -6, -2, 2, 14, 24, 22, 15, 8, 4, 6, 7, 12, 16, 25, 20, 7, -16, -41, -60, -67, -65, -54, -35, -11, 30,
    84, 175, 302, 455, 603, 707, 743, 714, 625, 519, 414, 337, 300, 281, 263, 239, 197, 163, 136, 109, 77, 34, -18, -50,
    -66, -74, -79, -92, -107, -117, -127, -129, -135, -139, -141, -155, -159, -167, -171, -169, -174, -175, -178, -191,
    -202, -223, -235, -243, -237, -240, -256, -298, -345, -393, -432, -475, -518, -565, -596, -619, -623, -623, -614,
    -599, -583, -559, -524, -477, -425, -383, -357, -331, -301, -252, -198, -143, -96, -57, -29, -8, 10, 31, 45, 60, 65,
    70, 74, 76, 79, 82, 79, 75, 62,
};

static void slider_x_event_cb(lv_event_t * e)
{
    lv_obj_t * obj = lv_event_get_target(e);
    int32_t v = lv_slider_get_value(obj);
    lv_chart_set_zoom_x(chart, v);
}

static void slider_y_event_cb(lv_event_t * e)
{
    lv_obj_t * obj = lv_event_get_target(e);
    int32_t v = lv_slider_get_value(obj);
    lv_chart_set_zoom_y(chart, v);
}

/**
 * Display 1000 data points with zooming and scrolling.
 * See how the chart changes drawing mode (draw only vertical lines) when
 * the points get too crowded.
 */
void lv_example_chart_5(void)
{
    /*Create a chart*/
    chart = lv_chart_create(lv_scr_act());
    lv_obj_set_size(chart, 200, 150);
    lv_obj_align(chart, LV_ALIGN_CENTER, -30, -30);
    lv_chart_set_range(chart, LV_CHART_AXIS_PRIMARY_Y, -1000, 1000);

    /*Do not display points on the data*/
    lv_obj_set_style_size(chart, 0, LV_PART_INDICATOR);

    lv_chart_series_t * ser = lv_chart_add_series(chart, lv_palette_main(LV_PALETTE_RED), LV_CHART_AXIS_PRIMARY_Y);

    uint32_t pcnt = sizeof(ecg_sample) / sizeof(ecg_sample[0]);
    lv_chart_set_point_count(chart, pcnt);
    lv_chart_set_ext_y_array(chart, ser, (lv_coord_t *)ecg_sample);

    lv_obj_t * slider;
    slider = lv_slider_create(lv_scr_act());
    lv_slider_set_range(slider, LV_IMG_ZOOM_NONE, LV_IMG_ZOOM_NONE * 10);
    lv_obj_add_event_cb(slider, slider_x_event_cb, LV_EVENT_VALUE_CHANGED, NULL);
    lv_obj_set_size(slider, 200, 10);
    lv_obj_align_to(slider, chart, LV_ALIGN_OUT_BOTTOM_MID, 0, 20);

    slider = lv_slider_create(lv_scr_act());
    lv_slider_set_range(slider, LV_IMG_ZOOM_NONE, LV_IMG_ZOOM_NONE * 10);
    lv_obj_add_event_cb(slider, slider_y_event_cb, LV_EVENT_VALUE_CHANGED, NULL);
    lv_obj_set_size(slider, 10, 150);
    lv_obj_align_to(slider, chart, LV_ALIGN_OUT_RIGHT_MID, 20, 0);
}

#endif

MicroPython code  

 GitHub Simulator
# Source: https://github.com/ankur219/ECG-Arrhythmia-classification/blob/642230149583adfae1e4bd26c6f0e1fd8af2be0e/sample.csv
ecg_sample = [
    -2, 2, 0, -15, -39, -63, -71, -68, -67, -69, -84, -95, -104, -107, -108, -107, -107, -107, -107, -114, -118, -117,
    -112, -100, -89, -83, -71, -64, -58, -58, -62, -62, -58, -51, -46, -39, -27, -10, 4, 7, 1, -3, 0, 14, 24, 30, 25, 19,
    13, 7, 12, 15, 18, 21, 13, 6, 9, 8, 17, 19, 13, 11, 11, 11, 23, 30, 37, 34, 25, 14, 15, 19, 28, 31, 26, 23, 25, 31,
    39, 37, 37, 34, 30, 32, 22, 29, 31, 33, 37, 23, 13, 7, 2, 4, -2, 2, 11, 22, 33, 19, -1, -27, -55, -67, -72, -71, -63,
    -49, -18, 35, 113, 230, 369, 525, 651, 722, 730, 667, 563, 454, 357, 305, 288, 274, 255, 212, 173, 143, 117, 82, 39,
    -13, -53, -78, -91, -101, -113, -124, -131, -131, -131, -129, -128, -129, -125, -123, -123, -129, -139, -148, -153,
    -159, -166, -183, -205, -227, -243, -248, -246, -254, -280, -327, -381, -429, -473, -517, -556, -592, -612, -620,
    -620, -614, -604, -591, -574, -540, -497, -441, -389, -358, -336, -313, -284, -222, -167, -114, -70, -47, -28, -4, 12,
    38, 52, 58, 56, 56, 57, 68, 77, 86, 86, 80, 69, 67, 70, 82, 85, 89, 90, 89, 89, 88, 91, 96, 97, 91, 83, 78, 82, 88, 95,
    96, 105, 106, 110, 102, 100, 96, 98, 97, 101, 98, 99, 100, 107, 113, 119, 115, 110, 96, 85, 73, 64, 69, 76, 79,
    78, 75, 85, 100, 114, 113, 105, 96, 84, 74, 66, 60, 75, 85, 89, 83, 67, 61, 67, 73, 79, 74, 63, 57, 56, 58, 61, 55,
    48, 45, 46, 55, 62, 55, 49, 43, 50, 59, 63, 57, 40, 31, 23, 25, 27, 31, 35, 34, 30, 36, 34, 42, 38, 36, 40, 46, 50,
    47, 32, 30, 32, 52, 67, 73, 71, 63, 54, 53, 45, 41, 28, 13, 3, 1, 4, 4, -8, -23, -32, -31, -19, -5, 3, 9, 13, 19,
    24, 27, 29, 25, 22, 26, 32, 42, 51, 56, 60, 57, 55, 53, 53, 54, 59, 54, 49, 26, -3, -11, -20, -47, -100, -194, -236,
    -212, -123, 8, 103, 142, 147, 120, 105, 98, 93, 81, 61, 40, 26, 28, 30, 30, 27, 19, 17, 21, 20, 19, 19, 22, 36, 40,
    35, 20, 7, 1, 10, 18, 27, 22, 6, -4, -2, 3, 6, -2, -13, -14, -10, -2, 3, 2, -1, -5, -10, -19, -32, -42, -55, -60,
    -68, -77, -86, -101, -110, -117, -115, -104, -92, -84, -85, -84, -73, -65, -52, -50, -45, -35, -20, -3, 12, 20, 25,
    26, 28, 28, 30, 28, 25, 28, 33, 42, 42, 36, 23, 9, 0, 1, -4, 1, -4, -4, 1, 5, 9, 9, -3, -1, -18, -50, -108, -190,
    -272, -340, -408, -446, -537, -643, -777, -894, -920, -853, -697, -461, -251, -60, 58, 103, 129, 139, 155, 170, 173,
    178, 185, 190, 193, 200, 208, 215, 225, 224, 232, 234, 240, 240, 236, 229, 226, 224, 232, 233, 232, 224, 219, 219,
    223, 231, 226, 223, 219, 218, 223, 223, 223, 233, 245, 268, 286, 296, 295, 283, 271, 263, 252, 243, 226, 210, 197,
    186, 171, 152, 133, 117, 114, 110, 107, 96, 80, 63, 48, 40, 38, 34, 28, 15, 2, -7, -11, -14, -18, -29, -37, -44, -50,
    -58, -63, -61, -52, -50, -48, -61, -59, -58, -54, -47, -52, -62, -61, -64, -54, -52, -59, -69, -76, -76, -69, -67,
    -74, -78, -81, -80, -73, -65, -57, -53, -51, -47, -35, -27, -22, -22, -24, -21, -17, -13, -10, -11, -13, -20, -20,
    -12, -2, 7, -1, -12, -16, -13, -2, 2, -4, -5, -2, 9, 19, 19, 14, 11, 13, 19, 21, 20, 18, 19, 19, 19, 16, 15, 13, 14,
    9, 3, -5, -9, -5, -3, -2, -3, -3, 2, 8, 9, 9, 5, 6, 8, 8, 7, 4, 3, 4, 5, 3, 5, 5, 13, 13, 12, 10, 10, 15, 22, 17,
    14, 7, 10, 15, 16, 11, 12, 10, 13, 9, -2, -4, -2, 7, 16, 16, 17, 16, 7, -1, -16, -18, -16, -9, -4, -5, -10, -9, -8,
    -3, -4, -10, -19, -20, -16, -9, -9, -23, -40, -48, -43, -33, -19, -21, -26, -31, -33, -19, 0, 17, 24, 9, -17, -47,
    -63, -67, -59, -52, -51, -50, -49, -42, -26, -21, -15, -20, -23, -22, -19, -12, -8, 5, 18, 27, 32, 26, 25, 26, 22,
    23, 17, 14, 17, 21, 25, 2, -45, -121, -196, -226, -200, -118, -9, 73, 126, 131, 114, 87, 60, 42, 29, 26, 34, 35, 34,
    25, 12, 9, 7, 3, 2, -8, -11, 2, 23, 38, 41, 23, 9, 10, 13, 16, 8, -8, -17, -23, -26, -25, -21, -15, -10, -13, -13,
    -19, -22, -29, -40, -48, -48, -54, -55, -66, -82, -85, -90, -92, -98, -114, -119, -124, -129, -132, -146, -146, -138,
    -124, -99, -85, -72, -65, -65, -65, -66, -63, -64, -64, -58, -46, -26, -9, 2, 2, 4, 0, 1, 4, 3, 10, 11, 10, 2, -4,
    0, 10, 18, 20, 6, 2, -9, -7, -3, -3, -2, -7, -12, -5, 5, 24, 36, 31, 25, 6, 3, 7, 12, 17, 11, 0, -6, -9, -8, -7, -5,
    -6, -2, -2, -6, -2, 2, 14, 24, 22, 15, 8, 4, 6, 7, 12, 16, 25, 20, 7, -16, -41, -60, -67, -65, -54, -35, -11, 30,
    84, 175, 302, 455, 603, 707, 743, 714, 625, 519, 414, 337, 300, 281, 263, 239, 197, 163, 136, 109, 77, 34, -18, -50,
    -66, -74, -79, -92, -107, -117, -127, -129, -135, -139, -141, -155, -159, -167, -171, -169, -174, -175, -178, -191,
    -202, -223, -235, -243, -237, -240, -256, -298, -345, -393, -432, -475, -518, -565, -596, -619, -623, -623, -614,
    -599, -583, -559, -524, -477, -425, -383, -357, -331, -301, -252, -198, -143, -96, -57, -29, -8, 10, 31, 45, 60, 65,
    70, 74, 76, 79, 82, 79, 75, 62,
]

def slider_x_event_cb(e):

    slider = e.get_target()
    v = slider.get_value()
    chart.set_zoom_x(v)

def slider_y_event_cb(e):

    slider = e.get_target()
    v = slider.get_value()
    chart.set_zoom_y(v)


#
# Display 1000 data points with zooming and scrolling.
# See how the chart changes drawing mode (draw only vertical lines) when
# the points get too crowded.
 
# Create a chart
chart = lv.chart(lv.scr_act())
chart.set_size(200, 150)
chart.align(lv.ALIGN.CENTER, -30, -30)
chart.set_range(lv.chart.AXIS.PRIMARY_Y, -1000, 1000)

# Do not display points on the data
chart.set_style_size(0, lv.PART.INDICATOR)

ser = chart.add_series(lv.palette_main(lv.PALETTE.RED), lv.chart.AXIS.PRIMARY_Y)

pcnt = len(ecg_sample)
chart.set_point_count(pcnt)
chart.set_ext_y_array(ser, ecg_sample)

slider = lv.slider(lv.scr_act())
slider.set_range(lv.IMG_ZOOM.NONE, lv.IMG_ZOOM.NONE * 10)
slider.add_event_cb(slider_x_event_cb, lv.EVENT.VALUE_CHANGED, None)
slider.set_size(200,10)
slider.align_to(chart, lv.ALIGN.OUT_BOTTOM_MID, 0, 20)

slider = lv.slider(lv.scr_act())
slider.set_range(lv.IMG_ZOOM.NONE, lv.IMG_ZOOM.NONE * 10)
slider.add_event_cb(slider_y_event_cb, lv.EVENT.VALUE_CHANGED, None)
slider.set_size(10, 150)
slider.align_to(chart, lv.ALIGN.OUT_RIGHT_MID, 20, 0)


Show cursor on the clicked point

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_CHART && LV_BUILD_EXAMPLES

static lv_obj_t * chart;
static lv_chart_series_t * ser;
static lv_chart_cursor_t * cursor;

static void event_cb(lv_event_t * e)
{
    static int32_t last_id = -1;
    lv_event_code_t code = lv_event_get_code(e);
    lv_obj_t * obj = lv_event_get_target(e);

    if(code == LV_EVENT_VALUE_CHANGED) {
        last_id = lv_chart_get_pressed_point(obj);
        if(last_id != LV_CHART_POINT_NONE) {
            lv_chart_set_cursor_point(obj, cursor, NULL, last_id);
        }
    }
    else if(code == LV_EVENT_DRAW_PART_END) {
        lv_obj_draw_part_dsc_t * dsc = lv_event_get_draw_part_dsc(e);
        if(!lv_obj_draw_part_check_type(dsc, &lv_chart_class, LV_CHART_DRAW_PART_CURSOR)) return;
        if(dsc->p1 == NULL || dsc->p2 == NULL || dsc->p1->y != dsc->p2->y || last_id < 0) return;

        lv_coord_t * data_array = lv_chart_get_y_array(chart, ser);
        lv_coord_t v = data_array[last_id];
        char buf[16];
        lv_snprintf(buf, sizeof(buf), "%d", v);

        lv_point_t size;
        lv_txt_get_size(&size, buf, LV_FONT_DEFAULT, 0, 0, LV_COORD_MAX, LV_TEXT_FLAG_NONE);

        lv_area_t a;
        a.y2 = dsc->p1->y - 5;
        a.y1 = a.y2 - size.y - 10;
        a.x1 = dsc->p1->x + 10;
        a.x2 = a.x1 + size.x + 10;

        lv_draw_rect_dsc_t draw_rect_dsc;
        lv_draw_rect_dsc_init(&draw_rect_dsc);
        draw_rect_dsc.bg_color = lv_palette_main(LV_PALETTE_BLUE);
        draw_rect_dsc.radius = 3;

        lv_draw_rect(dsc->draw_ctx, &draw_rect_dsc, &a);

        lv_draw_label_dsc_t draw_label_dsc;
        lv_draw_label_dsc_init(&draw_label_dsc);
        draw_label_dsc.color = lv_color_white();
        a.x1 += 5;
        a.x2 -= 5;
        a.y1 += 5;
        a.y2 -= 5;
        lv_draw_label(dsc->draw_ctx, &draw_label_dsc, &a, buf, NULL);
    }
}

/**
 * Show cursor on the clicked point
 */
void lv_example_chart_6(void)
{
    chart = lv_chart_create(lv_scr_act());
    lv_obj_set_size(chart, 200, 150);
    lv_obj_align(chart, LV_ALIGN_CENTER, 0, -10);

    lv_chart_set_axis_tick(chart, LV_CHART_AXIS_PRIMARY_Y, 10, 5, 6, 5, true, 40);
    lv_chart_set_axis_tick(chart, LV_CHART_AXIS_PRIMARY_X, 10, 5, 10, 1, true, 30);

    lv_obj_add_event_cb(chart, event_cb, LV_EVENT_ALL, NULL);
    lv_obj_refresh_ext_draw_size(chart);

    cursor = lv_chart_add_cursor(chart, lv_palette_main(LV_PALETTE_BLUE), LV_DIR_LEFT | LV_DIR_BOTTOM);

    ser = lv_chart_add_series(chart, lv_palette_main(LV_PALETTE_RED), LV_CHART_AXIS_PRIMARY_Y);
    uint32_t i;
    for(i = 0; i < 10; i++) {
        lv_chart_set_next_value(chart, ser, lv_rand(10,90));
    }

    lv_chart_set_zoom_x(chart, 500);

    lv_obj_t * label = lv_label_create(lv_scr_act());
    lv_label_set_text(label, "Click on a point");
    lv_obj_align_to(label, chart, LV_ALIGN_OUT_TOP_MID, 0, -5);
}

#endif

MicroPython code  

 GitHub Simulator
class ExampleChart_6():
    
    def __init__(self):
        self.last_id = -1
        #
        # Show cursor on the clicked point
        #

        chart = lv.chart(lv.scr_act())
        chart.set_size(200, 150)
        chart.align(lv.ALIGN.CENTER, 0, -10)
        
        chart.set_axis_tick(lv.chart.AXIS.PRIMARY_Y, 10, 5, 6, 5, True, 40)
        chart.set_axis_tick(lv.chart.AXIS.PRIMARY_X, 10, 5, 10, 1, True, 30)
        
        chart.add_event_cb(self.event_cb, lv.EVENT.ALL, None)
        chart.refresh_ext_draw_size()
        
        self.cursor = chart.add_cursor(lv.palette_main(lv.PALETTE.BLUE), lv.DIR.LEFT | lv.DIR.BOTTOM)
        
        self.ser = chart.add_series(lv.palette_main(lv.PALETTE.RED), lv.chart.AXIS.PRIMARY_Y)

        self.ser_p = []
        for i in range(10):
            self.ser_p.append(lv.rand(10,90))
        self.ser.y_points = self.ser_p                     

        newser = chart.get_series_next(None)
        # print("length of data points: ",len(newser.points))
        chart.set_zoom_x(500)

        label = lv.label(lv.scr_act())
        label.set_text("Click on a point")
        label.align_to(chart, lv.ALIGN.OUT_TOP_MID, 0, -5)
        
        
    def event_cb(self,e):

        code = e.get_code()
        chart = e.get_target()

        if code == lv.EVENT.VALUE_CHANGED:
            # print("last_id: ",self.last_id)
            self.last_id = chart.get_pressed_point()
            if self.last_id != lv.CHART_POINT.NONE:
                p = lv.point_t()
                chart.get_point_pos_by_id(self.ser, self.last_id, p)
                chart.set_cursor_point(self.cursor, None, self.last_id)
                
        elif code == lv.EVENT.DRAW_PART_END:
            # print("EVENT.DRAW_PART_END")
            dsc = lv.obj_draw_part_dsc_t.__cast__(e.get_param())
            # if dsc.p1 and dsc.p2:
                # print("p1, p2", dsc.p1,dsc.p2)
                # print("p1.y, p2.y", dsc.p1.y, dsc.p2.y)
                # print("last_id: ",self.last_id)
            if dsc.part == lv.PART.CURSOR and dsc.p1 and dsc.p2 and dsc.p1.y == dsc.p2.y and self.last_id >= 0:

                v = self.ser_p[self.last_id]
     
                # print("value: ",v)
                value_txt = str(v)
                size = lv.point_t()
                lv.txt_get_size(size, value_txt, lv.font_default(), 0, 0, lv.COORD.MAX, lv.TEXT_FLAG.NONE)
                
                a = lv.area_t()
                a.y2 = dsc.p1.y - 5
                a.y1 = a.y2 - size.y - 10
                a.x1 = dsc.p1.x + 10
                a.x2 = a.x1 + size.x + 10
                
                draw_rect_dsc = lv.draw_rect_dsc_t()
                draw_rect_dsc.init()
                draw_rect_dsc.bg_color = lv.palette_main(lv.PALETTE.BLUE)
                draw_rect_dsc.radius = 3
                
                lv.draw_rect(a, dsc.clip_area, draw_rect_dsc)
                
                draw_label_dsc = lv.draw_label_dsc_t()
                draw_label_dsc.init()
                draw_label_dsc.color = lv.color_white()
                a.x1 += 5
                a.x2 -= 5
                a.y1 += 5
                a.y2 -= 5
                lv.draw_label(a, dsc.clip_area, draw_label_dsc, value_txt, None)

example_chart_6 = ExampleChart_6()

Scatter chart

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_CHART && LV_BUILD_EXAMPLES

static void draw_event_cb(lv_event_t * e)
{
    lv_obj_draw_part_dsc_t * dsc = lv_event_get_draw_part_dsc(e);
    if(dsc->part == LV_PART_ITEMS) {
        lv_obj_t * obj = lv_event_get_target(e);
        lv_chart_series_t * ser = lv_chart_get_series_next(obj, NULL);
        uint32_t cnt = lv_chart_get_point_count(obj);
        /*Make older value more transparent*/
        dsc->rect_dsc->bg_opa = (LV_OPA_COVER *  dsc->id) / (cnt - 1);

        /*Make smaller values blue, higher values red*/
        lv_coord_t * x_array = lv_chart_get_x_array(obj, ser);
        lv_coord_t * y_array = lv_chart_get_y_array(obj, ser);
        /*dsc->id is the tells drawing order, but we need the ID of the point being drawn.*/
        uint32_t start_point = lv_chart_get_x_start_point(obj, ser);
        uint32_t p_act = (start_point + dsc->id) % cnt; /*Consider start point to get the index of the array*/
        lv_opa_t x_opa = (x_array[p_act] * LV_OPA_50) / 200;
        lv_opa_t y_opa = (y_array[p_act] * LV_OPA_50) / 1000;

        dsc->rect_dsc->bg_color = lv_color_mix(lv_palette_main(LV_PALETTE_RED),
                                                lv_palette_main(LV_PALETTE_BLUE),
                                                x_opa + y_opa);
    }
}

static void add_data(lv_timer_t * timer)
{
    LV_UNUSED(timer);
    lv_obj_t * chart = timer->user_data;
    lv_chart_set_next_value2(chart, lv_chart_get_series_next(chart, NULL), lv_rand(0,200), lv_rand(0,1000));
}

/**
 * A scatter chart
 */
void lv_example_chart_7(void)
{
    lv_obj_t * chart = lv_chart_create(lv_scr_act());
    lv_obj_set_size(chart, 200, 150);
    lv_obj_align(chart, LV_ALIGN_CENTER, 0, 0);
    lv_obj_add_event_cb(chart, draw_event_cb, LV_EVENT_DRAW_PART_BEGIN, NULL);
    lv_obj_set_style_line_width(chart, 0, LV_PART_ITEMS);   /*Remove the lines*/

    lv_chart_set_type(chart, LV_CHART_TYPE_SCATTER);

    lv_chart_set_axis_tick(chart, LV_CHART_AXIS_PRIMARY_X, 5, 5, 5, 1, true, 30);
    lv_chart_set_axis_tick(chart, LV_CHART_AXIS_PRIMARY_Y, 10, 5, 6, 5, true, 50);

    lv_chart_set_range(chart, LV_CHART_AXIS_PRIMARY_X, 0, 200);
    lv_chart_set_range(chart, LV_CHART_AXIS_PRIMARY_Y, 0, 1000);

    lv_chart_set_point_count(chart, 50);

    lv_chart_series_t * ser = lv_chart_add_series(chart, lv_palette_main(LV_PALETTE_RED), LV_CHART_AXIS_PRIMARY_Y);
    uint32_t i;
    for(i = 0; i < 50; i++) {
        lv_chart_set_next_value2(chart, ser, lv_rand(0, 200), lv_rand(0, 1000));
    }

    lv_timer_create(add_data, 100, chart);
}

#endif

MicroPython code  

 GitHub Simulator
#!/opt/bin/lv_micropython -i
import utime as time
import lvgl as lv
import display_driver

def draw_event_cb(e):
    dsc = e.get_draw_part_dsc()
    if dsc.part == lv.PART.ITEMS:
        obj = e.get_target()
        ser = obj.get_series_next(None)
        cnt = obj.get_point_count()
        # print("cnt: ",cnt)
        # Make older value more transparent
        dsc.rect_dsc.bg_opa = (lv.OPA.COVER *  dsc.id) // (cnt - 1)
        
        # Make smaller values blue, higher values red
        # x_array = chart.get_x_array(ser)
        # y_array = chart.get_y_array(ser)
        # dsc->id is the tells drawing order, but we need the ID of the point being drawn.
        start_point = chart.get_x_start_point(ser)
        # print("start point: ",start_point)
        p_act = (start_point + dsc.id) % cnt # Consider start point to get the index of the array
        # print("p_act", p_act)
        x_opa = (x_array[p_act] * lv.OPA._50) // 200
        y_opa = (y_array[p_act] * lv.OPA._50) // 1000
        
        dsc.rect_dsc.bg_color = lv.palette_main(lv.PALETTE.RED).color_mix(
                                             lv.palette_main(lv.PALETTE.BLUE),
                                             x_opa + y_opa)
        
def add_data(timer,chart):
    # print("add_data")
    x = lv.rand(0,200)
    y = lv.rand(0,1000)
    chart.set_next_value2(ser, x, y)
    # chart.set_next_value2(chart.gx, y)
    x_array.pop(0)
    x_array.append(x)
    y_array.pop(0)
    y_array.append(y)
    
#
# A scatter chart
#

chart = lv.chart(lv.scr_act())
chart.set_size(200, 150)
chart.align(lv.ALIGN.CENTER, 0, 0)
chart.add_event_cb(draw_event_cb, lv.EVENT.DRAW_PART_BEGIN, None)
chart.set_style_line_width(0, lv.PART.ITEMS)   # Remove the lines

chart.set_type(lv.chart.TYPE.SCATTER)

chart.set_axis_tick(lv.chart.AXIS.PRIMARY_X, 5, 5, 5, 1, True, 30)
chart.set_axis_tick(lv.chart.AXIS.PRIMARY_Y, 10, 5, 6, 5, True, 50)

chart.set_range(lv.chart.AXIS.PRIMARY_X, 0, 200)
chart.set_range(lv.chart.AXIS.PRIMARY_Y, 0, 1000)

chart.set_point_count(50)

ser = chart.add_series(lv.palette_main(lv.PALETTE.RED), lv.chart.AXIS.PRIMARY_Y)

x_array = []
y_array = []
for i in range(50):
    x_array.append(lv.rand(0, 200))
    y_array.append(lv.rand(0, 1000))
                        
ser.x_points = x_array
ser.y_points = y_array

# Create an `lv_timer` to update the chart.

timer = lv.timer_create_basic()
timer.set_period(100)
timer.set_cb(lambda src: add_data(timer,chart))

Stacked area chart

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_CHART && LV_DRAW_COMPLEX && LV_BUILD_EXAMPLES

/*  A struct is used to keep track of the series list because later we need to draw to the series in the reverse order to which they were initialised. */
typedef struct
{
    lv_obj_t *obj;
    lv_chart_series_t *series_list[3];
} stacked_area_chart_t;

static stacked_area_chart_t stacked_area_chart;

/**
 * Callback which draws the blocks of colour under the lines
 **/
static void draw_event_cb(lv_event_t *e)
{
    lv_obj_t *obj = lv_event_get_target(e);

    /*Add the faded area before the lines are drawn*/
    lv_obj_draw_part_dsc_t *dsc = lv_event_get_draw_part_dsc(e);
    if (dsc->part == LV_PART_ITEMS)
    {
        if (!dsc->p1 || !dsc->p2)
            return;

        /*Add a line mask that keeps the area below the line*/
        lv_draw_mask_line_param_t line_mask_param;
        lv_draw_mask_line_points_init(&line_mask_param, dsc->p1->x, dsc->p1->y, dsc->p2->x, dsc->p2->y, LV_DRAW_MASK_LINE_SIDE_BOTTOM);
        int16_t line_mask_id = lv_draw_mask_add(&line_mask_param, NULL);

        /*Draw a rectangle that will be affected by the mask*/
        lv_draw_rect_dsc_t draw_rect_dsc;
        lv_draw_rect_dsc_init(&draw_rect_dsc);
        draw_rect_dsc.bg_opa = LV_OPA_COVER;
        draw_rect_dsc.bg_color = dsc->line_dsc->color;

        lv_area_t a;
        a.x1 = dsc->p1->x;
        a.x2 = dsc->p2->x;
        a.y1 = LV_MIN(dsc->p1->y, dsc->p2->y);
        a.y2 = obj->coords.y2 - 13; /* -13 cuts off where the rectangle draws over the chart margin. Without this an area of 0 doesn't look like 0 */
        lv_draw_rect(dsc->draw_ctx, &draw_rect_dsc, &a);

        /*Remove the mask*/
        lv_draw_mask_free_param(&line_mask_param);
        lv_draw_mask_remove_id(line_mask_id);
    }
}

/**
 * Helper function to round a fixed point number
 **/
static int32_t round_fixed_point(int32_t n, int8_t shift)
{
    /* Create a bitmask to isolates the decimal part of the fixed point number */
    int32_t mask = 1;
    for (int32_t bit_pos = 0; bit_pos < shift; bit_pos++)
    {
        mask = (mask << 1) + 1;
    }

    int32_t decimal_part = n & mask;

    /* Get 0.5 as fixed point */
    int32_t rounding_boundary = 1 << (shift - 1);

    /* Return either the integer part of n or the integer part + 1 */
    return (decimal_part < rounding_boundary) ? (n & ~mask) : ((n >> shift) + 1) << shift;
}

/**
 * Stacked area chart
 */
void lv_example_chart_8(void)
{
    /*Create a stacked_area_chart.obj*/
    stacked_area_chart.obj = lv_chart_create(lv_scr_act());
    lv_obj_set_size(stacked_area_chart.obj, 200, 150);
    lv_obj_center(stacked_area_chart.obj);
    lv_chart_set_type(stacked_area_chart.obj, LV_CHART_TYPE_LINE);
    lv_chart_set_div_line_count(stacked_area_chart.obj, 5, 7);
    lv_obj_add_event_cb(stacked_area_chart.obj, draw_event_cb, LV_EVENT_DRAW_PART_BEGIN, NULL);

    /* Set range to 0 to 100 for percentages. Draw ticks */
    lv_chart_set_range(stacked_area_chart.obj,LV_CHART_AXIS_PRIMARY_Y,0,100);
    lv_chart_set_axis_tick(stacked_area_chart.obj, LV_CHART_AXIS_PRIMARY_Y, 3, 0, 5, 1, true, 30);

    /*Set point size to 0 so the lines are smooth */
    lv_obj_set_style_size(stacked_area_chart.obj, 0, LV_PART_INDICATOR);

    /*Add some data series*/
    stacked_area_chart.series_list[0] = lv_chart_add_series(stacked_area_chart.obj, lv_palette_main(LV_PALETTE_RED), LV_CHART_AXIS_PRIMARY_Y);
    stacked_area_chart.series_list[1] = lv_chart_add_series(stacked_area_chart.obj, lv_palette_main(LV_PALETTE_BLUE), LV_CHART_AXIS_PRIMARY_Y);
    stacked_area_chart.series_list[2] = lv_chart_add_series(stacked_area_chart.obj, lv_palette_main(LV_PALETTE_GREEN), LV_CHART_AXIS_PRIMARY_Y);

    for (int point = 0; point < 10; point++)
    {
        /* Make some random data */
        uint32_t vals[3] = {lv_rand(10, 20), lv_rand(20, 30), lv_rand(20, 30)};

        int8_t fixed_point_shift = 5;
        uint32_t total = vals[0] + vals[1] + vals[2];
        uint32_t draw_heights[3];
        uint32_t int_sum = 0;
        uint32_t decimal_sum = 0;

        /* Fixed point cascade rounding ensures percentages add to 100 */
        for (int32_t series_index = 0; series_index < 3; series_index++)
        {
            decimal_sum += (((vals[series_index] * 100) << fixed_point_shift) / total);
            int_sum += (vals[series_index] * 100) / total;

            int32_t modifier = (round_fixed_point(decimal_sum, fixed_point_shift) >> fixed_point_shift) - int_sum;

            /*  The draw heights are equal to the percentage of the total each value is + the cumulative sum of the previous percentages.
                The accumulation is how the values get "stacked" */
            draw_heights[series_index] = int_sum + modifier;

            /*  Draw to the series in the reverse order to which they were initialised.
                Without this the higher values will draw on top of the lower ones.
                This is because the Z-height of a series matches the order it was initialised */
            lv_chart_set_next_value(stacked_area_chart.obj, stacked_area_chart.series_list[3 - series_index - 1], draw_heights[series_index]);
        }
    }

    lv_chart_refresh(stacked_area_chart.obj);
}

#endif

MicroPython code  

 GitHub Simulator
import display_driver
import lvgl as lv

# A class is used to keep track of the series list because later we
#  need to draw to the series in the reverse order to which they were initialised.
class StackedAreaChart:
    def __init__(self):
        self.obj = None
        self.series_list = [None, None, None]

stacked_area_chart = StackedAreaChart()

#
# Callback which draws the blocks of colour under the lines
#
def draw_event_cb(e):

    obj = e.get_target()
    cont_a = lv.area_t()
    obj.get_coords(cont_a)

    #Add the faded area before the lines are drawn
    dsc = e.get_draw_part_dsc()
    if dsc.part == lv.PART.ITEMS:
        if not dsc.p1 or not dsc.p2:
            return

        # Add a line mask that keeps the area below the line
        line_mask_param = lv.draw_mask_line_param_t()
        line_mask_param.points_init(dsc.p1.x, dsc.p1.y, dsc.p2.x, dsc.p2.y, lv.DRAW_MASK_LINE_SIDE.BOTTOM)
        line_mask_id = lv.draw_mask_add(line_mask_param, None)

        #Draw a rectangle that will be affected by the mask
        draw_rect_dsc = lv.draw_rect_dsc_t()
        draw_rect_dsc.init()
        draw_rect_dsc.bg_opa = lv.OPA.COVER
        draw_rect_dsc.bg_color = dsc.line_dsc.color

        a = lv.area_t()
        a.x1 = dsc.p1.x
        a.x2 = dsc.p2.x
        a.y1 = min(dsc.p1.y, dsc.p2.y)
        a.y2 = cont_a.y2 - 13 # -13 cuts off where the rectangle draws over the chart margin. Without this an area of 0 doesn't look like 0
        dsc.draw_ctx.rect(draw_rect_dsc, a)

        # Remove the mask
        lv.draw_mask_free_param(line_mask_param)
        lv.draw_mask_remove_id(line_mask_id)


#
# Helper function to round a fixed point number
#
def round_fixed_point(n, shift):
    # Create a bitmask to isolates the decimal part of the fixed point number
    mask = 1
    for bit_pos in range(shift):
        mask = (mask << 1) + 1

    decimal_part = n & mask

    # Get 0.5 as fixed point
    rounding_boundary = 1 << (shift - 1)

    # Return either the integer part of n or the integer part + 1
    if decimal_part < rounding_boundary:
        return (n & ~mask)
    return ((n >> shift) + 1) << shift


#
# Stacked area chart
#
def lv_example_chart_8():

    #Create a stacked_area_chart.obj
    stacked_area_chart.obj = lv.chart(lv.scr_act())
    stacked_area_chart.obj.set_size(200, 150)
    stacked_area_chart.obj.center()
    stacked_area_chart.obj.set_type( lv.chart.TYPE.LINE)
    stacked_area_chart.obj.set_div_line_count(5, 7)
    stacked_area_chart.obj.add_event_cb( draw_event_cb, lv.EVENT.DRAW_PART_BEGIN, None)

    # Set range to 0 to 100 for percentages. Draw ticks 
    stacked_area_chart.obj.set_range(lv.chart.AXIS.PRIMARY_Y,0,100)
    stacked_area_chart.obj.set_axis_tick(lv.chart.AXIS.PRIMARY_Y, 3, 0, 5, 1, True, 30)

    #Set point size to 0 so the lines are smooth
    stacked_area_chart.obj.set_style_size(0, lv.PART.INDICATOR)

    # Add some data series
    stacked_area_chart.series_list[0] = stacked_area_chart.obj.add_series(lv.palette_main(lv.PALETTE.RED), lv.chart.AXIS.PRIMARY_Y)
    stacked_area_chart.series_list[1] = stacked_area_chart.obj.add_series(lv.palette_main(lv.PALETTE.BLUE), lv.chart.AXIS.PRIMARY_Y)
    stacked_area_chart.series_list[2] = stacked_area_chart.obj.add_series(lv.palette_main(lv.PALETTE.GREEN), lv.chart.AXIS.PRIMARY_Y)

    for point in range(10):
        # Make some random data
        vals = [lv.rand(10, 20), lv.rand(20, 30), lv.rand(20, 30)]

        fixed_point_shift = 5
        total = vals[0] + vals[1] + vals[2]
        draw_heights = [0, 0, 0]
        int_sum = 0
        decimal_sum = 0

        # Fixed point cascade rounding ensures percentages add to 100
        for series_index in range(3):
            decimal_sum += int(((vals[series_index] * 100) << fixed_point_shift) // total)
            int_sum += int((vals[series_index] * 100) / total)

            modifier = (round_fixed_point(decimal_sum, fixed_point_shift) >> fixed_point_shift) - int_sum

            #  The draw heights are equal to the percentage of the total each value is + the cumulative sum of the previous percentages.
            #   The accumulation is how the values get "stacked"
            draw_heights[series_index] = int(int_sum + modifier)

            #  Draw to the series in the reverse order to which they were initialised.
            #   Without this the higher values will draw on top of the lower ones.
            #   This is because the Z-height of a series matches the order it was initialised
            stacked_area_chart.obj.set_next_value( stacked_area_chart.series_list[3 - series_index - 1], draw_heights[series_index])

    stacked_area_chart.obj.refresh()

lv_example_chart_8()

Checkbox

Simple Checkboxes

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_CHECKBOX && LV_BUILD_EXAMPLES

static void event_handler(lv_event_t * e)
{
    lv_event_code_t code = lv_event_get_code(e);
    lv_obj_t * obj = lv_event_get_target(e);
    if(code == LV_EVENT_VALUE_CHANGED) {
        const char * txt = lv_checkbox_get_text(obj);
        const char * state = lv_obj_get_state(obj) & LV_STATE_CHECKED ? "Checked" : "Unchecked";
        LV_LOG_USER("%s: %s", txt, state);
    }
}

void lv_example_checkbox_1(void)
{
    lv_obj_set_flex_flow(lv_scr_act(), LV_FLEX_FLOW_COLUMN);
    lv_obj_set_flex_align(lv_scr_act(), LV_FLEX_ALIGN_CENTER, LV_FLEX_ALIGN_START, LV_FLEX_ALIGN_CENTER);

    lv_obj_t * cb;
    cb = lv_checkbox_create(lv_scr_act());
    lv_checkbox_set_text(cb, "Apple");
    lv_obj_add_event_cb(cb, event_handler, LV_EVENT_ALL, NULL);

    cb = lv_checkbox_create(lv_scr_act());
    lv_checkbox_set_text(cb, "Banana");
    lv_obj_add_state(cb, LV_STATE_CHECKED);
    lv_obj_add_event_cb(cb, event_handler, LV_EVENT_ALL, NULL);

    cb = lv_checkbox_create(lv_scr_act());
    lv_checkbox_set_text(cb, "Lemon");
    lv_obj_add_state(cb, LV_STATE_DISABLED);
    lv_obj_add_event_cb(cb, event_handler, LV_EVENT_ALL, NULL);

    cb = lv_checkbox_create(lv_scr_act());
    lv_obj_add_state(cb, LV_STATE_CHECKED | LV_STATE_DISABLED);
    lv_checkbox_set_text(cb, "Melon\nand a new line");
    lv_obj_add_event_cb(cb, event_handler, LV_EVENT_ALL, NULL);

    lv_obj_update_layout(cb);
}

#endif

MicroPython code  

 GitHub Simulator
def event_handler(e):
    code = e.get_code()
    obj = e.get_target()
    if code == lv.EVENT.VALUE_CHANGED:
        txt = obj.get_text()
        if obj.get_state() & lv.STATE.CHECKED:
            state = "Checked"
        else:
            state = "Unchecked"
        print(txt + ":" + state)


lv.scr_act().set_flex_flow(lv.FLEX_FLOW.COLUMN)
lv.scr_act().set_flex_align(lv.FLEX_ALIGN.CENTER, lv.FLEX_ALIGN.START, lv.FLEX_ALIGN.CENTER)

cb = lv.checkbox(lv.scr_act())
cb.set_text("Apple")
cb.add_event_cb(event_handler, lv.EVENT.ALL, None)

cb = lv.checkbox(lv.scr_act())
cb.set_text("Banana")
cb.add_state(lv.STATE.CHECKED)
cb.add_event_cb(event_handler, lv.EVENT.ALL, None)

cb = lv.checkbox(lv.scr_act())
cb.set_text("Lemon")
cb.add_state(lv.STATE.DISABLED)
cb.add_event_cb(event_handler, lv.EVENT.ALL, None)

cb = lv.checkbox(lv.scr_act())
cb.add_state(lv.STATE.CHECKED | lv.STATE.DISABLED)
cb.set_text("Melon")
cb.add_event_cb(event_handler, lv.EVENT.ALL, None)

cb.update_layout()


Checkboxes as radio buttons

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_CHECKBOX && LV_BUILD_EXAMPLES

static lv_style_t style_radio;
static lv_style_t style_radio_chk;
static uint32_t active_index_1 = 0;
static uint32_t active_index_2 = 0;

static void radio_event_handler(lv_event_t * e)
{
    uint32_t * active_id = lv_event_get_user_data(e);
    lv_obj_t * cont = lv_event_get_current_target(e);
    lv_obj_t * act_cb = lv_event_get_target(e);
    lv_obj_t * old_cb = lv_obj_get_child(cont, *active_id);

    /*Do nothing if the container was clicked*/
    if(act_cb == cont) return;

    lv_obj_clear_state(old_cb, LV_STATE_CHECKED);   /*Uncheck the previous radio button*/
    lv_obj_add_state(act_cb, LV_STATE_CHECKED);     /*Uncheck the current radio button*/

    *active_id = lv_obj_get_index(act_cb);

    LV_LOG_USER("Selected radio buttons: %d, %d", (int)active_index_1, (int)active_index_2);
}


static void radiobutton_create(lv_obj_t * parent, const char * txt)
{
    lv_obj_t * obj = lv_checkbox_create(parent);
    lv_checkbox_set_text(obj, txt);
    lv_obj_add_flag(obj, LV_OBJ_FLAG_EVENT_BUBBLE);
    lv_obj_add_style(obj, &style_radio, LV_PART_INDICATOR);
    lv_obj_add_style(obj, &style_radio_chk, LV_PART_INDICATOR | LV_STATE_CHECKED);
}

/**
 * Checkboxes as radio buttons
 */
void lv_example_checkbox_2(void)
{
    /* The idea is to enable `LV_OBJ_FLAG_EVENT_BUBBLE` on checkboxes and process the
     * `LV_EVENT_CLICKED` on the container.
     * A variable is passed as event user data where the index of the active
     * radiobutton is saved */


    lv_style_init(&style_radio);
    lv_style_set_radius(&style_radio, LV_RADIUS_CIRCLE);

    lv_style_init(&style_radio_chk);
    lv_style_set_bg_img_src(&style_radio_chk, NULL);

    uint32_t i;
    char buf[32];

    lv_obj_t * cont1 = lv_obj_create(lv_scr_act());
    lv_obj_set_flex_flow(cont1, LV_FLEX_FLOW_COLUMN);
    lv_obj_set_size(cont1, lv_pct(40), lv_pct(80));
    lv_obj_add_event_cb(cont1, radio_event_handler, LV_EVENT_CLICKED, &active_index_1);

    for (i = 0;i < 5;i++) {
        lv_snprintf(buf, sizeof(buf), "A %d", (int)i + 1);
        radiobutton_create(cont1, buf);

    }
    /*Make the first checkbox checked*/
    lv_obj_add_state(lv_obj_get_child(cont1, 0), LV_STATE_CHECKED);

    lv_obj_t * cont2 = lv_obj_create(lv_scr_act());
    lv_obj_set_flex_flow(cont2, LV_FLEX_FLOW_COLUMN);
    lv_obj_set_size(cont2, lv_pct(40), lv_pct(80));
    lv_obj_set_x(cont2, lv_pct(50));
    lv_obj_add_event_cb(cont2, radio_event_handler, LV_EVENT_CLICKED, &active_index_2);

    for (i = 0;i < 3;i++) {
        lv_snprintf(buf, sizeof(buf), "B %d", (int)i + 1);
        radiobutton_create(cont2, buf);
    }

    /*Make the first checkbox checked*/
    lv_obj_add_state(lv_obj_get_child(cont2, 0), LV_STATE_CHECKED);
}


#endif

MicroPython code  

 GitHub Simulator
Error encountered while trying to open /home/runner/work/100ask_lvgl_docs_8.x/100ask_lvgl_docs_8.x/examples/widgets/checkbox/lv_example_checkbox_2.py

Colorwheel

Simple Colorwheel

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_COLORWHEEL && LV_BUILD_EXAMPLES

void lv_example_colorwheel_1(void)
{
    lv_obj_t * cw;

    cw = lv_colorwheel_create(lv_scr_act(), true);
    lv_obj_set_size(cw, 200, 200);
    lv_obj_center(cw);
}

#endif

MicroPython code  

 GitHub Simulator
cw = lv.colorwheel(lv.scr_act(), True)
cw.set_size(200, 200)
cw.center()


Image

Image from variable and symbol

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_IMG && LV_BUILD_EXAMPLES


void lv_example_img_1(void)
{
    LV_IMG_DECLARE(img_cogwheel_argb);
    lv_obj_t * img1 = lv_img_create(lv_scr_act());
    lv_img_set_src(img1, &img_cogwheel_argb);
    lv_obj_align(img1, LV_ALIGN_CENTER, 0, -20);
    lv_obj_set_size(img1, 200, 200);

    lv_obj_t * img2 = lv_img_create(lv_scr_act());
    lv_img_set_src(img2, LV_SYMBOL_OK "Accept");
    lv_obj_align_to(img2, img1, LV_ALIGN_OUT_BOTTOM_MID, 0, 20);
}

#endif

MicroPython code  

 GitHub Simulator
#!/opt/bin/lv_micropython -i
import usys as sys
import lvgl as lv
import display_driver
from imagetools import get_png_info, open_png

# Register PNG image decoder
decoder = lv.img.decoder_create()
decoder.info_cb = get_png_info
decoder.open_cb = open_png

# Create an image from the png file
try:
    with open('../../assets/img_cogwheel_argb.png','rb') as f:
        png_data = f.read()
except:
    print("Could not find img_cogwheel_argb.png")
    sys.exit()
    
img_cogwheel_argb = lv.img_dsc_t({
  'data_size': len(png_data),
  'data': png_data 
})

img1 = lv.img(lv.scr_act())
img1.set_src(img_cogwheel_argb)
img1.align(lv.ALIGN.CENTER, 0, -20)
img1.set_size(200, 200)

img2 = lv.img(lv.scr_act())
img2.set_src(lv.SYMBOL.OK + "Accept")
img2.align_to(img1, lv.ALIGN.OUT_BOTTOM_MID, 0, 20)

Image recoloring

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_IMG && LV_USE_SLIDER && LV_BUILD_EXAMPLES

static lv_obj_t * create_slider(lv_color_t color);
static void slider_event_cb(lv_event_t * e);

static lv_obj_t * red_slider, * green_slider, * blue_slider, * intense_slider;
static lv_obj_t * img1;


/**
 * Demonstrate runtime image re-coloring
 */
void lv_example_img_2(void)
{
    /*Create 4 sliders to adjust RGB color and re-color intensity*/
    red_slider = create_slider(lv_palette_main(LV_PALETTE_RED));
    green_slider = create_slider(lv_palette_main(LV_PALETTE_GREEN));
    blue_slider = create_slider(lv_palette_main(LV_PALETTE_BLUE));
    intense_slider = create_slider(lv_palette_main(LV_PALETTE_GREY));

    lv_slider_set_value(red_slider, LV_OPA_20, LV_ANIM_OFF);
    lv_slider_set_value(green_slider, LV_OPA_90, LV_ANIM_OFF);
    lv_slider_set_value(blue_slider, LV_OPA_60, LV_ANIM_OFF);
    lv_slider_set_value(intense_slider, LV_OPA_50, LV_ANIM_OFF);

    lv_obj_align(red_slider, LV_ALIGN_LEFT_MID, 25, 0);
    lv_obj_align_to(green_slider, red_slider, LV_ALIGN_OUT_RIGHT_MID, 25, 0);
    lv_obj_align_to(blue_slider, green_slider, LV_ALIGN_OUT_RIGHT_MID, 25, 0);
    lv_obj_align_to(intense_slider, blue_slider, LV_ALIGN_OUT_RIGHT_MID, 25, 0);

    /*Now create the actual image*/
    LV_IMG_DECLARE(img_cogwheel_argb)
    img1 = lv_img_create(lv_scr_act());
    lv_img_set_src(img1, &img_cogwheel_argb);
    lv_obj_align(img1, LV_ALIGN_RIGHT_MID, -20, 0);

    lv_event_send(intense_slider, LV_EVENT_VALUE_CHANGED, NULL);
}

static void slider_event_cb(lv_event_t * e)
{
    LV_UNUSED(e);

    /*Recolor the image based on the sliders' values*/
    lv_color_t color  = lv_color_make(lv_slider_get_value(red_slider), lv_slider_get_value(green_slider), lv_slider_get_value(blue_slider));
    lv_opa_t intense = lv_slider_get_value(intense_slider);
    lv_obj_set_style_img_recolor_opa(img1, intense, 0);
    lv_obj_set_style_img_recolor(img1, color, 0);
}

static lv_obj_t * create_slider(lv_color_t color)
{
    lv_obj_t * slider = lv_slider_create(lv_scr_act());
    lv_slider_set_range(slider, 0, 255);
    lv_obj_set_size(slider, 10, 200);
    lv_obj_set_style_bg_color(slider, color, LV_PART_KNOB);
    lv_obj_set_style_bg_color(slider, lv_color_darken(color, LV_OPA_40), LV_PART_INDICATOR);
    lv_obj_add_event_cb(slider, slider_event_cb, LV_EVENT_VALUE_CHANGED, NULL);
    return slider;
}

#endif

MicroPython code  

 GitHub Simulator
#!/opt/bin/lv_micropython -i
import usys as sys
import lvgl as lv
import display_driver
from imagetools import get_png_info, open_png

# Register PNG image decoder
decoder = lv.img.decoder_create()
decoder.info_cb = get_png_info
decoder.open_cb = open_png

# Create an image from the png file
try:
    with open('../../assets/img_cogwheel_argb.png','rb') as f:
        png_data = f.read()
except:
    print("Could not find img_cogwheel_argb.png")
    sys.exit()
    
img_cogwheel_argb = lv.img_dsc_t({
  'data_size': len(png_data),
  'data': png_data 
})

def create_slider(color):
    slider = lv.slider(lv.scr_act())
    slider.set_range(0, 255)
    slider.set_size(10, 200)
    slider.set_style_bg_color(color, lv.PART.KNOB)
    slider.set_style_bg_color(color.color_darken(lv.OPA._40), lv.PART.INDICATOR)
    slider.add_event_cb(slider_event_cb, lv.EVENT.VALUE_CHANGED, None)
    return slider

def slider_event_cb(e):
    # Recolor the image based on the sliders' values
    color  = lv.color_make(red_slider.get_value(), green_slider.get_value(), blue_slider.get_value())
    intense = intense_slider.get_value()
    img1.set_style_img_recolor_opa(intense, 0)
    img1.set_style_img_recolor(color, 0)
    
#
# Demonstrate runtime image re-coloring
#
# Create 4 sliders to adjust RGB color and re-color intensity
red_slider = create_slider(lv.palette_main(lv.PALETTE.RED))
green_slider = create_slider(lv.palette_main(lv.PALETTE.GREEN))
blue_slider = create_slider(lv.palette_main(lv.PALETTE.BLUE))
intense_slider = create_slider(lv.palette_main(lv.PALETTE.GREY))

red_slider.set_value(lv.OPA._20, lv.ANIM.OFF)
green_slider.set_value(lv.OPA._90, lv.ANIM.OFF)
blue_slider.set_value(lv.OPA._60, lv.ANIM.OFF)
intense_slider.set_value(lv.OPA._50, lv.ANIM.OFF)

red_slider.align(lv.ALIGN.LEFT_MID, 25, 0)
green_slider.align_to(red_slider, lv.ALIGN.OUT_RIGHT_MID, 25, 0)
blue_slider.align_to(green_slider, lv.ALIGN.OUT_RIGHT_MID, 25, 0)
intense_slider.align_to(blue_slider, lv.ALIGN.OUT_RIGHT_MID, 25, 0)

# Now create the actual image
img1 = lv.img(lv.scr_act())
img1.set_src(img_cogwheel_argb)
img1.align(lv.ALIGN.RIGHT_MID, -20, 0)

lv.event_send(intense_slider, lv.EVENT.VALUE_CHANGED, None)






Rotate and zoom

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_IMG && LV_BUILD_EXAMPLES

static void set_angle(void * img, int32_t v)
{
    lv_img_set_angle(img, v);
}

static void set_zoom(void * img, int32_t v)
{
    lv_img_set_zoom(img, v);
}


/**
 * Show transformations (zoom and rotation) using a pivot point.
 */
void lv_example_img_3(void)
{
    LV_IMG_DECLARE(img_cogwheel_argb);

    /*Now create the actual image*/
    lv_obj_t * img = lv_img_create(lv_scr_act());
    lv_img_set_src(img, &img_cogwheel_argb);
    lv_obj_align(img, LV_ALIGN_CENTER, 50, 50);
    lv_img_set_pivot(img, 0, 0);    /*Rotate around the top left corner*/

    lv_anim_t a;
    lv_anim_init(&a);
    lv_anim_set_var(&a, img);
    lv_anim_set_exec_cb(&a, set_angle);
    lv_anim_set_values(&a, 0, 3600);
    lv_anim_set_time(&a, 5000);
    lv_anim_set_repeat_count(&a, LV_ANIM_REPEAT_INFINITE);
    lv_anim_start(&a);

    lv_anim_set_exec_cb(&a, set_zoom);
    lv_anim_set_values(&a, 128, 256);
    lv_anim_set_playback_time(&a, 3000);
    lv_anim_start(&a);
}

#endif

MicroPython code  

 GitHub Simulator
#!/opt/bin/lv_micropython -i
import usys as sys
import lvgl as lv
import display_driver
from imagetools import get_png_info, open_png

# Register PNG image decoder
decoder = lv.img.decoder_create()
decoder.info_cb = get_png_info
decoder.open_cb = open_png

# Create an image from the png file
try:
    with open('../../assets/img_cogwheel_argb.png','rb') as f:
        png_data = f.read()
except:
    print("Could not find img_cogwheel_argb.png")
    sys.exit()
    
img_cogwheel_argb = lv.img_dsc_t({
  'data_size': len(png_data),
  'data': png_data 
})

def set_angle(img, v):
    img.set_angle(v)

def set_zoom(img, v):
    img.set_zoom(v)


#
# Show transformations (zoom and rotation) using a pivot point.
#

# Now create the actual image
img = lv.img(lv.scr_act())
img.set_src(img_cogwheel_argb)
img.align(lv.ALIGN.CENTER, 50, 50)
img.set_pivot(0, 0)               # Rotate around the top left corner

a1 = lv.anim_t()
a1.init()
a1.set_var(img)
a1.set_custom_exec_cb(lambda a,val: set_angle(img,val))
a1.set_values(0, 3600)
a1.set_time(5000)
a1.set_repeat_count(lv.ANIM_REPEAT.INFINITE)
lv.anim_t.start(a1)

a2 = lv.anim_t()
a2.init()
a2.set_var(img)
a2.set_custom_exec_cb(lambda a,val: set_zoom(img,val))
a2.set_values(128, 256)
a2.set_time(5000)
a2.set_playback_time(3000)
a2.set_repeat_count(lv.ANIM_REPEAT.INFINITE)
lv.anim_t.start(a2)



Image offset and styling

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_IMG && LV_BUILD_EXAMPLES

static void ofs_y_anim(void * img, int32_t v)
{
    lv_img_set_offset_y(img, v);
}

/**
 * Image styling and offset
 */
void lv_example_img_4(void)
{
    LV_IMG_DECLARE(img_skew_strip);

    static lv_style_t style;
    lv_style_init(&style);
    lv_style_set_bg_color(&style, lv_palette_main(LV_PALETTE_YELLOW));
    lv_style_set_bg_opa(&style, LV_OPA_COVER);
    lv_style_set_img_recolor_opa(&style, LV_OPA_COVER);
    lv_style_set_img_recolor(&style, lv_color_black());

    lv_obj_t * img = lv_img_create(lv_scr_act());
    lv_obj_add_style(img, &style, 0);
    lv_img_set_src(img, &img_skew_strip);
    lv_obj_set_size(img, 150, 100);
    lv_obj_center(img);

    lv_anim_t a;
    lv_anim_init(&a);
    lv_anim_set_var(&a, img);
    lv_anim_set_exec_cb(&a, ofs_y_anim);
    lv_anim_set_values(&a, 0, 100);
    lv_anim_set_time(&a, 3000);
    lv_anim_set_playback_time(&a, 500);
    lv_anim_set_repeat_count(&a, LV_ANIM_REPEAT_INFINITE);
    lv_anim_start(&a);

}

#endif

MicroPython code  

 GitHub Simulator
from imagetools import get_png_info, open_png

def ofs_y_anim(img, v):    
    img.set_offset_y(v)
    # print(img,v)
    
# Register PNG image decoder
decoder = lv.img.decoder_create()
decoder.info_cb = get_png_info
decoder.open_cb = open_png

# Create an image from the png file
try:
    with open('../../assets/img_skew_strip.png','rb') as f:
        png_data = f.read()
except:
    print("Could not find img_skew_strip.png")
    sys.exit()
    
img_skew_strip = lv.img_dsc_t({
  'data_size': len(png_data),
  'data': png_data 
})

#
# Image styling and offset
#

style = lv.style_t()
style.init()
style.set_bg_color(lv.palette_main(lv.PALETTE.YELLOW))
style.set_bg_opa(lv.OPA.COVER)
style.set_img_recolor_opa(lv.OPA.COVER)
style.set_img_recolor(lv.color_black())

img = lv.img(lv.scr_act())
img.add_style(style, 0)
img.set_src(img_skew_strip)
img.set_size(150, 100)
img.center()

a = lv.anim_t()
a.init()
a.set_var(img)
a.set_values(0, 100)
a.set_time(3000)
a.set_playback_time(500)
a.set_repeat_count(lv.ANIM_REPEAT.INFINITE)
a.set_custom_exec_cb(lambda a,val: ofs_y_anim(img,val))
lv.anim_t.start(a)


Image button

Simple Image button

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_IMGBTN && LV_BUILD_EXAMPLES

void lv_example_imgbtn_1(void)
{
    LV_IMG_DECLARE(imgbtn_left);
    LV_IMG_DECLARE(imgbtn_right);
    LV_IMG_DECLARE(imgbtn_mid);

    /*Create a transition animation on width transformation and recolor.*/
    static lv_style_prop_t tr_prop[] = {LV_STYLE_TRANSFORM_WIDTH, LV_STYLE_IMG_RECOLOR_OPA, 0};
    static lv_style_transition_dsc_t tr;
    lv_style_transition_dsc_init(&tr, tr_prop, lv_anim_path_linear, 200, 0, NULL);

    static lv_style_t style_def;
    lv_style_init(&style_def);
    lv_style_set_text_color(&style_def, lv_color_white());
    lv_style_set_transition(&style_def, &tr);

    /*Darken the button when pressed and make it wider*/
    static lv_style_t style_pr;
    lv_style_init(&style_pr);
    lv_style_set_img_recolor_opa(&style_pr, LV_OPA_30);
    lv_style_set_img_recolor(&style_pr, lv_color_black());
    lv_style_set_transform_width(&style_pr, 20);

    /*Create an image button*/
    lv_obj_t * imgbtn1 = lv_imgbtn_create(lv_scr_act());
    lv_imgbtn_set_src(imgbtn1, LV_IMGBTN_STATE_RELEASED, &imgbtn_left, &imgbtn_mid, &imgbtn_right);
    lv_obj_add_style(imgbtn1, &style_def, 0);
    lv_obj_add_style(imgbtn1, &style_pr, LV_STATE_PRESSED);

    lv_obj_align(imgbtn1, LV_ALIGN_CENTER, 0, 0);

    /*Create a label on the image button*/
    lv_obj_t * label = lv_label_create(imgbtn1);
    lv_label_set_text(label, "Button");
    lv_obj_align(label, LV_ALIGN_CENTER, 0, -4);
}

#endif

MicroPython code  

 GitHub Simulator
from imagetools import get_png_info, open_png

# Register PNG image decoder
decoder = lv.img.decoder_create()
decoder.info_cb = get_png_info
decoder.open_cb = open_png

# Create an image from the png file
try:
    with open('../../assets/imgbtn_left.png','rb') as f:
        imgbtn_left_data = f.read()
except:
    print("Could not find imgbtn_left.png")
    sys.exit()
    
imgbtn_left_dsc = lv.img_dsc_t({
  'data_size': len(imgbtn_left_data),
  'data': imgbtn_left_data 
})

try:
    with open('../../assets/imgbtn_mid.png','rb') as f:
        imgbtn_mid_data = f.read()
except:
    print("Could not find imgbtn_mid.png")
    sys.exit()
    
imgbtn_mid_dsc = lv.img_dsc_t({
  'data_size': len(imgbtn_mid_data),
  'data': imgbtn_mid_data 
})

try:
    with open('../../assets/imgbtn_right.png','rb') as f:
        imgbtn_right_data = f.read()
except:
    print("Could not find imgbtn_right.png")
    sys.exit()
    
imgbtn_right_dsc = lv.img_dsc_t({
  'data_size': len(imgbtn_right_data),
  'data': imgbtn_right_data 
})

# Create a transition animation on width transformation and recolor.
tr_prop = [lv.STYLE.TRANSFORM_WIDTH, lv.STYLE.IMG_RECOLOR_OPA, 0]
tr = lv.style_transition_dsc_t()
tr.init(tr_prop, lv.anim_t.path_linear, 200, 0, None)

style_def = lv.style_t()
style_def.init()
style_def.set_text_color(lv.color_white())
style_def.set_transition(tr)

# Darken the button when pressed and make it wider
style_pr = lv.style_t()
style_pr.init()
style_pr.set_img_recolor_opa(lv.OPA._30)
style_pr.set_img_recolor(lv.color_black())
style_pr.set_transform_width(20)

# Create an image button
imgbtn1 = lv.imgbtn(lv.scr_act())
imgbtn1.set_src(lv.imgbtn.STATE.RELEASED, imgbtn_left_dsc, imgbtn_mid_dsc, imgbtn_right_dsc)
imgbtn1.add_style(style_def, 0)
imgbtn1.add_style(style_pr, lv.STATE.PRESSED)

imgbtn1.align(lv.ALIGN.CENTER, 0, 0)

# Create a label on the image button
label = lv.label(imgbtn1)
label.set_text("Button")
label.align(lv.ALIGN.CENTER, 0, -4)


Keyboard

Keyboard with text area

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_KEYBOARD && LV_BUILD_EXAMPLES

static void ta_event_cb(lv_event_t * e)
{
    lv_event_code_t code = lv_event_get_code(e);
    lv_obj_t * ta = lv_event_get_target(e);
    lv_obj_t * kb = lv_event_get_user_data(e);
    if(code == LV_EVENT_FOCUSED) {
        lv_keyboard_set_textarea(kb, ta);
        lv_obj_clear_flag(kb, LV_OBJ_FLAG_HIDDEN);
    }

    if(code == LV_EVENT_DEFOCUSED) {
        lv_keyboard_set_textarea(kb, NULL);
        lv_obj_add_flag(kb, LV_OBJ_FLAG_HIDDEN);
    }
}

void lv_example_keyboard_1(void)
{
    /*Create a keyboard to use it with an of the text areas*/
    lv_obj_t *kb = lv_keyboard_create(lv_scr_act());

    /*Create a text area. The keyboard will write here*/
    lv_obj_t * ta;
    ta = lv_textarea_create(lv_scr_act());
    lv_obj_align(ta, LV_ALIGN_TOP_LEFT, 10, 10);
    lv_obj_add_event_cb(ta, ta_event_cb, LV_EVENT_ALL, kb);
    lv_textarea_set_placeholder_text(ta, "Hello");
    lv_obj_set_size(ta, 140, 80);

    ta = lv_textarea_create(lv_scr_act());
    lv_obj_align(ta, LV_ALIGN_TOP_RIGHT, -10, 10);
    lv_obj_add_event_cb(ta, ta_event_cb, LV_EVENT_ALL, kb);
    lv_obj_set_size(ta, 140, 80);

    lv_keyboard_set_textarea(kb, ta);
}
#endif

MicroPython code  

 GitHub Simulator
def ta_event_cb(e,kb):
    code = e.get_code()
    ta = e.get_target()
    if code == lv.EVENT.FOCUSED:
        kb.set_textarea(ta)
        kb.clear_flag(lv.obj.FLAG.HIDDEN)

    if code == lv.EVENT.DEFOCUSED:
        kb.set_textarea(None)
        kb.add_flag(lv.obj.FLAG.HIDDEN)
        
# Create a keyboard to use it with one of the text areas
kb = lv.keyboard(lv.scr_act())

# Create a text area. The keyboard will write here
ta = lv.textarea(lv.scr_act())
ta.set_width(200)
ta.align(lv.ALIGN.TOP_LEFT, 10, 10)
ta.add_event_cb(lambda e: ta_event_cb(e,kb), lv.EVENT.ALL, None)
ta.set_placeholder_text("Hello")

ta = lv.textarea(lv.scr_act())
ta.