Animations（动画）¶

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You can automatically change the value of a variable between a start and an end value using animations. The animation will happen by periodically calling an "animator" function with the corresponding value parameter.

The animator functions have the following prototype:

您可以使用动画在开始值和结束值之间自动更改变量的值。动画将通过使用相应的 value 参数定期调用 “animator” 函数来发生。

animator 函数具有以下原型：

void func(void * var, lv_anim_var_t value);

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This prototype is compatible with the majority of the set functions of LVGL. For example lv_obj_set_x(obj, value) or lv_obj_set_width(obj, value)

该原型与 LVGL 的大多数 set 函数兼容。例如lv_obj_set_x(obj, value) 或lv_obj_set_width(obj, value)

Create an animation（创建动画）¶

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To create an animation an lv_anim_t variable has to be initialized and configured with lv_anim_set_...() functions.

要创建动画，必须使用 lv_anim_set_...() 函数初始化和配置 lv_anim_t 变量。

/* INITIALIZE AN ANIMATION
 *-----------------------*/

lv_anim_t a;
lv_anim_init(&a);

/* MANDATORY SETTINGS
 *------------------*/

/*Set the "animator" function*/
lv_anim_set_exec_cb(&a, (lv_anim_exec_xcb_t) lv_obj_set_x); 

/*Set the "animator" function*/
lv_anim_set_var(&a, obj); 

/*Length of the animation [ms]*/
lv_anim_set_time(&a, duration);

/*Set start and end values. E.g. 0, 150*/
lv_anim_set_values(&a, start, end);

/* OPTIONAL SETTINGS
 *------------------*/

/*Time to wait before starting the animation [ms]*/
lv_anim_set_delay(&a, delay);

/*Set path (curve). Default is linear*/
lv_anim_set_path(&a, lv_anim_path_ease_in);

/*Set a callback to call when animation is ready.*/
lv_anim_set_ready_cb(&a, ready_cb);

/*Set a callback to call when animation is started (after delay).*/
lv_anim_set_start_cb(&a, start_cb);

/*Play the animation backward too with this duration. Default is 0 (disabled) [ms]*/
lv_anim_set_playback_time(&a, wait_time); 

/*Delay before playback. Default is 0 (disabled) [ms]*/
lv_anim_set_playback_delay(&a, wait_time);

/*Number of repetitions. Default is 1.  LV_ANIM_REPEAT_INFINIT for infinite repetition*/
lv_anim_set_repeat_count(&a, wait_time);

/*Delay before repeat. Default is 0 (disabled) [ms]*/
lv_anim_set_repeat_delay(&a, wait_time);

/*true (default): apply the start vale immediately, false: apply start vale after delay when then anim. really starts. */
lv_anim_set_early_apply(&a, true/false);

/* START THE ANIMATION
 *------------------*/
lv_anim_start(&a);                             /*Start the animation*/

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You can apply multiple different animations on the same variable at the same time. For example, animate the x and y coordinates with lv_obj_set_x and lv_obj_set_y. However, only one animation can exist with a given variable and function pair. Therefore lv_anim_start() will delete the already existing variable-function animations.

您可以同时对同一个变量应用多个不同的动画。例如，使用 lv_obj_set_x 和 lv_obj_set_y 为 x 和 y 坐标设置动画。但是，对于给定的变量和函数对，只能存在一个动画。因此lv_anim_start() 将删除已经存在的可变函数动画。

Animation path（动画轨迹）¶

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You can determinate the path of animation. The most simple case is linear, meaning the current value between start and end is changed with fixed steps. A path is a function which calculates the next value to set based on the current state of the animation. Currently, there are the following built-in paths functions:

lv_anim_path_linear linear animation
lv_anim_path_step change in one step at the end
lv_anim_path_ease_in slow at the beginning
lv_anim_path_ease_out slow at the end
lv_anim_path_ease_in_out slow at the beginning and at the end
lv_anim_path_overshoot overshoot the end value
lv_anim_path_bounce bounce back a little from the end value (like hitting a wall)

您可以确定动画的路径。最简单的情况是线性的，这意味着 start 和 end 之间的当前值以固定步长变化。 path 是一个函数，它根据动画的当前状态计算要设置的下一个值。目前，有以下内置路径函数：

lv_anim_path_linear 线性动画
lv_anim_path_step最后一步改变
lv_anim_path_ease_in 开始时很慢
lv_anim_path_ease_out 最后慢
lv_anim_path_ease_in_out 开始和结束都很慢
lv_anim_path_overshoot 超过结束值
lv_anim_path_bounce 从最终值反弹一点（比如撞墙）

Speed vs time（速度与时间）¶

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By default, you set the animation time. But in some cases, setting the animation speed is more practical.

The lv_anim_speed_to_time(speed, start, end) function calculates the required time in milliseconds to reach the end value from a start value with the given speed. The speed is interpreted in unit/sec dimension. For example, lv_anim_speed_to_time(20,0,100) will yield 5000 milliseconds. For example, in case of lv_obj_set_x unit is pixels so 20 means 20 px/sec speed.

默认情况下，您设置动画时间。但在某些情况下，设置动画速度更实用。

lv_anim_speed_to_time(speed, start, end) 函数计算从给定速度的起始值到达结束值所需的时间（以毫秒为单位）。速度以 unit/sec 维度解释。例如，lv_anim_speed_to_time(20,0,100) 将产生 5000 毫秒。例如，在 lv_obj_set_x 的情况下 unit 是像素，所以 20 意味着 20 px/sec 速度。

Delete animations（删除动画）¶

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You can delete an animation with lv_anim_del(var, func) if you provide the animated variable and its animator function.

如果您提供动画变量及其动画器函数，您可以使用 lv_anim_del(var, func) 删除动画。

Timeline（时间线）¶

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Timeline is a collection of multiple Animations, which makes it easy to create complex composite animations.

Firstly, create the animation element, but don’t call lv_anim_start().

Secondly, create an animation timeline object, by calling lv_anim_timeline_create().

Thirdly, add animation elements to the animation timeline, by calling lv_anim_timeline_add(at, start_time, &a). start_time is the start time of the animation on the timeline. Note that start_time will override the value of delay.

Finally, call lv_anim_timeline_start(at) to start the animation timeline.

时间线是多个动画的集合，可以轻松创建复杂的复合动画。

首先，创建动画元素，但不要调用lv_anim_start()。

其次，通过调用lv_anim_timeline_create()创建一个动画时间线对象。

第三，通过调用lv_anim_timeline_add(at, start_time, &a)将动画元素添加到动画时间线。 start_time 是时间线上动画的开始时间。请注意，start_time 将覆盖 delay 的值。

最后，调用lv_anim_timeline_start(at)启动动画时间线。

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It supports forward and backward playback of the entire animation group, using lv_anim_timeline_set_reverse(at, reverse).

Call the lv_anim_timeline_set_progress(at, progress) function to set the state of the object corresponding to the progress of the timeline.

Call the lv_anim_timeline_get_playtime(at) function to get the total duration of the entire animation timeline.

Call the lv_anim_timeline_get_reverse(at) function to get whether to reverse the animation timeline.

Call the lv_anim_timeline_del(at) function to delete the animation timeline.

它支持整个动画组的向前和向后播放，使用lv_anim_timeline_set_reverse(at, reverse)。

调用lv_anim_timeline_set_progress(at,progress)函数设置时间线进度对应的对象状态。

调用lv_anim_timeline_get_playtime(at)函数获取整个动画时间线的总时长。

调用lv_anim_timeline_get_reverse(at)函数获取是否反转动画时间线。

调用lv_anim_timeline_del(at)函数删除动画时间线。

../_images/anim-timeline.png

Examples¶

API¶

Typedefs

typedef int32_t (*lv_anim_path_cb_t)(const struct _lv_anim_t*)¶: Get the current value during an animation

typedef void (*lv_anim_exec_xcb_t)(void*, int32_t)¶: Generic prototype of "animator" functions. First parameter is the variable to animate. Second parameter is the value to set. Compatible with lv_xxx_set_yyy(obj, value) functions The x in _xcb_t means it's not a fully generic prototype because it doesn't receive lv_anim_t * as its first argument

typedef void (*lv_anim_custom_exec_cb_t)(struct _lv_anim_t*, int32_t)¶: Same as lv_anim_exec_xcb_t but receives lv_anim_t * as the first parameter. It's more consistent but less convenient. Might be used by binding generator functions.

typedef void (*lv_anim_ready_cb_t)(struct _lv_anim_t*)¶: Callback to call when the animation is ready

typedef void (*lv_anim_start_cb_t)(struct _lv_anim_t*)¶: Callback to call when the animation really stars (considering delay)

typedef int32_t (*lv_anim_get_value_cb_t)(struct _lv_anim_t*)¶: Callback used when the animation values are relative to get the current value

typedef struct _lv_anim_t lv_anim_t¶: Describes an animation

Enums

enum lv_anim_enable_t¶

Can be used to indicate if animations are enabled or disabled in a case

Values:

enumerator LV_ANIM_OFF¶

enumerator LV_ANIM_ON¶

Functions

LV_EXPORT_CONST_INT(LV_ANIM_REPEAT_INFINITE)¶

LV_EXPORT_CONST_INT(LV_ANIM_PLAYTIME_INFINITE)¶

void _lv_anim_core_init(void)¶: Init. the animation module

void lv_anim_init(lv_anim_t *a)¶

Initialize an animation variable. E.g.: lv_anim_t a; lv_anim_init(&a); lv_anim_set_...(&a); lv_anim_start(&a);

参数: a -- pointer to an lv_anim_t variable to initialize

static inline void lv_anim_set_var(lv_anim_t *a, void *var)¶

Set a variable to animate

参数

a -- pointer to an initialized lv_anim_t variable
var -- pointer to a variable to animate

static inline void lv_anim_set_exec_cb(lv_anim_t *a, lv_anim_exec_xcb_t exec_cb)¶

Set a function to animate var

参数

a -- pointer to an initialized lv_anim_t variable
exec_cb -- a function to execute during animation LVGL's built-in functions can be used. E.g. lv_obj_set_x

static inline void lv_anim_set_time(lv_anim_t *a, uint32_t duration)¶

Set the duration of an animation

参数

a -- pointer to an initialized lv_anim_t variable
duration -- duration of the animation in milliseconds

static inline void lv_anim_set_delay(lv_anim_t *a, uint32_t delay)¶

Set a delay before starting the animation

参数

a -- pointer to an initialized lv_anim_t variable
delay -- delay before the animation in milliseconds

static inline void lv_anim_set_values(lv_anim_t *a, int32_t start, int32_t end)¶

Set the start and end values of an animation

参数

a -- pointer to an initialized lv_anim_t variable
start -- the start value
end -- the end value

static inline void lv_anim_set_custom_exec_cb(lv_anim_t *a, lv_anim_custom_exec_cb_t exec_cb)¶

Similar to lv_anim_set_exec_cb but lv_anim_custom_exec_cb_t receives lv_anim_t * as its first parameter instead of void *. This function might be used when LVGL is bound to other languages because it's more consistent to have lv_anim_t * as first parameter. The variable to animate can be stored in the animation's user_data

参数

a -- pointer to an initialized lv_anim_t variable
exec_cb -- a function to execute.

static inline void lv_anim_set_path_cb(lv_anim_t *a, lv_anim_path_cb_t path_cb)¶

Set the path (curve) of the animation.

参数

a -- pointer to an initialized lv_anim_t variable
path_cb -- a function to set the current value of the animation.

static inline void lv_anim_set_start_cb(lv_anim_t *a, lv_anim_start_cb_t start_cb)¶

Set a function call when the animation really starts (considering delay)

参数

a -- pointer to an initialized lv_anim_t variable
start_cb -- a function call when the animation starts

static inline void lv_anim_set_get_value_cb(lv_anim_t *a, lv_anim_get_value_cb_t get_value_cb)¶

Set a function to use the current value of the variable and make start and end value relative the the returned current value.

参数

a -- pointer to an initialized lv_anim_t variable
get_value_cb -- a function call when the animation starts

static inline void lv_anim_set_ready_cb(lv_anim_t *a, lv_anim_ready_cb_t ready_cb)¶

Set a function call when the animation is ready

参数

a -- pointer to an initialized lv_anim_t variable
ready_cb -- a function call when the animation is ready

static inline void lv_anim_set_playback_time(lv_anim_t *a, uint32_t time)¶

Make the animation to play back to when the forward direction is ready

参数

a -- pointer to an initialized lv_anim_t variable
time -- the duration of the playback animation in milliseconds. 0: disable playback

static inline void lv_anim_set_playback_delay(lv_anim_t *a, uint32_t delay)¶

Make the animation to play back to when the forward direction is ready

参数

a -- pointer to an initialized lv_anim_t variable
delay -- delay in milliseconds before starting the playback animation.

static inline void lv_anim_set_repeat_count(lv_anim_t *a, uint16_t cnt)¶

Make the animation repeat itself.

参数

a -- pointer to an initialized lv_anim_t variable
cnt -- repeat count or LV_ANIM_REPEAT_INFINITE for infinite repetition. 0: to disable repetition.

static inline void lv_anim_set_repeat_delay(lv_anim_t *a, uint32_t delay)¶

Set a delay before repeating the animation.

参数

a -- pointer to an initialized lv_anim_t variable
delay -- delay in milliseconds before repeating the animation.

static inline void lv_anim_set_early_apply(lv_anim_t *a, bool en)¶

Set a whether the animation's should be applied immediately or only when the delay expired.

参数

a -- pointer to an initialized lv_anim_t variable
en -- true: apply the start value immediately in lv_anim_start; false: apply the start value only when delay ms is elapsed and the animations really starts

static inline void lv_anim_set_user_data(lv_anim_t *a, void *user_data)¶

Set the custom user data field of the animation.

参数

a -- pointer to an initialized lv_anim_t variable
user_data -- pointer to the new user_data.

lv_anim_t *lv_anim_start(const lv_anim_t *a)¶

Create an animation

参数: a -- an initialized 'anim_t' variable. Not required after call.
返回: pointer to the created animation (different from the a parameter)

static inline uint32_t lv_anim_get_delay(lv_anim_t *a)¶

Get a delay before starting the animation

参数: a -- pointer to an initialized lv_anim_t variable
返回: delay before the animation in milliseconds

uint32_t lv_anim_get_playtime(lv_anim_t *a)¶

Get the time used to play the animation.

参数: a -- pointer to an animation.
返回: the play time in milliseconds.

static inline void *lv_anim_get_user_data(lv_anim_t *a)¶

Get the user_data field of the animation

参数: a -- pointer to an initialized lv_anim_t variable
返回: the pointer to the custom user_data of the animation

bool lv_anim_del(void *var, lv_anim_exec_xcb_t exec_cb)¶

Delete an animation of a variable with a given animator function

参数

var -- pointer to variable
exec_cb -- a function pointer which is animating 'var', or NULL to ignore it and delete all the animations of 'var

返回

true: at least 1 animation is deleted, false: no animation is deleted

void lv_anim_del_all(void)¶: Delete all the animations

lv_anim_t *lv_anim_get(void *var, lv_anim_exec_xcb_t exec_cb)¶

Get the animation of a variable and its exec_cb.

参数

var -- pointer to variable
exec_cb -- a function pointer which is animating 'var', or NULL to return first matching 'var'

返回

pointer to the animation.

static inline bool lv_anim_custom_del(lv_anim_t *a, lv_anim_custom_exec_cb_t exec_cb)¶

Delete an animation by getting the animated variable from a. Only animations with exec_cb will be deleted. This function exists because it's logical that all anim. functions receives an lv_anim_t as their first parameter. It's not practical in C but might make the API more consequent and makes easier to generate bindings.

参数

a -- pointer to an animation.
exec_cb -- a function pointer which is animating 'var', or NULL to ignore it and delete all the animations of 'var

返回

true: at least 1 animation is deleted, false: no animation is deleted

static inline lv_anim_t *lv_anim_custom_get(lv_anim_t *a, lv_anim_custom_exec_cb_t exec_cb)¶

Get the animation of a variable and its exec_cb. This function exists because it's logical that all anim. functions receives an lv_anim_t as their first parameter. It's not practical in C but might make the API more consequent and makes easier to generate bindings.

参数

a -- pointer to an animation.
exec_cb -- a function pointer which is animating 'var', or NULL to return first matching 'var'

返回

pointer to the animation.

uint16_t lv_anim_count_running(void)¶

Get the number of currently running animations

返回: the number of running animations

uint32_t lv_anim_speed_to_time(uint32_t speed, int32_t start, int32_t end)¶

Calculate the time of an animation with a given speed and the start and end values

参数

speed -- speed of animation in unit/sec
start -- start value of the animation
end -- end value of the animation

返回

the required time [ms] for the animation with the given parameters

void lv_anim_refr_now(void)¶: Manually refresh the state of the animations. Useful to make the animations running in a blocking process where lv_timer_handler can't run for a while. Shouldn't be used directly because it is called in lv_refr_now().

int32_t lv_anim_path_linear(const lv_anim_t *a)¶

Calculate the current value of an animation applying linear characteristic

参数: a -- pointer to an animation
返回: the current value to set

int32_t lv_anim_path_ease_in(const lv_anim_t *a)¶

Calculate the current value of an animation slowing down the start phase

参数: a -- pointer to an animation
返回: the current value to set

int32_t lv_anim_path_ease_out(const lv_anim_t *a)¶

Calculate the current value of an animation slowing down the end phase

参数: a -- pointer to an animation
返回: the current value to set

int32_t lv_anim_path_ease_in_out(const lv_anim_t *a)¶

Calculate the current value of an animation applying an "S" characteristic (cosine)

参数: a -- pointer to an animation
返回: the current value to set

int32_t lv_anim_path_overshoot(const lv_anim_t *a)¶

Calculate the current value of an animation with overshoot at the end

参数: a -- pointer to an animation
返回: the current value to set

int32_t lv_anim_path_bounce(const lv_anim_t *a)¶

Calculate the current value of an animation with 3 bounces

参数: a -- pointer to an animation
返回: the current value to set

int32_t lv_anim_path_step(const lv_anim_t *a)¶

Calculate the current value of an animation applying step characteristic. (Set end value on the end of the animation)

参数: a -- pointer to an animation
返回: the current value to set

struct _lv_anim_t¶

#include <lv_anim.h>

Describes an animation

Public Members

void *var¶: Variable to animate

lv_anim_exec_xcb_t exec_cb¶: Function to execute to animate

lv_anim_start_cb_t start_cb¶: Call it when the animation is starts (considering delay)

lv_anim_ready_cb_t ready_cb¶: Call it when the animation is ready

lv_anim_get_value_cb_t get_value_cb¶: Get the current value in relative mode

void *user_data¶: Custom user data

lv_anim_path_cb_t path_cb¶: Describe the path (curve) of animations

int32_t start_value¶: Start value

int32_t current_value¶: Current value

int32_t end_value¶: End value

int32_t time¶: Animation time in ms

int32_t act_time¶: Current time in animation. Set to negative to make delay.

uint32_t playback_delay¶: Wait before play back

uint32_t playback_time¶: Duration of playback animation

uint32_t repeat_delay¶: Wait before repeat

uint16_t repeat_cnt¶: Repeat count for the animation

uint8_t early_apply¶: 1: Apply start value immediately even is there is delay

uint8_t playback_now¶: Play back is in progress

uint8_t run_round¶: Indicates the animation has run in this round

uint8_t start_cb_called¶: Indicates that the start_cb was already called