Struct Animation 

pub struct Animation { /* private fields */ }

Fluent builder for an LVGL animation.

Configure the animation step-by-step, then call Animation::start — LVGL copies the state into its internal animation list, so the builder can be dropped immediately after.

Callback constraints

In no_std Rust we’re stuck with extern "C" fn pointers for exec_cb / ready_cb — no closures. Use the animate_x, animate_y, animate_width, animate_opa helpers for the common cases where you just want to tween a single property.

Implementations

impl Animation

pub fn new() -> Self

Create a fresh animation with default values (duration 0, no exec cb).

pub fn target(self, var: *mut c_void) -> Self

Set the target variable (typically obj.raw() as *mut c_void).

pub fn values(self, from: i32, to: i32) -> Self

Set start and end values.

pub fn duration(self, ms: u32) -> Self

Set duration in milliseconds.

pub fn delay(self, ms: u32) -> Self

Set the delay before the animation starts.

pub fn path(self, cb: lv_anim_path_cb_t) -> Self

Set the easing path callback. Use e.g. path_ease_out.

pub fn repeat_count(self, count: u32) -> Self

Set the repeat count; use ANIM_REPEAT_INFINITE for endless.

pub fn repeat_delay(self, ms: u32) -> Self

Set the delay between repeats.

pub fn playback_duration(self, ms: u32) -> Self

Set the duration of the reverse (playback) phase.

pub fn playback_delay(self, ms: u32) -> Self

Set the delay before the playback phase.

pub fn exec_cb(self, cb: lv_anim_exec_xcb_t) -> Self

Set the exec callback invoked every frame with (var, value).

pub fn completed_cb(self, cb: lv_anim_completed_cb_t) -> Self

Set the callback invoked when the animation completes (lv_anim_set_completed_cb).

pub fn start(self)

Start the animation. LVGL copies internal state, so the builder can be dropped immediately after.

pub fn stop(var: *mut c_void, exec_cb: lv_anim_exec_xcb_t) -> bool

Stop any animations matching (var, exec_cb).

impl Animation

pub fn duration_for_speed(speed: u32) -> u32

Configure the animation duration based on a movement speed (LVGL’s lv_anim_speed). Returns the precomputed duration value.

pub fn tick_fn<W: Widget>(self, obj: W, on_tick: fn(Obj, i32)) -> Self

Set both the animation target and a safe tick callback.

on_tick(obj, v) is invoked every frame with the target widget (as Obj) and the interpolated value. Uses LVGL’s custom exec callback so the fn pointer is smuggled through user_data.

Trait Implementations

impl Default for Animation

fn default() -> Self

Returns the “default value” for a type.