The LottieAnimation class enables control of advanced Lottie features. More...

#include <thorvg_lottie.h>

Inheritance diagram for LottieAnimation:

Collaboration diagram for LottieAnimation:

Public Member Functions
Result	segment (const char *marker) noexcept
	Specifies a segment by marker.

Result	tween (float from, float to, float progress) noexcept
	Interpolates between two frames over a specified duration.

uint32_t	markersCnt () noexcept
	Gets the marker count of the animation.

const char *	marker (uint32_t idx) noexcept
	Gets the marker name by a given index.

Result	assign (const char layer, uint32_t ix, const char var, float val)
	Updates the value of an expression variable for a specific layer.

uint32_t	gen (const char *slot) noexcept
	Creates a new slot based on the given Lottie slot data.

Result	apply (uint32_t id) noexcept
	Applies a previously generated slot to the animation.

Result	del (uint32_t id) noexcept
	Deletes a previously generated slot.

Result	quality (uint8_t value) noexcept
	Sets the quality level for Lottie effects.

Public Member Functions inherited from Animation
Result	frame (float no) noexcept
	Specifies the current frame in the animation.

Picture *	picture () const noexcept
	Retrieves a picture instance associated with this animation instance.

float	curFrame () const noexcept
	Retrieves the current frame number of the animation.

float	totalFrame () const noexcept
	Retrieves the total number of frames in the animation.

float	duration () const noexcept
	Retrieves the duration of the animation in seconds.

Result	segment (float begin, float end) noexcept
	Specifies the playback segment of the animation.

Result	segment (float begin, float end=nullptr) noexcept
	Gets the current segment range information.

Static Public Member Functions
static LottieAnimation *	gen () noexcept
	Creates a new LottieAnimation object.

Static Public Member Functions inherited from Animation
static Animation *	gen () noexcept
	Creates a new Animation object.

Detailed Description

The LottieAnimation class enables control of advanced Lottie features.

This class extends the Animation and has additional interfaces.

See also: Animation

Since: 0.15

Member Function Documentation

◆ apply()

Result apply ( uint32_t id )

noexcept

Applies a previously generated slot to the animation.

This function applies the animation parameters defined by a slot. If the provided slot ID is 0, all previously applied slots will be reset.

Parameters

[in] id The ID of the slot to apply. Use 0 to reset all slots.

Return values

Result::InvalidArguments If the animation is not loaded or the slot ID is invalid.

See also: gen(const char* slot)

Since: 1.0

◆ assign()

Result assign	(	const char *	layer,
		uint32_t	ix,
		const char *	var,
		float	val
	)

Updates the value of an expression variable for a specific layer.

This function sets the value of a specified expression variable within a particular layer. It is useful for dynamically changing the properties of a layer at runtime.

Parameters

[in]	layer	The name of the layer containing the variable to be updated.
[in]	ix	The property index of the variable within the layer.
[in]	var	The name of the variable to be updated.
[in]	val	The new value to assign to the variable.

Return values

Result::InsufficientCondition	If the animation is not loaded.
Result::InvalidArguments	When the given parameter is invalid.
Result::NonSupport	When neither the layer nor the property is found in the current animation.

Note: Experimental API

◆ del()

Result del ( uint32_t id )

noexcept

Deletes a previously generated slot.

This function removes a slot by its ID.

Parameters

[in] id The ID of the slot to delete. Retrieve the ID from gen().

Return values

Result::InvalidArguments If the animation is not loaded or the slot ID is invalid.

Note: This function should be paired with gen.

See also: gen(const char* slot)

Since: 1.0

◆ gen() [1/2]

static LottieAnimation * gen ( )

staticnoexcept

Creates a new LottieAnimation object.

Returns: A new LottieAnimation object.

Since: 0.15

◆ gen() [2/2]

uint32_t gen ( const char * slot )

noexcept

Creates a new slot based on the given Lottie slot data.

This function parses the provided JSON-formatted slot data and generates a new slot for animation control. The returned slot ID can be used to apply or delete the slot later.

Parameters

[in] slot A JSON string representing the Lottie slot data.

Returns: A unique, non-zero slot ID on success. Returns 0 if the slot generation fails.

See also: apply(uint32_t id); del(uint32_t id)

Since: 1.0

◆ marker()

const char * marker ( uint32_t idx )

noexcept

Gets the marker name by a given index.

Parameters

[in] idx The index of the animation marker, starts from 0.

Return values

The	name of marker when succeed, `nullptr` otherwise.

See also: LottieAnimation::markersCnt()

Since: 1.0

◆ markersCnt()

uint32_t markersCnt ( )

noexcept

Gets the marker count of the animation.

Return values

The	count of the markers, zero if there is no marker.

See also: LottieAnimation::marker()

Since: 1.0

◆ quality()

Result quality ( uint8_t value )

noexcept

Sets the quality level for Lottie effects.

This function controls the rendering quality of effects like blur, shadows, etc. Lower values prioritize performance while higher values prioritize quality.

Parameters

[in] value The quality level (0-100). 0 represents lowest quality/best performance, 100 represents highest quality/lowest performance, default is 50.

Return values

Result::InsufficientCondition If the animation is not loaded.

Since: 1.0

◆ segment()

Result segment ( const char * marker )

noexcept

Specifies a segment by marker.

Markers are used to control animation playback by specifying start and end points, eliminating the need to know the exact frame numbers. Generally, markers are designated at the design level, meaning the callers must know the marker name in advance to use it.

Parameters

[in] marker The name of the segment marker.

Return values

Result::InsufficientCondition	If the animation is not loaded.
Result::NonSupport	When it's not animatable.

Note: If a marker is specified, the previously set segment will be disregarded.; Set nullptr to reset the specified segment.

See also: Animation::segment(float begin, float end)

Since: 1.0

◆ tween()

Result tween	(	float	from,
		float	to,
		float	progress
	)

noexcept

Interpolates between two frames over a specified duration.

This method performs tweening, a process of generating intermediate frame between from and to based on the given progress.

Parameters

[in]	from	The start frame number of the interpolation.
[in]	to	The end frame number of the interpolation.
[in]	progress	The current progress of the interpolation (range: 0.0 to 1.0).

Return values

Result::InsufficientCondition In case the animation is not loaded.

Since: 1.0

Public Member Functions

Static Public Member Functions

Detailed Description

Member Function Documentation

◆ apply()

◆ assign()

◆ del()

◆ gen() [1/2]

◆ gen() [2/2]

◆ marker()

◆ markersCnt()

◆ quality()

◆ segment()

◆ tween()