#include <image_generator.h>

Inheritance diagram for flutter::BuiltinSkiaImageGenerator:

Public Member Functions
	~BuiltinSkiaImageGenerator ()

	BuiltinSkiaImageGenerator (std::unique_ptr< SkImageGenerator > generator)

const SkImageInfo &	GetInfo () override
	Returns basic information about the contents of the encoded image. This information can almost always be collected by just interpreting the header of a decoded image.

unsigned int	GetFrameCount () const override
	Get the number of frames that the encoded image stores. This method is always expected to be called before `GetFrameInfo`, as the underlying image decoder may interpret frame information that is then used when calling `GetFrameInfo`.

unsigned int	GetPlayCount () const override
	The number of times an animated image should play through before playback stops.

const ImageGenerator::FrameInfo	GetFrameInfo (unsigned int frame_index) override
	Get information about a single frame in the context of a multi-frame image, useful for animation and frame blending. This method should only ever be called after `GetFrameCount` has been called. This information is nonsensical for single-frame images.

SkISize	GetScaledDimensions (float desired_scale) override
	Given a scale value, find the closest image size that can be used for efficiently decoding the image. If subpixel image decoding is not supported by the decoder, this method should just return the original image size.

bool	GetPixels (const SkImageInfo &info, void *pixels, size_t row_bytes, unsigned int frame_index=0, std::optional< unsigned int > prior_frame=std::nullopt) override
	Decode the image into a given buffer. This method is currently always used for sub-pixel image decoding. For full-sized still images, `GetImage` is always attempted first.

Public Member Functions inherited from flutter::ImageGenerator
virtual	~ImageGenerator ()

sk_sp< SkImage >	GetImage ()
	Creates an `SkImage` based on the current `ImageInfo` of this `ImageGenerator`.

Static Public Member Functions
static std::unique_ptr< ImageGenerator >	MakeFromGenerator (std::unique_ptr< SkImageGenerator > generator)

Additional Inherited Members
Static Public Attributes inherited from flutter::ImageGenerator
static const unsigned int	kInfinitePlayCount
	Frame count value to denote infinite looping.

Detailed Description

Definition at line 144 of file image_generator.h.

Constructor & Destructor Documentation

◆ ~BuiltinSkiaImageGenerator()

flutter::BuiltinSkiaImageGenerator::~BuiltinSkiaImageGenerator ( )

default

◆ BuiltinSkiaImageGenerator()

flutter::BuiltinSkiaImageGenerator::BuiltinSkiaImageGenerator ( std::unique_ptr< SkImageGenerator > generator )

explicit

Definition at line 40 of file image_generator.cc.

42 : generator_(std::move(generator)) {}

Member Function Documentation

◆ GetFrameCount()

unsigned int flutter::BuiltinSkiaImageGenerator::GetFrameCount ( ) const

overridevirtual

Get the number of frames that the encoded image stores. This method is always expected to be called before GetFrameInfo, as the underlying image decoder may interpret frame information that is then used when calling GetFrameInfo.

Returns: The number of frames that the encoded image stores. This will always be 1 for single-frame images.

Implements flutter::ImageGenerator.

Definition at line 48 of file image_generator.cc.

                                                            {
  return 1;
}

◆ GetFrameInfo()

const ImageGenerator::FrameInfo flutter::BuiltinSkiaImageGenerator::GetFrameInfo ( unsigned int frame_index )

overridevirtual

Get information about a single frame in the context of a multi-frame image, useful for animation and frame blending. This method should only ever be called after GetFrameCount has been called. This information is nonsensical for single-frame images.

Parameters

[in] frame_index The index of the frame to get information about.

Returns: Information about the given frame. If the image is single-frame, a default result is returned.

See also: GetFrameCount

Implements flutter::ImageGenerator.

Definition at line 56 of file image_generator.cc.

                              {
  return {.required_frame = std::nullopt,
          .duration = 0,
          .disposal_method = SkCodecAnimation::DisposalMethod::kKeep};
}

◆ GetInfo()

const SkImageInfo & flutter::BuiltinSkiaImageGenerator::GetInfo ( )

overridevirtual

Returns basic information about the contents of the encoded image. This information can almost always be collected by just interpreting the header of a decoded image.

Returns: Size and color information describing the image.

Note: This method is executed on the UI thread and used for layout purposes by the framework, and so this method should not perform long synchronous tasks.

Implements flutter::ImageGenerator.

Definition at line 44 of file image_generator.cc.

                                                      {
  return generator_->getInfo();
}

◆ GetPixels()

bool flutter::BuiltinSkiaImageGenerator::GetPixels	(	const SkImageInfo &	info,
		void *	pixels,
		size_t	row_bytes,
		unsigned int	frame_index = `0`,
		std::optional< unsigned int >	prior_frame = `std::nullopt`
	)

overridevirtual

Decode the image into a given buffer. This method is currently always used for sub-pixel image decoding. For full-sized still images, GetImage is always attempted first.

Parameters

[in]	info	The desired size and color info of the decoded image to be returned. The implementation of `GetScaledDimensions` determines which sizes are supported by the image decoder.
[in]	pixels	The location where the raw decoded image data should be written.
[in]	row_bytes	The total number of bytes that should make up a single row of decoded image data (i.e. width * bytes_per_pixel).
[in]	frame_index	Which frame to decode. This is only useful for multi-frame images.
[in]	prior_frame	Optional frame index parameter for multi-frame images which specifies the previous frame that should be use for blending. This hints to the decoder that it should use a previously cached frame instead of decoding dependency frame(s). If an empty value is supplied, the decoder should decode any necessary frames first.

Returns: True if the image was successfully decoded.

Note: This method performs potentially long synchronous work, and so it should never be executed on the UI thread. Image decoders do not require GPU acceleration, and so threads without a GPU context may also be used.

See also: GetScaledDimensions

Implements flutter::ImageGenerator.

Definition at line 67 of file image_generator.cc.

                                           {
  return generator_->getPixels(info, pixels, row_bytes);
}

◆ GetPlayCount()

unsigned int flutter::BuiltinSkiaImageGenerator::GetPlayCount ( ) const

overridevirtual

The number of times an animated image should play through before playback stops.

Returns: If this image is animated, the number of times the animation should play through is returned, otherwise it'll just return 1. If the animation should loop forever, kInfinitePlayCount is returned.

Implements flutter::ImageGenerator.

Definition at line 52 of file image_generator.cc.

                                                           {
  return 1;
}

◆ GetScaledDimensions()

SkISize flutter::BuiltinSkiaImageGenerator::GetScaledDimensions ( float scale )

overridevirtual

Given a scale value, find the closest image size that can be used for efficiently decoding the image. If subpixel image decoding is not supported by the decoder, this method should just return the original image size.

Parameters

[in] scale The desired scale factor of the image for decoding.

Returns: The closest image size that can be used for efficiently decoding the image.

Note: This method is called prior to GetPixels in order to query for supported sizes.

See also: GetPixels

Implements flutter::ImageGenerator.

Definition at line 63 of file image_generator.cc.

                                                                          {
  return generator_->getInfo().dimensions();
}

◆ MakeFromGenerator()

std::unique_ptr< ImageGenerator > flutter::BuiltinSkiaImageGenerator::MakeFromGenerator ( std::unique_ptr< SkImageGenerator > generator )

static

Definition at line 76 of file image_generator.cc.

                                               {
  if (!generator) {
    return nullptr;
  }
  return std::make_unique<BuiltinSkiaImageGenerator>(std::move(generator));
}

The documentation for this class was generated from the following files:

lib/ui/painting/image_generator.h
lib/ui/painting/image_generator.cc

Public Member Functions

Static Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ ~BuiltinSkiaImageGenerator()

◆ BuiltinSkiaImageGenerator()

Member Function Documentation

◆ GetFrameCount()

◆ GetFrameInfo()

◆ GetInfo()

◆ GetPixels()

◆ GetPlayCount()

◆ GetScaledDimensions()

◆ MakeFromGenerator()