#include <directional_gaussian_blur_filter_contents.h>

Inheritance diagram for impeller::DirectionalGaussianBlurFilterContents:

Public Member Functions
	DirectionalGaussianBlurFilterContents ()

	~DirectionalGaussianBlurFilterContents () override

void	SetSigma (Sigma sigma)
	Set sigma (stddev) used for 'direction_'. More...

void	SetSecondarySigma (Sigma sigma)

void	SetDirection (Vector2 direction)

void	SetBlurStyle (BlurStyle blur_style)

void	SetTileMode (Entity::TileMode tile_mode)

void	SetIsSecondPass (bool is_second_pass)

std::optional< Rect >	GetFilterSourceCoverage (const Matrix &effect_transform, const Rect &output_limit) const override
	Internal utility method for \|GetSourceCoverage\| that computes the inverse effect of this transform on the specified output coverage, ignoring the inputs which will be accommodated by the caller. More...

std::optional< Rect >	GetFilterCoverage (const FilterInput::Vector &inputs, const Entity &entity, const Matrix &effect_transform) const override
	Internal utility method for \|GetLocalCoverage\| that computes the output coverage of this filter across the specified inputs, ignoring the coverage hint. More...

Public Member Functions inherited from impeller::FilterContents
	FilterContents ()

	~FilterContents () override

void	SetInputs (FilterInput::Vector inputs)
	The input texture sources for this filter. Each input's emitted texture is expected to have premultiplied alpha colors. More...

void	SetEffectTransform (const Matrix &effect_transform)
	Sets the transform which gets appended to the effect of this filter. Note that this is in addition to the entity's transform. More...

std::optional< Entity >	GetEntity (const ContentContext &renderer, const Entity &entity, const std::optional< Rect > &coverage_hint) const
	Create an Entity that renders this filter's output. More...

bool	Render (const ContentContext &renderer, const Entity &entity, RenderPass &pass) const override

std::optional< Rect >	GetCoverage (const Entity &entity) const override
	Get the area of the render pass that will be affected when this contents is rendered. More...

void	PopulateGlyphAtlas (const std::shared_ptr< LazyGlyphAtlas > &lazy_glyph_atlas, Scalar scale) override
	Add any text data to the specified lazy atlas. The scale parameter must be used again later when drawing the text. More...

std::optional< Snapshot >	RenderToSnapshot (const ContentContext &renderer, const Entity &entity, std::optional< Rect > coverage_limit=std::nullopt, const std::optional< SamplerDescriptor > &sampler_descriptor=std::nullopt, bool msaa_enabled=true, const std::string &label="Filter Snapshot") const override
	Render this contents to a snapshot, respecting the entity's transform, path, clip depth, and blend mode. The result texture size is always the size of `GetCoverage(entity)`. More...

const FilterContents *	AsFilter () const override
	Cast to a filter. Returns `nullptr` if this Contents is not a filter. More...

std::optional< Rect >	GetSourceCoverage (const Matrix &effect_transform, const Rect &output_limit) const
	Determines the coverage of source pixels that will be needed to produce results for the specified \|output_limit\| under the specified \|effect_transform\|. This is essentially a reverse of the \|GetCoverage\| method computing a source coverage from an intended \|output_limit\| coverage. More...

virtual Matrix	GetLocalTransform (const Matrix &parent_transform) const

Matrix	GetTransform (const Matrix &parent_transform) const

virtual bool	IsTranslationOnly () const
	Returns true if this filter graph doesn't perform any basis transforms to the filtered content. For example: Rotating, scaling, and skewing are all basis transforms, but translating is not. More...

bool	IsLeaf () const
	Returns `true` if this filter does not have any `FilterInput` children. More...

void	SetLeafInputs (const FilterInput::Vector &inputs)
	Replaces the set of all leaf `FilterContents` with a new set of `FilterInput`s. More...

virtual void	SetRenderingMode (Entity::RenderingMode rendering_mode)
	Marks this filter chain as applying in a subpass scenario. More...

Public Member Functions inherited from impeller::Contents
	Contents ()

virtual	~Contents ()

void	SetCoverageHint (std::optional< Rect > coverage_hint)
	Hint that specifies the coverage area of this Contents that will actually be used during rendering. This is for optimization purposes only and can not be relied on as a clip. May optionally affect the result of `GetCoverage()`. More...

const std::optional< Rect > &	GetCoverageHint () const

virtual bool	IsOpaque () const
	Whether this Contents only emits opaque source colors from the fragment stage. This value does not account for any entity properties (e.g. the blend mode), clips/visibility culling, or inherited opacity. More...

virtual ClipCoverage	GetClipCoverage (const Entity &entity, const std::optional< Rect > &current_clip_coverage) const
	Given the current pass space bounding rectangle of the clip buffer, return the expected clip coverage after this draw call. This should only be implemented for contents that may write to the clip buffer. More...

virtual bool	ShouldRender (const Entity &entity, const std::optional< Rect > clip_coverage) const

std::optional< Size >	GetColorSourceSize () const
	Return the color source's intrinsic size, if available. More...

void	SetColorSourceSize (Size size)

virtual bool	CanInheritOpacity (const Entity &entity) const
	Whether or not this contents can accept the opacity peephole optimization. More...

virtual void	SetInheritedOpacity (Scalar opacity)
	Inherit the provided opacity. More...

virtual std::optional< Color >	AsBackgroundColor (const Entity &entity, ISize target_size) const
	Returns a color if this Contents will flood the given `target_size` with a color. This output color is the "Source" color that will be used for the Entity's blend operation. More...

virtual bool	ApplyColorFilter (const ColorFilterProc &color_filter_proc)
	If possible, applies a color filter to this contents inputs on the CPU. More...

Additional Inherited Members
Public Types inherited from impeller::FilterContents
enum	BlurStyle { BlurStyle::kNormal, BlurStyle::kSolid, BlurStyle::kOuter, BlurStyle::kInner }

enum	MorphType { MorphType::kDilate, MorphType::kErode }

Public Types inherited from impeller::Contents
using	ColorFilterProc = std::function< Color(Color)>

using	RenderProc = std::function< bool(const ContentContext &renderer, const Entity &entity, RenderPass &pass)>

using	CoverageProc = std::function< std::optional< Rect >(const Entity &entity)>

Static Public Member Functions inherited from impeller::FilterContents
static std::shared_ptr< FilterContents >	MakeDirectionalGaussianBlur (FilterInput::Ref input, Sigma sigma, Vector2 direction, BlurStyle blur_style=BlurStyle::kNormal, Entity::TileMode tile_mode=Entity::TileMode::kDecal, bool is_second_pass=false, Sigma secondary_sigma={})

static std::shared_ptr< FilterContents >	MakeGaussianBlur (const FilterInput::Ref &input, Sigma sigma_x, Sigma sigma_y, BlurStyle blur_style=BlurStyle::kNormal, Entity::TileMode tile_mode=Entity::TileMode::kDecal)

static std::shared_ptr< FilterContents >	MakeBorderMaskBlur (FilterInput::Ref input, Sigma sigma_x, Sigma sigma_y, BlurStyle blur_style=BlurStyle::kNormal)

static std::shared_ptr< FilterContents >	MakeDirectionalMorphology (FilterInput::Ref input, Radius radius, Vector2 direction, MorphType morph_type)

static std::shared_ptr< FilterContents >	MakeMorphology (FilterInput::Ref input, Radius radius_x, Radius radius_y, MorphType morph_type)

static std::shared_ptr< FilterContents >	MakeMatrixFilter (FilterInput::Ref input, const Matrix &matrix, const SamplerDescriptor &desc)

static std::shared_ptr< FilterContents >	MakeLocalMatrixFilter (FilterInput::Ref input, const Matrix &matrix)

static std::shared_ptr< FilterContents >	MakeYUVToRGBFilter (std::shared_ptr< Texture > y_texture, std::shared_ptr< Texture > uv_texture, YUVColorSpace yuv_color_space)

Static Public Member Functions inherited from impeller::Contents
static std::shared_ptr< Contents >	MakeAnonymous (RenderProc render_proc, CoverageProc coverage_proc)

Detailed Description

A gaussian blur filter that performs the work for one dimension of a multi-dimensional Gaussian blur.

This filter takes a snapshot of its provided FilterInput, creates a new render pass and blurs the contents. Two of these are chained together to perform a full 2D blur effect.

Example:

  Input             Pass 1

+----------—+ +--—+ | | | | | | | | Pass 2 | | | | +-—+ | | | | | | | | -> | | -> | | | | | | | | | | | | +-—+ | | | | 87x102 +----------—+ +--—+ 586x678 97x678

The math for determining how much of the input should be processed for a given sigma (aka radius) is found in Sigma::operator Radius. The math for determining how much to scale down the input based on the radius is inside the curve function in this implementation.

Constructor & Destructor Documentation

◆ DirectionalGaussianBlurFilterContents()

impeller::DirectionalGaussianBlurFilterContents::DirectionalGaussianBlurFilterContents ( )

default

◆ ~DirectionalGaussianBlurFilterContents()

impeller::DirectionalGaussianBlurFilterContents::~DirectionalGaussianBlurFilterContents ( )

overridedefault

Member Function Documentation

◆ GetFilterCoverage()

std::optional< Rect > impeller::DirectionalGaussianBlurFilterContents::GetFilterCoverage	(	const FilterInput::Vector &	inputs,
		const Entity &	entity,
		const Matrix &	effect_transform
	)		const

overridevirtual

Internal utility method for |GetLocalCoverage| that computes the output coverage of this filter across the specified inputs, ignoring the coverage hint.

Reimplemented from impeller::FilterContents.

Definition at line 292 of file directional_gaussian_blur_filter_contents.cc.

                                           {
   if (inputs.empty()) {
     return std::nullopt;
   }
  
   auto coverage = inputs[0]->GetCoverage(entity);
   if (!coverage.has_value()) {
     return std::nullopt;
   }
  
   auto transform = inputs[0]->GetTransform(entity) * effect_transform.Basis();
   auto transformed_blur_vector =
       transform
           .TransformDirection(blur_direction_ *
                               Radius{ScaleSigma(blur_sigma_)}.radius)
           .Abs();
   return coverage->Expand(transformed_blur_vector);
 }

References impeller::Matrix::Basis(), impeller::TRect< T >::Expand(), impeller::ScaleSigma(), and impeller::Matrix::TransformDirection().

◆ GetFilterSourceCoverage()

std::optional< Rect > impeller::DirectionalGaussianBlurFilterContents::GetFilterSourceCoverage	(	const Matrix &	effect_transform,
		const Rect &	output_limit
	)		const

overridevirtual

Internal utility method for |GetSourceCoverage| that computes the inverse effect of this transform on the specified output coverage, ignoring the inputs which will be accommodated by the caller.

Implements impeller::FilterContents.

Definition at line 282 of file directional_gaussian_blur_filter_contents.cc.

                                     {
   auto transform = effect_transform.Basis();
   auto transformed_blur_vector =
       transform.TransformDirection(blur_direction_ * Radius{blur_sigma_}.radius)
           .Abs();
   return output_limit.Expand(transformed_blur_vector);
 }

References impeller::Matrix::Basis(), impeller::TRect< T >::Expand(), and impeller::Matrix::TransformDirection().

◆ SetBlurStyle()

void impeller::DirectionalGaussianBlurFilterContents::SetBlurStyle ( BlurStyle blur_style )

Definition at line 55 of file directional_gaussian_blur_filter_contents.cc.

                                                                              {
   blur_style_ = blur_style;
 }

◆ SetDirection()

void impeller::DirectionalGaussianBlurFilterContents::SetDirection ( Vector2 direction )

Definition at line 48 of file directional_gaussian_blur_filter_contents.cc.

                                                                           {
   blur_direction_ = direction.Normalize();
   if (blur_direction_.IsZero()) {
     blur_direction_ = Vector2(0, 1);
   }
 }

References impeller::TPoint< T >::IsZero(), and impeller::TPoint< T >::Normalize().

◆ SetIsSecondPass()

void impeller::DirectionalGaussianBlurFilterContents::SetIsSecondPass ( bool is_second_pass )

Determines if this filter represents the second pass in a chained 2D gaussian blur. If is_second_pass_ == true then the secondary_sigma_ is used to determine the blur radius in the 90 degree rotation of direction_. Its output aspect-ratio will closely match the FilterInput snapshot at the beginning of the chain.

Definition at line 64 of file directional_gaussian_blur_filter_contents.cc.

                          {
   is_second_pass_ = is_second_pass;
 }

◆ SetSecondarySigma()

void impeller::DirectionalGaussianBlurFilterContents::SetSecondarySigma ( Sigma sigma )

Set sigma (stddev) used for direction 90 degrees from 'direction_'. Not used if !is_second_pass_.

Definition at line 44 of file directional_gaussian_blur_filter_contents.cc.

                                                                          {
   secondary_blur_sigma_ = sigma;
 }

◆ SetSigma()

void impeller::DirectionalGaussianBlurFilterContents::SetSigma ( Sigma sigma )

Set sigma (stddev) used for 'direction_'.

Definition at line 40 of file directional_gaussian_blur_filter_contents.cc.

                                                                 {
   blur_sigma_ = sigma;
 }

◆ SetTileMode()

void impeller::DirectionalGaussianBlurFilterContents::SetTileMode ( Entity::TileMode tile_mode )

Definition at line 59 of file directional_gaussian_blur_filter_contents.cc.

                               {
   tile_mode_ = tile_mode;
 }

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

impeller/entity/contents/filters/directional_gaussian_blur_filter_contents.h
impeller/entity/contents/filters/directional_gaussian_blur_filter_contents.cc

Public Member Functions

Additional Inherited Members