impeller::SolidRRectBlurContents Class Reference

Draws a fast solid color blur of an rounded rectangle. Only supports RRects with fully symmetrical radii. Also produces correct results for rectangles (corner_radius=0) and circles (corner_radius=width/2=height/2). More...

#include <solid_rrect_blur_contents.h>

Inheritance diagram for impeller::SolidRRectBlurContents:

Public Member Functions
	SolidRRectBlurContents ()
	~SolidRRectBlurContents () override
void	SetRRect (std::optional< Rect > rect, Size corner_radii={})
void	SetSigma (Sigma sigma)
void	SetColor (Color color)
Color	GetColor () const
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...
bool	Render (const ContentContext &renderer, const Entity &entity, RenderPass &pass) const override
bool	ApplyColorFilter (const ColorFilterProc &color_filter_proc) override
	If possible, applies a color filter to this contents inputs on the CPU. More...
Public Member Functions inherited from impeller::Contents
	Contents ()
virtual	~Contents ()
virtual void	PopulateGlyphAtlas (const std::shared_ptr< LazyGlyphAtlas > &lazy_glyph_atlas, Scalar scale)
	Add any text data to the specified lazy atlas. The scale parameter must be used again later when drawing the text. More...
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 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, int32_t mip_count=1, const std::string &label="Snapshot") const
	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...
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 const FilterContents *	AsFilter () const
	Cast to a filter. Returns nullptr if this Contents is not a filter. More...

Additional Inherited Members
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::Contents
static std::shared_ptr< Contents >	MakeAnonymous (RenderProc render_proc, CoverageProc coverage_proc)

Detailed Description

Draws a fast solid color blur of an rounded rectangle. Only supports RRects with fully symmetrical radii. Also produces correct results for rectangles (corner_radius=0) and circles (corner_radius=width/2=height/2).

Definition at line 25 of file solid_rrect_blur_contents.h.

Constructor & Destructor Documentation

SolidRRectBlurContents()

impeller::SolidRRectBlurContents::SolidRRectBlurContents ( )

default

~SolidRRectBlurContents()

impeller::SolidRRectBlurContents::~SolidRRectBlurContents ( )

overridedefault

Member Function Documentation

ApplyColorFilter()

bool impeller::SolidRRectBlurContents::ApplyColorFilter ( const ColorFilterProc &  color_filter_proc )

overridevirtual

If possible, applies a color filter to this contents inputs on the CPU.

This method will either fully apply the color filter or perform no action. Partial/incorrect application of the color filter will never occur.

Parameters

[in]

color_filter_proc

A function that filters a given unpremultiplied color to produce a new unpremultiplied color.

Returns

True if the color filter was able to be fully applied to all all relevant inputs. Otherwise, this operation is a no-op and false is returned.

Reimplemented from impeller::Contents.

Definition at line 135 of file solid_rrect_blur_contents.cc.

                                              {
  color_ = color_filter_proc(color_);
  return true;
}

GetColor()

Color impeller::SolidRRectBlurContents::GetColor

(

)

const

Definition at line 47 of file solid_rrect_blur_contents.cc.

                                             {
  return color_;
}

GetCoverage()

std::optional< Rect > impeller::SolidRRectBlurContents::GetCoverage ( const Entity &  entity ) const

overridevirtual

Get the area of the render pass that will be affected when this contents is rendered.

During rendering, coverage coordinates count pixels from the top left corner of the framebuffer.

Returns

The coverage rectangle. An std::nullopt result means that rendering this contents has no effect on the output color.

Implements impeller::Contents.

Definition at line 51 of file solid_rrect_blur_contents.cc.

                                {
  if (!rect_.has_value()) {
    return std::nullopt;
  }
 
  Scalar radius = PadForSigma(sigma_.sigma);
 
  return rect_->Expand(radius).TransformBounds(entity.GetTransform());
}

References impeller::Entity::GetTransform(), and impeller::Sigma::sigma.

Render()

bool impeller::SolidRRectBlurContents::Render ( const ContentContext &  renderer, const Entity &  entity, RenderPass &  pass  ) const

overridevirtual

Implements impeller::Contents.

Definition at line 62 of file solid_rrect_blur_contents.cc.

                                                            {
  if (!rect_.has_value()) {
    return true;
  }
 
  using VS = RRectBlurPipeline::VertexShader;
  using FS = RRectBlurPipeline::FragmentShader;
 
  VertexBufferBuilder<VS::PerVertexData> vtx_builder;
 
  // Clamp the max kernel width/height to 1000 to limit the extent
  // of the blur and to kEhCloseEnough to prevent NaN calculations
  // trying to evaluate a Guassian distribution with a sigma of 0.
  auto blur_sigma = std::clamp(sigma_.sigma, kEhCloseEnough, 250.0f);
  // Increase quality by making the radius a bit bigger than the typical
  // sigma->radius conversion we use for slower blurs.
  auto blur_radius = PadForSigma(blur_sigma);
  auto positive_rect = rect_->GetPositive();
  {
    auto left = -blur_radius;
    auto top = -blur_radius;
    auto right = positive_rect.GetWidth() + blur_radius;
    auto bottom = positive_rect.GetHeight() + blur_radius;
 
    vtx_builder.AddVertices({
        {Point(left, top)},
        {Point(right, top)},
        {Point(left, bottom)},
        {Point(right, bottom)},
    });
  }
 
  ContentContextOptions opts = OptionsFromPassAndEntity(pass, entity);
  opts.primitive_type = PrimitiveType::kTriangleStrip;
  Color color = color_;
  if (entity.GetBlendMode() == BlendMode::kClear) {
    opts.is_for_rrect_blur_clear = true;
    color = Color::White();
  }
 
  VS::FrameInfo frame_info;
  frame_info.mvp = Entity::GetShaderTransform(
      entity.GetShaderClipDepth(), pass,
      entity.GetTransform() *
          Matrix::MakeTranslation(positive_rect.GetOrigin()));
 
  FS::FragInfo frag_info;
  frag_info.color = color;
  frag_info.blur_sigma = blur_sigma;
  frag_info.rect_size = Point(positive_rect.GetSize());
  frag_info.corner_radii = {std::clamp(corner_radii_.width, kEhCloseEnough,
                                       positive_rect.GetWidth() * 0.5f),
                            std::clamp(corner_radii_.height, kEhCloseEnough,
                                       positive_rect.GetHeight() * 0.5f)};
 
  pass.SetCommandLabel("RRect Shadow");
  pass.SetPipeline(renderer.GetRRectBlurPipeline(opts));
  pass.SetVertexBuffer(
      vtx_builder.CreateVertexBuffer(renderer.GetTransientsBuffer()));
  VS::BindFrameInfo(pass,
                    renderer.GetTransientsBuffer().EmplaceUniform(frame_info));
  FS::BindFragInfo(pass,
                   renderer.GetTransientsBuffer().EmplaceUniform(frag_info));
 
  if (!pass.Draw().ok()) {
    return false;
  }
 
  return true;
}

References impeller::VertexBufferBuilder< VertexType_, IndexType_ >::AddVertices(), blur_radius, color, impeller::VertexBufferBuilder< VertexType_, IndexType_ >::CreateVertexBuffer(), impeller::RenderPass::Draw(), impeller::HostBuffer::EmplaceUniform(), impeller::Entity::GetBlendMode(), impeller::ContentContext::GetRRectBlurPipeline(), impeller::Entity::GetShaderClipDepth(), impeller::Entity::GetShaderTransform(), impeller::Entity::GetTransform(), impeller::ContentContext::GetTransientsBuffer(), impeller::TSize< T >::height, impeller::ContentContextOptions::is_for_rrect_blur_clear, impeller::kClear, impeller::kEhCloseEnough, impeller::kTriangleStrip, impeller::Matrix::MakeTranslation(), impeller::OptionsFromPassAndEntity(), impeller::ContentContextOptions::primitive_type, impeller::RenderPass::SetCommandLabel(), impeller::RenderPass::SetPipeline(), impeller::RenderPass::SetVertexBuffer(), impeller::Sigma::sigma, impeller::Color::White(), and impeller::TSize< T >::width.

SetColor()

void impeller::SolidRRectBlurContents::SetColor

(

Color

color

)

Definition at line 43 of file solid_rrect_blur_contents.cc.

                                                 {
  color_ = color.Premultiply();
}

References color.

SetRRect()

void impeller::SolidRRectBlurContents::SetRRect	(	std::optional< Rect >	rect,
		Size	corner_radii = {}
	)

Definition at line 33 of file solid_rrect_blur_contents.cc.

                                                         {
  rect_ = rect;
  corner_radii_ = corner_radii;
}

SetSigma()

void impeller::SolidRRectBlurContents::SetSigma

(

Sigma

sigma

)

Definition at line 39 of file solid_rrect_blur_contents.cc.

                                                 {
  sigma_ = sigma;
}

---

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

• impeller/entity/contents/solid_rrect_blur_contents.h
• impeller/entity/contents/solid_rrect_blur_contents.cc