| Flutter Impeller |

Public Member Functions | List of all members
impeller::SolidRRectBlurContents Class Referencefinal

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 ()
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 Matrix &transform) 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 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, std::string_view 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...
std::optional< Size > | GetColorSourceSize () const
| Return the color source's intrinsic size, if available. More...
void | SetColorSourceSize (Size size)
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...

## 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 | ( |  | ) |
| override default

## Member Function Documentation

## ◆ ApplyColorFilter()

bool impeller::SolidRRectBlurContents::ApplyColorFilter | ( | const ColorFilterProc & | color_filter_proc | ) |
| override virtual

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 191 of file solid_rrect_blur_contents.cc.

192 {
193 color_ = color_filter_proc(color_);
194 return true;
195 }

## ◆ GetColor()

Color impeller::SolidRRectBlurContents::GetColor | ( |  | ) | const

Definition at line 47 of file solid_rrect_blur_contents.cc.

47 {
48 return color_;
49 }

## ◆ GetCoverage()

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

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 110 of file solid_rrect_blur_contents.cc.

111 {
112 if (!rect_.has_value()) {
113 return std::nullopt;
114 }
115
116 Scalar radius = PadForSigma(sigma_.sigma);
117
118 return rect_->Expand(radius).TransformBounds(entity.GetTransform());
119 }

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

## ◆ Render()

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

Implements impeller::Contents.

Definition at line 121 of file solid_rrect_blur_contents.cc.

123 {
124 if (!rect_.has_value()) {
125 return true;
126 }
127
128 using VS = RRectBlurPipeline::VertexShader;
129 using FS = RRectBlurPipeline::FragmentShader;
130
131 // Clamp the max kernel width/height to 1000 to limit the extent
132 // of the blur and to kEhCloseEnough to prevent NaN calculations
133 // trying to evaluate a Guassian distribution with a sigma of 0.
134 Scalar blur_sigma = std::clamp(sigma_.sigma, kEhCloseEnough, 250.0f);
135 // Increase quality by making the radius a bit bigger than the typical
136 // sigma->radius conversion we use for slower blurs.
137 Scalar blur_radius = PadForSigma(blur_sigma);
138 Rect positive_rect = rect_->GetPositive();
139 Scalar left = -blur_radius;
140 Scalar top = -blur_radius;
141 Scalar right = positive_rect.GetWidth() + blur_radius;
142 Scalar bottom = positive_rect.GetHeight() + blur_radius;
143
144 std::array<VS::PerVertexData, 4> vertices = {
145 VS::PerVertexData{Point(left, top)},
146 VS::PerVertexData{Point(right, top)},
147 VS::PerVertexData{Point(left, bottom)},
148 VS::PerVertexData{Point(right, bottom)},
149 };
150
151 ContentContextOptions opts = OptionsFromPassAndEntity(pass, entity);
152 opts.primitive_type = PrimitiveType::kTriangleStrip;
153 Color color = color_;
154 if (entity.GetBlendMode() == BlendMode::kClear) {
155 opts.is_for_rrect_blur_clear = true;
156 color = Color::White();
157 }
158
159 VS::FrameInfo frame_info;
160 frame_info.mvp = Entity::GetShaderTransform(
161 entity.GetShaderClipDepth(), pass,
162 entity.GetTransform() *
163 Matrix::MakeTranslation(positive_rect.GetOrigin()));
164
165 FS::FragInfo frag_info;
166 frag_info.color = color;
167 Scalar radius = std::min(std::clamp(corner_radii_.width, kEhCloseEnough,
168 positive_rect.GetWidth() * 0.5f),
169 std::clamp(corner_radii_.height, kEhCloseEnough,
170 positive_rect.GetHeight() * 0.5f));
171 if (!SetupFragInfo(frag_info, blur_sigma, positive_rect.GetCenter(),
172 Point(positive_rect.GetSize()), radius)) {
173 return true;
174 }
175
176 auto& host_buffer = renderer.GetTransientsBuffer();
177 pass.SetCommandLabel("RRect Shadow");
178 pass.SetPipeline(renderer.GetRRectBlurPipeline(opts));
179 pass.SetVertexBuffer(CreateVertexBuffer(vertices, host_buffer));
180
181 VS::BindFrameInfo(pass, host_buffer.EmplaceUniform(frame_info));
182 FS::BindFragInfo(pass, host_buffer.EmplaceUniform(frag_info));
183
184 if (!pass.Draw().ok()) {
185 return false;
186 }
187
188 return true;
189 }

References blur_radius, impeller::CreateVertexBuffer(), impeller::RenderPass::Draw(), impeller::Entity::GetBlendMode(), impeller::TRect< T >::GetCenter(), impeller::TRect< T >::GetHeight(), impeller::TRect< T >::GetOrigin(), impeller::ContentContext::GetRRectBlurPipeline(), impeller::Entity::GetShaderClipDepth(), impeller::Entity::GetShaderTransform(), impeller::TRect< T >::GetSize(), impeller::Entity::GetTransform(), impeller::ContentContext::GetTransientsBuffer(), impeller::TRect< T >::GetWidth(), 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::SetupFragInfo(), 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.

43 {
44 color_ = color.Premultiply();
45 }

References impeller::Color::Premultiply().

## ◆ SetRRect()

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

Definition at line 33 of file solid_rrect_blur_contents.cc.

34 {
35 rect_ = rect;
36 corner_radii_ = corner_radii;
37 }

## ◆ SetSigma()

void impeller::SolidRRectBlurContents::SetSigma | ( | Sigma | sigma | ) |

Definition at line 39 of file solid_rrect_blur_contents.cc.

39 {
40 sigma_ = sigma;
41 }

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

impeller::Sigma::sigma
Scalar sigma
Definition: sigma.h:33
impeller::RenderPipelineHandle::FragmentShader
FragmentShader_ FragmentShader
Definition: pipeline.h:114
impeller::Entity::GetShaderTransform
Matrix GetShaderTransform(const RenderPass &pass) const
Get the vertex shader transform used for drawing this Entity.
Definition: entity.cc:48
impeller::Scalar
float Scalar
Definition: scalar.h:18
impeller::kEhCloseEnough
constexpr float kEhCloseEnough
Definition: constants.h:56
impeller::VS
GlyphAtlasPipeline::VertexShader VS
Definition: text_contents.cc:25
impeller::Matrix::MakeTranslation
static constexpr Matrix MakeTranslation(const Vector3 &t)
Definition: matrix.h:95
impeller::OptionsFromPassAndEntity
ContentContextOptions OptionsFromPassAndEntity(const RenderPass &pass, const Entity &entity)
Definition: contents.cc:34
impeller::PrimitiveType::kTriangleStrip
@ kTriangleStrip
impeller::Point
TPoint< Scalar > Point
Definition: point.h:327
impeller::BlendMode::kClear
@ kClear
impeller::CreateVertexBuffer
VertexBuffer CreateVertexBuffer(std::array< VertexType, size > input, HostBuffer &host_buffer)
Create an index-less vertex buffer from a fixed size array.
Definition: vertex_buffer_builder.h:24
impeller::SetupFragInfo
static bool SetupFragInfo(RRectBlurPipeline::FragmentShader::FragInfo &frag_info, Scalar blurSigma, Point center, Point rSize, Scalar radius)
Definition: solid_rrect_blur_contents.cc:71
impeller::RenderPipelineHandle::VertexShader
VertexShader_ VertexShader
Definition: pipeline.h:113
impeller::Color::White
static constexpr Color White()
Definition: color.h:263
impeller::Rect
TRect< Scalar > Rect
Definition: rect.h:792
impeller::TSize::width
Type width
Definition: size.h:28
blur_radius
Vector2 blur_radius
Blur radius in source pixels based on scaled_sigma.
Definition: gaussian_blur_filter_contents.cc:84
impeller::TSize::height
Type height
Definition: size.h:29
impeller::FS
GlyphAtlasPipeline::FragmentShader FS
Definition: text_contents.cc:26
impeller::Color::Premultiply
constexpr Color Premultiply() const
Definition: color.h:211