| 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 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...
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...
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 | ( |  | ) |
| 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 179 of file solid_rrect_blur_contents.cc.

180 {
181 color_ = color_filter_proc(color_);
182 return true;
183 }

## ◆ 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 101 of file solid_rrect_blur_contents.cc.

102 {
103 if (!rect_.has_value()) {
104 return std::nullopt;
105 }
106
107 Scalar radius = PadForSigma(sigma_.sigma);
108
109 return rect_->Expand(radius).TransformBounds(entity.GetTransform());
110 }

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 112 of file solid_rrect_blur_contents.cc.

114 {
115 if (!rect_.has_value()) {
116 return true;
117 }
118
119 using VS = RRectBlurPipeline::VertexShader;
120 using FS = RRectBlurPipeline::FragmentShader;
121
122 // Clamp the max kernel width/height to 1000 to limit the extent
123 // of the blur and to kEhCloseEnough to prevent NaN calculations
124 // trying to evaluate a Guassian distribution with a sigma of 0.
125 Scalar blur_sigma = std::clamp(sigma_.sigma, kEhCloseEnough, 250.0f);
126 // Increase quality by making the radius a bit bigger than the typical
127 // sigma->radius conversion we use for slower blurs.
128 Scalar blur_radius = PadForSigma(blur_sigma);
129 Rect positive_rect = rect_->GetPositive();
130 Scalar left = -blur_radius;
131 Scalar top = -blur_radius;
132 Scalar right = positive_rect.GetWidth() + blur_radius;
133 Scalar bottom = positive_rect.GetHeight() + blur_radius;
134
135 std::array<VS::PerVertexData, 4> vertices = {
136 VS::PerVertexData{Point(left, top)},
137 VS::PerVertexData{Point(right, top)},
138 VS::PerVertexData{Point(left, bottom)},
139 VS::PerVertexData{Point(right, bottom)},
140 };
141
142 ContentContextOptions opts = OptionsFromPassAndEntity(pass, entity);
143 opts.primitive_type = PrimitiveType::kTriangleStrip;
144 Color color = color_;
145 if (entity.GetBlendMode() == BlendMode::kClear) {
146 opts.is_for_rrect_blur_clear = true;
147 color = Color::White();
148 }
149
150 VS::FrameInfo frame_info;
151 frame_info.mvp = Entity::GetShaderTransform(
152 entity.GetShaderClipDepth(), pass,
153 entity.GetTransform() *
154 Matrix::MakeTranslation(positive_rect.GetOrigin()));
155
156 FS::FragInfo frag_info;
157 frag_info.color = color;
158 Scalar radius = std::min(std::clamp(corner_radii_.width, kEhCloseEnough,
159 positive_rect.GetWidth() * 0.5f),
160 std::clamp(corner_radii_.height, kEhCloseEnough,
161 positive_rect.GetHeight() * 0.5f));
162 SetupFragInfo(frag_info, blur_sigma, positive_rect.GetCenter(),
163 Point(positive_rect.GetSize()), radius);
164 auto& host_buffer = renderer.GetTransientsBuffer();
165 pass.SetCommandLabel("RRect Shadow");
166 pass.SetPipeline(renderer.GetRRectBlurPipeline(opts));
167 pass.SetVertexBuffer(CreateVertexBuffer(vertices, host_buffer));
168
169 VS::BindFrameInfo(pass, host_buffer.EmplaceUniform(frame_info));
170 FS::BindFragInfo(pass, host_buffer.EmplaceUniform(frag_info));
171
172 if (!pass.Draw().ok()) {
173 return false;
174 }
175
176 return true;
177 }

References blur_radius, color, 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 color.

## ◆ 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:107
impeller::Entity::GetShaderTransform
Matrix GetShaderTransform(const RenderPass &pass) const
Get the vertex shader transform used for drawing this Entity.
Definition: entity.cc:51
impeller::Scalar
float Scalar
Definition: scalar.h:18
impeller::kEhCloseEnough
constexpr float kEhCloseEnough
Definition: constants.h:56
impeller::Matrix::MakeTranslation
static constexpr Matrix MakeTranslation(const Vector3 &t)
Definition: matrix.h:95
impeller::SetupFragInfo
static void SetupFragInfo(RRectBlurPipeline::FragmentShader::FragInfo &frag_info, Scalar blurSigma, Point center, Point rSize, Scalar radius)
Definition: solid_rrect_blur_contents.cc:71
impeller::VS
SolidFillVertexShader VS
Definition: stroke_path_geometry.cc:16
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::RenderPipelineHandle::VertexShader
VertexShader_ VertexShader
Definition: pipeline.h:106
impeller::Color::White
static constexpr Color White()
Definition: color.h:263
impeller::Rect
TRect< Scalar > Rect
Definition: rect.h:776
impeller::TSize::width
Type width
Definition: size.h:22
blur_radius
Vector2 blur_radius
Blur radius in source pixels based on scaled_sigma.
Definition: gaussian_blur_filter_contents.cc:83
color
DlColor color
Definition: dl_golden_blur_unittests.cc:24
impeller::TSize::height
Type height
Definition: size.h:23