| 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 ()
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 | ( |  | ) |
| 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 132 of file solid_rrect_blur_contents.cc.

133 {
134 color_ = color_filter_proc(color_);
135 return true;
136 }

## ◆ GetColor()

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

Definition at line 43 of file solid_rrect_blur_contents.cc.

43 {
44 return color_;
45 }

## ◆ 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 47 of file solid_rrect_blur_contents.cc.

48 {
49 if (!rect_.has_value()) {
50 return std::nullopt;
51 }
52
53 Scalar radius = PadForSigma(sigma_.sigma);
54
55 return rect_->Expand(radius).TransformBounds(entity.GetTransform());
56 }

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 58 of file solid_rrect_blur_contents.cc.

60 {
61 if (!rect_.has_value()) {
62 return true;
63 }
64
65 using VS = RRectBlurPipeline::VertexShader;
66 using FS = RRectBlurPipeline::FragmentShader;
67
68 VertexBufferBuilder<VS::PerVertexData> vtx_builder;
69
70 // Clamp the max kernel width/height to 1000 to limit the extent
71 // of the blur and to kEhCloseEnough to prevent NaN calculations
72 // trying to evaluate a Guassian distribution with a sigma of 0.
73 auto blur_sigma = std::clamp(sigma_.sigma, kEhCloseEnough, 250.0f);
74 // Increase quality by making the radius a bit bigger than the typical
75 // sigma->radius conversion we use for slower blurs.
76 auto blur_radius = PadForSigma(blur_sigma);
77 auto positive_rect = rect_->GetPositive();
78 {
79 auto left = -blur_radius;
80 auto top = -blur_radius;
81 auto right = positive_rect.GetWidth() + blur_radius;
82 auto bottom = positive_rect.GetHeight() + blur_radius;
83
84 vtx_builder.AddVertices({
85 {Point(left, top)},
86 {Point(right, top)},
87 {Point(left, bottom)},
88 {Point(right, bottom)},
89 });
90 }
91
92 ContentContextOptions opts = OptionsFromPassAndEntity(pass, entity);
93 opts.primitive_type = PrimitiveType::kTriangleStrip;
94 Color color = color_;
95 if (entity.GetBlendMode() == BlendMode::kClear) {
96 opts.is_for_rrect_blur_clear = true;
97 color = Color::White();
98 }
99
100 VS::FrameInfo frame_info;
101 frame_info.mvp = Entity::GetShaderTransform(
102 entity.GetShaderClipDepth(), pass,
103 entity.GetTransform() *
104 Matrix::MakeTranslation(positive_rect.GetOrigin()));
105
106 FS::FragInfo frag_info;
107 frag_info.color = color;
108 frag_info.blur_sigma = blur_sigma;
109 frag_info.rect_size = Point(positive_rect.GetSize());
110 frag_info.corner_radii = {std::clamp(corner_radii_.width, kEhCloseEnough,
111 positive_rect.GetWidth() * 0.5f),
112 std::clamp(corner_radii_.width, kEhCloseEnough,
113 positive_rect.GetHeight() * 0.5f)};
114
115 pass.SetCommandLabel("RRect Shadow");
116 pass.SetPipeline(renderer.GetRRectBlurPipeline(opts));
117 pass.SetStencilReference(entity.GetClipDepth());
118 pass.SetVertexBuffer(
119 vtx_builder.CreateVertexBuffer(renderer.GetTransientsBuffer()));
120 VS::BindFrameInfo(pass,
121 renderer.GetTransientsBuffer().EmplaceUniform(frame_info));
122 FS::BindFragInfo(pass,
123 renderer.GetTransientsBuffer().EmplaceUniform(frag_info));
124
125 if (!pass.Draw().ok()) {
126 return false;
127 }
128
129 return true;
130 }

References impeller::VertexBufferBuilder< VertexType_, IndexType_ >::AddVertices(), impeller::VertexBufferBuilder< VertexType_, IndexType_ >::CreateVertexBuffer(), impeller::RenderPass::Draw(), impeller::HostBuffer::EmplaceUniform(), impeller::Entity::GetBlendMode(), impeller::Entity::GetClipDepth(), impeller::ContentContext::GetRRectBlurPipeline(), impeller::Entity::GetShaderClipDepth(), impeller::Entity::GetShaderTransform(), impeller::Entity::GetTransform(), impeller::ContentContext::GetTransientsBuffer(), 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::SetStencilReference(), impeller::RenderPass::SetVertexBuffer(), impeller::Sigma::sigma, impeller::Color::White(), and impeller::TSize< T >::width.

## ◆ SetColor()

void impeller::SolidRRectBlurContents::SetColor | ( | Color | color | ) |

Definition at line 39 of file solid_rrect_blur_contents.cc.

39 {
40 color_ = color.Premultiply();
41 }

References impeller::Color::Premultiply().

## ◆ SetRRect()

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

Definition at line 29 of file solid_rrect_blur_contents.cc.

30 {
31 rect_ = rect;
32 corner_radii_ = corner_radii;
33 }

## ◆ SetSigma()

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

Definition at line 35 of file solid_rrect_blur_contents.cc.

35 {
36 sigma_ = sigma;
37 }

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::Entity::GetShaderTransform
Matrix GetShaderTransform(const RenderPass &pass) const
Get the vertex shader transform used for drawing this Entity.
Definition: entity.cc:53
impeller::Scalar
float Scalar
Definition: scalar.h:18
impeller::kEhCloseEnough
constexpr float kEhCloseEnough
Definition: constants.h:56
impeller::RenderPipelineT::FragmentShader
FragmentShader_ FragmentShader
Definition: pipeline.h:94
impeller::Matrix::MakeTranslation
static constexpr Matrix MakeTranslation(const Vector3 &t)
Definition: matrix.h:95
impeller::VS
SolidFillVertexShader VS
Definition: stroke_path_geometry.cc:15
impeller::OptionsFromPassAndEntity
ContentContextOptions OptionsFromPassAndEntity(const RenderPass &pass, const Entity &entity)
Definition: contents.cc:37
impeller::PrimitiveType::kTriangleStrip
@ kTriangleStrip
impeller::Point
TPoint< Scalar > Point
Definition: point.h:316
impeller::BlendMode::kClear
@ kClear
impeller::Color::White
static constexpr Color White()
Definition: color.h:256
impeller::TSize::width
Type width
Definition: size.h:22
impeller::RenderPipelineT::VertexShader
VertexShader_ VertexShader
Definition: pipeline.h:93
impeller::Color::Premultiply
constexpr Color Premultiply() const
Definition: color.h:214