| Flutter Impeller |

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

`#include <clip_contents.h>`

Inheritance diagram for impeller::ClipRestoreContents:

## Public Member Functions
| ClipRestoreContents ()
| ~ClipRestoreContents ()
void | SetRestoreCoverage (std::optional< Rect > coverage)
| The area on the pass texture where this clip restore will be applied. If unset, the entire pass texture will be restored. More...
std::optional< Rect > | GetCoverage (const Entity &entity) const override
| Get the screen space bounding rectangle that this contents affects. More...
StencilCoverage | GetStencilCoverage (const Entity &entity, const std::optional< Rect > &current_stencil_coverage) const override
| Given the current screen space bounding rectangle of the stencil, return the expected stencil coverage after this draw call. This should only be implemented for contents that may write to the stencil buffer. More...
bool | ShouldRender (const Entity &entity, const std::optional< Rect > stencil_coverage) const override
bool | Render (const ContentContext &renderer, const Entity &entity, RenderPass &pass) const override
bool | CanInheritOpacity (const Entity &entity) const override
| Whether or not this contents can accept the opacity peephole optimization. More...
void | SetInheritedOpacity (Scalar opacity) override
| Inherit the provided opacity. 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 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="Snapshot") const
| Render this contents to a snapshot, respecting the entity's transform, path, stencil 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 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...
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::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

Definition at line 57 of file clip_contents.h.

## Constructor & Destructor Documentation

## ◆ ClipRestoreContents()

impeller::ClipRestoreContents::ClipRestoreContents | ( |  | ) |
| default

## ◆ ~ClipRestoreContents()

impeller::ClipRestoreContents::~ClipRestoreContents | ( |  | ) |
| default

## Member Function Documentation

## ◆ CanInheritOpacity()

bool impeller::ClipRestoreContents::CanInheritOpacity | ( | const Entity & | entity | ) | const
| override virtual

Whether or not this contents can accept the opacity peephole optimization.

By default all contents return false. Contents are responsible for determining whether or not their own geometries intersect in a way that makes accepting opacity impossible. It is always safe to return false, especially if computing overlap would be computationally expensive.

Reimplemented from impeller::Contents.

Definition at line 170 of file clip_contents.cc.

170 {
171 return true;
172 }

## ◆ GetCoverage()

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

Get the screen space bounding rectangle that this contents affects.

Implements impeller::Contents.

Definition at line 153 of file clip_contents.cc.

154 {
155 return std::nullopt;
156 };

## ◆ GetStencilCoverage()

Contents::StencilCoverage impeller::ClipRestoreContents::GetStencilCoverage | ( | const Entity & | entity,
|  | const std::optional< Rect > & | current_stencil_coverage
| ) |  | const
| override virtual

Given the current screen space bounding rectangle of the stencil, return the expected stencil coverage after this draw call. This should only be implemented for contents that may write to the stencil buffer.

Reimplemented from impeller::Contents.

Definition at line 158 of file clip_contents.cc.

160 {
161 return {.type = StencilCoverage::Type::kRestore, .coverage = std::nullopt};
162 }

References impeller::Contents::StencilCoverage::type.

## ◆ Render()

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

Implements impeller::Contents.

Definition at line 176 of file clip_contents.cc.

178 {
179 using VS = ClipPipeline::VertexShader;
180
181 Command cmd;
182 DEBUG_COMMAND_INFO(cmd, "Restore Clip");
183 auto options = OptionsFromPass(pass);
184 options.blend_mode = BlendMode::kDestination;
185 options.stencil_compare = CompareFunction::kLess;
186 options.stencil_operation = StencilOperation::kSetToReferenceValue;
187 options.primitive_type = PrimitiveType::kTriangleStrip;
188 cmd.pipeline = renderer.GetClipPipeline(options);
189 cmd.stencil_reference = entity.GetStencilDepth();
190
191 // Create a rect that covers either the given restore area, or the whole
192 // render target texture.
193 auto ltrb = restore_coverage_.value_or(Rect(Size(pass.GetRenderTargetSize())))
194 .GetLTRB();
195 VertexBufferBuilder<VS::PerVertexData> vtx_builder;
196 vtx_builder.AddVertices({
197 {Point(ltrb[0], ltrb[1])},
198 {Point(ltrb[2], ltrb[1])},
199 {Point(ltrb[0], ltrb[3])},
200 {Point(ltrb[2], ltrb[3])},
201 });
202 cmd.BindVertices(vtx_builder.CreateVertexBuffer(pass.GetTransientsBuffer()));
203
204 VS::FrameInfo info;
205 info.mvp = Matrix::MakeOrthographic(pass.GetRenderTargetSize());
206 VS::BindFrameInfo(cmd, pass.GetTransientsBuffer().EmplaceUniform(info));
207
208 pass.AddCommand(std::move(cmd));
209 return true;
210 }

References impeller::RenderPass::AddCommand(), impeller::VertexBufferBuilder< VertexType_, IndexType_ >::AddVertices(), impeller::Command::BindVertices(), impeller::VertexBufferBuilder< VertexType_, IndexType_ >::CreateVertexBuffer(), DEBUG_COMMAND_INFO, impeller::HostBuffer::EmplaceUniform(), impeller::ContentContext::GetClipPipeline(), impeller::RenderPass::GetRenderTargetSize(), impeller::Entity::GetStencilDepth(), impeller::RenderPass::GetTransientsBuffer(), impeller::kDestination, impeller::kLess, impeller::kSetToReferenceValue, impeller::kTriangleStrip, impeller::Matrix::MakeOrthographic(), impeller::OptionsFromPass(), impeller::Command::pipeline, and impeller::Command::stencil_reference.

## ◆ SetInheritedOpacity()

void impeller::ClipRestoreContents::SetInheritedOpacity | ( | Scalar | opacity | ) |
| override virtual

Inherit the provided opacity.

       Use of this method is invalid if CanAcceptOpacity returns false.

Reimplemented from impeller::Contents.

Definition at line 174 of file clip_contents.cc.

174 {}

## ◆ SetRestoreCoverage()

void impeller::ClipRestoreContents::SetRestoreCoverage | ( | std::optional< Rect > | coverage | ) |

The area on the pass texture where this clip restore will be applied. If unset, the entire pass texture will be restored.

Note
  This rectangle is not transformed by the entity's transformation.

Definition at line 148 of file clip_contents.cc.

149 {
150 restore_coverage_ = restore_coverage;
151 }

## ◆ ShouldRender()

bool impeller::ClipRestoreContents::ShouldRender | ( | const Entity & | entity,
|  | const std::optional< Rect > | stencil_coverage
| ) |  | const
| override virtual

Reimplemented from impeller::Contents.

Definition at line 164 of file clip_contents.cc.

166 {
167 return true;
168 }

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

- impeller/entity/contents/clip_contents.h
- impeller/entity/contents/clip_contents.cc

impeller::OptionsFromPass
ContentContextOptions OptionsFromPass(const RenderPass &pass)
Definition: contents.cc:20
DEBUG_COMMAND_INFO
#define DEBUG_COMMAND_INFO(obj, arg)
Definition: command.h:31
impeller::Size
TSize< Scalar > Size
Definition: size.h:135
impeller::PrimitiveType::kTriangleStrip
@ kTriangleStrip
impeller::Point
TPoint< Scalar > Point
Definition: point.h:306
impeller::StencilOperation::kSetToReferenceValue
@ kSetToReferenceValue
Reset the stencil value to the reference value.
impeller::BlendMode::kDestination
@ kDestination
impeller::Rect
TRect< Scalar > Rect
Definition: rect.h:306
impeller::CompareFunction::kLess
@ kLess
Comparison test passes if new_value < current_value.
impeller::Matrix::MakeOrthographic
static constexpr Matrix MakeOrthographic(TSize< T > size)
Definition: matrix.h:448
impeller::RenderPipelineT::VertexShader
VertexShader_ VertexShader
Definition: pipeline.h:90