| 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 area of the render pass that will be affected when this contents is rendered. More...
ClipCoverage | GetClipCoverage (const Entity &entity, const std::optional< Rect > &current_clip_coverage) const override
| 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...
bool | ShouldRender (const Entity &entity, const std::optional< Rect > clip_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, 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 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 60 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 167 of file clip_contents.cc.

167 {
168 return true;
169 }

## ◆ GetClipCoverage()

Contents::ClipCoverage impeller::ClipRestoreContents::GetClipCoverage | ( | const Entity & | entity,
|  | const std::optional< Rect > & | current_clip_coverage
| ) |  | const
| override virtual

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.

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

Reimplemented from impeller::Contents.

Definition at line 155 of file clip_contents.cc.

157 {
158 return {.type = ClipCoverage::Type::kRestore, .coverage = std::nullopt};
159 }

References impeller::kRestore, and impeller::Contents::ClipCoverage::type.

## ◆ GetCoverage()

std::optional< Rect > impeller::ClipRestoreContents::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 150 of file clip_contents.cc.

151 {
152 return std::nullopt;
153 };

## ◆ Render()

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

Implements impeller::Contents.

Definition at line 173 of file clip_contents.cc.

175 {
176 using VS = ClipPipeline::VertexShader;
177
178 Command cmd;
179 DEBUG_COMMAND_INFO(cmd, "Restore Clip");
180 auto options = OptionsFromPass(pass);
181 options.blend_mode = BlendMode::kDestination;
182 options.stencil_compare = CompareFunction::kLess;
183 options.stencil_operation = StencilOperation::kSetToReferenceValue;
184 options.primitive_type = PrimitiveType::kTriangleStrip;
185 cmd.pipeline = renderer.GetClipPipeline(options);
186 cmd.stencil_reference = entity.GetClipDepth();
187
188 // Create a rect that covers either the given restore area, or the whole
189 // render target texture.
190 auto ltrb =
191 restore_coverage_.value_or(Rect::MakeSize(pass.GetRenderTargetSize()))
192 .GetLTRB();
193 VertexBufferBuilder<VS::PerVertexData> vtx_builder;
194 vtx_builder.AddVertices({
195 {Point(ltrb[0], ltrb[1])},
196 {Point(ltrb[2], ltrb[1])},
197 {Point(ltrb[0], ltrb[3])},
198 {Point(ltrb[2], ltrb[3])},
199 });
200 cmd.BindVertices(vtx_builder.CreateVertexBuffer(pass.GetTransientsBuffer()));
201
202 VS::FrameInfo info;
203 info.mvp = pass.GetOrthographicTransform();
204 VS::BindFrameInfo(cmd, pass.GetTransientsBuffer().EmplaceUniform(info));
205
206 pass.AddCommand(std::move(cmd));
207 return true;
208 }

References impeller::RenderPass::AddCommand(), impeller::VertexBufferBuilder< VertexType_, IndexType_ >::AddVertices(), impeller::Command::BindVertices(), impeller::VertexBufferBuilder< VertexType_, IndexType_ >::CreateVertexBuffer(), DEBUG_COMMAND_INFO, impeller::HostBuffer::EmplaceUniform(), impeller::Entity::GetClipDepth(), impeller::ContentContext::GetClipPipeline(), impeller::RenderPass::GetOrthographicTransform(), impeller::RenderPass::GetRenderTargetSize(), impeller::RenderPass::GetTransientsBuffer(), impeller::kDestination, impeller::kLess, impeller::kSetToReferenceValue, impeller::kTriangleStrip, impeller::TRect< Scalar >::MakeSize(), 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 171 of file clip_contents.cc.

171 {}

## ◆ 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 transform.

Definition at line 145 of file clip_contents.cc.

146 {
147 restore_coverage_ = restore_coverage;
148 }

## ◆ ShouldRender()

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

Reimplemented from impeller::Contents.

Definition at line 161 of file clip_contents.cc.

163 {
164 return true;
165 }

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:28
impeller::BlendMode::kDestination
@ kDestination
impeller::StencilOperation::kSetToReferenceValue
@ kSetToReferenceValue
Reset the stencil value to the reference value.
impeller::PrimitiveType::kTriangleStrip
@ kTriangleStrip
impeller::Point
TPoint< Scalar > Point
Definition: point.h:308
impeller::TRect< Scalar >::MakeSize
constexpr static TRect MakeSize(const TSize< U > &size)
Definition: rect.h:44
impeller::RenderPipelineT::VertexShader
VertexShader_ VertexShader
Definition: pipeline.h:92
impeller::CompareFunction::kLess
@ kLess
Comparison test passes if new_value < current_value.
impeller::kRestore
@ kRestore
Definition: canvas_recorder.h:23