| 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 | SetRestoreHeight (size_t clip_height)
size_t | GetRestoreHeight () const
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 | Render (const ContentContext &renderer, const Entity &entity, RenderPass &pass) const override
void | SetInheritedOpacity (Scalar opacity) override
| Inherit the provided opacity. 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, 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 49 of file clip_contents.h.

## Constructor & Destructor Documentation

## ◆ ClipRestoreContents()

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

## ◆ ~ClipRestoreContents()

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

## Member Function Documentation

## ◆ 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 192 of file clip_contents.cc.

194 {
195 return {.type = ClipCoverage::Type::kRestore, .coverage = std::nullopt};
196 }

References 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 187 of file clip_contents.cc.

188 {
189 return std::nullopt;
190 };

## ◆ GetRestoreHeight()

size_t impeller::ClipRestoreContents::GetRestoreHeight | ( |  | ) | const

Definition at line 178 of file clip_contents.cc.

178 {
179 return restore_height_;
180 }

Referenced by impeller::EntityPassClipStack::ApplyClipState().

## ◆ Render()

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

Implements impeller::Contents.

Definition at line 200 of file clip_contents.cc.

202 {
203 using VS = ClipPipeline::VertexShader;
204
205 pass.SetCommandLabel("Restore Clip");
206 auto options = OptionsFromPass(pass);
207 options.blend_mode = BlendMode::kDestination;
208 options.stencil_mode =
209 ContentContextOptions::StencilMode::kOverdrawPreventionRestore;
210 options.primitive_type = PrimitiveType::kTriangleStrip;
211 pass.SetPipeline(renderer.GetClipPipeline(options));
212 pass.SetStencilReference(0);
213
214 // Create a rect that covers either the given restore area, or the whole
215 // render target texture.
216 auto ltrb =
217 restore_coverage_.value_or(Rect::MakeSize(pass.GetRenderTargetSize()))
218 .GetLTRB();
219
220 std::array<VS::PerVertexData, 4> vertices = {
221 VS::PerVertexData{Point(ltrb[0], ltrb[1])},
222 VS::PerVertexData{Point(ltrb[2], ltrb[1])},
223 VS::PerVertexData{Point(ltrb[0], ltrb[3])},
224 VS::PerVertexData{Point(ltrb[2], ltrb[3])},
225 };
226 pass.SetVertexBuffer(
227 CreateVertexBuffer(vertices, renderer.GetTransientsBuffer()));
228
229 VS::FrameInfo info;
230 info.depth = GetShaderClipDepth(entity);
231 info.mvp = pass.GetOrthographicTransform();
232 VS::BindFrameInfo(pass, renderer.GetTransientsBuffer().EmplaceUniform(info));
233
234 return pass.Draw().ok();
235 }

References impeller::CreateVertexBuffer(), impeller::RenderPass::Draw(), impeller::HostBuffer::EmplaceUniform(), impeller::ContentContext::GetClipPipeline(), impeller::RenderPass::GetOrthographicTransform(), impeller::RenderPass::GetRenderTargetSize(), impeller::GetShaderClipDepth(), impeller::ContentContext::GetTransientsBuffer(), impeller::kDestination, impeller::ContentContextOptions::kOverdrawPreventionRestore, impeller::kTriangleStrip, impeller::TRect< Scalar >::MakeSize(), impeller::OptionsFromPass(), impeller::RenderPass::SetCommandLabel(), impeller::RenderPass::SetPipeline(), impeller::RenderPass::SetStencilReference(), and impeller::RenderPass::SetVertexBuffer().

## ◆ 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 198 of file clip_contents.cc.

198 {}

## ◆ 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 182 of file clip_contents.cc.

183 {
184 restore_coverage_ = restore_coverage;
185 }

## ◆ SetRestoreHeight()

void impeller::ClipRestoreContents::SetRestoreHeight | ( | size_t | clip_height | ) |

Definition at line 174 of file clip_contents.cc.

174 {
175 restore_height_ = clip_height;
176 }

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:19
impeller::BlendMode::kDestination
@ kDestination
impeller::GetShaderClipDepth
static Scalar GetShaderClipDepth(const Entity &entity)
Definition: clip_contents.cc:19
impeller::VS
SolidFillVertexShader VS
Definition: stroke_path_geometry.cc:16
impeller::PrimitiveType::kTriangleStrip
@ kTriangleStrip
impeller::Point
TPoint< Scalar > Point
Definition: point.h:327
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::TRect< Scalar >::MakeSize
constexpr static TRect MakeSize(const TSize< U > &size)
Definition: rect.h:150
impeller::ContentContextOptions::StencilMode::kOverdrawPreventionRestore
@ kOverdrawPreventionRestore