Flutter Impeller
impeller::ClipContents Class Referencefinal

#include <clip_contents.h>

Inheritance diagram for impeller::ClipContents:
impeller::Contents

Public Member Functions

 ClipContents ()
 
 ~ClipContents ()
 
void SetGeometry (const std::shared_ptr< Geometry > &geometry)
 
void SetClipOperation (Entity::ClipOperation clip_op)
 
std::optional< RectGetCoverage (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< SnapshotRenderToSnapshot (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< SizeGetColorSourceSize () const
 Return the color source's intrinsic size, if available. More...
 
void SetColorSourceSize (Size size)
 
virtual std::optional< ColorAsBackgroundColor (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 FilterContentsAsFilter () 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< ContentsMakeAnonymous (RenderProc render_proc, CoverageProc coverage_proc)
 

Detailed Description

Definition at line 19 of file clip_contents.h.

Constructor & Destructor Documentation

◆ ClipContents()

impeller::ClipContents::ClipContents ( )
default

◆ ~ClipContents()

impeller::ClipContents::~ClipContents ( )
default

Member Function Documentation

◆ CanInheritOpacity()

bool impeller::ClipContents::CanInheritOpacity ( const Entity entity) const
overridevirtual

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 79 of file clip_contents.cc.

79  {
80  return true;
81 }

◆ GetClipCoverage()

Contents::ClipCoverage impeller::ClipContents::GetClipCoverage ( const Entity entity,
const std::optional< Rect > &  current_clip_coverage 
) const
overridevirtual

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 46 of file clip_contents.cc.

48  {
49  if (!current_clip_coverage.has_value()) {
50  return {.type = ClipCoverage::Type::kAppend, .coverage = std::nullopt};
51  }
52  switch (clip_op_) {
54  // This can be optimized further by considering cases when the bounds of
55  // the current stencil will shrink.
56  return {.type = ClipCoverage::Type::kAppend,
57  .coverage = current_clip_coverage};
59  if (!geometry_) {
60  return {.type = ClipCoverage::Type::kAppend, .coverage = std::nullopt};
61  }
62  auto coverage = geometry_->GetCoverage(entity.GetTransform());
63  if (!coverage.has_value() || !current_clip_coverage.has_value()) {
64  return {.type = ClipCoverage::Type::kAppend, .coverage = std::nullopt};
65  }
66  return {
67  .type = ClipCoverage::Type::kAppend,
68  .coverage = current_clip_coverage->Intersection(coverage.value()),
69  };
70  }
71  FML_UNREACHABLE();
72 }

References impeller::Entity::GetTransform(), impeller::Entity::kDifference, impeller::Entity::kIntersect, and impeller::Contents::ClipCoverage::type.

◆ GetCoverage()

std::optional< Rect > impeller::ClipContents::GetCoverage ( const Entity entity) const
overridevirtual

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 42 of file clip_contents.cc.

42  {
43  return std::nullopt;
44 };

◆ Render()

bool impeller::ClipContents::Render ( const ContentContext renderer,
const Entity entity,
RenderPass pass 
) const
overridevirtual

Implements impeller::Contents.

Definition at line 235 of file clip_contents.cc.

237  {
238  if (!geometry_) {
239  return true;
240  }
242  return RenderDepthClip(renderer, entity, pass, clip_op_, *geometry_);
243  } else {
244  return RenderStencilClip(renderer, entity, pass, clip_op_, *geometry_);
245  }
246 }

References impeller::ContentContext::kEnableStencilThenCover.

◆ SetClipOperation()

void impeller::ClipContents::SetClipOperation ( Entity::ClipOperation  clip_op)

Definition at line 38 of file clip_contents.cc.

38  {
39  clip_op_ = clip_op;
40 }

◆ SetGeometry()

void impeller::ClipContents::SetGeometry ( const std::shared_ptr< Geometry > &  geometry)

Definition at line 34 of file clip_contents.cc.

34  {
35  geometry_ = geometry;
36 }

◆ SetInheritedOpacity()

void impeller::ClipContents::SetInheritedOpacity ( Scalar  opacity)
overridevirtual

Inherit the provided opacity.

   Use of this method is invalid if CanAcceptOpacity returns false.

Reimplemented from impeller::Contents.

Definition at line 83 of file clip_contents.cc.

83 {}

◆ ShouldRender()

bool impeller::ClipContents::ShouldRender ( const Entity entity,
const std::optional< Rect clip_coverage 
) const
overridevirtual

Reimplemented from impeller::Contents.

Definition at line 74 of file clip_contents.cc.

75  {
76  return true;
77 }

The documentation for this class was generated from the following files:
impeller::Entity::ClipOperation::kIntersect
@ kIntersect
impeller::Entity::ClipOperation::kDifference
@ kDifference
impeller::ContentContext::kEnableStencilThenCover
static constexpr bool kEnableStencilThenCover
Definition: content_context.h:411