Flutter Impeller
impeller::Contents Class Referenceabstract

#include <contents.h>

Inheritance diagram for impeller::Contents:
impeller::AnonymousContents impeller::AtlasColorContents impeller::AtlasContents impeller::AtlasTextureContents impeller::CheckerboardContents impeller::ClipContents impeller::ClipRestoreContents impeller::ColorSourceContents impeller::FilterContents impeller::SolidRRectBlurContents impeller::TextContents impeller::TextureContents impeller::VerticesColorContents impeller::VerticesContents impeller::VerticesUVContents

Classes

struct  ClipCoverage
 

Public Types

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)>
 

Public Member Functions

 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...
 
virtual bool Render (const ContentContext &renderer, const Entity &entity, RenderPass &pass) const =0
 
virtual std::optional< RectGetCoverage (const Entity &entity) const =0
 Get the area of the render pass that will be affected when this contents is rendered. 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< 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...
 
virtual bool ShouldRender (const Entity &entity, const std::optional< Rect > clip_coverage) const
 
std::optional< SizeGetColorSourceSize () 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< 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...
 

Static Public Member Functions

static std::shared_ptr< ContentsMakeAnonymous (RenderProc render_proc, CoverageProc coverage_proc)
 

Detailed Description

Definition at line 34 of file contents.h.

Member Typedef Documentation

◆ ColorFilterProc

A procedure that filters a given unpremultiplied color to produce a new unpremultiplied color.

Definition at line 38 of file contents.h.

◆ CoverageProc

using impeller::Contents::CoverageProc = std::function<std::optional<Rect>(const Entity& entity)>

Definition at line 50 of file contents.h.

◆ RenderProc

using impeller::Contents::RenderProc = std::function<bool(const ContentContext& renderer, const Entity& entity, RenderPass& pass)>

Definition at line 49 of file contents.h.

Constructor & Destructor Documentation

◆ Contents()

impeller::Contents::Contents ( )
default

◆ ~Contents()

impeller::Contents::~Contents ( )
virtualdefault

Member Function Documentation

◆ ApplyColorFilter()

bool impeller::Contents::ApplyColorFilter ( const ColorFilterProc color_filter_proc)
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_procA 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 in impeller::SolidColorContents, impeller::SolidRRectBlurContents, impeller::LinearGradientContents, impeller::SweepGradientContents, impeller::ConicalGradientContents, and impeller::RadialGradientContents.

Definition at line 140 of file contents.cc.

141  {
142  return false;
143 }

◆ AsBackgroundColor()

std::optional< Color > impeller::Contents::AsBackgroundColor ( const Entity entity,
ISize  target_size 
) const
virtual

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.

This is useful for absorbing full screen solid color draws into subpass clear colors.

Reimplemented in impeller::SolidColorContents.

Definition at line 131 of file contents.cc.

132  {
133  return {};
134 }

◆ AsFilter()

const FilterContents * impeller::Contents::AsFilter ( ) const
virtual

Cast to a filter. Returns nullptr if this Contents is not a filter.

Reimplemented in impeller::FilterContents.

Definition at line 136 of file contents.cc.

136  {
137  return nullptr;
138 }

◆ CanInheritOpacity()

bool impeller::Contents::CanInheritOpacity ( const Entity entity) const
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 in impeller::ColorSourceContents, impeller::ClipRestoreContents, impeller::TextureContents, impeller::ClipContents, impeller::TextContents, and impeller::RuntimeEffectContents.

Definition at line 122 of file contents.cc.

122  {
123  return false;
124 }

◆ GetClipCoverage()

Contents::ClipCoverage impeller::Contents::GetClipCoverage ( const Entity entity,
const std::optional< Rect > &  current_clip_coverage 
) const
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 in impeller::ClipRestoreContents, and impeller::ClipContents.

Definition at line 59 of file contents.cc.

61  {
62  return {.type = ClipCoverage::Type::kNoChange,
63  .coverage = current_clip_coverage};
64 }

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

◆ GetColorSourceSize()

std::optional< Size > impeller::Contents::GetColorSourceSize ( ) const

Return the color source's intrinsic size, if available.

    For example, a gradient has a size based on its end and beginning
    points, ignoring any tiling. Solid colors and runtime effects have
    no size.

Definition at line 168 of file contents.cc.

168  {
169  return color_source_size_;
170 };

◆ GetCoverage()

virtual std::optional<Rect> impeller::Contents::GetCoverage ( const Entity entity) const
pure 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.

Implemented in impeller::AtlasColorContents, impeller::FilterContents, impeller::AtlasTextureContents, impeller::ColorSourceContents, impeller::VerticesUVContents, impeller::ClipRestoreContents, impeller::AtlasContents, impeller::VerticesColorContents, impeller::TextureContents, impeller::TextContents, impeller::VerticesContents, impeller::SolidColorContents, impeller::SolidRRectBlurContents, impeller::AnonymousContents, impeller::ClipContents, and impeller::CheckerboardContents.

Referenced by RenderToSnapshot(), and ShouldRender().

◆ GetCoverageHint()

const std::optional< Rect > & impeller::Contents::GetCoverageHint ( ) const

Definition at line 164 of file contents.cc.

164  {
165  return coverage_hint_;
166 }

Referenced by impeller::VerticesContents::Render(), impeller::VerticesUVContents::Render(), and impeller::FilterContents::Render().

◆ IsOpaque()

bool impeller::Contents::IsOpaque ( ) const
virtual

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.

Reimplemented in impeller::SolidColorContents, impeller::TiledTextureContents, impeller::LinearGradientContents, impeller::SweepGradientContents, and impeller::RadialGradientContents.

Definition at line 55 of file contents.cc.

55  {
56  return false;
57 }

Referenced by impeller::testing::TEST_P().

◆ MakeAnonymous()

std::shared_ptr< Contents > impeller::Contents::MakeAnonymous ( Contents::RenderProc  render_proc,
Contents::CoverageProc  coverage_proc 
)
static

Definition at line 44 of file contents.cc.

46  {
47  return AnonymousContents::Make(std::move(render_proc),
48  std::move(coverage_proc));
49 }

References impeller::AnonymousContents::Make().

◆ PopulateGlyphAtlas()

virtual void impeller::Contents::PopulateGlyphAtlas ( const std::shared_ptr< LazyGlyphAtlas > &  lazy_glyph_atlas,
Scalar  scale 
)
inlinevirtual

Add any text data to the specified lazy atlas. The scale parameter must be used again later when drawing the text.

Reimplemented in impeller::FilterContents, and impeller::TextContents.

Definition at line 61 of file contents.h.

63  {}

◆ Render()

◆ RenderToSnapshot()

std::optional< Snapshot > impeller::Contents::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
virtual

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).

Reimplemented in impeller::TiledTextureContents, impeller::TextureContents, and impeller::FilterContents.

Definition at line 66 of file contents.cc.

73  {
74  auto coverage = GetCoverage(entity);
75  if (!coverage.has_value()) {
76  return std::nullopt;
77  }
78 
79  // Pad Contents snapshots with 1 pixel borders to ensure correct sampling
80  // behavior. Not doing so results in a coverage leak for filters that support
81  // customizing the input sampling mode. Snapshots of contents should be
82  // theoretically treated as infinite size just like layers.
83  coverage = coverage->Expand(1);
84 
85  if (coverage_limit.has_value()) {
86  coverage = coverage->Intersection(*coverage_limit);
87  if (!coverage.has_value()) {
88  return std::nullopt;
89  }
90  }
91 
92  ISize subpass_size = ISize::Ceil(coverage->GetSize());
93  fml::StatusOr<RenderTarget> render_target = renderer.MakeSubpass(
94  label, subpass_size,
95  [&contents = *this, &entity, &coverage](const ContentContext& renderer,
96  RenderPass& pass) -> bool {
97  Entity sub_entity;
98  sub_entity.SetBlendMode(BlendMode::kSourceOver);
99  sub_entity.SetTransform(
100  Matrix::MakeTranslation(Vector3(-coverage->GetOrigin())) *
101  entity.GetTransform());
102  return contents.Render(renderer, sub_entity, pass);
103  },
104  msaa_enabled, /*depth_stencil_enabled=*/true,
105  std::min(mip_count, static_cast<int32_t>(subpass_size.MipCount())));
106 
107  if (!render_target.ok()) {
108  return std::nullopt;
109  }
110 
111  auto snapshot = Snapshot{
112  .texture = render_target.value().GetRenderTargetTexture(),
113  .transform = Matrix::MakeTranslation(coverage->GetOrigin()),
114  };
115  if (sampler_descriptor.has_value()) {
116  snapshot.sampler_descriptor = sampler_descriptor.value();
117  }
118 
119  return snapshot;
120 }

References impeller::TSize< int64_t >::Ceil(), GetCoverage(), impeller::Entity::GetTransform(), impeller::kSourceOver, impeller::ContentContext::MakeSubpass(), impeller::Matrix::MakeTranslation(), impeller::TSize< T >::MipCount(), impeller::Entity::SetBlendMode(), impeller::Entity::SetTransform(), and impeller::Snapshot::texture.

Referenced by impeller::TiledTextureContents::RenderToSnapshot(), and impeller::TextureContents::RenderToSnapshot().

◆ SetColorSourceSize()

void impeller::Contents::SetColorSourceSize ( Size  size)

Definition at line 172 of file contents.cc.

172  {
173  color_source_size_ = size;
174 }

◆ SetCoverageHint()

void impeller::Contents::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().

Definition at line 160 of file contents.cc.

160  {
161  coverage_hint_ = coverage_hint;
162 }

◆ SetInheritedOpacity()

void impeller::Contents::SetInheritedOpacity ( Scalar  opacity)
virtual

Inherit the provided opacity.

   Use of this method is invalid if CanAcceptOpacity returns false.

Reimplemented in impeller::ColorSourceContents, impeller::ClipRestoreContents, impeller::TextureContents, impeller::ClipContents, and impeller::TextContents.

Definition at line 126 of file contents.cc.

126  {
127  VALIDATION_LOG << "Contents::SetInheritedOpacity should never be called when "
128  "Contents::CanAcceptOpacity returns false.";
129 }

References VALIDATION_LOG.

◆ ShouldRender()

bool impeller::Contents::ShouldRender ( const Entity entity,
const std::optional< Rect clip_coverage 
) const
virtual

Reimplemented in impeller::ClipRestoreContents, and impeller::ClipContents.

Definition at line 145 of file contents.cc.

146  {
147  if (!clip_coverage.has_value()) {
148  return false;
149  }
150  auto coverage = GetCoverage(entity);
151  if (!coverage.has_value()) {
152  return false;
153  }
154  if (coverage == Rect::MakeMaximum()) {
155  return true;
156  }
157  return clip_coverage->IntersectsWithRect(coverage.value());
158 }

References GetCoverage(), and impeller::TRect< Scalar >::MakeMaximum().


The documentation for this class was generated from the following files:
impeller::Contents::GetCoverage
virtual std::optional< Rect > GetCoverage(const Entity &entity) const =0
Get the area of the render pass that will be affected when this contents is rendered.
impeller::TSize< int64_t >::Ceil
constexpr TSize Ceil() const
Definition: size.h:96
impeller::Matrix::MakeTranslation
static constexpr Matrix MakeTranslation(const Vector3 &t)
Definition: matrix.h:95
impeller::ISize
TSize< int64_t > ISize
Definition: size.h:138
VALIDATION_LOG
#define VALIDATION_LOG
Definition: validation.h:73
impeller::TRect< Scalar >::MakeMaximum
constexpr static TRect MakeMaximum()
Definition: rect.h:174
impeller::Contents::ClipCoverage::Type::kNoChange
@ kNoChange
impeller::BlendMode::kSourceOver
@ kSourceOver
impeller::AnonymousContents::Make
static std::shared_ptr< Contents > Make(RenderProc render_proc, CoverageProc coverage_proc)
Definition: anonymous_contents.cc:11