Flutter Impeller
impeller::Contents Class Referenceabstract

#include <contents.h>

Inheritance diagram for impeller::Contents:
impeller::AnonymousContents impeller::AtlasContents impeller::ColorFilterAtlasContents impeller::ColorSourceContents impeller::FilterContents impeller::LineContents impeller::SolidRRectLikeBlurContents impeller::TextContents impeller::TextureContents impeller::VerticesSimpleBlendContents

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 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 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< 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, std::string_view 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 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 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 31 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 35 of file contents.h.

◆ CoverageProc

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

Definition at line 40 of file contents.h.

◆ RenderProc

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

Definition at line 37 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::SweepGradientContents, impeller::SolidRRectLikeBlurContents, impeller::SolidColorContents, impeller::RadialGradientContents, impeller::LinearGradientContents, and impeller::ConicalGradientContents.

Definition at line 131 of file contents.cc.

132  {
133  return false;
134 }

◆ 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 126 of file contents.cc.

127  {
128  return {};
129 }

◆ 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 144 of file contents.cc.

144  {
145  return color_source_size_;
146 };

◆ 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::VerticesSimpleBlendContents, impeller::TextureContents, impeller::TextContents, impeller::SolidRRectLikeBlurContents, impeller::SolidColorContents, impeller::LineContents, impeller::FilterContents, impeller::ColorSourceContents, impeller::ColorFilterAtlasContents, impeller::AtlasContents, and impeller::AnonymousContents.

Referenced by impeller::ColorSourceContents::DrawGeometry(), and RenderToSnapshot().

◆ GetCoverageHint()

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

Definition at line 140 of file contents.cc.

140  {
141  return coverage_hint_;
142 }

Referenced by impeller::FilterContents::Render().

◆ IsOpaque()

bool impeller::Contents::IsOpaque ( const Matrix transform) 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.

Parameters
transformThe current transform matrix of the entity that will render this contents.

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

Definition at line 52 of file contents.cc.

52  {
53  return false;
54 }

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 41 of file contents.cc.

43  {
44  return AnonymousContents::Make(std::move(render_proc),
45  std::move(coverage_proc));
46 }
static std::shared_ptr< Contents > Make(RenderProc render_proc, CoverageProc coverage_proc)

References impeller::AnonymousContents::Make().

◆ 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,
std::string_view  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 56 of file contents.cc.

63  {
64  auto coverage = GetCoverage(entity);
65  if (!coverage.has_value()) {
66  return std::nullopt;
67  }
68 
69  std::shared_ptr<CommandBuffer> command_buffer =
70  renderer.GetContext()->CreateCommandBuffer();
71  if (!command_buffer) {
72  return std::nullopt;
73  }
74 
75  // Pad Contents snapshots with 1 pixel borders to ensure correct sampling
76  // behavior. Not doing so results in a coverage leak for filters that support
77  // customizing the input sampling mode. Snapshots of contents should be
78  // theoretically treated as infinite size just like layers.
79  coverage = coverage->Expand(1);
80 
81  if (coverage_limit.has_value()) {
82  coverage = coverage->Intersection(*coverage_limit);
83  if (!coverage.has_value()) {
84  return std::nullopt;
85  }
86  }
87 
88  ISize subpass_size = ISize::Ceil(coverage->GetSize());
89  fml::StatusOr<RenderTarget> render_target = renderer.MakeSubpass(
90  label, subpass_size, command_buffer,
91  [&contents = *this, &entity, &coverage](const ContentContext& renderer,
92  RenderPass& pass) -> bool {
93  Entity sub_entity;
94  sub_entity.SetBlendMode(BlendMode::kSrcOver);
95  sub_entity.SetTransform(
96  Matrix::MakeTranslation(Vector3(-coverage->GetOrigin())) *
97  entity.GetTransform());
98  return contents.Render(renderer, sub_entity, pass);
99  },
100  msaa_enabled, /*depth_stencil_enabled=*/true,
101  std::min(mip_count, static_cast<int32_t>(subpass_size.MipCount())));
102 
103  if (!render_target.ok()) {
104  return std::nullopt;
105  }
106  if (!renderer.GetContext()->EnqueueCommandBuffer(std::move(command_buffer))) {
107  return std::nullopt;
108  }
109 
110  auto snapshot = Snapshot{
111  .texture = render_target.value().GetRenderTargetTexture(),
112  .transform = Matrix::MakeTranslation(coverage->GetOrigin()),
113  };
114  if (sampler_descriptor.has_value()) {
115  snapshot.sampler_descriptor = sampler_descriptor.value();
116  }
117 
118  return snapshot;
119 }
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.
ISize subpass_size
The output size of the down-sampling pass.
ISize64 ISize
Definition: size.h:162
static constexpr Matrix MakeTranslation(const Vector3 &t)
Definition: matrix.h:95
constexpr TSize Ceil() const
Definition: size.h:114

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

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

◆ SetColorSourceSize()

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

Definition at line 148 of file contents.cc.

148  {
149  color_source_size_ = size;
150 }

◆ 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 136 of file contents.cc.

136  {
137  coverage_hint_ = coverage_hint;
138 }

◆ 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::TextureContents, impeller::TextContents, impeller::ColorFilterContents, and impeller::ColorSourceContents.

Definition at line 121 of file contents.cc.

121  {
122  VALIDATION_LOG << "Contents::SetInheritedOpacity should never be called when "
123  "Contents::CanAcceptOpacity returns false.";
124 }
#define VALIDATION_LOG
Definition: validation.h:91

References VALIDATION_LOG.


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