Flutter Impeller
impeller::ColorSourceContents Class Reference

#include <color_source_contents.h>

Inheritance diagram for impeller::ColorSourceContents:
impeller::Contents impeller::ConicalGradientContents impeller::FramebufferBlendContents impeller::LinearGradientContents impeller::RadialGradientContents impeller::RuntimeEffectContents impeller::SceneContents impeller::SolidColorContents impeller::SweepGradientContents impeller::TiledTextureContents

Public Member Functions

 ColorSourceContents ()
 
 ~ColorSourceContents () override
 
void SetGeometry (std::shared_ptr< Geometry > geometry)
 Set the geometry that this contents will use to render. More...
 
const std::shared_ptr< Geometry > & GetGeometry () const
 Get the geometry that this contents will use to render. More...
 
void SetEffectTransform (Matrix matrix)
 Set the effect transform for this color source. More...
 
const MatrixGetInverseEffectTransform () const
 Set the inverted effect transform for this color source. More...
 
void SetOpacityFactor (Scalar opacity)
 Set the opacity factor for this color source. More...
 
Scalar GetOpacityFactor () const
 Get the opacity factor for this color source. More...
 
virtual bool IsSolidColor () const
 
std::optional< RectGetCoverage (const Entity &entity) const override
 Get the screen space bounding rectangle that this contents affects. More...
 
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...
 
virtual bool Render (const ContentContext &renderer, const Entity &entity, RenderPass &pass) const =0
 
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 StencilCoverage GetStencilCoverage (const Entity &entity, const std::optional< Rect > &current_stencil_coverage) const
 Given the current screen space bounding rectangle of the stencil, return the expected stencil coverage after this draw call. This should only be implemented for contents that may write to the stencil 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, const std::string &label="Snapshot") const
 Render this contents to a snapshot, respecting the entity's transform, path, stencil 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 > &stencil_coverage) const
 
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

Color sources are geometry-ignostic Contents capable of shading any area defined by an impeller::Geometry. Conceptually, impeller::ColorSourceContents implement a particular color shading behavior.

This separation of concerns between geometry and color source output allows Impeller to handle most possible draw combinations in a consistent way. For example: There are color sources for handling solid colors, gradients, textures, custom runtime effects, and even 3D scenes.

There are some special rendering exceptions that deviate from this pattern and cross geometry and color source concerns, such as text atlas and image atlas rendering. Special Contents exist for rendering these behaviors which don't implement ColorSourceContents.

See also
impeller::Geometry

Definition at line 33 of file color_source_contents.h.

Constructor & Destructor Documentation

◆ ColorSourceContents()

impeller::ColorSourceContents::ColorSourceContents ( )
default

◆ ~ColorSourceContents()

impeller::ColorSourceContents::~ColorSourceContents ( )
overridedefault

Member Function Documentation

◆ CanInheritOpacity()

bool impeller::ColorSourceContents::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.

Reimplemented in impeller::RuntimeEffectContents.

Definition at line 50 of file color_source_contents.cc.

50  {
51  return true;
52 }

◆ GetCoverage()

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

Get the screen space bounding rectangle that this contents affects.

Implements impeller::Contents.

Reimplemented in impeller::SolidColorContents.

Definition at line 45 of file color_source_contents.cc.

46  {
47  return geometry_->GetCoverage(entity.GetTransformation());
48 };

References impeller::Entity::GetTransformation().

Referenced by impeller::SceneContents::Render(), impeller::TiledTextureContents::Render(), and impeller::RuntimeEffectContents::Render().

◆ GetGeometry()

const std::shared_ptr< Geometry > & impeller::ColorSourceContents::GetGeometry ( ) const

◆ GetInverseEffectTransform()

const Matrix & impeller::ColorSourceContents::GetInverseEffectTransform ( ) const

Set the inverted effect transform for this color source.

     When the effect transform is set via `SetEffectTransform`, the
     value is inverted upon storage. The reason for this is that most
     color sources internally use the inverted transform.
Returns
The inverse of the transform set by SetEffectTransform.
See also
SetEffectTransform

Definition at line 37 of file color_source_contents.cc.

37  {
38  return inverse_matrix_;
39 }

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

◆ GetOpacityFactor()

Scalar impeller::ColorSourceContents::GetOpacityFactor ( ) const

Get the opacity factor for this color source.

    This value is is factored into the output of the color source in
    addition to opacity information that may be supplied any other
    inputs.
Note
If set, the output of this method factors factors in the inherited opacity of this Contents.
See also
Contents::CanInheritOpacity

Definition at line 29 of file color_source_contents.cc.

29  {
30  return opacity_ * inherited_opacity_;
31 }

Referenced by impeller::SolidColorContents::GetColor(), impeller::RadialGradientContents::IsOpaque(), impeller::LinearGradientContents::IsOpaque(), impeller::SweepGradientContents::IsOpaque(), impeller::TiledTextureContents::IsOpaque(), impeller::TiledTextureContents::Render(), and impeller::TiledTextureContents::RenderToSnapshot().

◆ IsSolidColor()

bool impeller::ColorSourceContents::IsSolidColor ( ) const
virtual

Reimplemented in impeller::SolidColorContents.

Definition at line 41 of file color_source_contents.cc.

41  {
42  return false;
43 }

◆ SetEffectTransform()

void impeller::ColorSourceContents::SetEffectTransform ( Matrix  matrix)

Set the effect transform for this color source.

    The effect transform is a transformation matrix that is applied to
    the shaded color output and does not impact geometry in any way.

    For example: With repeat tiling, any gradient or
    `TiledTextureContents` could be used with an effect transform to
    inexpensively draw an infinite scrolling background pattern.

Definition at line 33 of file color_source_contents.cc.

33  {
34  inverse_matrix_ = matrix.Invert();
35 }

References impeller::Matrix::Invert().

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

◆ SetGeometry()

void impeller::ColorSourceContents::SetGeometry ( std::shared_ptr< Geometry geometry)

Set the geometry that this contents will use to render.

Definition at line 17 of file color_source_contents.cc.

17  {
18  geometry_ = std::move(geometry);
19 }

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

◆ SetInheritedOpacity()

void impeller::ColorSourceContents::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 54 of file color_source_contents.cc.

54  {
55  inherited_opacity_ = opacity;
56 }

◆ SetOpacityFactor()

void impeller::ColorSourceContents::SetOpacityFactor ( Scalar  opacity)

Set the opacity factor for this color source.

Definition at line 25 of file color_source_contents.cc.

25  {
26  opacity_ = alpha;
27 }

The documentation for this class was generated from the following files:
impeller::Matrix::Invert
Matrix Invert() const
Definition: matrix.cc:97