| Flutter Impeller |

Public Types | Public Member Functions | Static Public Member Functions | List of all members
impeller::FilterContents Class Referenceabstract

`#include <filter_contents.h>`

Inheritance diagram for impeller::FilterContents:

## Public Types
enum | BlurStyle { BlurStyle::kNormal, BlurStyle::kSolid, BlurStyle::kOuter, BlurStyle::kInner }
enum | MorphType { MorphType::kDilate, MorphType::kErode }
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)>

## Public Member Functions
| FilterContents ()
| ~FilterContents () override
void | SetInputs (FilterInput::Vector inputs)
| The input texture sources for this filter. Each input's emitted texture is expected to have premultiplied alpha colors. More...
void | SetEffectTransform (const Matrix &effect_transform)
| Sets the transform which gets appended to the effect of this filter. Note that this is in addition to the entity's transform. More...
std::optional< Entity > | GetEntity (const ContentContext &renderer, const Entity &entity, const std::optional< Rect > &coverage_hint) const
| Create an Entity that renders this filter's output. More...
bool | Render (const ContentContext &renderer, const Entity &entity, RenderPass &pass) const override
std::optional< Rect > | GetCoverage (const Entity &entity) const override
| Get the screen space bounding rectangle that this contents affects. More...
void | PopulateGlyphAtlas (const std::shared_ptr< LazyGlyphAtlas > &lazy_glyph_atlas, Scalar scale) override
| Add any text data to the specified lazy atlas. The scale parameter must be used again later when drawing the text. More...
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, const std::string &label="Filter Snapshot") const override
| 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...
const FilterContents * | AsFilter () const override
| Cast to a filter. Returns `nullptr` if this Contents is not a filter. More...
virtual Matrix | GetLocalTransform (const Matrix &parent_transform) const
Matrix | GetTransform (const Matrix &parent_transform) const
virtual bool | IsTranslationOnly () const
| Returns true if this filter graph doesn't perform any basis transformations to the filtered content. For example: Rotating, scaling, and skewing are all basis transformations, but translating is not. More...
bool | IsLeaf () const
| Returns `true` if this filter does not have any `FilterInput` children. More...
void | SetLeafInputs (const FilterInput::Vector &inputs)
| Replaces the set of all leaf `FilterContents` with a new set of `FilterInput`s. More...
virtual void | SetRenderingMode (Entity::RenderingMode rendering_mode)
| Marks this filter chain as applying in a subpass scenario. 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
| 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 bool | ShouldRender (const Entity &entity, const std::optional< Rect > &stencil_coverage) const
std::optional< Size > | GetColorSourceSize () 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< 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 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< FilterContents > | MakeDirectionalGaussianBlur (FilterInput::Ref input, Sigma sigma, Vector2 direction, BlurStyle blur_style=BlurStyle::kNormal, Entity::TileMode tile_mode=Entity::TileMode::kDecal, bool is_second_pass=false, Sigma secondary_sigma={})
static std::shared_ptr< FilterContents > | MakeGaussianBlur (const FilterInput::Ref &input, Sigma sigma_x, Sigma sigma_y, BlurStyle blur_style=BlurStyle::kNormal, Entity::TileMode tile_mode=Entity::TileMode::kDecal)
static std::shared_ptr< FilterContents > | MakeBorderMaskBlur (FilterInput::Ref input, Sigma sigma_x, Sigma sigma_y, BlurStyle blur_style=BlurStyle::kNormal)
static std::shared_ptr< FilterContents > | MakeDirectionalMorphology (FilterInput::Ref input, Radius radius, Vector2 direction, MorphType morph_type)
static std::shared_ptr< FilterContents > | MakeMorphology (FilterInput::Ref input, Radius radius_x, Radius radius_y, MorphType morph_type)
static std::shared_ptr< FilterContents > | MakeMatrixFilter (FilterInput::Ref input, const Matrix &matrix, const SamplerDescriptor &desc)
static std::shared_ptr< FilterContents > | MakeLocalMatrixFilter (FilterInput::Ref input, const Matrix &matrix)
static std::shared_ptr< FilterContents > | MakeYUVToRGBFilter (std::shared_ptr< Texture > y_texture, std::shared_ptr< Texture > uv_texture, YUVColorSpace yuv_color_space)
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 19 of file filter_contents.h.

## Member Enumeration Documentation

## ◆ BlurStyle

enum impeller::FilterContents::BlurStyle
| strong

Enumerator
kNormal | Blurred inside and outside.
kSolid | Solid inside, blurred outside.
kOuter | Nothing inside, blurred outside.
kInner | Blurred inside, nothing outside.

Definition at line 21 of file filter_contents.h.

21 {
22 /// Blurred inside and outside.
23 kNormal,
24 /// Solid inside, blurred outside.
25 kSolid,
26 /// Nothing inside, blurred outside.
27 kOuter,
28 /// Blurred inside, nothing outside.
29 kInner,
30 };

## ◆ MorphType

enum impeller::FilterContents::MorphType
| strong

Enumerator
kDilate |
kErode |

Definition at line 32 of file filter_contents.h.

32 { kDilate, kErode };

## Constructor & Destructor Documentation

## ◆ FilterContents()

impeller::FilterContents::FilterContents | ( |  | ) |
| default

## ◆ ~FilterContents()

impeller::FilterContents::~FilterContents | ( |  | ) |
| override default

## Member Function Documentation

## ◆ AsFilter()

const FilterContents * impeller::FilterContents::AsFilter | ( |  | ) | const
| override virtual

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

Reimplemented from impeller::Contents.

Definition at line 262 of file filter_contents.cc.

262 {
263 return this;
264 }

## ◆ GetCoverage()

std::optional< Rect > impeller::FilterContents::GetCoverage | ( | const Entity & | entity | ) | const
| override virtual

Get the screen space bounding rectangle that this contents affects.

Implements impeller::Contents.

Definition at line 178 of file filter_contents.cc.

178 {
179 Entity entity_with_local_transform = entity;
180 entity_with_local_transform.SetTransformation(
181 GetTransform(entity.GetTransformation()));
182
183 return GetLocalCoverage(entity_with_local_transform);
184 }

References GetTransform(), impeller::Entity::GetTransformation(), and impeller::Entity::SetTransformation().

Referenced by Render().

## ◆ GetEntity()

std::optional< Entity > impeller::FilterContents::GetEntity | ( | const ContentContext & | renderer,
|  | const Entity & | entity,
|  | const std::optional< Rect > & | coverage_hint
| ) |  | const

Create an Entity that renders this filter's output.

Definition at line 221 of file filter_contents.cc.

224 {
225 Entity entity_with_local_transform = entity;
226 entity_with_local_transform.SetTransformation(
227 GetTransform(entity.GetTransformation()));
228
229 auto coverage = GetLocalCoverage(entity_with_local_transform);
230 if (!coverage.has_value() || coverage->IsEmpty()) {
231 return std::nullopt;
232 }
233
234 return RenderFilter(inputs_, renderer, entity_with_local_transform,
235 effect_transform_, coverage.value(), coverage_hint);
236 }

References GetTransform(), impeller::Entity::GetTransformation(), and impeller::Entity::SetTransformation().

Referenced by Render(), and RenderToSnapshot().

## ◆ GetLocalTransform()

Matrix impeller::FilterContents::GetLocalTransform | ( | const Matrix & | parent_transform | ) | const
| virtual

Reimplemented in impeller::LocalMatrixFilterContents.

Definition at line 266 of file filter_contents.cc.

266 {
267 return Matrix();
268 }

Referenced by GetTransform().

## ◆ GetTransform()

Matrix impeller::FilterContents::GetTransform | ( | const Matrix & | parent_transform | ) | const

Definition at line 270 of file filter_contents.cc.

270 {
271 return parent_transform * GetLocalTransform(parent_transform);
272 }

References GetLocalTransform().

Referenced by GetCoverage(), and GetEntity().

## ◆ IsLeaf()

bool impeller::FilterContents::IsLeaf | ( |  | ) | const

Returns `true` if this filter does not have any `FilterInput` children.

Definition at line 282 of file filter_contents.cc.

282 {
283 for (auto& input : inputs_) {
284 if (!input->IsLeaf()) {
285 return false;
286 }
287 }
288 return true;
289 }

Referenced by SetLeafInputs().

## ◆ IsTranslationOnly()

bool impeller::FilterContents::IsTranslationOnly | ( |  | ) | const
| virtual

Returns true if this filter graph doesn't perform any basis transformations to the filtered content. For example: Rotating, scaling, and skewing are all basis transformations, but translating is not.

This is useful for determining whether a filtered object's space is compatible enough with the parent pass space to perform certain subpass clipping optimizations.

Reimplemented in impeller::MatrixFilterContents.

Definition at line 273 of file filter_contents.cc.

273 {
274 for (auto& input : inputs_) {
275 if (!input->IsTranslationOnly()) {
276 return false;
277 }
278 }
279 return true;
280 }

Referenced by impeller::MatrixFilterContents::IsTranslationOnly().

## ◆ MakeBorderMaskBlur()

std::shared_ptr< FilterContents > impeller::FilterContents::MakeBorderMaskBlur | ( | FilterInput::Ref | input,
|  | Sigma | sigma_x,
|  | Sigma | sigma_y,
|  | BlurStyle | blur_style = `BlurStyle::kNormal`
| ) |  |
| static

Definition at line 66 of file filter_contents.cc.

70 {
71 auto filter = std::make_shared<BorderMaskBlurFilterContents>();
72 filter->SetInputs({std::move(input)});
73 filter->SetSigma(sigma_x, sigma_y);
74 filter->SetBlurStyle(blur_style);
75 return filter;
76 }

Referenced by impeller::Paint::MaskBlurDescriptor::CreateMaskBlur(), and impeller::testing::TEST_P().

## ◆ MakeDirectionalGaussianBlur()

std::shared_ptr< FilterContents > impeller::FilterContents::MakeDirectionalGaussianBlur | ( | FilterInput::Ref | input,
|  | Sigma | sigma,
|  | Vector2 | direction,
|  | BlurStyle | blur_style = `BlurStyle::kNormal`,
|  | Entity::TileMode | tile_mode = `Entity::TileMode::kDecal`,
|  | bool | is_second_pass = `false`,
|  | Sigma | secondary_sigma = `{}`
| ) |  |
| static

Definition at line 33 of file filter_contents.cc.

40 {
41 auto blur = std::make_shared<DirectionalGaussianBlurFilterContents>();
42 blur->SetInputs({std::move(input)});
43 blur->SetSigma(sigma);
44 blur->SetDirection(direction);
45 blur->SetBlurStyle(blur_style);
46 blur->SetTileMode(tile_mode);
47 blur->SetIsSecondPass(is_second_pass);
48 blur->SetSecondarySigma(secondary_sigma);
49 return blur;
50 }

Referenced by MakeGaussianBlur(), and impeller::testing::TEST_P().

## ◆ MakeDirectionalMorphology()

std::shared_ptr< FilterContents > impeller::FilterContents::MakeDirectionalMorphology | ( | FilterInput::Ref | input,
|  | Radius | radius,
|  | Vector2 | direction,
|  | MorphType | morph_type
| ) |  |
| static

Definition at line 78 of file filter_contents.cc.

82 {
83 auto filter = std::make_shared<DirectionalMorphologyFilterContents>();
84 filter->SetInputs({std::move(input)});
85 filter->SetRadius(radius);
86 filter->SetDirection(direction);
87 filter->SetMorphType(morph_type);
88 return filter;
89 }

Referenced by MakeMorphology().

## ◆ MakeGaussianBlur()

std::shared_ptr< FilterContents > impeller::FilterContents::MakeGaussianBlur | ( | const FilterInput::Ref & | input,
|  | Sigma | sigma_x,
|  | Sigma | sigma_y,
|  | BlurStyle | blur_style = `BlurStyle::kNormal`,
|  | Entity::TileMode | tile_mode = `Entity::TileMode::kDecal`
| ) |  |
| static

Definition at line 52 of file filter_contents.cc.

57 {
58 auto x_blur = MakeDirectionalGaussianBlur(
59 input, sigma_x, Point(1, 0), BlurStyle::kNormal, tile_mode, false, {});
60 auto y_blur = MakeDirectionalGaussianBlur(FilterInput::Make(x_blur), sigma_y,
61 Point(0, 1), blur_style, tile_mode,
62 true, sigma_x);
63 return y_blur;
64 }

References kNormal, impeller::FilterInput::Make(), and MakeDirectionalGaussianBlur().

Referenced by impeller::Paint::MaskBlurDescriptor::CreateMaskBlur(), impeller::testing::TEST_P(), and impeller::BlurImageFilter::WrapInput().

## ◆ MakeLocalMatrixFilter()

std::shared_ptr< FilterContents > impeller::FilterContents::MakeLocalMatrixFilter | ( | FilterInput::Ref | input,
|  | const Matrix & | matrix
| ) |  |
| static

Definition at line 114 of file filter_contents.cc.

116 {
117 auto filter = std::make_shared<LocalMatrixFilterContents>();
118 filter->SetInputs({std::move(input)});
119 filter->SetMatrix(matrix);
120 return filter;
121 }

Referenced by impeller::LocalMatrixImageFilter::WrapInput().

## ◆ MakeMatrixFilter()

std::shared_ptr< FilterContents > impeller::FilterContents::MakeMatrixFilter | ( | FilterInput::Ref | input,
|  | const Matrix & | matrix,
|  | const SamplerDescriptor & | desc
| ) |  |
| static

Definition at line 103 of file filter_contents.cc.

106 {
107 auto filter = std::make_shared<MatrixFilterContents>();
108 filter->SetInputs({std::move(input)});
109 filter->SetMatrix(matrix);
110 filter->SetSamplerDescriptor(desc);
111 return filter;
112 }

Referenced by impeller::testing::TEST(), and impeller::MatrixImageFilter::WrapInput().

## ◆ MakeMorphology()

std::shared_ptr< FilterContents > impeller::FilterContents::MakeMorphology | ( | FilterInput::Ref | input,
|  | Radius | radius_x,
|  | Radius | radius_y,
|  | MorphType | morph_type
| ) |  |
| static

Definition at line 91 of file filter_contents.cc.

95 {
96 auto x_morphology = MakeDirectionalMorphology(std::move(input), radius_x,
97 Point(1, 0), morph_type);
98 auto y_morphology = MakeDirectionalMorphology(
99 FilterInput::Make(x_morphology), radius_y, Point(0, 1), morph_type);
100 return y_morphology;
101 }

References impeller::FilterInput::Make(), and MakeDirectionalMorphology().

Referenced by impeller::testing::TEST_P(), impeller::DilateImageFilter::WrapInput(), and impeller::ErodeImageFilter::WrapInput().

## ◆ MakeYUVToRGBFilter()

std::shared_ptr< FilterContents > impeller::FilterContents::MakeYUVToRGBFilter | ( | std::shared_ptr< Texture > | y_texture,
|  | std::shared_ptr< Texture > | uv_texture,
|  | YUVColorSpace | yuv_color_space
| ) |  |
| static

Definition at line 123 of file filter_contents.cc.

126 {
127 auto filter = std::make_shared<impeller::YUVToRGBFilterContents>();
128 filter->SetInputs({impeller::FilterInput::Make(y_texture),
129 impeller::FilterInput::Make(uv_texture)});
130 filter->SetYUVColorSpace(yuv_color_space);
131 return filter;
132 }

References impeller::FilterInput::Make().

Referenced by impeller::DlImageImpeller::MakeFromYUVTextures(), and impeller::testing::TEST_P().

## ◆ PopulateGlyphAtlas()

void impeller::FilterContents::PopulateGlyphAtlas | ( | const std::shared_ptr< LazyGlyphAtlas > & | lazy_glyph_atlas,
|  | Scalar | scale
| ) |  |
| override virtual

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

Reimplemented from impeller::Contents.

Definition at line 186 of file filter_contents.cc.

188 {
189 for (auto& input : inputs_) {
190 input->PopulateGlyphAtlas(lazy_glyph_atlas, scale);
191 }
192 }

## ◆ Render()

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

Implements impeller::Contents.

Definition at line 150 of file filter_contents.cc.

152 {
153 auto filter_coverage = GetCoverage(entity);
154 if (!filter_coverage.has_value()) {
155 return true;
156 }
157
158 // Run the filter.
159
160 auto maybe_entity = GetEntity(renderer, entity, GetCoverageHint());
161 if (!maybe_entity.has_value()) {
162 return true;
163 }
164 return maybe_entity->Render(renderer, pass);
165 }

References GetCoverage(), impeller::Contents::GetCoverageHint(), and GetEntity().

## ◆ RenderToSnapshot()

std::optional< Snapshot > impeller::FilterContents::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`,
|  | const std::string & | label = `"Filter Snapshot"`
| ) |  | const
| override virtual

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)`.

Reimplemented from impeller::Contents.

Definition at line 238 of file filter_contents.cc.

244 {
245 // Resolve the render instruction (entity) from the filter and render it to a
246 // snapshot.
247 if (std::optional<Entity> result =
248 GetEntity(renderer, entity, coverage_limit);
249 result.has_value()) {
250 return result->GetContents()->RenderToSnapshot(
251 renderer, // renderer
252 result.value(), // entity
253 coverage_limit, // coverage_limit
254 std::nullopt, // sampler_descriptor
255 true, // msaa_enabled
256 label); // label
257 }
258
259 return std::nullopt;
260 }

References GetEntity().

## ◆ SetEffectTransform()

void impeller::FilterContents::SetEffectTransform | ( | const Matrix & | effect_transform | ) |

Sets the transform which gets appended to the effect of this filter. Note that this is in addition to the entity's transform.

This is useful for subpass rendering scenarios where it's difficult to encode the current transform of the layer into the Entity being rendered.

Definition at line 142 of file filter_contents.cc.

142 {
143 effect_transform_ = effect_transform;
144
145 for (auto& input : inputs_) {
146 input->SetEffectTransform(effect_transform);
147 }
148 }

## ◆ SetInputs()

void impeller::FilterContents::SetInputs | ( | FilterInput::Vector | inputs | ) |

The input texture sources for this filter. Each input's emitted texture is expected to have premultiplied alpha colors.

The number of required or optional textures depends on the particular filter's implementation.

Definition at line 138 of file filter_contents.cc.

138 {
139 inputs_ = std::move(inputs);
140 }

## ◆ SetLeafInputs()

void impeller::FilterContents::SetLeafInputs | ( | const FilterInput::Vector & | inputs | ) |

Replaces the set of all leaf `FilterContents` with a new set of `FilterInput`s.

See also
  `FilterContents::IsLeaf`

Definition at line 291 of file filter_contents.cc.

291 {
292 if (IsLeaf()) {
293 inputs_ = inputs;
294 return;
295 }
296 for (auto& input : inputs_) {
297 input->SetLeafInputs(inputs);
298 }
299 }

References IsLeaf().

## ◆ SetRenderingMode()

void impeller::FilterContents::SetRenderingMode | ( | Entity::RenderingMode | rendering_mode | ) |
| virtual

Marks this filter chain as applying in a subpass scenario.

        Subpasses render in screenspace, and this setting informs filters
        that the current transformation matrix of the entity is not stored
        in the Entity transformation matrix. Instead, the effect transform
        is used in this case.

Reimplemented in impeller::MatrixFilterContents.

Definition at line 301 of file filter_contents.cc.

301 {
302 for (auto& input : inputs_) {
303 input->SetRenderingMode(rendering_mode);
304 }
305 }

Referenced by impeller::MatrixFilterContents::SetRenderingMode().

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

- impeller/entity/contents/filters/filter_contents.h
- impeller/entity/contents/filters/filter_contents.cc

impeller::FilterContents::IsLeaf
bool IsLeaf() const
Returns true if this filter does not have any FilterInput children.
Definition: filter_contents.cc:282
impeller::FilterInput::Make
static FilterInput::Ref Make(Variant input, bool msaa_enabled=true)
Definition: filter_input.cc:19
impeller::FilterContents::GetTransform
Matrix GetTransform(const Matrix &parent_transform) const
Definition: filter_contents.cc:270
impeller::FilterContents::MakeDirectionalGaussianBlur
static std::shared_ptr< FilterContents > MakeDirectionalGaussianBlur(FilterInput::Ref input, Sigma sigma, Vector2 direction, BlurStyle blur_style=BlurStyle::kNormal, Entity::TileMode tile_mode=Entity::TileMode::kDecal, bool is_second_pass=false, Sigma secondary_sigma={})
Definition: filter_contents.cc:33
impeller::FilterContents::BlurStyle::kNormal
@ kNormal
Blurred inside and outside.
impeller::Contents::GetCoverageHint
const std::optional< Rect > & GetCoverageHint() const
Definition: contents.cc:155
impeller::Point
TPoint< Scalar > Point
Definition: point.h:306
impeller::FilterContents::MakeDirectionalMorphology
static std::shared_ptr< FilterContents > MakeDirectionalMorphology(FilterInput::Ref input, Radius radius, Vector2 direction, MorphType morph_type)
Definition: filter_contents.cc:78
impeller::FilterContents::GetCoverage
std::optional< Rect > GetCoverage(const Entity &entity) const override
Get the screen space bounding rectangle that this contents affects.
Definition: filter_contents.cc:178
impeller::FilterContents::GetEntity
std::optional< Entity > GetEntity(const ContentContext &renderer, const Entity &entity, const std::optional< Rect > &coverage_hint) const
Create an Entity that renders this filter's output.
Definition: filter_contents.cc:221
impeller::FilterContents::GetLocalTransform
virtual Matrix GetLocalTransform(const Matrix &parent_transform) const
Definition: filter_contents.cc:266