| Flutter Impeller |

contents.h
Go to the documentation of this file.
1 // Copyright 2013 The Flutter Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #ifndef FLUTTER_IMPELLER_ENTITY_CONTENTS_CONTENTS_H_
6 #define FLUTTER_IMPELLER_ENTITY_CONTENTS_CONTENTS_H_
7
8 #include <functional>
9 #include <memory>
10 #include <vector>
11
12 #include "flutter/fml/macros.h"
13 #include "impeller/core/sampler_descriptor.h"
14 #include "impeller/core/texture.h"
15 #include "impeller/geometry/color.h"
16 #include "impeller/geometry/rect.h"
17 #include "impeller/renderer/snapshot.h"
18 #include "impeller/typographer/lazy_glyph_atlas.h"
19
20 namespace impeller {
21
22 class ContentContext;
23 struct ContentContextOptions;
24 class Entity;
25 class Surface;
26 class RenderPass;
27 class FilterContents;
28
29 ContentContextOptions OptionsFromPass(const RenderPass& pass);
30
31 ContentContextOptions OptionsFromPassAndEntity(const RenderPass& pass,
32 const Entity& entity);
33
34 class Contents {
35 public:
36 /// A procedure that filters a given unpremultiplied color to produce a new
37 /// unpremultiplied color.
38 using ColorFilterProc = std::function<Color(Color)>;
39
40 struct ClipCoverage {
41 enum class Type { kNoChange, kAppend, kRestore };
42
43 Type type = Type::kNoChange;
44 std::optional<Rect> coverage = std::nullopt;
45 };
46
47 using RenderProc = std::function<bool(const ContentContext& renderer,
48 const Entity& entity,
49 RenderPass& pass)>;
50 using CoverageProc = std::function<std::optional<Rect>(const Entity& entity)>;
51
52 static std::shared_ptr<Contents> MakeAnonymous(RenderProc render_proc,
53 CoverageProc coverage_proc);
54
55 Contents();
56
57 virtual ~Contents();
58
59 /// @brief Add any text data to the specified lazy atlas. The scale parameter
60 /// must be used again later when drawing the text.
61 virtual void PopulateGlyphAtlas(
62 const std::shared_ptr<LazyGlyphAtlas>& lazy_glyph_atlas,
63 Scalar scale) {}
64
65 virtual bool Render(const ContentContext& renderer,
66 const Entity& entity,
67 RenderPass& pass) const = 0;
68
69 //----------------------------------------------------------------------------
70 /// @brief Get the area of the render pass that will be affected when this
71 /// contents is rendered.
72 ///
73 /// During rendering, coverage coordinates count pixels from the top
74 /// left corner of the framebuffer.
75 ///
76 /// @return The coverage rectangle. An `std::nullopt` result means that
77 /// rendering this contents has no effect on the output color.
78 ///
79 virtual std::optional<Rect> GetCoverage(const Entity& entity) const = 0;
80
81 //----------------------------------------------------------------------------
82 /// @brief Hint that specifies the coverage area of this Contents that will
83 /// actually be used during rendering. This is for optimization
84 /// purposes only and can not be relied on as a clip. May optionally
85 /// affect the result of `GetCoverage()`.
86 ///
87 void SetCoverageHint(std::optional<Rect> coverage_hint);
88
89 const std::optional<Rect>& GetCoverageHint() const;
90
91 //----------------------------------------------------------------------------
92 /// @brief Whether this Contents only emits opaque source colors from the
93 /// fragment stage. This value does not account for any entity
94 /// properties (e.g. the blend mode), clips/visibility culling, or
95 /// inherited opacity.
96 ///
97 virtual bool IsOpaque() const;
98
99 //----------------------------------------------------------------------------
100 /// @brief Given the current pass space bounding rectangle of the clip
101 /// buffer, return the expected clip coverage after this draw call.
102 /// This should only be implemented for contents that may write to the
103 /// clip buffer.
104 ///
105 /// During rendering, coverage coordinates count pixels from the top
106 /// left corner of the framebuffer.
107 ///
108 virtual ClipCoverage GetClipCoverage(
109 const Entity& entity,
110 const std::optional<Rect>& current_clip_coverage) const;
111
112 //----------------------------------------------------------------------------
113 /// @brief Render this contents to a snapshot, respecting the entity's
114 /// transform, path, clip depth, and blend mode.
115 /// The result texture size is always the size of
116 /// `GetCoverage(entity)`.
117 ///
118 virtual std::optional<Snapshot> RenderToSnapshot(
119 const ContentContext& renderer,
120 const Entity& entity,
121 std::optional<Rect> coverage_limit = std::nullopt,
122 const std::optional<SamplerDescriptor>& sampler_descriptor = std::nullopt,
123 bool msaa_enabled = true,
124 const std::string& label = "Snapshot") const;
125
126 virtual bool ShouldRender(const Entity& entity,
127 const std::optional<Rect> clip_coverage) const;
128
129 //----------------------------------------------------------------------------
130 /// @brief Return the color source's intrinsic size, if available.
131 ///
132 /// For example, a gradient has a size based on its end and beginning
133 /// points, ignoring any tiling. Solid colors and runtime effects have
134 /// no size.
135 ///
136 std::optional<Size> GetColorSourceSize() const;
137
138 void SetColorSourceSize(Size size);
139
140 //----------------------------------------------------------------------------
141 /// @brief Whether or not this contents can accept the opacity peephole
142 /// optimization.
143 ///
144 /// By default all contents return false. Contents are responsible
145 /// for determining whether or not their own geometries intersect in
146 /// a way that makes accepting opacity impossible. It is always safe
147 /// to return false, especially if computing overlap would be
148 /// computationally expensive.
149 ///
150 virtual bool CanInheritOpacity(const Entity& entity) const;
151
152 //----------------------------------------------------------------------------
153 /// @brief Inherit the provided opacity.
154 ///
155 /// Use of this method is invalid if CanAcceptOpacity returns false.
156 ///
157 virtual void SetInheritedOpacity(Scalar opacity);
158
159 //----------------------------------------------------------------------------
160 /// @brief Returns a color if this Contents will flood the given `target_size`
161 /// with a color. This output color is the "Source" color that will be
162 /// used for the Entity's blend operation.
163 ///
164 /// This is useful for absorbing full screen solid color draws into
165 /// subpass clear colors.
166 ///
167 virtual std::optional<Color> AsBackgroundColor(const Entity& entity,
168 ISize target_size) const;
169
170 //----------------------------------------------------------------------------
171 /// @brief Cast to a filter. Returns `nullptr` if this Contents is not a
172 /// filter.
173 ///
174 virtual const FilterContents* AsFilter() const;
175
176 //----------------------------------------------------------------------------
177 /// @brief If possible, applies a color filter to this contents inputs on
178 /// the CPU.
179 ///
180 /// This method will either fully apply the color filter or
181 /// perform no action. Partial/incorrect application of the color
182 /// filter will never occur.
183 ///
184 /// @param[in] color_filter_proc A function that filters a given
185 /// unpremultiplied color to produce a new
186 /// unpremultiplied color.
187 ///
188 /// @return True if the color filter was able to be fully applied to all
189 /// all relevant inputs. Otherwise, this operation is a no-op and
190 /// false is returned.
191 ///
192 [[nodiscard]] virtual bool ApplyColorFilter(
193 const ColorFilterProc& color_filter_proc);
194
195 private:
196 std::optional<Rect> coverage_hint_;
197 std::optional<Size> color_source_size_;
198
199 Contents(const Contents&) = delete;
200
201 Contents& operator=(const Contents&) = delete;
202 };
203
204 } // namespace impeller
205
206 #endif // FLUTTER_IMPELLER_ENTITY_CONTENTS_CONTENTS_H_
impeller::Contents::GetColorSourceSize
std::optional< Size > GetColorSourceSize() const
Return the color source's intrinsic size, if available.
Definition: contents.cc:156
impeller::OptionsFromPass
ContentContextOptions OptionsFromPass(const RenderPass &pass)
Definition: contents.cc:20
lazy_glyph_atlas.h
impeller::Scalar
float Scalar
Definition: scalar.h:18
impeller::Contents::SetCoverageHint
void SetCoverageHint(std::optional< Rect > coverage_hint)
Hint that specifies the coverage area of this Contents that will actually be used during rendering....
Definition: contents.cc:148
impeller::Contents::AsBackgroundColor
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 ...
Definition: contents.cc:119
impeller::Contents::ClipCoverage::Type
Type
Definition: contents.h:41
impeller::Color
Definition: color.h:124
impeller::Contents::SetColorSourceSize
void SetColorSourceSize(Size size)
Definition: contents.cc:160
impeller::Contents::CanInheritOpacity
virtual bool CanInheritOpacity(const Entity &entity) const
Whether or not this contents can accept the opacity peephole optimization.
Definition: contents.cc:110
impeller::Contents::Contents
Contents()
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::Contents::ClipCoverage::Type::kRestore
@ kRestore
impeller::Contents::GetClipCoverage
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...
Definition: contents.cc:50
impeller::Entity
Definition: entity.h:21
impeller::OptionsFromPassAndEntity
ContentContextOptions OptionsFromPassAndEntity(const RenderPass &pass, const Entity &entity)
Definition: contents.cc:28
impeller::Contents::GetCoverageHint
const std::optional< Rect > & GetCoverageHint() const
Definition: contents.cc:152
impeller::TSize< Scalar >
impeller::Contents::ClipCoverage::coverage
std::optional< Rect > coverage
Definition: contents.h:44
impeller::Contents::~Contents
virtual ~Contents()
impeller::Contents::ColorFilterProc
std::function< Color(Color)> ColorFilterProc
Definition: contents.h:38
impeller::Contents::ClipCoverage::type
Type type
Definition: contents.h:43
impeller::Contents::ShouldRender
virtual bool ShouldRender(const Entity &entity, const std::optional< Rect > clip_coverage) const
Definition: contents.cc:133
impeller::Contents::PopulateGlyphAtlas
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 draw...
Definition: contents.h:61
impeller::RenderPass
Render passes encode render commands directed as one specific render target into an underlying comman...
Definition: render_pass.h:29
sampler_descriptor.h
impeller::Contents::RenderProc
std::function< bool(const ContentContext &renderer, const Entity &entity, RenderPass &pass)> RenderProc
Definition: contents.h:49
impeller::Contents::Render
virtual bool Render(const ContentContext &renderer, const Entity &entity, RenderPass &pass) const =0
snapshot.h
rect.h
impeller::Contents::SetInheritedOpacity
virtual void SetInheritedOpacity(Scalar opacity)
Inherit the provided opacity.
Definition: contents.cc:114
impeller::Contents::ClipCoverage
Definition: contents.h:40
texture.h
impeller::Contents::ClipCoverage::Type::kAppend
@ kAppend
color.h
impeller::Contents::MakeAnonymous
static std::shared_ptr< Contents > MakeAnonymous(RenderProc render_proc, CoverageProc coverage_proc)
Definition: contents.cc:35
impeller::Contents::ApplyColorFilter
virtual bool ApplyColorFilter(const ColorFilterProc &color_filter_proc)
If possible, applies a color filter to this contents inputs on the CPU.
Definition: contents.cc:128
impeller::Contents::CoverageProc
std::function< std::optional< Rect >(const Entity &entity)> CoverageProc
Definition: contents.h:50
impeller::Contents
Definition: contents.h:34
impeller::Contents::IsOpaque
virtual bool IsOpaque() const
Whether this Contents only emits opaque source colors from the fragment stage. This value does not ac...
Definition: contents.cc:46
impeller
Definition: aiks_context.cc:10
impeller::ContentContext
Definition: content_context.h:332
impeller::Contents::AsFilter
virtual const FilterContents * AsFilter() const
Cast to a filter. Returns nullptr if this Contents is not a filter.
Definition: contents.cc:124
impeller::Contents::ClipCoverage::Type::kNoChange
@ kNoChange
impeller::FilterContents
Definition: filter_contents.h:21
impeller::Contents::RenderToSnapshot
virtual 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="Snapshot") const
Render this contents to a snapshot, respecting the entity's transform, path, clip depth,...
Definition: contents.cc:57