| Flutter Impeller |

contents.h
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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 int32_t mip_count = 1,
125 const std::string& label = "Snapshot") const;
126
127 virtual bool ShouldRender(const Entity& entity,
128 const std::optional<Rect> clip_coverage) const;
129
130 //----------------------------------------------------------------------------
131 /// @brief Return the color source's intrinsic size, if available.
132 ///
133 /// For example, a gradient has a size based on its end and beginning
134 /// points, ignoring any tiling. Solid colors and runtime effects have
135 /// no size.
136 ///
137 std::optional<Size> GetColorSourceSize() const;
138
139 void SetColorSourceSize(Size size);
140
141 //----------------------------------------------------------------------------
142 /// @brief Whether or not this contents can accept the opacity peephole
143 /// optimization.
144 ///
145 /// By default all contents return false. Contents are responsible
146 /// for determining whether or not their own geometries intersect in
147 /// a way that makes accepting opacity impossible. It is always safe
148 /// to return false, especially if computing overlap would be
149 /// computationally expensive.
150 ///
151 virtual bool CanInheritOpacity(const Entity& entity) const;
152
153 //----------------------------------------------------------------------------
154 /// @brief Inherit the provided opacity.
155 ///
156 /// Use of this method is invalid if CanAcceptOpacity returns false.
157 ///
158 virtual void SetInheritedOpacity(Scalar opacity);
159
160 //----------------------------------------------------------------------------
161 /// @brief Returns a color if this Contents will flood the given `target_size`
162 /// with a color. This output color is the "Source" color that will be
163 /// used for the Entity's blend operation.
164 ///
165 /// This is useful for absorbing full screen solid color draws into
166 /// subpass clear colors.
167 ///
168 virtual std::optional<Color> AsBackgroundColor(const Entity& entity,
169 ISize target_size) const;
170
171 //----------------------------------------------------------------------------
172 /// @brief Cast to a filter. Returns `nullptr` if this Contents is not a
173 /// filter.
174 ///
175 virtual const FilterContents* AsFilter() const;
176
177 //----------------------------------------------------------------------------
178 /// @brief If possible, applies a color filter to this contents inputs on
179 /// the CPU.
180 ///
181 /// This method will either fully apply the color filter or
182 /// perform no action. Partial/incorrect application of the color
183 /// filter will never occur.
184 ///
185 /// @param[in] color_filter_proc A function that filters a given
186 /// unpremultiplied color to produce a new
187 /// unpremultiplied color.
188 ///
189 /// @return True if the color filter was able to be fully applied to all
190 /// all relevant inputs. Otherwise, this operation is a no-op and
191 /// false is returned.
192 ///
193 [[nodiscard]] virtual bool ApplyColorFilter(
194 const ColorFilterProc& color_filter_proc);
195
196 private:
197 std::optional<Rect> coverage_hint_;
198 std::optional<Size> color_source_size_;
199
200 Contents(const Contents&) = delete;
201
202 Contents& operator=(const Contents&) = delete;
203 };
204
205 } // namespace impeller
206
207 #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:168
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:160
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:131
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:172
impeller::Contents::CanInheritOpacity
virtual bool CanInheritOpacity(const Entity &entity) const
Whether or not this contents can accept the opacity peephole optimization.
Definition: contents.cc:122
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, 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,...
Definition: contents.cc:66
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:59
impeller::Entity
Definition: entity.h:21
impeller::OptionsFromPassAndEntity
ContentContextOptions OptionsFromPassAndEntity(const RenderPass &pass, const Entity &entity)
Definition: contents.cc:37
impeller::Contents::GetCoverageHint
const std::optional< Rect > & GetCoverageHint() const
Definition: contents.cc:164
impeller::TSize
Definition: size.h:19
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:145
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:33
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:126
impeller::Contents::ClipCoverage
Definition: contents.h:40
texture.h
scale
const Scalar scale
Definition: stroke_path_geometry.cc:297
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:44
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:140
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:55
impeller
Definition: aiks_blur_unittests.cc:20
impeller::ContentContext
Definition: content_context.h:392
impeller::Contents::AsFilter
virtual const FilterContents * AsFilter() const
Cast to a filter. Returns nullptr if this Contents is not a filter.
Definition: contents.cc:136
impeller::Contents::ClipCoverage::Type::kNoChange
@ kNoChange
impeller::FilterContents
Definition: filter_contents.h:22