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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
11 #include "impeller/core/sampler_descriptor.h"
12 #include "impeller/geometry/color.h"
13 #include "impeller/geometry/rect.h"
14 #include "impeller/renderer/snapshot.h"
15 #include "impeller/typographer/lazy_glyph_atlas.h"
16
17 namespace impeller {
18
19 class ContentContext;
20 struct ContentContextOptions;
21 class Entity;
22 class Surface;
23 class RenderPass;
24 class FilterContents;
25
26 ContentContextOptions OptionsFromPass(const RenderPass& pass);
27
28 ContentContextOptions OptionsFromPassAndEntity(const RenderPass& pass,
29 const Entity& entity);
30
31 class Contents {
32 public:
33 /// A procedure that filters a given unpremultiplied color to produce a new
34 /// unpremultiplied color.
35 using ColorFilterProc = std::function<Color(Color)>;
36
37 struct ClipCoverage {
38 enum class Type { kNoChange, kAppend, kRestore };
39
40 Type type = Type::kNoChange;
41 // TODO(jonahwilliams): this should probably use the Entity::ClipOperation
42 // enum, but that has transitive import errors.
43 bool is_difference_or_non_square = false;
44
45 /// @brief This coverage is the outer coverage of the clip.
46 ///
47 /// For example, if the clip is a circular clip, this is the rectangle that
48 /// contains the circle and not the rectangle that is contained within the
49 /// circle. This means that we cannot use the coverage alone to determine if
50 /// a clip can be culled, and instead also use the somewhat hacky
51 /// "is_difference_or_non_square" field.
52 std::optional<Rect> coverage = std::nullopt;
53 };
54
55 using RenderProc = std::function<bool(const ContentContext& renderer,
56 const Entity& entity,
57 RenderPass& pass)>;
58 using CoverageProc = std::function<std::optional<Rect>(const Entity& entity)>;
59
60 static std::shared_ptr<Contents> MakeAnonymous(RenderProc render_proc,
61 CoverageProc coverage_proc);
62
63 Contents();
64
65 virtual ~Contents();
66
67 virtual bool Render(const ContentContext& renderer,
68 const Entity& entity,
69 RenderPass& pass) const = 0;
70
71 //----------------------------------------------------------------------------
72 /// @brief Get the area of the render pass that will be affected when this
73 /// contents is rendered.
74 ///
75 /// During rendering, coverage coordinates count pixels from the top
76 /// left corner of the framebuffer.
77 ///
78 /// @return The coverage rectangle. An `std::nullopt` result means that
79 /// rendering this contents has no effect on the output color.
80 ///
81 virtual std::optional<Rect> GetCoverage(const Entity& entity) const = 0;
82
83 //----------------------------------------------------------------------------
84 /// @brief Hint that specifies the coverage area of this Contents that will
85 /// actually be used during rendering. This is for optimization
86 /// purposes only and can not be relied on as a clip. May optionally
87 /// affect the result of `GetCoverage()`.
88 ///
89 void SetCoverageHint(std::optional<Rect> coverage_hint);
90
91 const std::optional<Rect>& GetCoverageHint() const;
92
93 //----------------------------------------------------------------------------
94 /// @brief Whether this Contents only emits opaque source colors from the
95 /// fragment stage. This value does not account for any entity
96 /// properties (e.g. the blend mode), clips/visibility culling, or
97 /// inherited opacity.
98 ///
99 /// @param transform The current transform matrix of the entity that will
100 /// render this contents.
101 virtual bool IsOpaque(const Matrix& transform) const;
102
103 //----------------------------------------------------------------------------
104 /// @brief Given the current pass space bounding rectangle of the clip
105 /// buffer, return the expected clip coverage after this draw call.
106 /// This should only be implemented for contents that may write to the
107 /// clip buffer.
108 ///
109 /// During rendering, coverage coordinates count pixels from the top
110 /// left corner of the framebuffer.
111 ///
112 virtual ClipCoverage GetClipCoverage(
113 const Entity& entity,
114 const std::optional<Rect>& current_clip_coverage) const;
115
116 //----------------------------------------------------------------------------
117 /// @brief Render this contents to a snapshot, respecting the entity's
118 /// transform, path, clip depth, and blend mode.
119 /// The result texture size is always the size of
120 /// `GetCoverage(entity)`.
121 ///
122 virtual std::optional<Snapshot> RenderToSnapshot(
123 const ContentContext& renderer,
124 const Entity& entity,
125 std::optional<Rect> coverage_limit = std::nullopt,
126 const std::optional<SamplerDescriptor>& sampler_descriptor = std::nullopt,
127 bool msaa_enabled = true,
128 int32_t mip_count = 1,
129 const std::string& label = "Snapshot") const;
130
131 //----------------------------------------------------------------------------
132 /// @brief Return the color source's intrinsic size, if available.
133 ///
134 /// For example, a gradient has a size based on its end and beginning
135 /// points, ignoring any tiling. Solid colors and runtime effects have
136 /// no size.
137 ///
138 std::optional<Size> GetColorSourceSize() const;
139
140 void SetColorSourceSize(Size size);
141
142 //----------------------------------------------------------------------------
143 /// @brief Inherit the provided opacity.
144 ///
145 /// Use of this method is invalid if CanAcceptOpacity returns false.
146 ///
147 virtual void SetInheritedOpacity(Scalar opacity);
148
149 //----------------------------------------------------------------------------
150 /// @brief Returns a color if this Contents will flood the given `target_size`
151 /// with a color. This output color is the "Source" color that will be
152 /// used for the Entity's blend operation.
153 ///
154 /// This is useful for absorbing full screen solid color draws into
155 /// subpass clear colors.
156 ///
157 virtual std::optional<Color> AsBackgroundColor(const Entity& entity,
158 ISize target_size) const;
159
160 //----------------------------------------------------------------------------
161 /// @brief Cast to a filter. Returns `nullptr` if this Contents is not a
162 /// filter.
163 ///
164 virtual const FilterContents* AsFilter() const;
165
166 //----------------------------------------------------------------------------
167 /// @brief If possible, applies a color filter to this contents inputs on
168 /// the CPU.
169 ///
170 /// This method will either fully apply the color filter or
171 /// perform no action. Partial/incorrect application of the color
172 /// filter will never occur.
173 ///
174 /// @param[in] color_filter_proc A function that filters a given
175 /// unpremultiplied color to produce a new
176 /// unpremultiplied color.
177 ///
178 /// @return True if the color filter was able to be fully applied to all
179 /// all relevant inputs. Otherwise, this operation is a no-op and
180 /// false is returned.
181 ///
182 [[nodiscard]] virtual bool ApplyColorFilter(
183 const ColorFilterProc& color_filter_proc);
184
185 private:
186 std::optional<Rect> coverage_hint_;
187 std::optional<Size> color_source_size_;
188
189 Contents(const Contents&) = delete;
190
191 Contents& operator=(const Contents&) = delete;
192 };
193
194 } // namespace impeller
195
196 #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:158
impeller::OptionsFromPass
ContentContextOptions OptionsFromPass(const RenderPass &pass)
Definition: contents.cc:19
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:150
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:136
impeller::Contents::ClipCoverage::Type
Type
Definition: contents.h:38
impeller::Color
Definition: color.h:123
impeller::Contents::SetColorSourceSize
void SetColorSourceSize(Size size)
Definition: contents.cc:162
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:63
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:56
impeller::Entity
Definition: entity.h:20
impeller::OptionsFromPassAndEntity
ContentContextOptions OptionsFromPassAndEntity(const RenderPass &pass, const Entity &entity)
Definition: contents.cc:34
impeller::Contents::GetCoverageHint
const std::optional< Rect > & GetCoverageHint() const
Definition: contents.cc:154
impeller::TSize< Scalar >
impeller::Contents::ClipCoverage::coverage
std::optional< Rect > coverage
This coverage is the outer coverage of the clip.
Definition: contents.h:52
impeller::Contents::~Contents
virtual ~Contents()
transform
Matrix transform
Definition: gaussian_blur_filter_contents.cc:213
impeller::Contents::ColorFilterProc
std::function< Color(Color)> ColorFilterProc
Definition: contents.h:35
impeller::Contents::ClipCoverage::type
Type type
Definition: contents.h:40
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:57
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:131
impeller::Contents::ClipCoverage
Definition: contents.h:37
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:41
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:145
impeller::Contents::CoverageProc
std::function< std::optional< Rect >(const Entity &entity)> CoverageProc
Definition: contents.h:58
impeller::Contents
Definition: contents.h:31
impeller::Contents::IsOpaque
virtual bool IsOpaque(const Matrix &transform) const
Whether this Contents only emits opaque source colors from the fragment stage. This value does not ac...
Definition: contents.cc:52
impeller
Definition: allocation.cc:12
impeller::ContentContext
Definition: content_context.h:366
impeller::Contents::AsFilter
virtual const FilterContents * AsFilter() const
Cast to a filter. Returns nullptr if this Contents is not a filter.
Definition: contents.cc:141
impeller::Matrix
A 4x4 matrix using column-major storage.
Definition: matrix.h:37
impeller::Contents::ClipCoverage::Type::kNoChange
@ kNoChange
impeller::FilterContents
Definition: filter_contents.h:22
impeller::Contents::ClipCoverage::is_difference_or_non_square
bool is_difference_or_non_square
Definition: contents.h:43