| Flutter Impeller |

line_geometry.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_GEOMETRY_LINE_GEOMETRY_H_
6 #define FLUTTER_IMPELLER_ENTITY_GEOMETRY_LINE_GEOMETRY_H_
7
8 #include "impeller/entity/geometry/geometry.h"
9
10 namespace impeller {
11
12 class LineGeometry final : public Geometry {
13 public:
14 explicit LineGeometry(Point p0, Point p1, Scalar width, Cap cap);
15
16 ~LineGeometry() override;
17
18 static Scalar ComputePixelHalfWidth(const Matrix& transform,
19 Scalar width,
20 bool msaa);
21
22 // |Geometry|
23 bool CoversArea(const Matrix& transform, const Rect& rect) const override;
24
25 // |Geometry|
26 bool IsAxisAlignedRect() const override;
27
28 Scalar ComputeAlphaCoverage(const Matrix& transform) const override;
29
30 private:
31 // Computes the 4 corners of a rectangle that defines the line and
32 // possibly extended endpoints which will be rendered under the given
33 // transform, and returns true if such a rectangle is defined.
34 //
35 // The coordinates will be generated in the original coordinate system
36 // of the line end points and the transform will only be used to determine
37 // the minimum line width.
38 //
39 // For kButt and kSquare end caps the ends should always be exteded as
40 // per that decoration, but for kRound caps the ends might be extended
41 // if the goal is to get a conservative bounds and might not be extended
42 // if the calling code is planning to draw the round caps on the ends.
43 //
44 // @return true if the transform and width were not degenerate
45 bool ComputeCorners(Point corners[4],
46 const Matrix& transform,
47 bool extend_endpoints,
48 bool msaa) const;
49
50 Vector2 ComputeAlongVector(const Matrix& transform,
51 bool allow_zero_length,
52 bool msaa) const;
53
54 // |Geometry|
55 GeometryResult GetPositionBuffer(const ContentContext& renderer,
56 const Entity& entity,
57 RenderPass& pass) const override;
58
59 // |Geometry|
60 std::optional<Rect> GetCoverage(const Matrix& transform) const override;
61
62 Point p0_;
63 Point p1_;
64 Scalar width_;
65 Cap cap_;
66
67 LineGeometry(const LineGeometry&) = delete;
68
69 LineGeometry& operator=(const LineGeometry&) = delete;
70 };
71
72 } // namespace impeller
73
74 #endif // FLUTTER_IMPELLER_ENTITY_GEOMETRY_LINE_GEOMETRY_H_
impeller::Scalar
float Scalar
Definition: scalar.h:18
geometry.h
impeller::LineGeometry::ComputeAlphaCoverage
Scalar ComputeAlphaCoverage(const Matrix &transform) const override
Definition: line_geometry.cc:73
impeller::LineGeometry::LineGeometry
LineGeometry(Point p0, Point p1, Scalar width, Cap cap)
Definition: line_geometry.cc:10
impeller::LineGeometry::ComputePixelHalfWidth
static Scalar ComputePixelHalfWidth(const Matrix &transform, Scalar width, bool msaa)
Definition: line_geometry.cc:17
impeller::Entity
Definition: entity.h:20
impeller::LineGeometry::CoversArea
bool CoversArea(const Matrix &transform, const Rect &rect) const override
Determines if this geometry, transformed by the given transform, will completely cover all surface ar...
Definition: line_geometry.cc:136
transform
Matrix transform
Definition: gaussian_blur_filter_contents.cc:213
impeller::LineGeometry
Definition: line_geometry.h:12
impeller::GeometryResult
Definition: geometry.h:26
impeller::LineGeometry::IsAxisAlignedRect
bool IsAxisAlignedRect() const override
Definition: line_geometry.cc:144
impeller::RenderPass
Render passes encode render commands directed as one specific render target into an underlying comman...
Definition: render_pass.h:33
impeller::Geometry
Definition: geometry.h:55
impeller::TPoint< Scalar >
impeller
Definition: allocation.cc:12
impeller::ContentContext
Definition: content_context.h:366
impeller::TRect< Scalar >
impeller::Matrix
A 4x4 matrix using column-major storage.
Definition: matrix.h:37
impeller::Cap
Cap
Definition: path.h:18
impeller::LineGeometry::~LineGeometry
~LineGeometry() override