Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2012 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #ifndef ANDROID_HWUI_PATH_TESSELLATOR_H |
| 18 | #define ANDROID_HWUI_PATH_TESSELLATOR_H |
| 19 | |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 20 | #include "Matrix.h" |
| 21 | #include "Rect.h" |
| 22 | #include "Vertex.h" |
ztenghui | 55bfb4e | 2013-12-03 10:38:55 -0800 | [diff] [blame] | 23 | #include "VertexBuffer.h" |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 24 | |
John Reck | 272a685 | 2015-07-29 16:48:58 -0700 | [diff] [blame^] | 25 | #include <vector> |
| 26 | |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 27 | namespace android { |
| 28 | namespace uirenderer { |
| 29 | |
ztenghui | 21ef820 | 2015-05-28 16:06:28 -0700 | [diff] [blame] | 30 | /** |
| 31 | * Structure used for threshold values in outline path tessellation. |
| 32 | * |
| 33 | * TODO: PaintInfo should store one of this object, and initialized all values in constructor |
| 34 | * depending on its type (point, line or path). |
| 35 | */ |
| 36 | struct PathApproximationInfo { |
| 37 | PathApproximationInfo(float invScaleX, float invScaleY, float pixelThreshold) |
| 38 | : thresholdSquared(pixelThreshold * pixelThreshold) |
| 39 | , sqrInvScaleX(invScaleX * invScaleX) |
| 40 | , sqrInvScaleY(invScaleY * invScaleY) |
| 41 | , thresholdForConicQuads(pixelThreshold * MathUtils::min(invScaleX, invScaleY) / 2.0f) { |
| 42 | }; |
| 43 | |
| 44 | const float thresholdSquared; |
| 45 | const float sqrInvScaleX; |
| 46 | const float sqrInvScaleY; |
| 47 | const float thresholdForConicQuads; |
| 48 | }; |
| 49 | |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 50 | class PathTessellator { |
| 51 | public: |
Chris Craik | 05f3d6e | 2014-06-02 16:27:04 -0700 | [diff] [blame] | 52 | /** |
| 53 | * Populates scaleX and scaleY with the 'tessellation scale' of the transform - the effective X |
| 54 | * and Y scales that tessellation will take into account when generating the 1.0 pixel thick |
| 55 | * ramp. |
| 56 | * |
| 57 | * Two instances of the same shape (size, paint, etc.) will only generate the same vertices if |
| 58 | * their tessellation scales are equal. |
| 59 | */ |
| 60 | static void extractTessellationScales(const Matrix4& transform, float* scaleX, float* scaleY); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 61 | |
Chris Craik | 15a07a2 | 2014-01-26 13:43:53 -0800 | [diff] [blame] | 62 | /** |
| 63 | * Populates a VertexBuffer with a tessellated approximation of the input convex path, as a single |
| 64 | * triangle strip. Note: joins are not currently supported. |
| 65 | * |
| 66 | * @param path The path to be approximated |
| 67 | * @param paint The paint the path will be drawn with, indicating AA, painting style |
| 68 | * (stroke vs fill), stroke width, stroke cap & join style, etc. |
| 69 | * @param transform The transform the path is to be drawn with, used to drive stretch-aware path |
| 70 | * vertex approximation, and correct AA ramp offsetting. |
| 71 | * @param vertexBuffer The output buffer |
| 72 | */ |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 73 | static void tessellatePath(const SkPath& path, const SkPaint* paint, |
Chris Craik | d6b65f6 | 2014-01-01 14:45:21 -0800 | [diff] [blame] | 74 | const mat4& transform, VertexBuffer& vertexBuffer); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 75 | |
Chris Craik | 15a07a2 | 2014-01-26 13:43:53 -0800 | [diff] [blame] | 76 | /** |
| 77 | * Populates a VertexBuffer with a tessellated approximation of points as a single triangle |
| 78 | * strip (with degenerate tris separating), respecting the shape defined by the paint cap. |
| 79 | * |
| 80 | * @param points The center vertices of the points to be drawn |
| 81 | * @param count The number of floats making up the point vertices |
| 82 | * @param paint The paint the points will be drawn with indicating AA, stroke width & cap |
| 83 | * @param transform The transform the points will be drawn with, used to drive stretch-aware path |
| 84 | * vertex approximation, and correct AA ramp offsetting |
Chris Craik | 15a07a2 | 2014-01-26 13:43:53 -0800 | [diff] [blame] | 85 | * @param vertexBuffer The output buffer |
| 86 | */ |
Chris Craik | d218a92 | 2014-01-02 17:13:34 -0800 | [diff] [blame] | 87 | static void tessellatePoints(const float* points, int count, const SkPaint* paint, |
Chris Craik | 05f3d6e | 2014-06-02 16:27:04 -0700 | [diff] [blame] | 88 | const mat4& transform, VertexBuffer& vertexBuffer); |
Chris Craik | 6d29c8d | 2013-05-08 18:35:44 -0700 | [diff] [blame] | 89 | |
Chris Craik | 15a07a2 | 2014-01-26 13:43:53 -0800 | [diff] [blame] | 90 | /** |
| 91 | * Populates a VertexBuffer with a tessellated approximation of lines as a single triangle |
| 92 | * strip (with degenerate tris separating). |
| 93 | * |
| 94 | * @param points Pairs of endpoints defining the lines to be drawn |
| 95 | * @param count The number of floats making up the line vertices |
| 96 | * @param paint The paint the lines will be drawn with indicating AA, stroke width & cap |
| 97 | * @param transform The transform the points will be drawn with, used to drive stretch-aware path |
| 98 | * vertex approximation, and correct AA ramp offsetting |
Chris Craik | 15a07a2 | 2014-01-26 13:43:53 -0800 | [diff] [blame] | 99 | * @param vertexBuffer The output buffer |
| 100 | */ |
Chris Craik | d218a92 | 2014-01-02 17:13:34 -0800 | [diff] [blame] | 101 | static void tessellateLines(const float* points, int count, const SkPaint* paint, |
Chris Craik | 05f3d6e | 2014-06-02 16:27:04 -0700 | [diff] [blame] | 102 | const mat4& transform, VertexBuffer& vertexBuffer); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 103 | |
Chris Craik | 15a07a2 | 2014-01-26 13:43:53 -0800 | [diff] [blame] | 104 | /** |
Chris Craik | fca52b75 | 2015-04-28 11:45:59 -0700 | [diff] [blame] | 105 | * Approximates a convex outline into a clockwise Vector of 2d vertices. |
Chris Craik | 15a07a2 | 2014-01-26 13:43:53 -0800 | [diff] [blame] | 106 | * |
| 107 | * @param path The outline to be approximated |
ztenghui | 21ef820 | 2015-05-28 16:06:28 -0700 | [diff] [blame] | 108 | * @param threshold The threshold of acceptable error (in pixels) when approximating |
Chris Craik | 15a07a2 | 2014-01-26 13:43:53 -0800 | [diff] [blame] | 109 | * @param outputVertices An empty Vector which will be populated with the output |
| 110 | */ |
ztenghui | 21ef820 | 2015-05-28 16:06:28 -0700 | [diff] [blame] | 111 | static bool approximatePathOutlineVertices(const SkPath &path, float threshold, |
John Reck | 272a685 | 2015-07-29 16:48:58 -0700 | [diff] [blame^] | 112 | std::vector<Vertex> &outputVertices); |
Chris Craik | 15a07a2 | 2014-01-26 13:43:53 -0800 | [diff] [blame] | 113 | |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 114 | private: |
| 115 | static bool approximatePathOutlineVertices(const SkPath &path, bool forceClose, |
John Reck | 272a685 | 2015-07-29 16:48:58 -0700 | [diff] [blame^] | 116 | const PathApproximationInfo& approximationInfo, std::vector<Vertex> &outputVertices); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 117 | |
| 118 | /* |
| 119 | endpoints a & b, |
| 120 | control c |
| 121 | */ |
| 122 | static void recursiveQuadraticBezierVertices( |
| 123 | float ax, float ay, |
| 124 | float bx, float by, |
| 125 | float cx, float cy, |
ztenghui | 21ef820 | 2015-05-28 16:06:28 -0700 | [diff] [blame] | 126 | const PathApproximationInfo& approximationInfo, |
John Reck | 272a685 | 2015-07-29 16:48:58 -0700 | [diff] [blame^] | 127 | std::vector<Vertex> &outputVertices, int depth = 0); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 128 | |
| 129 | /* |
| 130 | endpoints p1, p2 |
| 131 | control c1, c2 |
| 132 | */ |
| 133 | static void recursiveCubicBezierVertices( |
| 134 | float p1x, float p1y, |
| 135 | float c1x, float c1y, |
| 136 | float p2x, float p2y, |
| 137 | float c2x, float c2y, |
ztenghui | 21ef820 | 2015-05-28 16:06:28 -0700 | [diff] [blame] | 138 | const PathApproximationInfo& approximationInfo, |
John Reck | 272a685 | 2015-07-29 16:48:58 -0700 | [diff] [blame^] | 139 | std::vector<Vertex> &outputVertices, int depth = 0); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 140 | }; |
| 141 | |
| 142 | }; // namespace uirenderer |
| 143 | }; // namespace android |
| 144 | |
| 145 | #endif // ANDROID_HWUI_PATH_TESSELLATOR_H |