1bcacfdcab
Test: No code changes, just ran through clang-format Change-Id: Id23aa4ec7eebc0446fe3a30260f33e7fd455bb8c
149 lines
6.2 KiB
C++
149 lines
6.2 KiB
C++
/*
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* Copyright (C) 2012 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef ANDROID_HWUI_PATH_TESSELLATOR_H
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#define ANDROID_HWUI_PATH_TESSELLATOR_H
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#include "Matrix.h"
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#include "Rect.h"
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#include "Vertex.h"
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#include "VertexBuffer.h"
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#include <algorithm>
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#include <vector>
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class SkPath;
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class SkPaint;
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namespace android {
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namespace uirenderer {
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/**
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* Structure used for threshold values in outline path tessellation.
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*
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* TODO: PaintInfo should store one of this object, and initialized all values in constructor
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* depending on its type (point, line or path).
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*/
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struct PathApproximationInfo {
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PathApproximationInfo(float invScaleX, float invScaleY, float pixelThreshold)
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: thresholdSquared(pixelThreshold * pixelThreshold)
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, sqrInvScaleX(invScaleX * invScaleX)
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, sqrInvScaleY(invScaleY * invScaleY)
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, thresholdForConicQuads(pixelThreshold * std::min(invScaleX, invScaleY) / 2.0f){};
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const float thresholdSquared;
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const float sqrInvScaleX;
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const float sqrInvScaleY;
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const float thresholdForConicQuads;
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};
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class PathTessellator {
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public:
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/**
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* Populates scaleX and scaleY with the 'tessellation scale' of the transform - the effective X
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* and Y scales that tessellation will take into account when generating the 1.0 pixel thick
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* ramp.
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*
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* Two instances of the same shape (size, paint, etc.) will only generate the same vertices if
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* their tessellation scales are equal.
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*/
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static void extractTessellationScales(const Matrix4& transform, float* scaleX, float* scaleY);
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/**
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* Populates a VertexBuffer with a tessellated approximation of the input convex path, as a
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* single
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* triangle strip. Note: joins are not currently supported.
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*
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* @param path The path to be approximated
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* @param paint The paint the path will be drawn with, indicating AA, painting style
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* (stroke vs fill), stroke width, stroke cap & join style, etc.
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* @param transform The transform the path is to be drawn with, used to drive stretch-aware path
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* vertex approximation, and correct AA ramp offsetting.
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* @param vertexBuffer The output buffer
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*/
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static void tessellatePath(const SkPath& path, const SkPaint* paint, const mat4& transform,
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VertexBuffer& vertexBuffer);
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/**
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* Populates a VertexBuffer with a tessellated approximation of points as a single triangle
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* strip (with degenerate tris separating), respecting the shape defined by the paint cap.
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*
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* @param points The center vertices of the points to be drawn
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* @param count The number of floats making up the point vertices
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* @param paint The paint the points will be drawn with indicating AA, stroke width & cap
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* @param transform The transform the points will be drawn with, used to drive stretch-aware
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* path
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* vertex approximation, and correct AA ramp offsetting
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* @param vertexBuffer The output buffer
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*/
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static void tessellatePoints(const float* points, int count, const SkPaint* paint,
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const mat4& transform, VertexBuffer& vertexBuffer);
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/**
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* Populates a VertexBuffer with a tessellated approximation of lines as a single triangle
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* strip (with degenerate tris separating).
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*
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* @param points Pairs of endpoints defining the lines to be drawn
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* @param count The number of floats making up the line vertices
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* @param paint The paint the lines will be drawn with indicating AA, stroke width & cap
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* @param transform The transform the points will be drawn with, used to drive stretch-aware
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* path
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* vertex approximation, and correct AA ramp offsetting
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* @param vertexBuffer The output buffer
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*/
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static void tessellateLines(const float* points, int count, const SkPaint* paint,
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const mat4& transform, VertexBuffer& vertexBuffer);
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/**
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* Approximates a convex outline into a clockwise Vector of 2d vertices.
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*
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* @param path The outline to be approximated
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* @param threshold The threshold of acceptable error (in pixels) when approximating
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* @param outputVertices An empty Vector which will be populated with the output
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*/
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static bool approximatePathOutlineVertices(const SkPath& path, float threshold,
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std::vector<Vertex>& outputVertices);
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private:
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static bool approximatePathOutlineVertices(const SkPath& path, bool forceClose,
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const PathApproximationInfo& approximationInfo,
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std::vector<Vertex>& outputVertices);
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/*
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endpoints a & b,
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control c
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*/
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static void recursiveQuadraticBezierVertices(float ax, float ay, float bx, float by, float cx,
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float cy,
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const PathApproximationInfo& approximationInfo,
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std::vector<Vertex>& outputVertices,
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int depth = 0);
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/*
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endpoints p1, p2
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control c1, c2
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*/
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static void recursiveCubicBezierVertices(float p1x, float p1y, float c1x, float c1y, float p2x,
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float p2y, float c2x, float c2y,
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const PathApproximationInfo& approximationInfo,
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std::vector<Vertex>& outputVertices, int depth = 0);
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};
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}; // namespace uirenderer
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}; // namespace android
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#endif // ANDROID_HWUI_PATH_TESSELLATOR_H
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