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skia2/experimental/AndroidPathRenderer/AndroidPathRenderer.cpp

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/*
* Copyright 2012 The Android Open Source Project
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#define LOG_TAG "PathRenderer"
#define LOG_NDEBUG 1
#define ATRACE_TAG ATRACE_TAG_GRAPHICS
#define VERTEX_DEBUG 0
#include <SkPath.h>
#include <SkStrokeRec.h>
#include <stdlib.h>
#include <stdint.h>
#include <sys/types.h>
#include <SkTypes.h>
#include <SkTraceEvent.h>
#include <SkMatrix.h>
#include <SkPoint.h>
#ifdef VERBOSE
#define ALOGV SkDebugf
#else
#define ALOGV(x, ...)
#endif
#include "AndroidPathRenderer.h"
#include "Vertex.h"
namespace android {
namespace uirenderer {
#define THRESHOLD 0.5f
SkRect PathRenderer::ComputePathBounds(const SkPath& path, const SkPaint* paint) {
SkRect bounds = path.getBounds();
if (paint->getStyle() != SkPaint::kFill_Style) {
float outset = paint->getStrokeWidth() * 0.5f;
bounds.outset(outset, outset);
}
return bounds;
}
inline void computeInverseScales(const SkMatrix* transform, float &inverseScaleX, float& inverseScaleY) {
if (transform && transform->getType() & (SkMatrix::kScale_Mask|SkMatrix::kAffine_Mask|SkMatrix::kPerspective_Mask)) {
float m00 = transform->getScaleX();
float m01 = transform->getSkewY();
float m10 = transform->getSkewX();
float m11 = transform->getScaleY();
float scaleX = sk_float_sqrt(m00 * m00 + m01 * m01);
float scaleY = sk_float_sqrt(m10 * m10 + m11 * m11);
inverseScaleX = (scaleX != 0) ? (1.0f / scaleX) : 1.0f;
inverseScaleY = (scaleY != 0) ? (1.0f / scaleY) : 1.0f;
} else {
inverseScaleX = 1.0f;
inverseScaleY = 1.0f;
}
}
inline void copyVertex(Vertex* destPtr, const Vertex* srcPtr) {
Vertex::set(destPtr, srcPtr->position[0], srcPtr->position[1]);
}
inline void copyAlphaVertex(AlphaVertex* destPtr, const AlphaVertex* srcPtr) {
AlphaVertex::set(destPtr, srcPtr->position[0], srcPtr->position[1], srcPtr->alpha);
}
/**
* Produces a pseudo-normal for a vertex, given the normals of the two incoming lines. If the offset
* from each vertex in a perimeter is calculated, the resultant lines connecting the offset vertices
* will be offset by 1.0
*
* Note that we can't add and normalize the two vectors, that would result in a rectangle having an
* offset of (sqrt(2)/2, sqrt(2)/2) at each corner, instead of (1, 1)
*
* NOTE: assumes angles between normals 90 degrees or less
*/
inline SkVector totalOffsetFromNormals(const SkVector& normalA, const SkVector& normalB) {
SkVector pseudoNormal = normalA + normalB;
pseudoNormal.scale(1.0f / (1.0f + sk_float_abs(normalA.dot(normalB))));
return pseudoNormal;
}
inline void scaleOffsetForStrokeWidth(SkVector& offset, float halfStrokeWidth,
float inverseScaleX, float inverseScaleY) {
if (halfStrokeWidth == 0.0f) {
// hairline - compensate for scale
offset.fX *= 0.5f * inverseScaleX;
offset.fY *= 0.5f * inverseScaleY;
} else {
offset.scale(halfStrokeWidth);
}
}
static void getFillVerticesFromPerimeter(const SkTArray<Vertex, true>& perimeter, VertexBuffer* vertexBuffer) {
Vertex* buffer = vertexBuffer->alloc<Vertex>(perimeter.count());
int currentIndex = 0;
// zig zag between all previous points on the inside of the hull to create a
// triangle strip that fills the hull
int srcAindex = 0;
int srcBindex = perimeter.count() - 1;
while (srcAindex <= srcBindex) {
copyVertex(&buffer[currentIndex++], &perimeter[srcAindex]);
if (srcAindex == srcBindex) break;
copyVertex(&buffer[currentIndex++], &perimeter[srcBindex]);
srcAindex++;
srcBindex--;
}
}
static void getStrokeVerticesFromPerimeter(const SkTArray<Vertex, true>& perimeter, float halfStrokeWidth,
VertexBuffer* vertexBuffer, float inverseScaleX, float inverseScaleY) {
Vertex* buffer = vertexBuffer->alloc<Vertex>(perimeter.count() * 2 + 2);
int currentIndex = 0;
const Vertex* last = &(perimeter[perimeter.count() - 1]);
const Vertex* current = &(perimeter[0]);
SkVector lastNormal;
lastNormal.set(current->position[1] - last->position[1],
last->position[0] - current->position[0]);
lastNormal.normalize();
for (int i = 0; i < perimeter.count(); i++) {
const Vertex* next = &(perimeter[i + 1 >= perimeter.count() ? 0 : i + 1]);
SkVector nextNormal;
nextNormal.set(next->position[1] - current->position[1],
current->position[0] - next->position[0]);
nextNormal.normalize();
SkVector totalOffset = totalOffsetFromNormals(lastNormal, nextNormal);
scaleOffsetForStrokeWidth(totalOffset, halfStrokeWidth, inverseScaleX, inverseScaleY);
Vertex::set(&buffer[currentIndex++],
current->position[0] + totalOffset.fX,
current->position[1] + totalOffset.fY);
Vertex::set(&buffer[currentIndex++],
current->position[0] - totalOffset.fX,
current->position[1] - totalOffset.fY);
last = current;
current = next;
lastNormal = nextNormal;
}
// wrap around to beginning
copyVertex(&buffer[currentIndex++], &buffer[0]);
copyVertex(&buffer[currentIndex++], &buffer[1]);
}
static void getStrokeVerticesFromUnclosedVertices(const SkTArray<Vertex, true>& vertices, float halfStrokeWidth,
VertexBuffer* vertexBuffer, float inverseScaleX, float inverseScaleY) {
Vertex* buffer = vertexBuffer->alloc<Vertex>(vertices.count() * 2);
int currentIndex = 0;
const Vertex* current = &(vertices[0]);
SkVector lastNormal;
for (int i = 0; i < vertices.count() - 1; i++) {
const Vertex* next = &(vertices[i + 1]);
SkVector nextNormal;
nextNormal.set(next->position[1] - current->position[1],
current->position[0] - next->position[0]);
nextNormal.normalize();
SkVector totalOffset;
if (i == 0) {
totalOffset = nextNormal;
} else {
totalOffset = totalOffsetFromNormals(lastNormal, nextNormal);
}
scaleOffsetForStrokeWidth(totalOffset, halfStrokeWidth, inverseScaleX, inverseScaleY);
Vertex::set(&buffer[currentIndex++],
current->position[0] + totalOffset.fX,
current->position[1] + totalOffset.fY);
Vertex::set(&buffer[currentIndex++],
current->position[0] - totalOffset.fX,
current->position[1] - totalOffset.fY);
current = next;
lastNormal = nextNormal;
}
SkVector totalOffset = lastNormal;
scaleOffsetForStrokeWidth(totalOffset, halfStrokeWidth, inverseScaleX, inverseScaleY);
Vertex::set(&buffer[currentIndex++],
current->position[0] + totalOffset.fX,
current->position[1] + totalOffset.fY);
Vertex::set(&buffer[currentIndex++],
current->position[0] - totalOffset.fX,
current->position[1] - totalOffset.fY);
#if VERTEX_DEBUG
for (unsigned int i = 0; i < vertexBuffer.getSize(); i++) {
SkDebugf("point at %f %f", buffer[i].position[0], buffer[i].position[1]);
}
#endif
}
static void getFillVerticesFromPerimeterAA(const SkTArray<Vertex, true>& perimeter, VertexBuffer* vertexBuffer,
float inverseScaleX, float inverseScaleY) {
AlphaVertex* buffer = vertexBuffer->alloc<AlphaVertex>(perimeter.count() * 3 + 2);
// generate alpha points - fill Alpha vertex gaps in between each point with
// alpha 0 vertex, offset by a scaled normal.
int currentIndex = 0;
const Vertex* last = &(perimeter[perimeter.count() - 1]);
const Vertex* current = &(perimeter[0]);
SkVector lastNormal;
lastNormal.set(current->position[1] - last->position[1],
last->position[0] - current->position[0]);
lastNormal.normalize();
for (int i = 0; i < perimeter.count(); i++) {
const Vertex* next = &(perimeter[i + 1 >= perimeter.count() ? 0 : i + 1]);
SkVector nextNormal;
nextNormal.set(next->position[1] - current->position[1],
current->position[0] - next->position[0]);
nextNormal.normalize();
// AA point offset from original point is that point's normal, such that each side is offset
// by .5 pixels
SkVector totalOffset = totalOffsetFromNormals(lastNormal, nextNormal);
totalOffset.fX *= 0.5f * inverseScaleX;
totalOffset.fY *= 0.5f * inverseScaleY;
AlphaVertex::set(&buffer[currentIndex++],
current->position[0] + totalOffset.fX,
current->position[1] + totalOffset.fY,
0.0f);
AlphaVertex::set(&buffer[currentIndex++],
current->position[0] - totalOffset.fX,
current->position[1] - totalOffset.fY,
1.0f);
last = current;
current = next;
lastNormal = nextNormal;
}
// wrap around to beginning
copyAlphaVertex(&buffer[currentIndex++], &buffer[0]);
copyAlphaVertex(&buffer[currentIndex++], &buffer[1]);
// zig zag between all previous points on the inside of the hull to create a
// triangle strip that fills the hull, repeating the first inner point to
// create degenerate tris to start inside path
int srcAindex = 0;
int srcBindex = perimeter.count() - 1;
while (srcAindex <= srcBindex) {
copyAlphaVertex(&buffer[currentIndex++], &buffer[srcAindex * 2 + 1]);
if (srcAindex == srcBindex) break;
copyAlphaVertex(&buffer[currentIndex++], &buffer[srcBindex * 2 + 1]);
srcAindex++;
srcBindex--;
}
#if VERTEX_DEBUG
for (unsigned int i = 0; i < vertexBuffer.getSize(); i++) {
SkDebugf("point at %f %f, alpha %f", buffer[i].position[0], buffer[i].position[1], buffer[i].alpha);
}
#endif
}
static void getStrokeVerticesFromUnclosedVerticesAA(const SkTArray<Vertex, true>& vertices, float halfStrokeWidth,
VertexBuffer* vertexBuffer, float inverseScaleX, float inverseScaleY) {
AlphaVertex* buffer = vertexBuffer->alloc<AlphaVertex>(6 * vertices.count() + 2);
// avoid lines smaller than hairline since they break triangle based sampling. instead reducing
// alpha value (TODO: support different X/Y scale)
float maxAlpha = 1.0f;
if (halfStrokeWidth != 0 && inverseScaleX == inverseScaleY &&
halfStrokeWidth * inverseScaleX < 0.5f) {
maxAlpha *= (2 * halfStrokeWidth) / inverseScaleX;
halfStrokeWidth = 0.0f;
}
// there is no outer/inner here, using them for consistency with below approach
int offset = 2 * (vertices.count() - 2);
int currentAAOuterIndex = 2;
int currentAAInnerIndex = 2 * offset + 5; // reversed
int currentStrokeIndex = currentAAInnerIndex + 7;
const Vertex* last = &(vertices[0]);
const Vertex* current = &(vertices[1]);
SkVector lastNormal;
lastNormal.set(current->position[1] - last->position[1],
last->position[0] - current->position[0]);
lastNormal.normalize();
{
// start cap
SkVector totalOffset = lastNormal;
SkVector AAOffset = totalOffset;
AAOffset.fX *= 0.5f * inverseScaleX;
AAOffset.fY *= 0.5f * inverseScaleY;
SkVector innerOffset = totalOffset;
scaleOffsetForStrokeWidth(innerOffset, halfStrokeWidth, inverseScaleX, inverseScaleY);
SkVector outerOffset = innerOffset + AAOffset;
innerOffset -= AAOffset;
// TODO: support square cap by changing this offset to incorporate halfStrokeWidth
SkVector capAAOffset;
capAAOffset.set(AAOffset.fY, -AAOffset.fX);
AlphaVertex::set(&buffer[0],
last->position[0] + outerOffset.fX + capAAOffset.fX,
last->position[1] + outerOffset.fY + capAAOffset.fY,
0.0f);
AlphaVertex::set(&buffer[1],
last->position[0] + innerOffset.fX - capAAOffset.fX,
last->position[1] + innerOffset.fY - capAAOffset.fY,
maxAlpha);
AlphaVertex::set(&buffer[2 * offset + 6],
last->position[0] - outerOffset.fX + capAAOffset.fX,
last->position[1] - outerOffset.fY + capAAOffset.fY,
0.0f);
AlphaVertex::set(&buffer[2 * offset + 7],
last->position[0] - innerOffset.fX - capAAOffset.fX,
last->position[1] - innerOffset.fY - capAAOffset.fY,
maxAlpha);
copyAlphaVertex(&buffer[2 * offset + 8], &buffer[0]);
copyAlphaVertex(&buffer[2 * offset + 9], &buffer[1]);
copyAlphaVertex(&buffer[2 * offset + 10], &buffer[1]); // degenerate tris (the only two!)
copyAlphaVertex(&buffer[2 * offset + 11], &buffer[2 * offset + 7]);
}
for (int i = 1; i < vertices.count() - 1; i++) {
const Vertex* next = &(vertices[i + 1]);
SkVector nextNormal;
nextNormal.set(next->position[1] - current->position[1],
current->position[0] - next->position[0]);
nextNormal.normalize();
SkVector totalOffset = totalOffsetFromNormals(lastNormal, nextNormal);
SkVector AAOffset = totalOffset;
AAOffset.fX *= 0.5f * inverseScaleX;
AAOffset.fY *= 0.5f * inverseScaleY;
SkVector innerOffset = totalOffset;
scaleOffsetForStrokeWidth(innerOffset, halfStrokeWidth, inverseScaleX, inverseScaleY);
SkVector outerOffset = innerOffset + AAOffset;
innerOffset -= AAOffset;
AlphaVertex::set(&buffer[currentAAOuterIndex++],
current->position[0] + outerOffset.fX,
current->position[1] + outerOffset.fY,
0.0f);
AlphaVertex::set(&buffer[currentAAOuterIndex++],
current->position[0] + innerOffset.fX,
current->position[1] + innerOffset.fY,
maxAlpha);
AlphaVertex::set(&buffer[currentStrokeIndex++],
current->position[0] + innerOffset.fX,
current->position[1] + innerOffset.fY,
maxAlpha);
AlphaVertex::set(&buffer[currentStrokeIndex++],
current->position[0] - innerOffset.fX,
current->position[1] - innerOffset.fY,
maxAlpha);
AlphaVertex::set(&buffer[currentAAInnerIndex--],
current->position[0] - innerOffset.fX,
current->position[1] - innerOffset.fY,
maxAlpha);
AlphaVertex::set(&buffer[currentAAInnerIndex--],
current->position[0] - outerOffset.fX,
current->position[1] - outerOffset.fY,
0.0f);
last = current;
current = next;
lastNormal = nextNormal;
}
{
// end cap
SkVector totalOffset = lastNormal;
SkVector AAOffset = totalOffset;
AAOffset.fX *= 0.5f * inverseScaleX;
AAOffset.fY *= 0.5f * inverseScaleY;
SkVector innerOffset = totalOffset;
scaleOffsetForStrokeWidth(innerOffset, halfStrokeWidth, inverseScaleX, inverseScaleY);
SkVector outerOffset = innerOffset + AAOffset;
innerOffset -= AAOffset;
// TODO: support square cap by changing this offset to incorporate halfStrokeWidth
SkVector capAAOffset;
capAAOffset.set(-AAOffset.fY, AAOffset.fX);
AlphaVertex::set(&buffer[offset + 2],
current->position[0] + outerOffset.fX + capAAOffset.fX,
current->position[1] + outerOffset.fY + capAAOffset.fY,
0.0f);
AlphaVertex::set(&buffer[offset + 3],
current->position[0] + innerOffset.fX - capAAOffset.fX,
current->position[1] + innerOffset.fY - capAAOffset.fY,
maxAlpha);
AlphaVertex::set(&buffer[offset + 4],
current->position[0] - outerOffset.fX + capAAOffset.fX,
current->position[1] - outerOffset.fY + capAAOffset.fY,
0.0f);
AlphaVertex::set(&buffer[offset + 5],
current->position[0] - innerOffset.fX - capAAOffset.fX,
current->position[1] - innerOffset.fY - capAAOffset.fY,
maxAlpha);
copyAlphaVertex(&buffer[vertexBuffer->getSize() - 2], &buffer[offset + 3]);
copyAlphaVertex(&buffer[vertexBuffer->getSize() - 1], &buffer[offset + 5]);
}
#if VERTEX_DEBUG
for (unsigned int i = 0; i < vertexBuffer.getSize(); i++) {
SkDebugf("point at %f %f, alpha %f", buffer[i].position[0], buffer[i].position[1], buffer[i].alpha);
}
#endif
}
static void getStrokeVerticesFromPerimeterAA(const SkTArray<Vertex, true>& perimeter, float halfStrokeWidth,
VertexBuffer* vertexBuffer, float inverseScaleX, float inverseScaleY) {
AlphaVertex* buffer = vertexBuffer->alloc<AlphaVertex>(6 * perimeter.count() + 8);
// avoid lines smaller than hairline since they break triangle based sampling. instead reducing
// alpha value (TODO: support different X/Y scale)
float maxAlpha = 1.0f;
if (halfStrokeWidth != 0 && inverseScaleX == inverseScaleY &&
halfStrokeWidth * inverseScaleX < 0.5f) {
maxAlpha *= (2 * halfStrokeWidth) / inverseScaleX;
halfStrokeWidth = 0.0f;
}
int offset = 2 * perimeter.count() + 3;
int currentAAOuterIndex = 0;
int currentStrokeIndex = offset;
int currentAAInnerIndex = offset * 2;
const Vertex* last = &(perimeter[perimeter.count() - 1]);
const Vertex* current = &(perimeter[0]);
SkVector lastNormal;
lastNormal.set(current->position[1] - last->position[1],
last->position[0] - current->position[0]);
lastNormal.normalize();
for (int i = 0; i < perimeter.count(); i++) {
const Vertex* next = &(perimeter[i + 1 >= perimeter.count() ? 0 : i + 1]);
SkVector nextNormal;
nextNormal.set(next->position[1] - current->position[1],
current->position[0] - next->position[0]);
nextNormal.normalize();
SkVector totalOffset = totalOffsetFromNormals(lastNormal, nextNormal);
SkVector AAOffset = totalOffset;
AAOffset.fX *= 0.5f * inverseScaleX;
AAOffset.fY *= 0.5f * inverseScaleY;
SkVector innerOffset = totalOffset;
scaleOffsetForStrokeWidth(innerOffset, halfStrokeWidth, inverseScaleX, inverseScaleY);
SkVector outerOffset = innerOffset + AAOffset;
innerOffset -= AAOffset;
AlphaVertex::set(&buffer[currentAAOuterIndex++],
current->position[0] + outerOffset.fX,
current->position[1] + outerOffset.fY,
0.0f);
AlphaVertex::set(&buffer[currentAAOuterIndex++],
current->position[0] + innerOffset.fX,
current->position[1] + innerOffset.fY,
maxAlpha);
AlphaVertex::set(&buffer[currentStrokeIndex++],
current->position[0] + innerOffset.fX,
current->position[1] + innerOffset.fY,
maxAlpha);
AlphaVertex::set(&buffer[currentStrokeIndex++],
current->position[0] - innerOffset.fX,
current->position[1] - innerOffset.fY,
maxAlpha);
AlphaVertex::set(&buffer[currentAAInnerIndex++],
current->position[0] - innerOffset.fX,
current->position[1] - innerOffset.fY,
maxAlpha);
AlphaVertex::set(&buffer[currentAAInnerIndex++],
current->position[0] - outerOffset.fX,
current->position[1] - outerOffset.fY,
0.0f);
last = current;
current = next;
lastNormal = nextNormal;
}
// wrap each strip around to beginning, creating degenerate tris to bridge strips
copyAlphaVertex(&buffer[currentAAOuterIndex++], &buffer[0]);
copyAlphaVertex(&buffer[currentAAOuterIndex++], &buffer[1]);
copyAlphaVertex(&buffer[currentAAOuterIndex++], &buffer[1]);
copyAlphaVertex(&buffer[currentStrokeIndex++], &buffer[offset]);
copyAlphaVertex(&buffer[currentStrokeIndex++], &buffer[offset + 1]);
copyAlphaVertex(&buffer[currentStrokeIndex++], &buffer[offset + 1]);
copyAlphaVertex(&buffer[currentAAInnerIndex++], &buffer[2 * offset]);
copyAlphaVertex(&buffer[currentAAInnerIndex++], &buffer[2 * offset + 1]);
// don't need to create last degenerate tri
#if VERTEX_DEBUG
for (unsigned int i = 0; i < vertexBuffer.getSize(); i++) {
SkDebugf("point at %f %f, alpha %f", buffer[i].position[0], buffer[i].position[1], buffer[i].alpha);
}
#endif
}
void PathRenderer::ConvexPathVertices(const SkPath &path, const SkStrokeRec& stroke, bool isAA,
const SkMatrix* transform, VertexBuffer* vertexBuffer) {
SkStrokeRec::Style style = stroke.getStyle();
float inverseScaleX, inverseScaleY;
computeInverseScales(transform, inverseScaleX, inverseScaleY);
SkTArray<Vertex, true> tempVertices;
float threshInvScaleX = inverseScaleX;
float threshInvScaleY = inverseScaleY;
if (style == SkStrokeRec::kStroke_Style) {
// alter the bezier recursion threshold values we calculate in order to compensate for
// expansion done after the path vertices are found
SkRect bounds = path.getBounds();
if (!bounds.isEmpty()) {
threshInvScaleX *= bounds.width() / (bounds.width() + stroke.getWidth());
threshInvScaleY *= bounds.height() / (bounds.height() + stroke.getWidth());
}
}
// force close if we're filling the path, since fill path expects closed perimeter.
bool forceClose = style != SkStrokeRec::kStroke_Style;
bool wasClosed = ConvexPathPerimeterVertices(path, forceClose, threshInvScaleX * threshInvScaleX,
threshInvScaleY * threshInvScaleY, &tempVertices);
if (!tempVertices.count()) {
// path was empty, return without allocating vertex buffer
return;
}
#if VERTEX_DEBUG
for (unsigned int i = 0; i < tempVertices.count(); i++) {
SkDebugf("orig path: point at %f %f", tempVertices[i].position[0], tempVertices[i].position[1]);
}
#endif
if (style == SkStrokeRec::kStroke_Style) {
float halfStrokeWidth = stroke.getWidth() * 0.5f;
if (!isAA) {
if (wasClosed) {
getStrokeVerticesFromPerimeter(tempVertices, halfStrokeWidth, vertexBuffer,
inverseScaleX, inverseScaleY);
} else {
getStrokeVerticesFromUnclosedVertices(tempVertices, halfStrokeWidth, vertexBuffer,
inverseScaleX, inverseScaleY);
}
} else {
if (wasClosed) {
getStrokeVerticesFromPerimeterAA(tempVertices, halfStrokeWidth, vertexBuffer,
inverseScaleX, inverseScaleY);
} else {
getStrokeVerticesFromUnclosedVerticesAA(tempVertices, halfStrokeWidth, vertexBuffer,
inverseScaleX, inverseScaleY);
}
}
} else {
// For kStrokeAndFill style, the path should be adjusted externally, as it will be treated as a fill here.
if (!isAA) {
getFillVerticesFromPerimeter(tempVertices, vertexBuffer);
} else {
getFillVerticesFromPerimeterAA(tempVertices, vertexBuffer, inverseScaleX, inverseScaleY);
}
}
}
static void pushToVector(SkTArray<Vertex, true>* vertices, float x, float y) {
// TODO: make this not yuck
vertices->push_back();
Vertex* newVertex = &((*vertices)[vertices->count() - 1]);
Vertex::set(newVertex, x, y);
}
bool PathRenderer::ConvexPathPerimeterVertices(const SkPath& path, bool forceClose,
float sqrInvScaleX, float sqrInvScaleY, SkTArray<Vertex, true>* outputVertices) {
// TODO: to support joins other than sharp miter, join vertices should be labelled in the
// perimeter, or resolved into more vertices. Reconsider forceClose-ing in that case.
SkPath::Iter iter(path, forceClose);
SkPoint pts[4];
SkPath::Verb v;
while (SkPath::kDone_Verb != (v = iter.next(pts))) {
switch (v) {
case SkPath::kMove_Verb:
pushToVector(outputVertices, pts[0].x(), pts[0].y());
ALOGV("Move to pos %f %f", pts[0].x(), pts[0].y());
break;
case SkPath::kClose_Verb:
ALOGV("Close at pos %f %f", pts[0].x(), pts[0].y());
break;
case SkPath::kLine_Verb:
ALOGV("kLine_Verb %f %f -> %f %f",
pts[0].x(), pts[0].y(),
pts[1].x(), pts[1].y());
pushToVector(outputVertices, pts[1].x(), pts[1].y());
break;
case SkPath::kQuad_Verb:
ALOGV("kQuad_Verb");
RecursiveQuadraticBezierVertices(
pts[0].x(), pts[0].y(),
pts[2].x(), pts[2].y(),
pts[1].x(), pts[1].y(),
sqrInvScaleX, sqrInvScaleY, outputVertices);
break;
case SkPath::kCubic_Verb:
ALOGV("kCubic_Verb");
RecursiveCubicBezierVertices(
pts[0].x(), pts[0].y(),
pts[1].x(), pts[1].y(),
pts[3].x(), pts[3].y(),
pts[2].x(), pts[2].y(),
sqrInvScaleX, sqrInvScaleY, outputVertices);
break;
default:
break;
}
}
int size = outputVertices->count();
if (size >= 2 && (*outputVertices)[0].position[0] == (*outputVertices)[size - 1].position[0] &&
(*outputVertices)[0].position[1] == (*outputVertices)[size - 1].position[1]) {
outputVertices->pop_back();
return true;
}
return false;
}
void PathRenderer::RecursiveCubicBezierVertices(
float p1x, float p1y, float c1x, float c1y,
float p2x, float p2y, float c2x, float c2y,
float sqrInvScaleX, float sqrInvScaleY, SkTArray<Vertex, true>* outputVertices) {
float dx = p2x - p1x;
float dy = p2y - p1y;
float d1 = sk_float_abs((c1x - p2x) * dy - (c1y - p2y) * dx);
float d2 = sk_float_abs((c2x - p2x) * dy - (c2y - p2y) * dx);
float d = d1 + d2;
// multiplying by sqrInvScaleY/X equivalent to multiplying in dimensional scale factors
if (d * d < THRESHOLD * THRESHOLD * (dx * dx * sqrInvScaleY + dy * dy * sqrInvScaleX)) {
// below thresh, draw line by adding endpoint
pushToVector(outputVertices, p2x, p2y);
} else {
float p1c1x = (p1x + c1x) * 0.5f;
float p1c1y = (p1y + c1y) * 0.5f;
float p2c2x = (p2x + c2x) * 0.5f;
float p2c2y = (p2y + c2y) * 0.5f;
float c1c2x = (c1x + c2x) * 0.5f;
float c1c2y = (c1y + c2y) * 0.5f;
float p1c1c2x = (p1c1x + c1c2x) * 0.5f;
float p1c1c2y = (p1c1y + c1c2y) * 0.5f;
float p2c1c2x = (p2c2x + c1c2x) * 0.5f;
float p2c1c2y = (p2c2y + c1c2y) * 0.5f;
float mx = (p1c1c2x + p2c1c2x) * 0.5f;
float my = (p1c1c2y + p2c1c2y) * 0.5f;
RecursiveCubicBezierVertices(
p1x, p1y, p1c1x, p1c1y,
mx, my, p1c1c2x, p1c1c2y,
sqrInvScaleX, sqrInvScaleY, outputVertices);
RecursiveCubicBezierVertices(
mx, my, p2c1c2x, p2c1c2y,
p2x, p2y, p2c2x, p2c2y,
sqrInvScaleX, sqrInvScaleY, outputVertices);
}
}
void PathRenderer::RecursiveQuadraticBezierVertices(
float ax, float ay,
float bx, float by,
float cx, float cy,
float sqrInvScaleX, float sqrInvScaleY, SkTArray<Vertex, true>* outputVertices) {
float dx = bx - ax;
float dy = by - ay;
float d = (cx - bx) * dy - (cy - by) * dx;
if (d * d < THRESHOLD * THRESHOLD * (dx * dx * sqrInvScaleY + dy * dy * sqrInvScaleX)) {
// below thresh, draw line by adding endpoint
pushToVector(outputVertices, bx, by);
} else {
float acx = (ax + cx) * 0.5f;
float bcx = (bx + cx) * 0.5f;
float acy = (ay + cy) * 0.5f;
float bcy = (by + cy) * 0.5f;
// midpoint
float mx = (acx + bcx) * 0.5f;
float my = (acy + bcy) * 0.5f;
RecursiveQuadraticBezierVertices(ax, ay, mx, my, acx, acy,
sqrInvScaleX, sqrInvScaleY, outputVertices);
RecursiveQuadraticBezierVertices(mx, my, bx, by, bcx, bcy,
sqrInvScaleX, sqrInvScaleY, outputVertices);
}
}
}; // namespace uirenderer
}; // namespace android
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