/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkAnalyticEdge.h"
#include "SkEdge.h"
#include "SkEdgeBuilder.h"
#include "SkEdgeClipper.h"
#include "SkGeometry.h"
#include "SkLineClipper.h"
#include "SkPath.h"
#include "SkPathPriv.h"
#include "SkSafeMath.h"
#include "SkTo.h"
SkEdgeBuilder::Combine SkBasicEdgeBuilder::combineVertical(const SkEdge* edge, SkEdge* last) {
if (last->fCurveCount || last->fDX || edge->fX != last->fX) {
return kNo_Combine;
}
if (edge->fWinding == last->fWinding) {
if (edge->fLastY + 1 == last->fFirstY) {
last->fFirstY = edge->fFirstY;
return kPartial_Combine;
}
if (edge->fFirstY == last->fLastY + 1) {
last->fLastY = edge->fLastY;
return kPartial_Combine;
}
return kNo_Combine;
}
if (edge->fFirstY == last->fFirstY) {
if (edge->fLastY == last->fLastY) {
return kTotal_Combine;
}
if (edge->fLastY < last->fLastY) {
last->fFirstY = edge->fLastY + 1;
return kPartial_Combine;
}
last->fFirstY = last->fLastY + 1;
last->fLastY = edge->fLastY;
last->fWinding = edge->fWinding;
return kPartial_Combine;
}
if (edge->fLastY == last->fLastY) {
if (edge->fFirstY > last->fFirstY) {
last->fLastY = edge->fFirstY - 1;
return kPartial_Combine;
}
last->fLastY = last->fFirstY - 1;
last->fFirstY = edge->fFirstY;
last->fWinding = edge->fWinding;
return kPartial_Combine;
}
return kNo_Combine;
}
SkEdgeBuilder::Combine SkAnalyticEdgeBuilder::combineVertical(const SkAnalyticEdge* edge,
SkAnalyticEdge* last) {
auto approximately_equal = [](SkFixed a, SkFixed b) {
return SkAbs32(a - b) < 0x100;
};
if (last->fCurveCount || last->fDX || edge->fX != last->fX) {
return kNo_Combine;
}
if (edge->fWinding == last->fWinding) {
if (edge->fLowerY == last->fUpperY) {
last->fUpperY = edge->fUpperY;
last->fY = last->fUpperY;
return kPartial_Combine;
}
if (approximately_equal(edge->fUpperY, last->fLowerY)) {
last->fLowerY = edge->fLowerY;
return kPartial_Combine;
}
return kNo_Combine;
}
if (approximately_equal(edge->fUpperY, last->fUpperY)) {
if (approximately_equal(edge->fLowerY, last->fLowerY)) {
return kTotal_Combine;
}
if (edge->fLowerY < last->fLowerY) {
last->fUpperY = edge->fLowerY;
last->fY = last->fUpperY;
return kPartial_Combine;
}
last->fUpperY = last->fLowerY;
last->fY = last->fUpperY;
last->fLowerY = edge->fLowerY;
last->fWinding = edge->fWinding;
return kPartial_Combine;
}
if (approximately_equal(edge->fLowerY, last->fLowerY)) {
if (edge->fUpperY > last->fUpperY) {
last->fLowerY = edge->fUpperY;
return kPartial_Combine;
}
last->fLowerY = last->fUpperY;
last->fUpperY = edge->fUpperY;
last->fY = last->fUpperY;
last->fWinding = edge->fWinding;
return kPartial_Combine;
}
return kNo_Combine;
}
template <typename Edge>
static bool is_vertical(const Edge* edge) {
return edge->fDX == 0
&& edge->fCurveCount == 0;
}
// TODO: we can deallocate the edge if edge->setFoo() fails
// or when we don't use it (kPartial_Combine or kTotal_Combine).
void SkBasicEdgeBuilder::addLine(const SkPoint pts[]) {
SkEdge* edge = fAlloc.make<SkEdge>();
if (edge->setLine(pts[0], pts[1], fClipShift)) {
Combine combine = is_vertical(edge) && !fList.empty()
? this->combineVertical(edge, (SkEdge*)fList.top())
: kNo_Combine;
switch (combine) {
case kTotal_Combine: fList.pop(); break;
case kPartial_Combine: break;
case kNo_Combine: fList.push_back(edge); break;
}
}
}
void SkAnalyticEdgeBuilder::addLine(const SkPoint pts[]) {
SkAnalyticEdge* edge = fAlloc.make<SkAnalyticEdge>();
if (edge->setLine(pts[0], pts[1])) {
Combine combine = is_vertical(edge) && !fList.empty()
? this->combineVertical(edge, (SkAnalyticEdge*)fList.top())
: kNo_Combine;
switch (combine) {
case kTotal_Combine: fList.pop(); break;
case kPartial_Combine: break;
case kNo_Combine: fList.push_back(edge); break;
}
}
}
void SkBezierEdgeBuilder::addLine(const SkPoint pts[]) {
SkLine* line = fAlloc.make<SkLine>();
if (line->set(pts)) {
fList.push_back(line);
}
}
void SkBasicEdgeBuilder::addQuad(const SkPoint pts[]) {
SkQuadraticEdge* edge = fAlloc.make<SkQuadraticEdge>();
if (edge->setQuadratic(pts, fClipShift)) {
fList.push_back(edge);
}
}
void SkAnalyticEdgeBuilder::addQuad(const SkPoint pts[]) {
SkAnalyticQuadraticEdge* edge = fAlloc.make<SkAnalyticQuadraticEdge>();
if (edge->setQuadratic(pts)) {
fList.push_back(edge);
}
}
void SkBezierEdgeBuilder::addQuad(const SkPoint pts[]) {
SkQuad* quad = fAlloc.make<SkQuad>();
if (quad->set(pts)) {
fList.push_back(quad);
}
}
void SkBasicEdgeBuilder::addCubic(const SkPoint pts[]) {
SkCubicEdge* edge = fAlloc.make<SkCubicEdge>();
if (edge->setCubic(pts, fClipShift)) {
fList.push_back(edge);
}
}
void SkAnalyticEdgeBuilder::addCubic(const SkPoint pts[]) {
SkAnalyticCubicEdge* edge = fAlloc.make<SkAnalyticCubicEdge>();
if (edge->setCubic(pts)) {
fList.push_back(edge);
}
}
void SkBezierEdgeBuilder::addCubic(const SkPoint pts[]) {
SkCubic* cubic = fAlloc.make<SkCubic>();
if (cubic->set(pts)) {
fList.push_back(cubic);
}
}
// TODO: merge addLine() and addPolyLine()?
SkEdgeBuilder::Combine SkBasicEdgeBuilder::addPolyLine(SkPoint pts[],
char* arg_edge, char** arg_edgePtr) {
auto edge = (SkEdge*) arg_edge;
auto edgePtr = (SkEdge**)arg_edgePtr;
if (edge->setLine(pts[0], pts[1], fClipShift)) {
return is_vertical(edge) && edgePtr > (SkEdge**)fEdgeList
? this->combineVertical(edge, edgePtr[-1])
: kNo_Combine;
}
return SkEdgeBuilder::kPartial_Combine; // A convenient lie. Same do-nothing behavior.
}
SkEdgeBuilder::Combine SkAnalyticEdgeBuilder::addPolyLine(SkPoint pts[],
char* arg_edge, char** arg_edgePtr) {
auto edge = (SkAnalyticEdge*) arg_edge;
auto edgePtr = (SkAnalyticEdge**)arg_edgePtr;
if (edge->setLine(pts[0], pts[1])) {
return is_vertical(edge) && edgePtr > (SkAnalyticEdge**)fEdgeList
? this->combineVertical(edge, edgePtr[-1])
: kNo_Combine;
}
return SkEdgeBuilder::kPartial_Combine; // As above.
}
SkEdgeBuilder::Combine SkBezierEdgeBuilder::addPolyLine(SkPoint pts[],
char* arg_edge, char** arg_edgePtr) {
auto edge = (SkLine*)arg_edge;
if (edge->set(pts)) {
return kNo_Combine;
}
return SkEdgeBuilder::kPartial_Combine; // As above.
}
SkRect SkBasicEdgeBuilder::recoverClip(const SkIRect& src) const {
return { SkIntToScalar(src.fLeft >> fClipShift),
SkIntToScalar(src.fTop >> fClipShift),
SkIntToScalar(src.fRight >> fClipShift),
SkIntToScalar(src.fBottom >> fClipShift), };
}
SkRect SkAnalyticEdgeBuilder::recoverClip(const SkIRect& src) const {
return SkRect::Make(src);
}
SkRect SkBezierEdgeBuilder::recoverClip(const SkIRect& src) const {
return SkRect::Make(src);
}
char* SkBasicEdgeBuilder::allocEdges(size_t n, size_t* size) {
*size = sizeof(SkEdge);
return (char*)fAlloc.makeArrayDefault<SkEdge>(n);
}
char* SkAnalyticEdgeBuilder::allocEdges(size_t n, size_t* size) {
*size = sizeof(SkAnalyticEdge);
return (char*)fAlloc.makeArrayDefault<SkAnalyticEdge>(n);
}
char* SkBezierEdgeBuilder::allocEdges(size_t n, size_t* size) {
*size = sizeof(SkLine);
return (char*)fAlloc.makeArrayDefault<SkLine>(n);
}
// TODO: maybe get rid of buildPoly() entirely?
int SkEdgeBuilder::buildPoly(const SkPath& path, const SkIRect* iclip, bool canCullToTheRight) {
SkPath::Iter iter(path, true);
SkPoint pts[4];
SkPath::Verb verb;
size_t maxEdgeCount = path.countPoints();
if (iclip) {
// clipping can turn 1 line into (up to) kMaxClippedLineSegments, since
// we turn portions that are clipped out on the left/right into vertical
// segments.
SkSafeMath safe;
maxEdgeCount = safe.mul(maxEdgeCount, SkLineClipper::kMaxClippedLineSegments);
if (!safe) {
return 0;
}
}
size_t edgeSize;
char* edge = this->allocEdges(maxEdgeCount, &edgeSize);
SkDEBUGCODE(char* edgeStart = edge);
char** edgePtr = fAlloc.makeArrayDefault<char*>(maxEdgeCount);
fEdgeList = (void**)edgePtr;
if (iclip) {
SkRect clip = this->recoverClip(*iclip);
while ((verb = iter.next(pts, false)) != SkPath::kDone_Verb) {
switch (verb) {
case SkPath::kMove_Verb:
case SkPath::kClose_Verb:
// we ignore these, and just get the whole segment from
// the corresponding line/quad/cubic verbs
break;
case SkPath::kLine_Verb: {
SkPoint lines[SkLineClipper::kMaxPoints];
int lineCount = SkLineClipper::ClipLine(pts, clip, lines, canCullToTheRight);
SkASSERT(lineCount <= SkLineClipper::kMaxClippedLineSegments);
for (int i = 0; i < lineCount; i++) {
switch( this->addPolyLine(lines + i, edge, edgePtr) ) {
case kTotal_Combine: edgePtr--; break;
case kPartial_Combine: break;
case kNo_Combine: *edgePtr++ = edge;
edge += edgeSize;
}
}
break;
}
default:
SkDEBUGFAIL("unexpected verb");
break;
}
}
} else {
while ((verb = iter.next(pts, false)) != SkPath::kDone_Verb) {
switch (verb) {
case SkPath::kMove_Verb:
case SkPath::kClose_Verb:
// we ignore these, and just get the whole segment from
// the corresponding line/quad/cubic verbs
break;
case SkPath::kLine_Verb: {
switch( this->addPolyLine(pts, edge, edgePtr) ) {
case kTotal_Combine: edgePtr--; break;
case kPartial_Combine: break;
case kNo_Combine: *edgePtr++ = edge;
edge += edgeSize;
}
break;
}
default:
SkDEBUGFAIL("unexpected verb");
break;
}
}
}
SkASSERT((size_t)(edge - edgeStart) <= maxEdgeCount * edgeSize);
SkASSERT((size_t)(edgePtr - (char**)fEdgeList) <= maxEdgeCount);
return SkToInt(edgePtr - (char**)fEdgeList);
}
int SkEdgeBuilder::build(const SkPath& path, const SkIRect* iclip, bool canCullToTheRight) {
SkAutoConicToQuads quadder;
const SkScalar conicTol = SK_Scalar1 / 4;
SkPath::Iter iter(path, true);
SkPoint pts[4];
SkPath::Verb verb;
bool is_finite = true;
if (iclip) {
SkRect clip = this->recoverClip(*iclip);
SkEdgeClipper clipper(canCullToTheRight);
auto apply_clipper = [this, &clipper, &is_finite] {
SkPoint pts[4];
SkPath::Verb verb;
while ((verb = clipper.next(pts)) != SkPath::kDone_Verb) {
const int count = SkPathPriv::PtsInIter(verb);
if (!SkScalarsAreFinite(&pts[0].fX, count*2)) {
is_finite = false;
return;
}
switch (verb) {
case SkPath::kLine_Verb: this->addLine (pts); break;
case SkPath::kQuad_Verb: this->addQuad (pts); break;
case SkPath::kCubic_Verb: this->addCubic(pts); break;
default: break;
}
}
};
while ((verb = iter.next(pts, false)) != SkPath::kDone_Verb) {
switch (verb) {
case SkPath::kMove_Verb:
case SkPath::kClose_Verb:
// we ignore these, and just get the whole segment from
// the corresponding line/quad/cubic verbs
break;
case SkPath::kLine_Verb:
if (clipper.clipLine(pts[0], pts[1], clip)) {
apply_clipper();
}
break;
case SkPath::kQuad_Verb:
if (clipper.clipQuad(pts, clip)) {
apply_clipper();
}
break;
case SkPath::kConic_Verb: {
const SkPoint* quadPts = quadder.computeQuads(
pts, iter.conicWeight(), conicTol);
for (int i = 0; i < quadder.countQuads(); ++i) {
if (clipper.clipQuad(quadPts, clip)) {
apply_clipper();
}
quadPts += 2;
}
} break;
case SkPath::kCubic_Verb:
if (clipper.clipCubic(pts, clip)) {
apply_clipper();
}
break;
default:
SkDEBUGFAIL("unexpected verb");
break;
}
}
} else {
while ((verb = iter.next(pts, false)) != SkPath::kDone_Verb) {
auto handle_quad = [this](const SkPoint pts[3]) {
SkPoint monoX[5];
int n = SkChopQuadAtYExtrema(pts, monoX);
for (int i = 0; i <= n; i++) {
this->addQuad(&monoX[i * 2]);
}
};
switch (verb) {
case SkPath::kMove_Verb:
case SkPath::kClose_Verb:
// we ignore these, and just get the whole segment from
// the corresponding line/quad/cubic verbs
break;
case SkPath::kLine_Verb:
this->addLine(pts);
break;
case SkPath::kQuad_Verb: {
handle_quad(pts);
break;
}
case SkPath::kConic_Verb: {
const SkPoint* quadPts = quadder.computeQuads(
pts, iter.conicWeight(), conicTol);
for (int i = 0; i < quadder.countQuads(); ++i) {
handle_quad(quadPts);
quadPts += 2;
}
} break;
case SkPath::kCubic_Verb: {
if (!this->chopCubics()) {
this->addCubic(pts);
break;
}
SkPoint monoY[10];
int n = SkChopCubicAtYExtrema(pts, monoY);
for (int i = 0; i <= n; i++) {
this->addCubic(&monoY[i * 3]);
}
break;
}
default:
SkDEBUGFAIL("unexpected verb");
break;
}
}
}
fEdgeList = fList.begin();
return is_finite ? fList.count() : 0;
}
int SkEdgeBuilder::buildEdges(const SkPath& path,
const SkIRect* shiftedClip) {
// If we're convex, then we need both edges, even if the right edge is past the clip.
const bool canCullToTheRight = !path.isConvex();
// We can use our buildPoly() optimization if all the segments are lines.
// (Edges are homogenous and stored contiguously in memory, no need for indirection.)
const int count = SkPath::kLine_SegmentMask == path.getSegmentMasks()
? this->buildPoly(path, shiftedClip, canCullToTheRight)
: this->build (path, shiftedClip, canCullToTheRight);
SkASSERT(count >= 0);
// If we can't cull to the right, we should have count > 1 (or 0),
// unless we're in DAA which doesn't need to chop edges at y extrema.
// For example, a single cubic edge with a valley shape \_/ is fine for DAA.
if (!canCullToTheRight && count == 1) {
SkASSERT(!this->chopCubics());
}
return count;
}