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/*
* Copyright 2006 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.
*/
#include "SkCullPoints.h"
#include "Sk64.h"
static bool cross_product_is_neg(const SkIPoint& v, int dx, int dy) {
#if 0
return v.fX * dy - v.fY * dx < 0;
#else
Sk64 tmp0, tmp1;
tmp0.setMul(v.fX, dy);
tmp1.setMul(dx, v.fY);
tmp0.sub(tmp1);
return tmp0.isNeg() != 0;
#endif
}
bool SkCullPoints::sect_test(int x0, int y0, int x1, int y1) const {
const SkIRect& r = fR;
if ((x0 < r.fLeft && x1 < r.fLeft) ||
(x0 > r.fRight && x1 > r.fRight) ||
(y0 < r.fTop && y1 < r.fTop) ||
(y0 > r.fBottom && y1 > r.fBottom)) {
return false;
}
// since the crossprod test is a little expensive, check for easy-in cases first
if (r.contains(x0, y0) || r.contains(x1, y1)) {
return true;
}
// At this point we're not sure, so we do a crossprod test
SkIPoint vec;
const SkIPoint* rAsQuad = fAsQuad;
vec.set(x1 - x0, y1 - y0);
bool isNeg = cross_product_is_neg(vec, x0 - rAsQuad[0].fX, y0 - rAsQuad[0].fY);
for (int i = 1; i < 4; i++) {
if (cross_product_is_neg(vec, x0 - rAsQuad[i].fX, y0 - rAsQuad[i].fY) != isNeg) {
return true;
}
}
return false; // we didn't intersect
}
static void toQuad(const SkIRect& r, SkIPoint quad[4]) {
SkASSERT(quad);
quad[0].set(r.fLeft, r.fTop);
quad[1].set(r.fRight, r.fTop);
quad[2].set(r.fRight, r.fBottom);
quad[3].set(r.fLeft, r.fBottom);
}
SkCullPoints::SkCullPoints() {
SkIRect r;
r.setEmpty();
this->reset(r);
}
SkCullPoints::SkCullPoints(const SkIRect& r) {
this->reset(r);
}
void SkCullPoints::reset(const SkIRect& r) {
fR = r;
toQuad(fR, fAsQuad);
fPrevPt.set(0, 0);
fPrevResult = kNo_Result;
}
void SkCullPoints::moveTo(int x, int y) {
fPrevPt.set(x, y);
fPrevResult = kNo_Result; // so we trigger a movetolineto later
}
SkCullPoints::LineToResult SkCullPoints::lineTo(int x, int y, SkIPoint line[]) {
SkASSERT(line != NULL);
LineToResult result = kNo_Result;
int x0 = fPrevPt.fX;
int y0 = fPrevPt.fY;
// need to upgrade sect_test to chop the result
// and to correctly return kLineTo_Result when the result is connected
// to the previous call-out
if (this->sect_test(x0, y0, x, y)) {
line[0].set(x0, y0);
line[1].set(x, y);
if (fPrevResult != kNo_Result && fPrevPt.equals(x0, y0)) {
result = kLineTo_Result;
} else {
result = kMoveToLineTo_Result;
}
}
fPrevPt.set(x, y);
fPrevResult = result;
return result;
}
/////////////////////////////////////////////////////////////////////////////////////////////////
#include "SkPath.h"
SkCullPointsPath::SkCullPointsPath()
: fCP(), fPath(NULL) {
}
SkCullPointsPath::SkCullPointsPath(const SkIRect& r, SkPath* dst)
: fCP(r), fPath(dst) {
}
void SkCullPointsPath::reset(const SkIRect& r, SkPath* dst) {
fCP.reset(r);
fPath = dst;
}
void SkCullPointsPath::moveTo(int x, int y) {
fCP.moveTo(x, y);
}
void SkCullPointsPath::lineTo(int x, int y) {
SkIPoint pts[2];
switch (fCP.lineTo(x, y, pts)) {
case SkCullPoints::kMoveToLineTo_Result:
fPath->moveTo(SkIntToScalar(pts[0].fX), SkIntToScalar(pts[0].fY));
// fall through to the lineto case
case SkCullPoints::kLineTo_Result:
fPath->lineTo(SkIntToScalar(pts[1].fX), SkIntToScalar(pts[1].fY));
break;
default:
break;
}
}
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