// Modify pts[] in place so that it is clipped in Y to the clip rect
static void chop_quad_in_Y(SkPoint pts[3], const SkRect& clip) {
SkScalar t;
SkPoint tmp[5]; // for SkChopQuadAt
// are we partially above
if (pts[0].fY < clip.fTop) {
if (chopMonoQuadAtY(pts, clip.fTop, &t)) {
// take the 2nd chopped quad
SkChopQuadAt(pts, tmp, t);
// clamp to clean up imprecise numerics in the chop
tmp[2].fY = clip.fTop;
clamp_ge(tmp[3].fY, clip.fTop);
pts[0] = tmp[2];
pts[1] = tmp[3];
} else {
// if chopMonoQuadAtY failed, then we may have hit inexact numerics
// so we just clamp against the top
for (int i = 0; i < 3; i++) {
if (pts[i].fY < clip.fTop) {
pts[i].fY = clip.fTop;
}
}
}
}
// are we partially below
if (pts[2].fY > clip.fBottom) {
if (chopMonoQuadAtY(pts, clip.fBottom, &t)) {
SkChopQuadAt(pts, tmp, t);
// clamp to clean up imprecise numerics in the chop
clamp_le(tmp[1].fY, clip.fBottom);
tmp[2].fY = clip.fBottom;
pts[1] = tmp[1];
pts[2] = tmp[2];
} else {
// if chopMonoQuadAtY failed, then we may have hit inexact numerics
// so we just clamp against the bottom
for (int i = 0; i < 3; i++) {
if (pts[i].fY > clip.fBottom) {
pts[i].fY = clip.fBottom;
}
}
}
}
}
/* If we somehow returned the fact that we had to flip the pts in Y, we could
communicate that to setQuadratic, and then avoid having to flip it back
here (only to have setQuadratic do the flip again)
*/
bool SkQuadClipper::clipQuad(const SkPoint srcPts[3], SkPoint dst[3]) {
bool reverse;
// we need the data to be monotonically descending in Y
if (srcPts[0].fY > srcPts[2].fY) {
dst[0] = srcPts[2];
dst[1] = srcPts[1];
dst[2] = srcPts[0];
reverse = true;
} else {
memcpy(dst, srcPts, 3 * sizeof(SkPoint));
reverse = false;
}
// are we completely above or below
const SkScalar ctop = fClip.fTop;
const SkScalar cbot = fClip.fBottom;
if (dst[2].fY <= ctop || dst[0].fY >= cbot) {
return false;
}
SkScalar t;
SkPoint tmp[5]; // for SkChopQuadAt
// are we partially above
if (dst[0].fY < ctop && chopMonoQuadAtY(dst, ctop, &t)) {
SkChopQuadAt(dst, tmp, t);
dst[0] = tmp[2];
dst[1] = tmp[3];
}
// are we partially below
if (dst[2].fY > cbot && chopMonoQuadAtY(dst, cbot, &t)) {
SkChopQuadAt(dst, tmp, t);
dst[1] = tmp[1];
dst[2] = tmp[2];
}
if (reverse) {
SkTSwap<SkPoint>(dst[0], dst[2]);
}
return true;
}
