// Modify pts[] in place so that it is clipped in Y to the clip rect
static void chop_cubic_in_Y(SkPoint pts[4], const SkRect& clip) {
// are we partially above
if (pts[0].fY < clip.fTop) {
SkScalar t;
if (chopMonoCubicAtY(pts, clip.fTop, &t)) {
SkPoint tmp[7];
SkChopCubicAt(pts, tmp, t);
// tmp[3, 4, 5].fY should all be to the below clip.fTop.
// Since we can't trust the numerics of
// the chopper, we force those conditions now
tmp[3].fY = clip.fTop;
clamp_ge(tmp[4].fY, clip.fTop);
clamp_ge(tmp[5].fY, clip.fTop);
pts[0] = tmp[3];
pts[1] = tmp[4];
pts[2] = tmp[5];
} else {
// if chopMonoCubicAtY failed, then we may have hit inexact numerics
// so we just clamp against the top
for (int i = 0; i < 4; i++) {
clamp_ge(pts[i].fY, clip.fTop);
}
}
}
// are we partially below
if (pts[3].fY > clip.fBottom) {
SkScalar t;
if (chopMonoCubicAtY(pts, clip.fBottom, &t)) {
SkPoint tmp[7];
SkChopCubicAt(pts, tmp, t);
tmp[3].fY = clip.fBottom;
clamp_le(tmp[2].fY, clip.fBottom);
pts[1] = tmp[1];
pts[2] = tmp[2];
pts[3] = tmp[3];
} else {
// if chopMonoCubicAtY failed, then we may have hit inexact numerics
// so we just clamp against the bottom
for (int i = 0; i < 4; i++) {
clamp_le(pts[i].fY, clip.fBottom);
}
}
}
}
bool SkCubicClipper::clipCubic(const SkPoint srcPts[4], SkPoint dst[4]) {
bool reverse;
// we need the data to be monotonically descending in Y
if (srcPts[0].fY > srcPts[3].fY) {
dst[0] = srcPts[3];
dst[1] = srcPts[2];
dst[2] = srcPts[1];
dst[3] = srcPts[0];
reverse = true;
} else {
memcpy(dst, srcPts, 4 * sizeof(SkPoint));
reverse = false;
}
// are we completely above or below
const SkScalar ctop = fClip.fTop;
const SkScalar cbot = fClip.fBottom;
if (dst[3].fY <= ctop || dst[0].fY >= cbot) {
return false;
}
SkScalar t;
SkPoint tmp[7]; // for SkChopCubicAt
// are we partially above
if (dst[0].fY < ctop && chopMonoCubicAtY(dst, ctop, &t)) {
SkChopCubicAt(dst, tmp, t);
dst[0] = tmp[3];
dst[1] = tmp[4];
dst[2] = tmp[5];
}
// are we partially below
if (dst[3].fY > cbot && chopMonoCubicAtY(dst, cbot, &t)) {
SkChopCubicAt(dst, tmp, t);
dst[1] = tmp[1];
dst[2] = tmp[2];
dst[3] = tmp[3];
}
if (reverse) {
SkTSwap<SkPoint>(dst[0], dst[3]);
SkTSwap<SkPoint>(dst[1], dst[2]);
}
return true;
}
// Modify pts[] in place so that it is clipped in Y to the clip rect
static void chop_cubic_in_Y(SkPoint pts[4], const SkRect& clip) {
SkScalar t;
SkPoint tmp[7]; // for SkChopCubicAt
// are we partially above
if (pts[0].fY < clip.fTop) {
if (chopMonoCubicAtY(pts, clip.fTop, &t)) {
SkChopCubicAt(pts, tmp, t);
// given the imprecision of computing t, we just slam our Y coord
// to the top of the clip. This also saves us in the bad case where
// the t was soooo bad that the entire segment could have been
// below fBottom
tmp[3].fY = clip.fTop;
clamp_ge(tmp[4].fY, clip.fTop);
clamp_ge(tmp[5].fY, clip.fTop);
pts[0] = tmp[3];
pts[1] = tmp[4];
pts[2] = tmp[5];
} else {
// if chopMonoCubicAtY failed, then we may have hit inexact numerics
// so we just clamp against the top
for (int i = 0; i < 4; i++) {
clamp_ge(pts[i].fY, clip.fTop);
}
}
}
// are we partially below
if (pts[3].fY > clip.fBottom) {
if (chopMonoCubicAtY(pts, clip.fBottom, &t)) {
SkChopCubicAt(pts, tmp, t);
clamp_le(tmp[1].fY, clip.fBottom);
clamp_le(tmp[2].fY, clip.fBottom);
clamp_le(tmp[3].fY, clip.fBottom);
pts[1] = tmp[1];
pts[2] = tmp[2];
pts[3] = tmp[3];
} else {
// if chopMonoCubicAtY failed, then we may have hit inexact numerics
// so we just clamp against the bottom
for (int i = 0; i < 4; i++) {
clamp_le(pts[i].fY, clip.fBottom);
}
}
}
}
