void SkLinearGradient::
LinearGradient4fContext::mapTs(int x, int y, SkScalar ts[], int count) const {
SkASSERT(count > 0);
SkASSERT(fDstToPosClass != kLinear_MatrixClass);
SkScalar sx = x + SK_ScalarHalf;
const SkScalar sy = y + SK_ScalarHalf;
SkPoint pt;
if (fDstToPosClass != kPerspective_MatrixClass) {
// kLinear_MatrixClass, kFixedStepInX_MatrixClass => fixed dt per scanline
const SkScalar dtdx = fDstToPos.fixedStepInX(sy).x();
fDstToPosProc(fDstToPos, sx, sy, &pt);
const Sk4f dtdx4 = Sk4f(4 * dtdx);
Sk4f t4 = Sk4f(pt.x() + 0 * dtdx,
pt.x() + 1 * dtdx,
pt.x() + 2 * dtdx,
pt.x() + 3 * dtdx);
while (count >= 4) {
t4.store(ts);
t4 = t4 + dtdx4;
ts += 4;
count -= 4;
}
if (count & 2) {
*ts++ = t4[0];
*ts++ = t4[1];
t4 = SkNx_shuffle<2, 0, 1, 3>(t4);
}
if (count & 1) {
*ts++ = t4[0];
}
} else {
for (int i = 0; i < count; ++i) {
fDstToPosProc(fDstToPos, sx, sy, &pt);
ts[i] = pt.x();
sx += SK_Scalar1;
}
}
}
void SkLinearGradient::
LinearGradient4fContext::shadeSpanInternal(int x, int y, dstType dst[], int count,
float bias0, float bias1) const {
SkPoint pt;
fDstToPosProc(fDstToPos,
x + SK_ScalarHalf,
y + SK_ScalarHalf,
&pt);
const SkScalar fx = pinFx<tileMode>(pt.x());
const SkScalar dx = fDstToPos.getScaleX();
LinearIntervalProcessor<dstType, premul, tileMode> proc(fIntervals->begin(),
fIntervals->end() - 1,
this->findInterval(fx),
fx,
dx,
SkScalarNearlyZero(dx * count));
Sk4f bias4f0(bias0),
bias4f1(bias1);
while (count > 0) {
// What we really want here is SkTPin(advance, 1, count)
// but that's a significant perf hit for >> stops; investigate.
const int n = SkScalarTruncToInt(
SkTMin<SkScalar>(proc.currentAdvance() + 1, SkIntToScalar(count)));
// The current interval advance can be +inf (e.g. when reaching
// the clamp mode end intervals) - when that happens, we expect to
// a) consume all remaining count in one swoop
// b) return a zero color gradient
SkASSERT(SkScalarIsFinite(proc.currentAdvance())
|| (n == count && proc.currentRampIsZero()));
if (proc.currentRampIsZero()) {
DstTraits<dstType, premul>::store(proc.currentColor(), dst, n);
} else {
ramp<dstType, premul>(proc.currentColor(), proc.currentColorGrad(), dst, n,
bias4f0, bias4f1);
}
proc.advance(SkIntToScalar(n));
count -= n;
dst += n;
if (n & 1) {
SkTSwap(bias4f0, bias4f1);
}
}
}
