void GrPathUtils::getCubicKLM(const SkPoint p[4], SkScalar klm[9]) {
SkScalar d[3];
calc_cubic_inflection_func(p, d);
CubicType cType = classify_cubic(p, d);
SkScalar controlK[4];
SkScalar controlL[4];
SkScalar controlM[4];
if (kSerpentine_CubicType == cType || (kCusp_CubicType == cType && 0.f != d[0])) {
set_serp_klm(d, controlK, controlL, controlM);
} else if (kLoop_CubicType == cType) {
set_loop_klm(d, controlK, controlL, controlM);
} else if (kCusp_CubicType == cType) {
SkASSERT(0.f == d[0]);
set_cusp_klm(d, controlK, controlL, controlM);
} else if (kQuadratic_CubicType == cType) {
set_quadratic_klm(d, controlK, controlL, controlM);
}
calc_cubic_klm(p, controlK, controlL, controlM, klm, &klm[3], &klm[6]);
}
SkCubicType SkClassifyCubic(const SkPoint src[4], SkScalar d[3]) {
calc_cubic_inflection_func(src, d);
return classify_cubic(src, d);
}
int GrPathUtils::chopCubicAtLoopIntersection(const SkPoint src[4], SkPoint dst[10], SkScalar klm[9],
SkScalar klm_rev[3]) {
// Variable to store the two parametric values at the loop double point
SkScalar smallS = 0.f;
SkScalar largeS = 0.f;
SkScalar d[3];
calc_cubic_inflection_func(src, d);
CubicType cType = classify_cubic(src, d);
int chop_count = 0;
if (kLoop_CubicType == cType) {
SkScalar tempSqrt = SkScalarSqrt(4.f * d[0] * d[2] - 3.f * d[1] * d[1]);
SkScalar ls = d[1] - tempSqrt;
SkScalar lt = 2.f * d[0];
SkScalar ms = d[1] + tempSqrt;
SkScalar mt = 2.f * d[0];
ls = ls / lt;
ms = ms / mt;
// need to have t values sorted since this is what is expected by SkChopCubicAt
if (ls <= ms) {
smallS = ls;
largeS = ms;
} else {
smallS = ms;
largeS = ls;
}
SkScalar chop_ts[2];
if (smallS > 0.f && smallS < 1.f) {
chop_ts[chop_count++] = smallS;
}
if (largeS > 0.f && largeS < 1.f) {
chop_ts[chop_count++] = largeS;
}
if(dst) {
SkChopCubicAt(src, dst, chop_ts, chop_count);
}
} else {
if (dst) {
memcpy(dst, src, sizeof(SkPoint) * 4);
}
}
if (klm && klm_rev) {
// Set klm_rev to to match the sub_section of cubic that needs to have its orientation
// flipped. This will always be the section that is the "loop"
if (2 == chop_count) {
klm_rev[0] = 1.f;
klm_rev[1] = -1.f;
klm_rev[2] = 1.f;
} else if (1 == chop_count) {
if (smallS < 0.f) {
klm_rev[0] = -1.f;
klm_rev[1] = 1.f;
} else {
klm_rev[0] = 1.f;
klm_rev[1] = -1.f;
}
} else {
if (smallS < 0.f && largeS > 1.f) {
klm_rev[0] = -1.f;
} else {
klm_rev[0] = 1.f;
}
}
SkScalar controlK[4];
SkScalar controlL[4];
SkScalar controlM[4];
if (kSerpentine_CubicType == cType || (kCusp_CubicType == cType && 0.f != d[0])) {
set_serp_klm(d, controlK, controlL, controlM);
} else if (kLoop_CubicType == cType) {
set_loop_klm(d, controlK, controlL, controlM);
} else if (kCusp_CubicType == cType) {
SkASSERT(0.f == d[0]);
set_cusp_klm(d, controlK, controlL, controlM);
} else if (kQuadratic_CubicType == cType) {
set_quadratic_klm(d, controlK, controlL, controlM);
}
calc_cubic_klm(src, controlK, controlL, controlM, klm, &klm[3], &klm[6]);
}
return chop_count + 1;
}
