void SkPathStroker::quad_to(const SkPoint pts[3],
const SkVector& normalAB, const SkVector& unitNormalAB,
SkVector* normalBC, SkVector* unitNormalBC,
int subDivide) {
if (!set_normal_unitnormal(pts[1], pts[2], fRadius,
normalBC, unitNormalBC)) {
// pts[1] nearly equals pts[2], so just draw a line to pts[2]
this->line_to(pts[2], normalAB);
*normalBC = normalAB;
*unitNormalBC = unitNormalAB;
return;
}
if (--subDivide >= 0 && normals_too_curvy(unitNormalAB, *unitNormalBC)) {
SkPoint tmp[5];
SkVector norm, unit;
SkChopQuadAtHalf(pts, tmp);
this->quad_to(&tmp[0], normalAB, unitNormalAB, &norm, &unit, subDivide);
this->quad_to(&tmp[2], norm, unit, normalBC, unitNormalBC, subDivide);
} else {
SkVector normalB;
normalB = pts[2] - pts[0];
normalB.rotateCCW();
SkScalar dot = SkPoint::DotProduct(unitNormalAB, *unitNormalBC);
SkAssertResult(normalB.setLength(SkScalarDiv(fRadius,
SkScalarSqrt((SK_Scalar1 + dot)/2))));
fOuter.quadTo( pts[1].fX + normalB.fX, pts[1].fY + normalB.fY,
pts[2].fX + normalBC->fX, pts[2].fY + normalBC->fY);
fInner.quadTo( pts[1].fX - normalB.fX, pts[1].fY - normalB.fY,
pts[2].fX - normalBC->fX, pts[2].fY - normalBC->fY);
}
}
void SkPathStroker::cubic_to(const SkPoint pts[4],
const SkVector& normalAB, const SkVector& unitNormalAB,
SkVector* normalCD, SkVector* unitNormalCD,
int subDivide) {
SkVector ab = pts[1] - pts[0];
SkVector cd = pts[3] - pts[2];
SkVector normalBC, unitNormalBC;
bool degenerateAB = degenerate_vector(ab);
bool degenerateCD = degenerate_vector(cd);
if (degenerateAB && degenerateCD) {
DRAW_LINE:
this->line_to(pts[3], normalAB);
*normalCD = normalAB;
*unitNormalCD = unitNormalAB;
return;
}
if (degenerateAB) {
ab = pts[2] - pts[0];
degenerateAB = degenerate_vector(ab);
}
if (degenerateCD) {
cd = pts[3] - pts[1];
degenerateCD = degenerate_vector(cd);
}
if (degenerateAB || degenerateCD) {
goto DRAW_LINE;
}
SkAssertResult(set_normal_unitnormal(cd, fRadius, normalCD, unitNormalCD));
bool degenerateBC = !set_normal_unitnormal(pts[1], pts[2], fRadius,
&normalBC, &unitNormalBC);
if (degenerateBC || normals_too_curvy(unitNormalAB, unitNormalBC) ||
normals_too_curvy(unitNormalBC, *unitNormalCD)) {
// subdivide if we can
if (--subDivide < 0) {
goto DRAW_LINE;
}
SkPoint tmp[7];
SkVector norm, unit, dummy, unitDummy;
SkChopCubicAtHalf(pts, tmp);
this->cubic_to(&tmp[0], normalAB, unitNormalAB, &norm, &unit,
subDivide);
// we use dummys since we already have a valid (and more accurate)
// normals for CD
this->cubic_to(&tmp[3], norm, unit, &dummy, &unitDummy, subDivide);
} else {
SkVector normalB, normalC;
// need normals to inset/outset the off-curve pts B and C
if (0) { // this is normal to the line between our adjacent pts
normalB = pts[2] - pts[0];
normalB.rotateCCW();
SkAssertResult(normalB.setLength(fRadius));
normalC = pts[3] - pts[1];
normalC.rotateCCW();
SkAssertResult(normalC.setLength(fRadius));
} else { // miter-join
SkVector unitBC = pts[2] - pts[1];
unitBC.normalize();
unitBC.rotateCCW();
normalB = unitNormalAB + unitBC;
normalC = *unitNormalCD + unitBC;
SkScalar dot = SkPoint::DotProduct(unitNormalAB, unitBC);
SkAssertResult(normalB.setLength(SkScalarDiv(fRadius,
SkScalarSqrt((SK_Scalar1 + dot)/2))));
dot = SkPoint::DotProduct(*unitNormalCD, unitBC);
SkAssertResult(normalC.setLength(SkScalarDiv(fRadius,
SkScalarSqrt((SK_Scalar1 + dot)/2))));
}
fOuter.cubicTo( pts[1].fX + normalB.fX, pts[1].fY + normalB.fY,
pts[2].fX + normalC.fX, pts[2].fY + normalC.fY,
pts[3].fX + normalCD->fX, pts[3].fY + normalCD->fY);
fInner.cubicTo( pts[1].fX - normalB.fX, pts[1].fY - normalB.fY,
pts[2].fX - normalC.fX, pts[2].fY - normalC.fY,
pts[3].fX - normalCD->fX, pts[3].fY - normalCD->fY);
}
}
static void Perterb(SkPoint* p, const SkVector& tangent, SkScalar scale) {
SkVector normal = tangent;
normal.rotateCCW();
normal.setLength(scale);
*p += normal;
}