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);
}
}
static void addbump(SkPath* path, const SkPoint pts[2], SkScalar bump) {
SkVector tang;
tang.setLength(pts[1].fX - pts[0].fX, pts[1].fY - pts[0].fY, bump);
path->lineTo(SkScalarHalf(pts[0].fX + pts[1].fX) - tang.fY,
SkScalarHalf(pts[0].fY + pts[1].fY) + tang.fX);
path->lineTo(pts[1]);
}
bool SkEmbossMaskFilter::filterMask(SkMask* dst, const SkMask& src,
const SkMatrix& matrix, SkIPoint* margin) const {
SkScalar sigma = matrix.mapRadius(fBlurSigma);
if (!SkBlurMask::BoxBlur(dst, src, sigma, SkBlurMask::kInner_Style,
SkBlurMask::kLow_Quality)) {
return false;
}
dst->fFormat = SkMask::k3D_Format;
if (margin) {
margin->set(SkScalarCeilToInt(3*sigma), SkScalarCeilToInt(3*sigma));
}
if (src.fImage == NULL) {
return true;
}
// create a larger buffer for the other two channels (should force fBlur to do this for us)
{
uint8_t* alphaPlane = dst->fImage;
size_t planeSize = dst->computeImageSize();
if (0 == planeSize) {
return false; // too big to allocate, abort
}
dst->fImage = SkMask::AllocImage(planeSize * 3);
memcpy(dst->fImage, alphaPlane, planeSize);
SkMask::FreeImage(alphaPlane);
}
// run the light direction through the matrix...
Light light = fLight;
matrix.mapVectors((SkVector*)(void*)light.fDirection,
(SkVector*)(void*)fLight.fDirection, 1);
// now restore the length of the XY component
// cast to SkVector so we can call setLength (this double cast silences alias warnings)
SkVector* vec = (SkVector*)(void*)light.fDirection;
vec->setLength(light.fDirection[0],
light.fDirection[1],
SkPoint::Length(fLight.fDirection[0], fLight.fDirection[1]));
SkEmbossMask::Emboss(dst, light);
// restore original alpha
memcpy(dst->fImage, src.fImage, src.computeImageSize());
return true;
}
// Offset line segment p0-p1 'd0' and 'd1' units in the direction specified by 'side'
bool SkOffsetSegment(const SkPoint& p0, const SkPoint& p1, SkScalar d0, SkScalar d1,
int side, SkPoint* offset0, SkPoint* offset1) {
SkASSERT(side == -1 || side == 1);
SkVector perp = SkVector::Make(p0.fY - p1.fY, p1.fX - p0.fX);
if (SkScalarNearlyEqual(d0, d1)) {
// if distances are equal, can just outset by the perpendicular
perp.setLength(d0*side);
*offset0 = p0 + perp;
*offset1 = p1 + perp;
} else {
// Otherwise we need to compute the outer tangent.
// See: http://www.ambrsoft.com/TrigoCalc/Circles2/Circles2Tangent_.htm
if (d0 < d1) {
side = -side;
}
SkScalar dD = d0 - d1;
// if one circle is inside another, we can't compute an offset
if (dD*dD >= p0.distanceToSqd(p1)) {
return false;
}
SkPoint outerTangentIntersect = SkPoint::Make((p1.fX*d0 - p0.fX*d1) / dD,
(p1.fY*d0 - p0.fY*d1) / dD);
SkScalar d0sq = d0*d0;
SkVector dP = outerTangentIntersect - p0;
SkScalar dPlenSq = dP.lengthSqd();
SkScalar discrim = SkScalarSqrt(dPlenSq - d0sq);
offset0->fX = p0.fX + (d0sq*dP.fX - side*d0*dP.fY*discrim) / dPlenSq;
offset0->fY = p0.fY + (d0sq*dP.fY + side*d0*dP.fX*discrim) / dPlenSq;
SkScalar d1sq = d1*d1;
dP = outerTangentIntersect - p1;
dPlenSq = dP.lengthSqd();
discrim = SkScalarSqrt(dPlenSq - d1sq);
offset1->fX = p1.fX + (d1sq*dP.fX - side*d1*dP.fY*discrim) / dPlenSq;
offset1->fY = p1.fY + (d1sq*dP.fY + side*d1*dP.fX*discrim) / dPlenSq;
}
return true;
}
static void Perterb(SkPoint* p, const SkVector& tangent, SkScalar scale) {
SkVector normal = tangent;
SkPointPriv::RotateCCW(&normal);
normal.setLength(scale);
*p += normal;
}
static void MiterJoiner(SkPath* outer, SkPath* inner, const SkVector& beforeUnitNormal,
const SkPoint& pivot, const SkVector& afterUnitNormal,
SkScalar radius, SkScalar invMiterLimit,
bool prevIsLine, bool currIsLine)
{
// negate the dot since we're using normals instead of tangents
SkScalar dotProd = SkPoint::DotProduct(beforeUnitNormal, afterUnitNormal);
AngleType angleType = Dot2AngleType(dotProd);
SkVector before = beforeUnitNormal;
SkVector after = afterUnitNormal;
SkVector mid;
SkScalar sinHalfAngle;
bool ccw;
if (angleType == kNearlyLine_AngleType)
return;
if (angleType == kNearly180_AngleType)
{
currIsLine = false;
goto DO_BLUNT;
}
ccw = !is_clockwise(before, after);
if (ccw)
{
SkTSwap<SkPath*>(outer, inner);
before.negate();
after.negate();
}
/* Before we enter the world of square-roots and divides,
check if we're trying to join an upright right angle
(common case for stroking rectangles). If so, special case
that (for speed an accuracy).
Note: we only need to check one normal if dot==0
*/
if (0 == dotProd && invMiterLimit <= kOneOverSqrt2)
{
mid.set(SkScalarMul(before.fX + after.fX, radius),
SkScalarMul(before.fY + after.fY, radius));
goto DO_MITER;
}
/* midLength = radius / sinHalfAngle
if (midLength > miterLimit * radius) abort
if (radius / sinHalf > miterLimit * radius) abort
if (1 / sinHalf > miterLimit) abort
if (1 / miterLimit > sinHalf) abort
My dotProd is opposite sign, since it is built from normals and not tangents
hence 1 + dot instead of 1 - dot in the formula
*/
sinHalfAngle = SkScalarSqrt(SkScalarHalf(SK_Scalar1 + dotProd));
if (sinHalfAngle < invMiterLimit)
{
currIsLine = false;
goto DO_BLUNT;
}
// choose the most accurate way to form the initial mid-vector
if (angleType == kSharp_AngleType)
{
mid.set(after.fY - before.fY, before.fX - after.fX);
if (ccw)
mid.negate();
}
else
mid.set(before.fX + after.fX, before.fY + after.fY);
mid.setLength(SkScalarDiv(radius, sinHalfAngle));
DO_MITER:
if (prevIsLine)
outer->setLastPt(pivot.fX + mid.fX, pivot.fY + mid.fY);
else
outer->lineTo(pivot.fX + mid.fX, pivot.fY + mid.fY);
DO_BLUNT:
after.scale(radius);
if (!currIsLine)
outer->lineTo(pivot.fX + after.fX, pivot.fY + after.fY);
HandleInnerJoin(inner, pivot, after);
}
