// called from a curve subclass
int SkEdge::updateLine(SkFixed x0, SkFixed y0, SkFixed x1, SkFixed y1)
{
SkASSERT(fWinding == 1 || fWinding == -1);
SkASSERT(fCurveCount != 0);
// SkASSERT(fCurveShift != 0);
y0 >>= 10;
y1 >>= 10;
SkASSERT(y0 <= y1);
int top = SkFDot6Round(y0);
int bot = SkFDot6Round(y1);
// SkASSERT(top >= fFirstY);
// are we a zero-height line?
if (top == bot)
return 0;
x0 >>= 10;
x1 >>= 10;
SkFixed slope = SkFDot6Div(x1 - x0, y1 - y0);
const SkFDot6 dy = SkEdge_Compute_DY(top, y0);
fX = SkFDot6ToFixed(x0 + SkFixedMul(slope, dy)); // + SK_Fixed1/2
fDX = slope;
fFirstY = top;
fLastY = bot - 1;
return 1;
}
int SkEdge::setLine(const SkPoint& p0, const SkPoint& p1, const SkIRect* clip,
int shift) {
SkFDot6 x0, y0, x1, y1;
{
#ifdef SK_SCALAR_IS_FLOAT
float scale = float(1 << (shift + 6));
x0 = int(p0.fX * scale);
y0 = int(p0.fY * scale);
x1 = int(p1.fX * scale);
y1 = int(p1.fY * scale);
#else
shift = 10 - shift;
x0 = p0.fX >> shift;
y0 = p0.fY >> shift;
x1 = p1.fX >> shift;
y1 = p1.fY >> shift;
#endif
}
int winding = 1;
if (y0 > y1) {
SkTSwap(x0, x1);
SkTSwap(y0, y1);
winding = -1;
}
int top = SkFDot6Round(y0);
int bot = SkFDot6Round(y1);
// are we a zero-height line?
if (top == bot) {
return 0;
}
// are we completely above or below the clip?
if (NULL != clip && (top >= clip->fBottom || bot <= clip->fTop)) {
return 0;
}
SkFixed slope = SkFDot6Div(x1 - x0, y1 - y0);
fX = SkFDot6ToFixed(x0 + SkFixedMul(slope, (32 - y0) & 63)); // + SK_Fixed1/2
fDX = slope;
fFirstY = top;
fLastY = bot - 1;
fCurveCount = 0;
fWinding = SkToS8(winding);
fCurveShift = 0;
if (clip) {
this->chopLineWithClip(*clip);
}
return 1;
}
int SkEdge::setLine(const SkPoint& p0, const SkPoint& p1, const SkIRect* clip,
int shift) {
SkFDot6 x0, y0, x1, y1;
{
#ifdef SK_RASTERIZE_EVEN_ROUNDING
x0 = SkScalarRoundToFDot6(p0.fX, shift);
y0 = SkScalarRoundToFDot6(p0.fY, shift);
x1 = SkScalarRoundToFDot6(p1.fX, shift);
y1 = SkScalarRoundToFDot6(p1.fY, shift);
#else
float scale = float(1 << (shift + 6));
x0 = int(p0.fX * scale);
y0 = int(p0.fY * scale);
x1 = int(p1.fX * scale);
y1 = int(p1.fY * scale);
#endif
}
int winding = 1;
if (y0 > y1) {
SkTSwap(x0, x1);
SkTSwap(y0, y1);
winding = -1;
}
int top = SkFDot6Round(y0);
int bot = SkFDot6Round(y1);
// are we a zero-height line?
if (top == bot) {
return 0;
}
// are we completely above or below the clip?
if (clip && (top >= clip->fBottom || bot <= clip->fTop)) {
return 0;
}
SkFixed slope = SkFDot6Div(x1 - x0, y1 - y0);
const SkFDot6 dy = SkEdge_Compute_DY(top, y0);
fX = SkFDot6ToFixed(x0 + SkFixedMul(slope, dy)); // + SK_Fixed1/2
fDX = slope;
fFirstY = top;
fLastY = bot - 1;
fCurveCount = 0;
fWinding = SkToS8(winding);
fCurveShift = 0;
if (clip) {
this->chopLineWithClip(*clip);
}
return 1;
}
static inline SkFixed quickSkFDot6Div(SkFDot6 a, SkFDot6 b) {
if (SkAbs32(b) < kInverseTableSize) {
SkASSERT((int64_t)a * QuickFDot6Inverse::Lookup(b) <= SK_MaxS32);
SkFixed ourAnswer = (a * QuickFDot6Inverse::Lookup(b)) >> 6;
#ifdef SK_DEBUG
SkFixed directAnswer = SkFDot6Div(a, b);
SkASSERT(
(directAnswer == 0 && ourAnswer == 0) ||
SkFixedDiv(SkAbs32(directAnswer - ourAnswer), SkAbs32(directAnswer)) <= 1 << 10
);
#endif
return ourAnswer;
} else {
