зеркало из https://github.com/mozilla/gecko-dev.git
Bug 996108 - Use even rounding for better results when converting from scalar to fdot6 r=upstream
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Родитель
03016f7132
Коммит
fb0f3526ce
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@ -36,11 +36,18 @@ int SkEdge::setLine(const SkPoint& p0, const SkPoint& p1, const SkIRect* clip,
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SkFDot6 x0, y0, x1, y1;
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SkFDot6 x0, y0, x1, y1;
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{
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{
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#ifdef SK_RASTERIZE_EVEN_ROUNDING
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x0 = SkScalarRoundToFDot6(p0.fX, shift);
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y0 = SkScalarRoundToFDot6(p0.fY, shift);
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x1 = SkScalarRoundToFDot6(p1.fX, shift);
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y1 = SkScalarRoundToFDot6(p1.fY, shift);
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#else
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float scale = float(1 << (shift + 6));
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float scale = float(1 << (shift + 6));
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x0 = int(p0.fX * scale);
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x0 = int(p0.fX * scale);
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y0 = int(p0.fY * scale);
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y0 = int(p0.fY * scale);
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x1 = int(p1.fX * scale);
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x1 = int(p1.fX * scale);
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y1 = int(p1.fY * scale);
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y1 = int(p1.fY * scale);
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#endif
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}
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}
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int winding = 1;
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int winding = 1;
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@ -171,6 +178,14 @@ int SkQuadraticEdge::setQuadratic(const SkPoint pts[3], int shift)
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SkFDot6 x0, y0, x1, y1, x2, y2;
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SkFDot6 x0, y0, x1, y1, x2, y2;
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{
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{
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#ifdef SK_RASTERIZE_EVEN_ROUNDING
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x0 = SkScalarRoundToFDot6(pts[0].fX, shift);
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y0 = SkScalarRoundToFDot6(pts[0].fY, shift);
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x1 = SkScalarRoundToFDot6(pts[1].fX, shift);
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y1 = SkScalarRoundToFDot6(pts[1].fY, shift);
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x2 = SkScalarRoundToFDot6(pts[2].fX, shift);
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y2 = SkScalarRoundToFDot6(pts[2].fY, shift);
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#else
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float scale = float(1 << (shift + 6));
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float scale = float(1 << (shift + 6));
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x0 = int(pts[0].fX * scale);
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x0 = int(pts[0].fX * scale);
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y0 = int(pts[0].fY * scale);
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y0 = int(pts[0].fY * scale);
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@ -178,6 +193,7 @@ int SkQuadraticEdge::setQuadratic(const SkPoint pts[3], int shift)
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y1 = int(pts[1].fY * scale);
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y1 = int(pts[1].fY * scale);
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x2 = int(pts[2].fX * scale);
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x2 = int(pts[2].fX * scale);
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y2 = int(pts[2].fY * scale);
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y2 = int(pts[2].fY * scale);
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#endif
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}
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}
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int winding = 1;
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int winding = 1;
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@ -321,6 +337,16 @@ int SkCubicEdge::setCubic(const SkPoint pts[4], const SkIRect* clip, int shift)
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SkFDot6 x0, y0, x1, y1, x2, y2, x3, y3;
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SkFDot6 x0, y0, x1, y1, x2, y2, x3, y3;
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{
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{
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#ifdef SK_RASTERIZE_EVEN_ROUNDING
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x0 = SkScalarRoundToFDot6(pts[0].fX, shift);
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y0 = SkScalarRoundToFDot6(pts[0].fY, shift);
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x1 = SkScalarRoundToFDot6(pts[1].fX, shift);
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y1 = SkScalarRoundToFDot6(pts[1].fY, shift);
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x2 = SkScalarRoundToFDot6(pts[2].fX, shift);
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y2 = SkScalarRoundToFDot6(pts[2].fY, shift);
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x3 = SkScalarRoundToFDot6(pts[3].fX, shift);
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y3 = SkScalarRoundToFDot6(pts[3].fY, shift);
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#else
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float scale = float(1 << (shift + 6));
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float scale = float(1 << (shift + 6));
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x0 = int(pts[0].fX * scale);
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x0 = int(pts[0].fX * scale);
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y0 = int(pts[0].fY * scale);
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y0 = int(pts[0].fY * scale);
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@ -330,6 +356,7 @@ int SkCubicEdge::setCubic(const SkPoint pts[4], const SkIRect* clip, int shift)
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y2 = int(pts[2].fY * scale);
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y2 = int(pts[2].fY * scale);
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x3 = int(pts[3].fX * scale);
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x3 = int(pts[3].fX * scale);
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y3 = int(pts[3].fY * scale);
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y3 = int(pts[3].fY * scale);
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#endif
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}
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}
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int winding = 1;
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int winding = 1;
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@ -89,11 +89,18 @@ int SkEdge::setLine(const SkPoint& p0, const SkPoint& p1, int shift) {
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SkFDot6 x0, y0, x1, y1;
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SkFDot6 x0, y0, x1, y1;
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{
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{
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#ifdef SK_RASTERIZE_EVEN_ROUNDING
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x0 = SkScalarRoundToFDot6(p0.fX, shift);
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y0 = SkScalarRoundToFDot6(p0.fY, shift);
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x1 = SkScalarRoundToFDot6(p1.fX, shift);
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y1 = SkScalarRoundToFDot6(p1.fY, shift);
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#else
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float scale = float(1 << (shift + 6));
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float scale = float(1 << (shift + 6));
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x0 = int(p0.fX * scale);
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x0 = int(p0.fX * scale);
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y0 = int(p0.fY * scale);
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y0 = int(p0.fY * scale);
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x1 = int(p1.fX * scale);
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x1 = int(p1.fX * scale);
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y1 = int(p1.fY * scale);
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y1 = int(p1.fY * scale);
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#endif
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}
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}
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int winding = 1;
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int winding = 1;
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@ -15,6 +15,28 @@
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typedef int32_t SkFDot6;
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typedef int32_t SkFDot6;
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/* This uses the magic number approach suggested here:
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* http://stereopsis.com/sree/fpu2006.html and used in
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* _cairo_fixed_from_double. It does banker's rounding
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* (i.e. round to nearest even)
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*/
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inline SkFDot6 SkScalarRoundToFDot6(SkScalar x, int shift = 0)
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{
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union {
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double fDouble;
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int32_t fBits[2];
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} tmp;
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int fractionalBits = 6 + shift;
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double magic = (1LL << (52 - (fractionalBits))) * 1.5;
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tmp.fDouble = SkScalarToDouble(x) + magic;
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#ifdef SK_CPU_BENDIAN
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return tmp.fBits[1];
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#else
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return tmp.fBits[0];
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#endif
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}
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#define SK_FDot6One (64)
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#define SK_FDot6One (64)
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#define SK_FDot6Half (32)
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#define SK_FDot6Half (32)
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