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gecko-dev/gfx/skia/patches/archive/0016-Bug-718849-Radial-grad...

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Bug 718849; patch to keep Skia up to date. r=gw280
2012-07-31 10:30:10 +04:00
# HG changeset patch
# User Matt Woodrow <mwoodrow@mozilla.com>
# Date 1339988782 -43200
# Node ID 1e9dae659ee6c992f719fd4136efbcc5410ded37
# Parent 946750f6d95febd199fb7b748e9d2c48fd01c8a6
[mq]: skia-windows-gradients
diff --git a/gfx/skia/src/effects/SkGradientShader.cpp b/gfx/skia/src/effects/SkGradientShader.cpp
--- a/gfx/skia/src/effects/SkGradientShader.cpp
+++ b/gfx/skia/src/effects/SkGradientShader.cpp
@@ -847,16 +847,19 @@ bool Linear_Gradient::setContext(const S
fFlags |= SkShader::kConstInY32_Flag;
if ((fFlags & SkShader::kHasSpan16_Flag) && !paint.isDither()) {
// only claim this if we do have a 16bit mode (i.e. none of our
// colors have alpha), and if we are not dithering (which obviously
// is not const in Y).
fFlags |= SkShader::kConstInY16_Flag;
}
}
+ if (fStart == fEnd) {
+ fFlags &= ~kOpaqueAlpha_Flag;
+ }
return true;
}
#define NO_CHECK_ITER \
do { \
unsigned fi = fx >> Gradient_Shader::kCache32Shift; \
SkASSERT(fi <= 0xFF); \
fx += dx; \
@@ -976,16 +979,21 @@ void Linear_Gradient::shadeSpan(int x, i
TileProc proc = fTileProc;
const SkPMColor* SK_RESTRICT cache = this->getCache32();
#ifdef USE_DITHER_32BIT_GRADIENT
int toggle = ((x ^ y) & 1) * kDitherStride32;
#else
int toggle = 0;
#endif
+ if (fStart == fEnd) {
+ sk_bzero(dstC, count * sizeof(*dstC));
+ return;
+ }
+
if (fDstToIndexClass != kPerspective_MatrixClass) {
dstProc(fDstToIndex, SkIntToScalar(x) + SK_ScalarHalf,
SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
SkFixed dx, fx = SkScalarToFixed(srcPt.fX);
if (fDstToIndexClass == kFixedStepInX_MatrixClass) {
SkFixed dxStorage[1];
(void)fDstToIndex.fixedStepInX(SkIntToScalar(y), dxStorage, NULL);
@@ -1169,16 +1177,21 @@ void Linear_Gradient::shadeSpan16(int x,
SkASSERT(count > 0);
SkPoint srcPt;
SkMatrix::MapXYProc dstProc = fDstToIndexProc;
TileProc proc = fTileProc;
const uint16_t* SK_RESTRICT cache = this->getCache16();
int toggle = ((x ^ y) & 1) * kDitherStride16;
+ if (fStart == fEnd) {
+ sk_bzero(dstC, count * sizeof(*dstC));
+ return;
+ }
+
if (fDstToIndexClass != kPerspective_MatrixClass) {
dstProc(fDstToIndex, SkIntToScalar(x) + SK_ScalarHalf,
SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
SkFixed dx, fx = SkScalarToFixed(srcPt.fX);
if (fDstToIndexClass == kFixedStepInX_MatrixClass) {
SkFixed dxStorage[1];
(void)fDstToIndex.fixedStepInX(SkIntToScalar(y), dxStorage, NULL);
@@ -1739,21 +1752,25 @@ void Radial_Gradient::shadeSpan(int x, i
possible circles on which the point may fall. Solving for t yields
the gradient value to use.
If a<0, the start circle is entirely contained in the
end circle, and one of the roots will be <0 or >1 (off the line
segment). If a>0, the start circle falls at least partially
outside the end circle (or vice versa), and the gradient
defines a "tube" where a point may be on one circle (on the
- inside of the tube) or the other (outside of the tube). We choose
- one arbitrarily.
+ inside of the tube) or the other (outside of the tube). We choose
+ the one with the highest t value, as long as the radius that it
+ corresponds to is >=0. In the case where neither root has a positive
+ radius, we don't draw anything.
+ XXXmattwoodrow: I've removed this for now since it breaks
+ down when Dr == 0. Is there something else we can do instead?
In order to keep the math to within the limits of fixed point,
- we divide the entire quadratic by Dr^2, and replace
+ we divide the entire quadratic by Dr, and replace
(x - Sx)/Dr with x' and (y - Sy)/Dr with y', giving
[Dx^2 / Dr^2 + Dy^2 / Dr^2 - 1)] * t^2
+ 2 * [x' * Dx / Dr + y' * Dy / Dr - Sr / Dr] * t
+ [x'^2 + y'^2 - Sr^2/Dr^2] = 0
(x' and y' are computed by appending the subtract and scale to the
fDstToIndex matrix in the constructor).
@@ -1763,99 +1780,122 @@ void Radial_Gradient::shadeSpan(int x, i
x' and y', if x and y are linear in the span, 'B' can be computed
incrementally with a simple delta (db below). If it is not (e.g.,
a perspective projection), it must be computed in the loop.
*/
namespace {
-inline SkFixed two_point_radial(SkScalar b, SkScalar fx, SkScalar fy,
- SkScalar sr2d2, SkScalar foura,
- SkScalar oneOverTwoA, bool posRoot) {
+inline bool two_point_radial(SkScalar b, SkScalar fx, SkScalar fy,
+ SkScalar sr2d2, SkScalar foura,
+ SkScalar oneOverTwoA, SkScalar diffRadius,
+ SkScalar startRadius, SkFixed& t) {
SkScalar c = SkScalarSquare(fx) + SkScalarSquare(fy) - sr2d2;
if (0 == foura) {
- return SkScalarToFixed(SkScalarDiv(-c, b));
+ SkScalar result = SkScalarDiv(-c, b);
+ if (result * diffRadius + startRadius >= 0) {
+ t = SkScalarToFixed(result);
+ return true;
+ }
+ return false;
}
SkScalar discrim = SkScalarSquare(b) - SkScalarMul(foura, c);
if (discrim < 0) {
- discrim = -discrim;
+ return false;
}
SkScalar rootDiscrim = SkScalarSqrt(discrim);
- SkScalar result;
- if (posRoot) {
- result = SkScalarMul(-b + rootDiscrim, oneOverTwoA);
- } else {
- result = SkScalarMul(-b - rootDiscrim, oneOverTwoA);
+
+ // Make sure the results corresponds to a positive radius.
+ SkScalar result = SkScalarMul(-b + rootDiscrim, oneOverTwoA);
+ if (result * diffRadius + startRadius >= 0) {
+ t = SkScalarToFixed(result);
+ return true;
}
- return SkScalarToFixed(result);
+ result = SkScalarMul(-b - rootDiscrim, oneOverTwoA);
+ if (result * diffRadius + startRadius >= 0) {
+ t = SkScalarToFixed(result);
+ return true;
+ }
+
+ return false;
}
typedef void (* TwoPointRadialShadeProc)(SkScalar fx, SkScalar dx,
SkScalar fy, SkScalar dy,
SkScalar b, SkScalar db,
- SkScalar fSr2D2, SkScalar foura, SkScalar fOneOverTwoA, bool posRoot,
+ SkScalar fSr2D2, SkScalar foura, SkScalar fOneOverTwoA,
+ SkScalar fDiffRadius, SkScalar fRadius1,
SkPMColor* SK_RESTRICT dstC, const SkPMColor* SK_RESTRICT cache,
int count);
void shadeSpan_twopoint_clamp(SkScalar fx, SkScalar dx,
SkScalar fy, SkScalar dy,
SkScalar b, SkScalar db,
- SkScalar fSr2D2, SkScalar foura, SkScalar fOneOverTwoA, bool posRoot,
+ SkScalar fSr2D2, SkScalar foura, SkScalar fOneOverTwoA,
+ SkScalar fDiffRadius, SkScalar fRadius1,
SkPMColor* SK_RESTRICT dstC, const SkPMColor* SK_RESTRICT cache,
int count) {
for (; count > 0; --count) {
- SkFixed t = two_point_radial(b, fx, fy, fSr2D2, foura,
- fOneOverTwoA, posRoot);
-
- if (t < 0) {
+ SkFixed t;
+ if (!two_point_radial(b, fx, fy, fSr2D2, foura, fOneOverTwoA, fDiffRadius, fRadius1, t)) {
+ *(dstC++) = 0;
+ } else if (t < 0) {
*dstC++ = cache[-1];
} else if (t > 0xFFFF) {
*dstC++ = cache[Gradient_Shader::kCache32Count * 2];
} else {
SkASSERT(t <= 0xFFFF);
*dstC++ = cache[t >> Gradient_Shader::kCache32Shift];
}
fx += dx;
fy += dy;
b += db;
}
}
void shadeSpan_twopoint_mirror(SkScalar fx, SkScalar dx,
SkScalar fy, SkScalar dy,
SkScalar b, SkScalar db,
- SkScalar fSr2D2, SkScalar foura, SkScalar fOneOverTwoA, bool posRoot,
+ SkScalar fSr2D2, SkScalar foura, SkScalar fOneOverTwoA,
+ SkScalar fDiffRadius, SkScalar fRadius1,
SkPMColor* SK_RESTRICT dstC, const SkPMColor* SK_RESTRICT cache,
int count) {
for (; count > 0; --count) {
- SkFixed t = two_point_radial(b, fx, fy, fSr2D2, foura,
- fOneOverTwoA, posRoot);
- SkFixed index = mirror_tileproc(t);
- SkASSERT(index <= 0xFFFF);
- *dstC++ = cache[index >> Gradient_Shader::kCache32Shift];
+ SkFixed t;
+ if (!two_point_radial(b, fx, fy, fSr2D2, foura, fOneOverTwoA, fDiffRadius, fRadius1, t)) {
+ *(dstC++) = 0;
+ } else {
+ SkFixed index = mirror_tileproc(t);
+ SkASSERT(index <= 0xFFFF);
+ *dstC++ = cache[index >> (16 - Gradient_Shader::kCache32Shift)];
+ }
fx += dx;
fy += dy;
b += db;
}
}
void shadeSpan_twopoint_repeat(SkScalar fx, SkScalar dx,
SkScalar fy, SkScalar dy,
SkScalar b, SkScalar db,
- SkScalar fSr2D2, SkScalar foura, SkScalar fOneOverTwoA, bool posRoot,
+ SkScalar fSr2D2, SkScalar foura, SkScalar fOneOverTwoA,
+ SkScalar fDiffRadius, SkScalar fRadius1,
SkPMColor* SK_RESTRICT dstC, const SkPMColor* SK_RESTRICT cache,
int count) {
for (; count > 0; --count) {
- SkFixed t = two_point_radial(b, fx, fy, fSr2D2, foura,
- fOneOverTwoA, posRoot);
- SkFixed index = repeat_tileproc(t);
- SkASSERT(index <= 0xFFFF);
- *dstC++ = cache[index >> Gradient_Shader::kCache32Shift];
+ SkFixed t;
+ if (!two_point_radial(b, fx, fy, fSr2D2, foura, fOneOverTwoA, fDiffRadius, fRadius1, t)) {
+ *(dstC++) = 0;
+ } else {
+ SkFixed index = repeat_tileproc(t);
+ SkASSERT(index <= 0xFFFF);
+ *dstC++ = cache[index >> (16 - Gradient_Shader::kCache32Shift)];
+ }
fx += dx;
fy += dy;
b += db;
}
}
@@ -1935,17 +1975,16 @@ public:
sk_bzero(dstC, count * sizeof(*dstC));
return;
}
SkMatrix::MapXYProc dstProc = fDstToIndexProc;
TileProc proc = fTileProc;
const SkPMColor* SK_RESTRICT cache = this->getCache32();
SkScalar foura = fA * 4;
- bool posRoot = fDiffRadius < 0;
if (fDstToIndexClass != kPerspective_MatrixClass) {
SkPoint srcPt;
dstProc(fDstToIndex, SkIntToScalar(x) + SK_ScalarHalf,
SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
SkScalar dx, fx = srcPt.fX;
SkScalar dy, fy = srcPt.fY;
if (fDstToIndexClass == kFixedStepInX_MatrixClass) {
@@ -1954,60 +1993,69 @@ public:
dx = SkFixedToScalar(fixedX);
dy = SkFixedToScalar(fixedY);
} else {
SkASSERT(fDstToIndexClass == kLinear_MatrixClass);
dx = fDstToIndex.getScaleX();
dy = fDstToIndex.getSkewY();
}
SkScalar b = (SkScalarMul(fDiff.fX, fx) +
- SkScalarMul(fDiff.fY, fy) - fStartRadius) * 2;
+ SkScalarMul(fDiff.fY, fy) - fStartRadius * fDiffRadius) * 2;
SkScalar db = (SkScalarMul(fDiff.fX, dx) +
SkScalarMul(fDiff.fY, dy)) * 2;
TwoPointRadialShadeProc shadeProc = shadeSpan_twopoint_repeat;
if (proc == clamp_tileproc) {
shadeProc = shadeSpan_twopoint_clamp;
} else if (proc == mirror_tileproc) {
shadeProc = shadeSpan_twopoint_mirror;
} else {
SkASSERT(proc == repeat_tileproc);
}
(*shadeProc)(fx, dx, fy, dy, b, db,
- fSr2D2, foura, fOneOverTwoA, posRoot,
+ fSr2D2, foura, fOneOverTwoA, fDiffRadius, fRadius1,
dstC, cache, count);
} else { // perspective case
SkScalar dstX = SkIntToScalar(x);
SkScalar dstY = SkIntToScalar(y);
for (; count > 0; --count) {
SkPoint srcPt;
dstProc(fDstToIndex, dstX, dstY, &srcPt);
SkScalar fx = srcPt.fX;
SkScalar fy = srcPt.fY;
SkScalar b = (SkScalarMul(fDiff.fX, fx) +
SkScalarMul(fDiff.fY, fy) - fStartRadius) * 2;
- SkFixed t = two_point_radial(b, fx, fy, fSr2D2, foura,
- fOneOverTwoA, posRoot);
- SkFixed index = proc(t);
- SkASSERT(index <= 0xFFFF);
- *dstC++ = cache[index >> Gradient_Shader::kCache32Shift];
+ SkFixed t;
+ if (!two_point_radial(b, fx, fy, fSr2D2, foura, fOneOverTwoA, fDiffRadius, fRadius1, t)) {
+ *(dstC++) = 0;
+ } else {
+ SkFixed index = proc(t);
+ SkASSERT(index <= 0xFFFF);
+ *dstC++ = cache[index >> (16 - kCache32Bits)];
+ }
dstX += SK_Scalar1;
}
}
}
virtual bool setContext(const SkBitmap& device,
const SkPaint& paint,
const SkMatrix& matrix) SK_OVERRIDE {
if (!this->INHERITED::setContext(device, paint, matrix)) {
return false;
}
// we don't have a span16 proc
fFlags &= ~kHasSpan16_Flag;
+
+ // If we might end up wanting to draw nothing as part of the gradient
+ // then we should mark ourselves as not being opaque.
+ if (fA >= 0 || (fDiffRadius == 0 && fCenter1 == fCenter2)) {
+ fFlags &= ~kOpaqueAlpha_Flag;
+ }
return true;
}
SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(Two_Point_Radial_Gradient)
protected:
Two_Point_Radial_Gradient(SkFlattenableReadBuffer& buffer)
: INHERITED(buffer),
@@ -2033,26 +2081,22 @@ private:
const SkScalar fRadius1;
const SkScalar fRadius2;
SkPoint fDiff;
SkScalar fStartRadius, fDiffRadius, fSr2D2, fA, fOneOverTwoA;
void init() {
fDiff = fCenter1 - fCenter2;
fDiffRadius = fRadius2 - fRadius1;
- SkScalar inv = SkScalarInvert(fDiffRadius);
- fDiff.fX = SkScalarMul(fDiff.fX, inv);
- fDiff.fY = SkScalarMul(fDiff.fY, inv);
- fStartRadius = SkScalarMul(fRadius1, inv);
+ fStartRadius = fRadius1;
fSr2D2 = SkScalarSquare(fStartRadius);
- fA = SkScalarSquare(fDiff.fX) + SkScalarSquare(fDiff.fY) - SK_Scalar1;
+ fA = SkScalarSquare(fDiff.fX) + SkScalarSquare(fDiff.fY) - SkScalarSquare(fDiffRadius);
fOneOverTwoA = fA ? SkScalarInvert(fA * 2) : 0;
fPtsToUnit.setTranslate(-fCenter1.fX, -fCenter1.fY);
- fPtsToUnit.postScale(inv, inv);
}
};
///////////////////////////////////////////////////////////////////////////////
class Sweep_Gradient : public Gradient_Shader {
public:
Sweep_Gradient(SkScalar cx, SkScalar cy, const SkColor colors[],
@@ -2488,16 +2532,20 @@ SkShader* SkGradientShader::CreateTwoPoi
int colorCount,
SkShader::TileMode mode,
SkUnitMapper* mapper) {
if (startRadius < 0 || endRadius < 0 || NULL == colors || colorCount < 1) {
return NULL;
}
EXPAND_1_COLOR(colorCount);
+ if (start == end && startRadius == 0) {
+ return CreateRadial(start, endRadius, colors, pos, colorCount, mode, mapper);
+ }
+
return SkNEW_ARGS(Two_Point_Radial_Gradient,
(start, startRadius, end, endRadius, colors, pos,
colorCount, mode, mapper));
}
SkShader* SkGradientShader::CreateSweep(SkScalar cx, SkScalar cy,
const SkColor colors[],
const SkScalar pos[],