The Tor Browser: gfx/skia/patches/archive/0016-Bug-718849-Radial-gradients.patch@6474c204b198 (annotated)

gfx/skia/patches/archive/0016-Bug-718849-Radial-gradients.patch@6474c204b198 (annotated)

gfx/skia/patches/archive/0016-Bug-718849-Radial-gradients.patch

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 # 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[],

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gfx/skia/patches/archive/0016-Bug-718849-Radial-gradients.patch@6474c204b198 (annotated)

gfx/skia/patches/archive/0016-Bug-718849-Radial-gradients.patch