Extract most of the mutable state of SkShader into a separate Context object.

src/effects/gradients/SkRadialGradient.cpp

 
 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkRadialGradient.h"
 #include "SkRadialGradient_Table.h"
@@ skipping 139 matching lines @@
     : SkGradientShaderBase(desc),
       fCenter(center),
       fRadius(radius)
 {
     // make sure our table is insync with our current #define for kSQRT_TABLE_SIZE
     SkASSERT(sizeof(gSqrt8Table) == kSQRT_TABLE_SIZE);
 
     rad_to_unit_matrix(center, radius, &fPtsToUnit);
 }
 
-void SkRadialGradient::shadeSpan16(int x, int y, uint16_t* dstCParam,
-                         int count) {
+size_t SkRadialGradient::contextSize() const {
+    return sizeof(RadialGradientContext);
+}
+
+SkShader::Context* SkRadialGradient::createContext(const SkBitmap& device, const SkPaint& paint,
+                                                   const SkMatrix& matrix, void* storage) const {
+    if (!this->validContext(device, paint, matrix)) {
+        return NULL;
+    }
+
+    return SkNEW_PLACEMENT_ARGS(storage, RadialGradientContext, (*this, device, paint, matrix));
+}
+
+SkRadialGradient::RadialGradientContext::RadialGradientContext(
+        const SkRadialGradient& shader, const SkBitmap& device,
+        const SkPaint& paint, const SkMatrix& matrix)
+    : INHERITED(shader, device, paint, matrix) {}
+
+void SkRadialGradient::RadialGradientContext::shadeSpan16(int x, int y, uint16_t* dstCParam,
+                                                          int count) {
     SkASSERT(count > 0);
 
+    const SkRadialGradient& radialGradient = static_cast<const SkRadialGradient&>(fShader);
+
     uint16_t* SK_RESTRICT dstC = dstCParam;
 
     SkPoint             srcPt;
     SkMatrix::MapXYProc dstProc = fDstToIndexProc;
-    TileProc            proc = fTileProc;
-    const uint16_t* SK_RESTRICT cache = this->getCache16();
+    TileProc            proc = radialGradient.fTileProc;
+    const uint16_t* SK_RESTRICT cache = fCache->getCache16();
     int                 toggle = init_dither_toggle16(x, y);
 
     if (fDstToIndexClass != kPerspective_MatrixClass) {
         dstProc(fDstToIndex, SkIntToScalar(x) + SK_ScalarHalf,
                              SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
 
         SkScalar sdx = fDstToIndex.getScaleX();
         SkScalar sdy = fDstToIndex.getSkewY();
 
         if (fDstToIndexClass == kFixedStepInX_MatrixClass) {
             SkFixed storage[2];
             (void)fDstToIndex.fixedStepInX(SkIntToScalar(y),
                                            &storage[0], &storage[1]);
             sdx = SkFixedToScalar(storage[0]);
             sdy = SkFixedToScalar(storage[1]);
         } else {
             SkASSERT(fDstToIndexClass == kLinear_MatrixClass);
         }
 
         RadialShade16Proc shadeProc = shadeSpan16_radial_repeat;
-        if (SkShader::kClamp_TileMode == fTileMode) {
+        if (SkShader::kClamp_TileMode == radialGradient.fTileMode) {
             shadeProc = shadeSpan16_radial_clamp;
-        } else if (SkShader::kMirror_TileMode == fTileMode) {
+        } else if (SkShader::kMirror_TileMode == radialGradient.fTileMode) {
             shadeProc = shadeSpan16_radial_mirror;
         } else {
-            SkASSERT(SkShader::kRepeat_TileMode == fTileMode);
+            SkASSERT(SkShader::kRepeat_TileMode == radialGradient.fTileMode);
         }
         (*shadeProc)(srcPt.fX, sdx, srcPt.fY, sdy, dstC,
                      cache, toggle, count);
     } else {    // perspective case
         SkScalar dstX = SkIntToScalar(x);
         SkScalar dstY = SkIntToScalar(y);
         do {
             dstProc(fDstToIndex, dstX, dstY, &srcPt);
             unsigned fi = proc(SkScalarToFixed(srcPt.length()));
             SkASSERT(fi <= 0xFFFF);
@@ skipping 176 matching lines @@
 }
 
 void shadeSpan_radial_repeat(SkScalar fx, SkScalar dx, SkScalar fy, SkScalar dy,
                              SkPMColor* SK_RESTRICT dstC, const SkPMColor* SK_RESTRICT cache,
                              int count, int toggle) {
     shadeSpan_radial<repeat_tileproc_nonstatic>(fx, dx, fy, dy, dstC, cache, count, toggle);
 }
 
 }  // namespace
 
-void SkRadialGradient::shadeSpan(int x, int y,
-                                SkPMColor* SK_RESTRICT dstC, int count) {
+void SkRadialGradient::RadialGradientContext::shadeSpan(int x, int y,
+                                                        SkPMColor* SK_RESTRICT dstC, int count) {
     SkASSERT(count > 0);
 
+    const SkRadialGradient& radialGradient = static_cast<const SkRadialGradient&>(fShader);
+
     SkPoint             srcPt;
     SkMatrix::MapXYProc dstProc = fDstToIndexProc;
-    TileProc            proc = fTileProc;
-    const SkPMColor* SK_RESTRICT cache = this->getCache32();
+    TileProc            proc = radialGradient.fTileProc;
+    const SkPMColor* SK_RESTRICT cache = fCache->getCache32();
     int toggle = init_dither_toggle(x, y);
 
     if (fDstToIndexClass != kPerspective_MatrixClass) {
         dstProc(fDstToIndex, SkIntToScalar(x) + SK_ScalarHalf,
                              SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
         SkScalar sdx = fDstToIndex.getScaleX();
         SkScalar sdy = fDstToIndex.getSkewY();
 
         if (fDstToIndexClass == kFixedStepInX_MatrixClass) {
             SkFixed storage[2];
             (void)fDstToIndex.fixedStepInX(SkIntToScalar(y),
                                            &storage[0], &storage[1]);
             sdx = SkFixedToScalar(storage[0]);
             sdy = SkFixedToScalar(storage[1]);
         } else {
             SkASSERT(fDstToIndexClass == kLinear_MatrixClass);
         }
 
         RadialShadeProc shadeProc = shadeSpan_radial_repeat;
-        if (SkShader::kClamp_TileMode == fTileMode) {
+        if (SkShader::kClamp_TileMode == radialGradient.fTileMode) {
             shadeProc = shadeSpan_radial_clamp;
-        } else if (SkShader::kMirror_TileMode == fTileMode) {
+        } else if (SkShader::kMirror_TileMode == radialGradient.fTileMode) {
             shadeProc = shadeSpan_radial_mirror;
         } else {
-            SkASSERT(SkShader::kRepeat_TileMode == fTileMode);
+            SkASSERT(SkShader::kRepeat_TileMode == radialGradient.fTileMode);
         }
         (*shadeProc)(srcPt.fX, sdx, srcPt.fY, sdy, dstC, cache, count, toggle);
     } else {    // perspective case
         SkScalar dstX = SkIntToScalar(x);
         SkScalar dstY = SkIntToScalar(y);
         do {
             dstProc(fDstToIndex, dstX, dstY, &srcPt);
             unsigned fi = proc(SkScalarToFixed(srcPt.length()));
             SkASSERT(fi <= 0xFFFF);
             *dstC++ = cache[fi >> SkGradientShaderBase::kCache32Shift];
@@ skipping 138 matching lines @@
     str->appendScalar(fCenter.fY);
     str->append(") radius: ");
     str->appendScalar(fRadius);
     str->append(" ");
 
     this->INHERITED::toString(str);
 
     str->append(")");
 }
 #endif