create struct to hold all the params passed around for shader::context

src/effects/SkPerlinNoiseShader.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkDither.h"
 #include "SkPerlinNoiseShader.h"
 #include "SkColorFilter.h"
@@ skipping 407 matching lines @@
 
     U8CPU rgba[4];
     for (int channel = 3; channel >= 0; --channel) {
         rgba[channel] = SkScalarFloorToInt(255 *
             calculateTurbulenceValueForPoint(channel, *perlinNoiseShader.fPaintingData,
                                              stitchData, newPoint));
     }
     return SkPreMultiplyARGB(rgba[3], rgba[0], rgba[1], rgba[2]);
 }
 
-SkShader::Context* SkPerlinNoiseShader::createContext(const SkBitmap& device, const SkPaint& paint,
-                                                      const SkMatrix& matrix, void* storage) const {
-    if (!this->validContext(device, paint, matrix)) {
+SkShader::Context* SkPerlinNoiseShader::createContext(const ContextRec& rec, void* storage) const {
+    if (!this->validContext(rec)) {
         return NULL;
     }
 
-    return SkNEW_PLACEMENT_ARGS(storage, PerlinNoiseShaderContext, (*this, device, paint, matrix));
+    return SkNEW_PLACEMENT_ARGS(storage, PerlinNoiseShaderContext, (*this, rec));
 }
 
 size_t SkPerlinNoiseShader::contextSize() const {
     return sizeof(PerlinNoiseShaderContext);
 }
 
 SkPerlinNoiseShader::PerlinNoiseShaderContext::PerlinNoiseShaderContext(
-        const SkPerlinNoiseShader& shader, const SkBitmap& device,
-        const SkPaint& paint, const SkMatrix& matrix)
-    : INHERITED(shader, device, paint, matrix)
+        const SkPerlinNoiseShader& shader, const ContextRec& rec)
+    : INHERITED(shader, rec)
 {
-    SkMatrix newMatrix = matrix;
+    SkMatrix newMatrix = *rec.fMatrix;
     newMatrix.postConcat(shader.getLocalMatrix());
     SkMatrix invMatrix;
     if (!newMatrix.invert(&invMatrix)) {
         invMatrix.reset();
     }
     // This (1,1) translation is due to WebKit's 1 based coordinates for the noise
     // (as opposed to 0 based, usually). The same adjustment is in the setData() function.
     newMatrix.postTranslate(SK_Scalar1, SK_Scalar1);
     newMatrix.postConcat(invMatrix);
     newMatrix.postConcat(invMatrix);
@@ skipping 908 matching lines @@
     str->append(" seed: ");
     str->appendScalar(fSeed);
     str->append(" stitch tiles: ");
     str->append(fStitchTiles ? "true " : "false ");
 
     this->INHERITED::toString(str);
 
     str->append(")");
 }
 #endif