Added support for non-separable blending modes and fixed scalar issue

src/pdf/SkPDFGraphicState.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkPDFFormXObject.h"
 #include "SkPDFGraphicState.h"
 #include "SkPDFUtils.h"
 #include "SkStream.h"
 #include "SkTypes.h"
 
 static const char* blend_mode_from_xfermode(SkXfermode::Mode mode) {
     switch (mode) {
         case SkXfermode::kSrcOver_Mode:    return "Normal";
-        case SkXfermode::kModulate_Mode:   return "Multiply";
+        // kModulate is not really like multipy but similar most of the time.
+        case SkXfermode::kModulate_Mode: 
+        case SkXfermode::kMultiply_Mode:   return "Multiply";
         case SkXfermode::kScreen_Mode:     return "Screen";
         case SkXfermode::kOverlay_Mode:    return "Overlay";
         case SkXfermode::kDarken_Mode:     return "Darken";
         case SkXfermode::kLighten_Mode:    return "Lighten";
         case SkXfermode::kColorDodge_Mode: return "ColorDodge";
         case SkXfermode::kColorBurn_Mode:  return "ColorBurn";
         case SkXfermode::kHardLight_Mode:  return "HardLight";
         case SkXfermode::kSoftLight_Mode:  return "SoftLight";
         case SkXfermode::kDifference_Mode: return "Difference";
         case SkXfermode::kExclusion_Mode:  return "Exclusion";
+        case SkXfermode::kHue_Mode:        return "Hue";
+        case SkXfermode::kSaturation_Mode: return "Saturation";
+        case SkXfermode::kColor_Mode:      return "Color";
+        case SkXfermode::kLuminosity_Mode: return "Luminosity";
 
         // These are handled in SkPDFDevice::setUpContentEntry.
         case SkXfermode::kClear_Mode:
         case SkXfermode::kSrc_Mode:
         case SkXfermode::kDst_Mode:
         case SkXfermode::kDstOver_Mode:
         case SkXfermode::kSrcIn_Mode:
         case SkXfermode::kDstIn_Mode:
         case SkXfermode::kSrcOut_Mode:
         case SkXfermode::kDstOut_Mode:
             return "Normal";
 
         // TODO(vandebo): Figure out if we can support more of these modes.
         case SkXfermode::kSrcATop_Mode:
         case SkXfermode::kDstATop_Mode:
         case SkXfermode::kXor_Mode:
         case SkXfermode::kPlus_Mode:
-        case SkXfermode::kMultiply_Mode:
             return NULL;
     }
     return NULL;
 }
 
 SkPDFGraphicState::~SkPDFGraphicState() {
     SkAutoMutexAcquire lock(CanonicalPaintsMutex());
     if (!fSMask) {
         int index = Find(fPaint);
         SkASSERT(index >= 0);
@@ skipping 213 matching lines @@
     }
     if (bXfermodeName < 0 || bXfermodeName > SkXfermode::kLastMode ||
             blend_mode_from_xfermode(bXfermodeName) == NULL) {
         bXfermodeName = SkXfermode::kSrcOver_Mode;
     }
     const char* bXfermodeString = blend_mode_from_xfermode(bXfermodeName);
     SkASSERT(bXfermodeString != NULL);
 
     return strcmp(aXfermodeString, bXfermodeString) == 0;
 }