Refactored SkColorSpace_A2B to allow arbitrary ordering of elements

gm/labpcsdemo.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include <cmath>
 #include "gm.h"
 #include "Resources.h"
@@ skipping 157 matching lines @@
         const int imageHeight = codec->getInfo().height();
         // Using nullptr as the color space instructs the codec to decode in legacy mode,
         // meaning that we will get the raw encoded bytes without any color correction.
         SkImageInfo imageInfo = SkImageInfo::Make(imageWidth, imageHeight, kN32_SkColorType,  
                                                   kOpaque_SkAlphaType, nullptr);
         bitmap.allocPixels(imageInfo);
         codec->getPixels(imageInfo, bitmap.getPixels(), bitmap.rowBytes());
         if (convertLabToXYZ) {
             SkASSERT(SkColorSpace_Base::Type::kA2B == as_CSB(colorSpace)->type());
             SkColorSpace_A2B& cs = *static_cast<SkColorSpace_A2B*>(colorSpace.get());
+            const SkColorLookUpTable* colorLUT = nullptr;
             bool printConversions = false;
-            SkASSERT(cs.colorLUT());
             // We're skipping evaluating the TRCs and the matrix here since they aren't
             // in the ICC profile initially used here.
-            SkASSERT(kLinear_SkGammaNamed == cs.aCurveNamed());
-            SkASSERT(kLinear_SkGammaNamed == cs.mCurveNamed());
-            SkASSERT(kLinear_SkGammaNamed == cs.bCurveNamed());
-            SkASSERT(cs.matrix().isIdentity());
+            for (size_t e = 0; e < cs.count(); ++e) {
+                switch (cs.element(e).type()) {
+                    case SkColorSpace_A2B::Element::Type::kGammaNamed:
+                        SkASSERT(kLinear_SkGammaNamed == cs.element(e).gammaNamed());
+                        break;
+                    case SkColorSpace_A2B::Element::Type::kGammas:
+                        SkASSERT(false);
+                        break;
+                    case SkColorSpace_A2B::Element::Type::kCLUT:
+                        colorLUT = &cs.element(e).colorLUT();
+                        break;
+                    case SkColorSpace_A2B::Element::Type::kMatrix:
+                        SkASSERT(cs.element(e).matrix().isIdentity());
+                        break;
+                }
+            }
+            SkASSERT(colorLUT);
             for (int y = 0; y < imageHeight; ++y) {
                 for (int x = 0; x < imageWidth; ++x) {
                     uint32_t& p = *bitmap.getAddr32(x, y);
                     const int r = SkColorGetR(p);
                     const int g = SkColorGetG(p);
                     const int b = SkColorGetB(p);
                     if (printConversions) {
                         SkColorSpacePrintf("\nraw = (%d, %d, %d)\t", r, g, b);
                     }
 
                     float lab[4] = { r * (1.f/255.f), g * (1.f/255.f), b * (1.f/255.f), 1.f };
                     
-                    interp_3d_clut(lab, lab, cs.colorLUT());
+                    interp_3d_clut(lab, lab, colorLUT);
                     
                     // Lab has ranges [0,100] for L and [-128,127] for a and b
                     // but the ICC profile loader stores as [0,1]. The ICC
                     // specifies an offset of -128 to convert.
                     // note: formula could be adjusted to remove this conversion,
                     //       but for now let's keep it like this for clarity until
                     //       an optimized version is added.
                     lab[0] *= 100.f;
                     lab[1] = 255.f * lab[1] - 128.f;
                     lab[2] = 255.f * lab[2] - 128.f;
@@ skipping 54 matching lines @@
     }
 
 private:
     const int fWidth;
     const int fHeight;
 
     typedef skiagm::GM INHERITED;
 };
 
 DEF_GM( return new LabPCSDemoGM; )