Adding 3D lut color filter

include/effects/SkColorProfileFilter.h

Index: include/effects/SkColorProfileFilter.h
diff --git a/include/effects/SkColorProfileFilter.h b/include/effects/SkColorProfileFilter.h
new file mode 100644
index 0000000000000000000000000000000000000000..ff485b04943a7777257c0cf897a4e65d11b4ec05
--- /dev/null
+++ b/include/effects/SkColorProfileFilter.h
@@ -0,0 +1,75 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkColorProfileFilter_DEFINED
+#define SkColorProfileFilter_DEFINED
+
+#include "SkColorFilter.h"
+#include "SkData.h"
+
+class SK_API SkColorProfileFilter : public SkColorFilter {
+public:
+    // cubeData must containt a 3D data in the form of cube of the size:
+    // cubeDimension * cubeDimension * cubeDimension * sizeof(SkPMColor)
+    // This cube contains a transform where (x,y,z) maps to the (r,g,b).
+    static SkColorProfileFilter* Create(SkData* cubeData, int cubeDimension);

[bsalomon, 2014/10/03 19:45:00]

Can this return SkColorFilter* rather than the derived class?

[sugoi1, 2014/10/06 15:04:54]

Done.

+
+    virtual void filterSpan(const SkPMColor src[], int count, SkPMColor[]) const SK_OVERRIDE;
+
+#if SK_SUPPORT_GPU
+   virtual GrFragmentProcessor* asFragmentProcessor(GrContext*) const SK_OVERRIDE;
+#endif
+
+    SK_TO_STRING_OVERRIDE()
+    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkColorProfileFilter)
+
+protected:
+    SkColorProfileFilter(SkData* cubeData, int cubeDimension);
+#ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
+    SkColorProfileFilter(SkReadBuffer& buffer);
+#endif
+    virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE;
+
+private:
+    // The cache is initialized on-demand when getColorLuts is called.
+    class ColorProfileCache {

[bsalomon, 2014/10/03 19:45:00]

Why is this dynamically allocated when it is created in the constructor of the
filter?

[sugoi1, 2014/10/06 15:04:54]

If I don't keep it as a pointer, then I get an error for calling
ColorProfileCache::getProcessingLuts (which isn't const) from
SkColorProfileFilter::filterSpan (which is const). I changed it to a mutable
member instead.

[bsalomon, 2014/10/06 17:26:17]

I don't fully grok the immutability requirements for SkPaint effects. I'd like
reed@ to look at this part.

+    public:
+        ColorProfileCache(int cubeDimension);
+
+        void getProcessingLuts(const int* (*colorToIndex)[2],
+                               const SkScalar* (*colorToFactors)[2],
+                               const SkScalar** colorToScalar);
+
+        int cubeDimension() const { return fCubeDimension; }
+
+    private:
+        // Working pointers. If any of these is NULL,
+        // we need to recompute the corresponding cache values.
+        int* fColorToIndex[2];
+        SkScalar* fColorToFactors[2];
+        SkScalar* fColorToScalar;
+
+        SkAutoMalloc fLutStorage;
+
+        const int fCubeDimension;
+
+        // Make sure we only initialize the caches once.
+        SkMutex fLutsMutex;
+        bool fLutsInited;
+
+        static void initProcessingLuts(ColorProfileCache* cache);
+    };
+
+    SkAutoDataUnref fCubeData;
+    int32_t fUniqueID;
+
+    SkAutoTDelete<ColorProfileCache> fCache;
+
+    typedef SkColorFilter INHERITED;
+};
+
+#endif