Support Float32 output from SkColorSpaceXform

src/core/SkColorSpaceXform.h

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkColorSpaceXform_DEFINED
 #define SkColorSpaceXform_DEFINED
 
 #include "SkColorSpace.h"
 #include "SkColorSpace_Base.h"
 #include "SkImageInfo.h"
 
 class SkColorSpaceXform : SkNoncopyable {
 public:
 
     /**
      *  Create an object to handle color space conversions.
      *
      *  @param srcSpace The encoded color space.
      *  @param dstSpace The destination color space.
      *
      */
     static std::unique_ptr<SkColorSpaceXform> New(const sk_sp<SkColorSpace>& srcSpace,
                                                   const sk_sp<SkColorSpace>& dstSpace);
 
+    enum ColorFormat : uint8_t {
+        kRGBA_8888_ColorFormat,
+        kBGRA_8888_ColorFormat,
+        kRGBA_F16_ColorFormat,
+        kRGBA_F32_ColorFormat,
+    };
+
     /**
      *  Apply the color conversion to a |src| buffer, storing the output in the |dst| buffer.
      *
-     *  @param dst          Stored in the format described by |dstColorType| and |dstAlphaType|
-     *  @param src          Stored as RGBA_8888, kUnpremul (note kOpaque is a form of kUnpremul)
-     *  @param len          Number of pixels in the buffers
-     *  @param dstColorType Describes color type of |dst|
-     *  @param dstAlphaType Describes alpha type of |dst|
-     *                      kUnpremul preserves input alpha values
-     *                      kPremul   performs a premultiplication and also preserves alpha values
-     *                      kOpaque   optimization hint, |dst| alphas set to 1
+     *  @param dst            Stored in the format described by |dstColorType| and |dstAlphaType|
+     *  @param src            Stored as RGBA_8888, kUnpremul (note kOpaque is a form of kUnpremul)
+     *  @param len            Number of pixels in the buffers
+     *  @param dstColorFormat Describes color format of |dst|
+     *  @param dstAlphaType   Describes alpha type of |dst|
+     *                        kUnpremul preserves input alpha values
+     *                        kPremul   performs a premultiplication and also preserves alpha values
+     *                        kOpaque   optimization hint, |dst| alphas set to 1
      *
      */
-    virtual void apply(void* dst, const uint32_t* src, int len, SkColorType dstColorType,
+    virtual void apply(void* dst, const uint32_t* src, int len, ColorFormat dstColorFormat,
                        SkAlphaType dstAlphaType) const = 0;
 
     virtual ~SkColorSpaceXform() {}
 };
 
 enum SrcGamma {
     kLinear_SrcGamma,
     kTable_SrcGamma,
 };
 
 enum DstGamma {
     kLinear_DstGamma,
     kSRGB_DstGamma,
     k2Dot2_DstGamma,
     kTable_DstGamma,
 };
 
 enum ColorSpaceMatch {
     kNone_ColorSpaceMatch,
     kGamut_ColorSpaceMatch,
     kFull_ColorSpaceMatch,
 };
 
 template <SrcGamma kSrc, DstGamma kDst, ColorSpaceMatch kCSM>
 class SkColorSpaceXform_Base : public SkColorSpaceXform {
 public:
 
-    void apply(void* dst, const uint32_t* src, int len, SkColorType dstColorType,
+    void apply(void* dst, const uint32_t* src, int len, ColorFormat dstColorFormat,
                SkAlphaType dstAlphaType) const override;
 
     static constexpr int      kDstGammaTableSize = 1024;
 
 private:
     SkColorSpaceXform_Base(const sk_sp<SkColorSpace>& srcSpace, const SkMatrix44& srcToDst,
                            const sk_sp<SkColorSpace>& dstSpace);
 
     sk_sp<SkColorLookUpTable> fColorLUT;
 
     // Contain pointers into storage or pointers into precomputed tables.
     const float*              fSrcGammaTables[3];
     const uint8_t*            fDstGammaTables[3];
     SkAutoMalloc              fStorage;
 
     float                     fSrcToDst[16];
 
     friend class SkColorSpaceXform;
     friend std::unique_ptr<SkColorSpaceXform> SlowIdentityXform(const sk_sp<SkColorSpace>& space);
 };
 
 // For testing.  Bypasses opts for when src and dst color spaces are equal.
 std::unique_ptr<SkColorSpaceXform> SlowIdentityXform(const sk_sp<SkColorSpace>& space);
 
 #endif