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      1 /*
      2  * Copyright 2016 Google Inc.
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 
      8 #ifndef SkColorSpaceXform_DEFINED
      9 #define SkColorSpaceXform_DEFINED
     10 
     11 #include "SkImageInfo.h"
     12 
     13 class SkColorSpace;
     14 
     15 class SK_API SkColorSpaceXform : SkNoncopyable {
     16 public:
     17 
     18     /**
     19      *  Create an object to handle color space conversions.
     20      *
     21      *  @param srcSpace The encoded color space.
     22      *  @param dstSpace The destination color space.
     23      *
     24      */
     25     static std::unique_ptr<SkColorSpaceXform> New(SkColorSpace* srcSpace, SkColorSpace* dstSpace);
     26 
     27     enum ColorFormat {
     28         kRGBA_8888_ColorFormat,
     29         kBGRA_8888_ColorFormat,
     30 
     31         // Unsigned, big-endian, 16-bit integer
     32         kRGB_U16_BE_ColorFormat,   // Src only
     33         kRGBA_U16_BE_ColorFormat,  // Src only
     34 
     35         kRGBA_F16_ColorFormat,
     36         kRGBA_F32_ColorFormat,
     37 
     38         kBGR_565_ColorFormat,      // Dst only, kOpaque only
     39     };
     40 
     41     /**
     42      *  Apply the color conversion to a |src| buffer, storing the output in the |dst| buffer.
     43      *
     44      *  F16 and F32 are only supported when the color space is linear. This function will return
     45      *  false in unsupported cases.
     46      *
     47      *  @param dst            Stored in the format described by |dstColorFormat|
     48      *  @param src            Stored in the format described by |srcColorFormat|
     49      *  @param len            Number of pixels in the buffers
     50      *  @param dstColorFormat Describes color format of |dst|
     51      *  @param srcColorFormat Describes color format of |src|
     52      *  @param alphaType      Describes alpha properties of the |dst| (and |src|)
     53      *                        kUnpremul preserves input alpha values
     54      *                        kPremul   performs a premultiplication and also preserves alpha values
     55      *                        kOpaque   optimization hint, |dst| alphas set to 1
     56      *
     57      */
     58     bool apply(ColorFormat dstFormat, void* dst, ColorFormat srcFormat, const void* src, int count,
     59                SkAlphaType alphaType) const;
     60 
     61     virtual ~SkColorSpaceXform() {}
     62 
     63     enum AlphaOp {
     64         kPreserve_AlphaOp,      // just transfer src-alpha to dst-alpha
     65         kPremul_AlphaOp,        // like kPreserve, but multiplies RGB by it
     66         kSrcIsOpaque_AlphaOp,   // src alphas are all 1, this is a perf hint
     67     };
     68     static bool Apply(SkColorSpace* dstCS, ColorFormat dstFormat, void* dst,
     69                       SkColorSpace* srcCS, ColorFormat srcFormat, const void* src,
     70                       int count, AlphaOp);
     71 
     72 protected:
     73     SkColorSpaceXform() {}
     74 };
     75 
     76 #endif
     77