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      1 
      2 /*
      3  * Copyright 2012 Google Inc.
      4  *
      5  * Use of this source code is governed by a BSD-style license that can be
      6  * found in the LICENSE file.
      7  */
      8 
      9 
     10 #ifndef SkColorTable_DEFINED
     11 #define SkColorTable_DEFINED
     12 
     13 #include "SkColor.h"
     14 #include "SkFlattenable.h"
     15 #include "SkImageInfo.h"
     16 
     17 /** \class SkColorTable
     18 
     19     SkColorTable holds an array SkPMColors (premultiplied 32-bit colors) used by
     20     8-bit bitmaps, where the bitmap bytes are interpreted as indices into the colortable.
     21 */
     22 class SkColorTable : public SkRefCnt {
     23 public:
     24     SK_DECLARE_INST_COUNT(SkColorTable)
     25 
     26     /** Makes a deep copy of colors.
     27      */
     28     SkColorTable(const SkColorTable& src);
     29     SkColorTable(const SkPMColor colors[], int count,
     30                  SkAlphaType alphaType = kPremul_SkAlphaType);
     31     virtual ~SkColorTable();
     32 
     33     SkAlphaType alphaType() const { return (SkAlphaType)fAlphaType; }
     34 
     35     bool isOpaque() const {
     36         return SkAlphaTypeIsOpaque(this->alphaType());
     37     }
     38 
     39     /** Returns the number of colors in the table.
     40     */
     41     int count() const { return fCount; }
     42 
     43     /** Returns the specified color from the table. In the debug build, this asserts that
     44         the index is in range (0 <= index < count).
     45     */
     46     SkPMColor operator[](int index) const {
     47         SkASSERT(fColors != NULL && (unsigned)index < fCount);
     48         return fColors[index];
     49     }
     50 
     51     /**
     52      *  Return the array of colors for reading. This must be balanced by a call
     53      *  to unlockColors().
     54      */
     55     const SkPMColor* lockColors() {
     56         SkDEBUGCODE(sk_atomic_inc(&fColorLockCount);)
     57         return fColors;
     58     }
     59 
     60     /**
     61      *  Balancing call to lockColors().
     62      */
     63     void unlockColors();
     64 
     65     /** Similar to lockColors(), lock16BitCache() returns the array of
     66         RGB16 colors that mirror the 32bit colors. However, this function
     67         will return null if kColorsAreOpaque_Flag is not set.
     68         Also, unlike lockColors(), the returned array here cannot be modified.
     69     */
     70     const uint16_t* lock16BitCache();
     71     /** Balancing call to lock16BitCache().
     72     */
     73     void unlock16BitCache() {
     74         SkASSERT(f16BitCacheLockCount > 0);
     75         SkDEBUGCODE(f16BitCacheLockCount -= 1);
     76     }
     77 
     78     explicit SkColorTable(SkReadBuffer&);
     79     void writeToBuffer(SkWriteBuffer&) const;
     80 
     81 private:
     82     SkPMColor*  fColors;
     83     uint16_t*   f16BitCache;
     84     uint16_t    fCount;
     85     uint8_t     fAlphaType;
     86     SkDEBUGCODE(int fColorLockCount;)
     87     SkDEBUGCODE(int f16BitCacheLockCount;)
     88 
     89     void inval16BitCache();
     90 
     91     typedef SkRefCnt INHERITED;
     92 };
     93 
     94 #endif
     95