add colortable support to imagegenerator

include/core/SkImageGenerator.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkImageGenerator_DEFINED
 #define SkImageGenerator_DEFINED
 
 #include "SkImageInfo.h"
+#include "SkColor.h"
 
 class SkBitmap;
 class SkData;
 class SkImageGenerator;
 
 /**
  *  Takes ownership of SkImageGenerator.  If this method fails for
  *  whatever reason, it will return false and immediatetely delete
  *  the generator.  If it succeeds, it will modify destination
  *  bitmap.
@@ skipping 18 matching lines @@
  *  SkDiscardablePixelRef) to decode and re-decode an image as needed.
  */
 class SK_API SkImageGenerator {
 public:
     /**
      *  The PixelRef which takes ownership of this SkImageGenerator
      *  will call the image generator's destructor.
      */
     virtual ~SkImageGenerator() { }
 
+#ifdef SK_SUPPORT_LEGACY_IMAGEGENERATORAPI
+    virtual bool refEncodedData() { return this->onRefEncodedData(); }
+    virtual bool getInfo(SkImageInfo* info) { return this->onGetInfo(info); }
+    virtual bool getPixels(const SkImageInfo& info, void* pixels, size_t rowBytes) {
+        return this->onGetPixels(info, pixels, rowBytes, NULL, NULL);
+    }
+#else
     /**
      *  Return a ref to the encoded (i.e. compressed) representation,
      *  of this data.
      *
      *  If non-NULL is returned, the caller is responsible for calling
      *  unref() on the data when it is finished.
      */
-    virtual SkData* refEncodedData() { return NULL; }
+    SkData* refEncodedData() { return this->onRefEncodedData(); }
 
     /**
      *  Return some information about the image, allowing the owner of
      *  this object to allocate pixels.
      *
      *  Repeated calls to this function should give the same results,
      *  allowing the PixelRef to be immutable.
      *
      *  @return false if anything goes wrong.
      */
-    virtual bool getInfo(SkImageInfo* info) = 0;
+    bool getInfo(SkImageInfo* info);
 
     /**
      *  Decode into the given pixels, a block of memory of size at
      *  least (info.fHeight - 1) * rowBytes + (info.fWidth *
      *  bytesPerPixel)
      *
      *  Repeated calls to this function should give the same results,
      *  allowing the PixelRef to be immutable.
      *
      *  @param info A description of the format (config, size)
      *         expected by the caller.  This can simply be identical
      *         to the info returned by getInfo().
      *
      *         This contract also allows the caller to specify
      *         different output-configs, which the implementation can
      *         decide to support or not.
      *
+     *  If info is kIndex8_SkColorType, then the caller must provide storage for up to 256
+     *  SkPMColor values in ctable. On success the generator must copy N colors into that storage,
+     *  (where N is the logical number of table entries) and set ctableCount to N.
+     *
+     *  If info is not kIndex8_SkColorType, then the last two parameters may be NULL. If ctableCount
+     *  is not null, it will be set to 0.
+     *
      *  @return false if anything goes wrong or if the image info is
      *          unsupported.
      */
-    virtual bool getPixels(const SkImageInfo& info,
-                           void* pixels,
-                           size_t rowBytes) = 0;
+    bool getPixels(const SkImageInfo& info, void* pixels, size_t rowBytes,
+                   SkPMColor ctable[], int* ctableCount);
+
+    /**
+     *  Simplified version of getPixels() that asserts that info is NOT kIndex8_SkColorType.
+     */
+    bool getPixels(const SkImageInfo& info, void* pixels, size_t rowBytes);
+#endif
+
+protected:
+    virtual SkData* onRefEncodedData();
+    virtual bool onGetInfo(SkImageInfo* info);
+    virtual bool onGetPixels(const SkImageInfo& info,
+                             void* pixels, size_t rowBytes,
+                             SkPMColor ctable[], int* ctableCount);
 };
 
 #endif  // SkImageGenerator_DEFINED