Scanline decoding for bmp

src/codec/SkBmpCodec.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef SkBmpCodec_DEFINED
 #define SkBmpCodec_DEFINED
 
 #include "SkCodec.h"
 #include "SkColorTable.h"
 #include "SkImageInfo.h"
 #include "SkMaskSwizzler.h"
+#include "SkScanlineDecoder.h"
 #include "SkStream.h"
 #include "SkSwizzler.h"
 #include "SkTypes.h"
 
 /*
  * This class enables code sharing between its bmp codec subclasses.  The
  * subclasses actually do the work.
  */
 class SkBmpCodec : public SkCodec {
 public:
 
     /*
      * Describes if rows of the input start at the top or bottom of the image
      */
     enum RowOrder {
         kTopDown_RowOrder,
         kBottomUp_RowOrder
     };
 
     /*
+     * Used to define the input format of the bmp
+     */
+    enum BmpInputFormat {
+        kStandard_BmpInputFormat,
+        kRLE_BmpInputFormat,
+        kBitMask_BmpInputFormat,
+        kUnknown_BmpInputFormat
+    };
+
+    /*
      * Checks the start of the stream to see if the image is a bmp
      */
     static bool IsBmp(SkStream*);
 
     /*
      * Assumes IsBmp was called and returned true
      * Creates a bmp decoder
      * Reads enough of the stream to determine the image format
      */
     static SkCodec* NewFromStream(SkStream*);
 
     /*
      * Creates a bmp decoder for a bmp embedded in ico
      * Reads enough of the stream to determine the image format
      */
     static SkCodec* NewFromIco(SkStream*);
 
+    /*
+     * Assumes IsBmp was called and returned true
+     * Creates a bmp scanline decoder
+     * Takes ownership of the stream
+     */
+    static SkScanlineDecoder* NewSDFromStream(SkStream* stream);
+
 protected:
 
-    SkBmpCodec(const SkImageInfo& info, SkStream* stream, uint16_t bitsPerPixel,
-            RowOrder rowOrder);
+    SkBmpCodec(const SkImageInfo& info, SkStream* stream, BmpInputFormat inputFormat,
+            uint16_t bitsPerPixel, RowOrder rowOrder);
 
     SkEncodedFormat onGetEncodedFormat() const override { return kBMP_SkEncodedFormat; }
 
     /*
      * Read enough of the stream to initialize the SkBmpCodec. Returns a bool
      * representing success or failure. If it returned true, and codecOut was
      * not NULL, it will be set to a new SkBmpCodec.
      * Does *not* take ownership of the passed in SkStream.
      */
     static bool ReadHeader(SkStream*, bool inIco, SkCodec** codecOut);
@@ skipping 32 matching lines @@
     RowOrder rowOrder() const { return fRowOrder; }
 
 private:
 
     /*
      * Creates a bmp decoder
      * Reads enough of the stream to determine the image format
      */
     static SkCodec* NewFromStream(SkStream*, bool inIco);
 
-    const uint16_t fBitsPerPixel;
-    const RowOrder fRowOrder;
+    const BmpInputFormat fInputFormat;
+    const uint16_t       fBitsPerPixel;
+    const RowOrder       fRowOrder;
 
     typedef SkCodec INHERITED;
 };
 
 #endif