Do JPEG tile-based decoding.

Change-Id: I795129d55a0a7da90b4d604a902066868933d2a9

3 files changed, 87 insertions, 2 deletions

diff --git a/include/images/SkImageDecoder.h b/include/images/SkImageDecoder.h
index f8a941f..be1046b 100644
--- a/include/images/SkImageDecoder.h
+++ b/include/images/SkImageDecoder.h
@@ -18,10 +18,17 @@
 #define SkImageDecoder_DEFINED
 
 #include "SkBitmap.h"
+#include "SkRect.h"
 #include "SkRefCnt.h"
 
 class SkStream;
 
+class SkVMMemoryReporter : public SkRefCnt {
+public:
+    virtual ~SkVMMemoryReporter() {}
+    virtual bool reportMemory(size_t memorySize);
+};
+
 /** \class SkImageDecoder
 
     Base class for decoding compressed images into a SkBitmap
@@ -30,6 +37,7 @@ class SkImageDecoder {
 public:
     virtual ~SkImageDecoder();
 
+    // Should be consistent with kFormatName
     enum Format {
         kUnknown_Format,
         kBMP_Format,
@@ -42,10 +50,21 @@ public:
         kLastKnownFormat = kWBMP_Format
     };
 
+    /** Contains the image format name.
+     *  This should be consistent with Format.
+     *
+     *  The format name gives a more meaningful error message than enum.
+     */
+    static const char *kFormatName[7];
+
     /** Return the compressed data's format (see Format enum)
     */
     virtual Format getFormat() const;
 
+    /** Return the compressed data's format name.
+    */
+    const char* getFormatName() const { return kFormatName[getFormat()]; }
+
     /** Returns true if the decoder should try to dither the resulting image.
         The default setting is true.
     */
@@ -118,6 +137,7 @@ public:
 
     SkBitmap::Allocator* getAllocator() const { return fAllocator; }
     SkBitmap::Allocator* setAllocator(SkBitmap::Allocator*);
+    SkVMMemoryReporter* setReporter(SkVMMemoryReporter*);
 
     // sample-size, if set to > 1, tells the decoder to return a smaller than
     // original bitmap, sampling 1 pixel for every size pixels. e.g. if sample
@@ -176,6 +196,29 @@ public:
         return this->decode(stream, bitmap, SkBitmap::kNo_Config, mode);
     }
 
+    /**
+     * Given a stream, build an index for doing tile-based decode.
+     * The built index will be saved in the decoder, and the image size will
+     * be returned in width and height.
+     *
+     * Return true for success or false on failure.
+     */
+    virtual bool buildTileIndex(SkStream*,
+                                int *width, int *height, bool isShareable) {
+        return false;
+    }
+
+    /**
+     * Decode a rectangle region in the image specified by rect.
+     * The method can only be called after buildTileIndex().
+     *
+     * Return true for success.
+     * Return false if the index is never built or failing in decoding.
+     */
+    virtual bool decodeRegion(SkBitmap* bitmap, SkIRect rect,
+                              SkBitmap::Config pref);
+
+
     /** Given a stream, this will try to find an appropriate decoder object.
         If none is found, the method returns NULL.
     */
@@ -264,6 +307,11 @@ protected:
     // must be overridden in subclasses. This guy is called by decode(...)
     virtual bool onDecode(SkStream*, SkBitmap* bitmap, Mode) = 0;
 
+    // must be overridden in subclasses. This guy is called by decodeRegion(...)
+    virtual bool onDecodeRegion(SkBitmap* bitmap, SkIRect rect) {
+        return false;
+    }
+
     /** Can be queried from within onDecode, to see if the user (possibly in
         a different thread) has requested the decode to cancel. If this returns
         true, your onDecode() should stop and return false.
@@ -304,6 +352,8 @@ protected:
      */
     SkBitmap::Config getPrefConfig(SrcDepth, bool hasAlpha) const;
 
+    SkVMMemoryReporter*      fReporter;
+
 private:
     Peeker*                 fPeeker;
     Chooser*                fChooser;
diff --git a/include/images/SkJpegUtility.h b/include/images/SkJpegUtility.h
index cc9d246..5dd789c 100644
--- a/include/images/SkJpegUtility.h
+++ b/include/images/SkJpegUtility.h
@@ -41,11 +41,13 @@ void skjpeg_error_exit(j_common_ptr cinfo);
 /* Our source struct for directing jpeg to our stream object.
 */
 struct skjpeg_source_mgr : jpeg_source_mgr {
-    skjpeg_source_mgr(SkStream* stream, SkImageDecoder* decoder);
+    skjpeg_source_mgr(SkStream* stream, SkImageDecoder* decoder, bool copyStream, bool ownStream);
+    ~skjpeg_source_mgr();
 
     SkStream*   fStream;
-    const void* fMemoryBase;
+    void*       fMemoryBase;
     size_t      fMemoryBaseSize;
+    bool        fUnrefStream;
     SkImageDecoder* fDecoder;
     enum {
         kBufferSize = 1024
diff --git a/include/images/SkLargeBitmap.h b/include/images/SkLargeBitmap.h
new file mode 100644
index 0000000..0d19f32
--- /dev/null
+++ b/include/images/SkLargeBitmap.h
@@ -0,0 +1,33 @@
+#ifndef SkLargeBitmap_DEFINED
+#define SkLargeBitmap_DEFINED
+
+#include "SkBitmap.h"
+#include "SkRect.h"
+#include "SkImageDecoder.h"
+
+class SkLargeBitmap {
+public:
+    SkLargeBitmap(SkImageDecoder *decoder, int width, int height) {
+        fDecoder = decoder;
+        fWidth = width;
+        fHeight = height;
+    }
+    virtual ~SkLargeBitmap() {
+        delete fDecoder;
+    }
+
+    virtual bool decodeRegion(SkBitmap* bitmap, SkIRect rect,
+                              SkBitmap::Config pref, int sampleSize);
+
+    virtual int getWidth() { return fWidth; }
+    virtual int getHeight() { return fHeight; }
+
+    virtual SkImageDecoder* getDecoder() { return fDecoder; }
+
+private:
+    SkImageDecoder *fDecoder;
+    int fWidth;
+    int fHeight;
+};
+
+#endif