New API for encoding bitmaps during serialization.

src/core/SkOrderedWriteBuffer.cpp

 
 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkOrderedWriteBuffer.h"
 #include "SkBitmap.h"
 #include "SkData.h"
-#include "SkPixelRef.h"
 #include "SkPtrRecorder.h"
 #include "SkStream.h"
 #include "SkTypeface.h"
 
 SkOrderedWriteBuffer::SkOrderedWriteBuffer(size_t minSize)
     : INHERITED()
     , fFactorySet(NULL)
     , fNamedFactorySet(NULL)
     , fWriter(minSize)
     , fBitmapHeap(NULL)
@@ skipping 114 matching lines @@
     if (bytesWritten < length) {
         fWriter.reservePad(length - bytesWritten);
     }
     return bytesWritten;
 }
 
 bool SkOrderedWriteBuffer::writeToStream(SkWStream* stream) {
     return fWriter.writeToStream(stream);
 }
 
+// Defined in SkBitmap.cpp
+bool get_upper_left_from_offset(SkBitmap::Config config, size_t offset, size_t rowBytes,
+                            int32_t* x, int32_t* y);
+
 void SkOrderedWriteBuffer::writeBitmap(const SkBitmap& bitmap) {
     // Record the width and height. This way if readBitmap fails a dummy bitmap can be drawn at the
     // right size.
     this->writeInt(bitmap.width());
     this->writeInt(bitmap.height());
 
     // Record information about the bitmap in one of three ways, in order of priority:
     // 1. If there is an SkBitmapHeap, store it in the heap. The client can avoid serializing the
     //    bitmap entirely or serialize it later as desired. A boolean value of true will be written
     //    to the stream to signify that a heap was used.
-    // 2. Write an encoded version of the bitmap. After writing a boolean value of false, signifying
-    //    that a heap was not used, write the size of the encoded data. A non-zero size signifies
-    //    that encoded data was written.
-    //    A. If the bitmap has an encoded representation, write it to the stream.
-    //    B. If there is a function for encoding bitmaps, use it.
+    // 2. If there is a function for encoding bitmaps, use it to write an encoded version of the
+    //    bitmap. After writing a boolean value of false, signifying that a heap was not used, write
+    //    the size of the encoded data. A non-zero size signifies that encoded data was written.
     // 3. Call SkBitmap::flatten. After writing a boolean value of false, signifying that a heap was
     //    not used, write a zero to signify that the data was not encoded.
     bool useBitmapHeap = fBitmapHeap != NULL;
     // Write a bool: true if the SkBitmapHeap is to be used, in which case the reader must use an
     // SkBitmapHeapReader to read the SkBitmap. False if the bitmap was serialized another way.
     this->writeBool(useBitmapHeap);
     if (useBitmapHeap) {
         SkASSERT(NULL == fBitmapEncoder);
         int32_t slot = fBitmapHeap->insert(bitmap);
         fWriter.write32(slot);
         // crbug.com/155875
         // The generation ID is not required information. We write it to prevent collisions
         // in SkFlatDictionary.  It is possible to get a collision when a previously
         // unflattened (i.e. stale) instance of a similar flattenable is in the dictionary
         // and the instance currently being written is re-using the same slot from the
         // bitmap heap.
         fWriter.write32(bitmap.getGenerationID());
         return;
     }
-    bool encoded = false;
-    // Before attempting to encode the SkBitmap, check to see if there is already an encoded
-    // version.
-    SkPixelRef* ref = bitmap.pixelRef();
-    if (ref != NULL) {
-        SkAutoDataUnref data(ref->refEncodedData());
+    if (fBitmapEncoder != NULL) {
+        SkASSERT(NULL == fBitmapHeap);
+        size_t offset;
+        SkAutoDataUnref data(fBitmapEncoder(&offset, bitmap));
         if (data.get() != NULL) {
             // Write the length to indicate that the bitmap was encoded successfully, followed
-            // by the actual data. This must match the case where fBitmapEncoder is used so the
-            // reader need not know the difference.
+            // by the actual data.
             this->writeUInt(SkToU32(data->size()));
             fWriter.writePad(data->data(), data->size());
-            encoded = true;
+#ifdef BUMP_PICTURE_VERSION
+            // Recording this fixes https://code.google.com/p/skia/issues/detail?id=1301, but
+            // also requires bumping PICTURE_VERSION, so leaving out for now.
+            // Store the coordinate of the offset, rather than fPixelRefOffset, which may be
+            // different depending on the decoder.
+            int32_t x, y;
+            if (0 == offset || !get_upper_left_from_offset(bitmap.config(), offset,
+                                                           bitmap.rowBytes(), &x, &y)) {
+                x = y = 0;
+            }
+            this->write32(x);
+            this->write32(y);
+#endif
+            return;
         }
     }
-    if (fBitmapEncoder != NULL && !encoded) {
-        SkASSERT(NULL == fBitmapHeap);
-        SkDynamicMemoryWStream stream;
-        if (fBitmapEncoder(&stream, bitmap)) {
-            uint32_t offset = fWriter.bytesWritten();
-            // Write the length to indicate that the bitmap was encoded successfully, followed
-            // by the actual data. This must match the case where the original data is used so the
-            // reader need not know the difference.
-            size_t length = stream.getOffset();
-            this->writeUInt(SkToU32(length));
-            if (stream.read(fWriter.reservePad(length), 0, length)) {
-                encoded = true;
-            } else {
-                // Writing the stream failed, so go back to original state to store another way.
-                fWriter.rewindToOffset(offset);
-            }
-        }
-    }
-    if (!encoded) {
-        // Bitmap was not encoded. Record a zero, implying that the reader need not decode.
-        this->writeUInt(0);
-        bitmap.flatten(*this);
-    }
+    // Bitmap was not encoded. Record a zero, implying that the reader need not decode.
+    this->writeUInt(0);
+    bitmap.flatten(*this);
 }
 
 void SkOrderedWriteBuffer::writeTypeface(SkTypeface* obj) {
     if (NULL == obj || NULL == fTFSet) {
         fWriter.write32(0);
     } else {
         fWriter.write32(fTFSet->add(obj));
     }
 }
 
@@ skipping 89 matching lines @@
     // make room for the size of the flattened object
     (void)fWriter.reserve(sizeof(uint32_t));
     // record the current size, so we can subtract after the object writes.
     uint32_t offset = fWriter.size();
     // now flatten the object
     flattenObject(flattenable, *this);
     uint32_t objSize = fWriter.size() - offset;
     // record the obj's size
     *fWriter.peek32(offset - sizeof(uint32_t)) = objSize;
 }