Method writeBitmap

third-part/skia/src/core/SkWriteBuffer.cpp:154–211

}

void SkWriteBuffer::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. 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;
    }

    // see if the pixelref already has an encoded version
    if (bitmap.pixelRef()) {
        SkAutoDataUnref data(bitmap.pixelRef()->refEncodedData());
        if (data.get() != NULL) {
            write_encoded_bitmap(this, data, bitmap.pixelRefOrigin());
            return;
        }
    }

    // see if the caller wants to manually encode
    if (fBitmapEncoder != NULL) {
        SkASSERT(NULL == fBitmapHeap);
        size_t offset = 0;  // this parameter is deprecated/ignored
        // if we have to "encode" the bitmap, then we assume there is no
        // offset to share, since we are effectively creating a new pixelref
        SkAutoDataUnref data(fBitmapEncoder(&offset, bitmap));
        if (data.get() != NULL) {
            write_encoded_bitmap(this, data, SkIPoint::Make(0, 0));
            return;
        }
    }

    this->writeUInt(0); // signal raw pixels
    SkBitmap::WriteRawPixels(this, bitmap);
}