[Qt][Texmap] All layers with backingStore are opaque when using TextureMapperGL.

[Dongseong Hwang]

The bug originated from StillImage that is not override
Image::currentFrameHasAlpha(), so it always returns false.
StillImage is used by ImageBuffer, and if Texmap draws contents on ImageBuffer,
TextureMapperBackingStore thinks contents does not have alpha.

[Dongseong Hwang]

Created attachment 146690 [details]
patch v.1

[Dongseong Hwang]

Following code causes this bug.

void TextureMapperLayer::updateBackingStore(TextureMapper* textureMapper, GraphicsLayerTextureMapper* layer)
{
    ...
    // Paint the entire dirty rect into an image buffer. This ensures we only paint once.
    OwnPtr<ImageBuffer> imageBuffer = ImageBuffer::create(dirtyRect.size());
    ...
    RefPtr<Image> image = imageBuffer->copyImage(DontCopyBackingStore);
    TextureMapperTiledBackingStore* backingStore = static_cast<TextureMapperTiledBackingStore*>(m_backingStore.get());
    backingStore->updateContents(textureMapper, image.get(), m_size, dirtyRect);
    ...
}

void TextureMapperTiledBackingStore::updateContents(TextureMapper* textureMapper, Image* image, const FloatSize& totalSize, const IntRect& dirtyRect)
{
    createOrDestroyTilesIfNeeded(totalSize, textureMapper->maxTextureSize(), image->currentFrameHasAlpha());
    for (size_t i = 0; i < m_tiles.size(); ++i)
        m_tiles[i].updateContents(textureMapper, image, dirtyRect);
}

[WebKit Review Bot]

Comment on attachment 146690 [details]
patch v.1

Clearing flags on attachment: 146690

Committed r119908: <http://trac.webkit.org/changeset/119908>

[WebKit Review Bot]

All reviewed patches have been landed.  Closing bug.