dhyanb / open-imaging Goto Github PK

It looks like some gifs are being decoded incorrectly.
For example this gif from giphy - https://media.giphy.com/media/26DN81TqLPIzBlksw/giphy.gif
I got broken frames starting from 11-th frame:


Can you please take a look?

GifImage.getFrame(int) returns an internal representation of the animation.

This has two consequences:

• Internal state is exposed to the user, akin to returning arrays or modifiable collections or exporting public fields in the API. Very bad practice in general.
• There's no easy way to obtain the animation as a sequence of separate images.

This behavior is undocumented, and lead to a bug in my application, where I saw an animation of only the last frame.

Fortunately the API doesn't have to change in order to fix this, keeping backwards compatibility.

	public BufferedImage getFrame(int index) {
		if (img == null || index < prevIndex) { // (Re)Init
			img = new BufferedImage(width, height, 2); // 2 = ARGB
			prevImg = new BufferedImage(width, height, 2);
			prevIndex = -1;
			prevDisposal = 2;
		}
		// Draw current frame on top of previous frames
		for (int i = prevIndex + 1; i <= index; i++) {
			GifFrame fr = frames.get(i);
			drawFrame(fr);
			prevIndex = i;
			prevDisposal = fr.disposalMethod;
		}

		BufferedImage copy = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
		Graphics      g    = copy.createGraphics();
		try {
			g.drawImage(img, 0, 0, null);
		} finally {
			g.dispose();
		}
		return copy;
	}

hi，jdk8 support? I see readme only support jdk1.7

While debugging some gifs that even Paint Shop Pro fails to render (but Windows, Firefox and Microsoft GIF Animator do read correctly) I found all of them had no clear code as the first code in each frame.

Removing line 202 fixed it.

bits.read(); // Skip leading clear code

However this breaks all other GIFs because now their clear code is interpreted as a color code. Need to investigate.