How to save GIF frames into BufferedImage with TYPE_BYTE_INDEXED?

Question

Hi All,
I have a code that saves every animated GIF frame into BufferedImage of TYPE_INT_ARGB. So an animated GIF will correspond to a list of images with 32-bit pixel size.
I mainly refer to the code in
http://forum.java.sun.com/thread.jspa?forumID=20&threadID=629277
But what I need to do now is to store each frame into TYPE_BYTE_INDEXED image instead. What I'm doing is I get the IndexColorModel from the first frame, and that color model will be shared for all frames.
As for the frames, I've been trying several ways:
*1.* read it per usual into 32-bit pixel size image
sourceImage        = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
RenderedImage renderedImg = reader.readAsRenderedImage(index, null);*reader is the ImageReader for the GIF file.
then trying to convert the image into 8-bit pixel size by creating new destination image
BufferedImage destImage = new BufferedImage(width, height, BufferedImage.TYPE_BYTE_INDEXED, ICM);and then draw the original (32-bit pixel size) onto the newly created image.
Graphics2D g = destImage.createGraphics();
g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC));
g.drawImage(sourceImage, imageLeft, imageTop, null);*2.* read it as:
BufferedImage sourceImage = reader.read(index);then create new 8-bit image and draw the source onto it as No. 1.
The problem is, for No. 1 , the destination image always lose its transparency. And No. 2 only works well with some GIFs. But mostly the destination image will lose the transparency as well.
I hope someone more familiar with java imaging can help point out to me where did I do wrong...
I'm thinking maybe the way I draw the source onto the destination. Or maybe there's another way of getting GIF frames into TYPE_BYTE_INDEXED images..
Thank you in advanced :)
Edited by: irma_k on Dec 12, 2007 8:42 PM

Answer 1

I found that java has weird issues with GIF's (ImageIO wont even write transparency to GIFs when writing to a file).
But PNGs seemed to work a lot better. Not sure if it will fix your problem, as I don't know all that much about java imaging, but using PNGs seemed to work a lot better for me when I needed to draw transparency.