Showing posts with label Image Scaling. Show all posts
Showing posts with label Image Scaling. Show all posts

Wednesday, October 24, 2007

How to prevent gifs from rendering grainy using .Net GDI

I recently built a Http Handler for an Asp.net application that needed to generate image thumbnails from different image types on the fly. Sounds easy enough, right?

Well it was a simple task until I tried to generate a thumbnail from a gif. After hours and hours trying to figure out how to improve the resolution I found a great article addressing this particular issue.

The key to this conundrum you ask? Color quantization.

Unfortunately System.Drawing uses a web-safe palette even though just about every gif you've ever seen uses an adaptive palette.

The result:

After implementing Brendan Tompkins Octree-based quantization technique...