by DST » Wed Apr 23, 2008 2:23 pm
Yes reusing improper sprite sheets can be a real pain. What you need is a graphics editor that can use Guidelines and snap to them.
Here's how to do it in Gimp:
1. Open the spritesheet. Create a new transparent layer.
2. Use the color selection tool to select the background. Then choose select>inverse.
3. Copy that to the new layer. Delete the original layer.
4. Drag guides by clicking and dragging the rulers at the edge of the image. Position them in a nice grid.
5. Using the rectangle selection or lasso tool, select an individual sprite. With the same tool, drag that sprite to its new location matching the guides. Do this for every sprite until its all aligned.
6. Make sure that the distance between the edge sprites and the edge of the image is exactly 1/2 the size of the distance between sprites (from sprite center to sprite center).
7. Save the file as a png and then you're done.
This may sound complicated but do it a couple of times and it'll be cake!
Another nice thing about using spritesheets (i'm starting to use them for everything) is that it makes it very easy to palleteswap your characters.