spriterotator

Non-destructive sprite rotator

Rotates sprites in a non-destructive manner using the three shears method: https://cohost.org/tomforsyth/post/891823-rotation-with-three

Since the rotation is performed with point sampled shears, every frame of the animation contains all the original pixels, just in a different configuration.

The tool takes in image files (most common formats supported) and the number of desired output frames.

The tool outputs separate .png frames as well as a .gif animation preview.

Options:

• -f output frames
• -s output safe frame
• -g output preview gif animation
• -i output intermediary files

Frames are what you most likely want eventually.

Safe frame shows which pixels are retained when rotating. The safe frame depends on the resolution and number of desired steps.

Gif animation is handy to see how the rotation works for your input file without having to parse lots of single frame images.

Intermediary files show how the shears look like, and may be useful for debugging.