Index:
ppm2rgba
rgba2ppm
rgbaadd
rgbaaddB
rgbaautocrop
rgbadither
rgbafade
rgbamerge
rgbamergeB
rgbaquant
rgbascale
rgbascaleB
rgbascaleF
rgbasub
rgbasubB
rgbatrans

the RGBA32 manual and style guide: rgbaautocrop

Command line:

rgbaautocrop [inputfile]

Usage:

Rgbaautocrop can take input either from stdin or from a file specified on the command line. If a filename appears on the command line, stdin will not be checked for input. Output is directed to stdout and errors to stderr.

Rgbaautocrop will check the RGB value of the first pixel in the image, then shrink the edges of the image such that the left, right, upper and lower edges all contain at least one pixel whose color differs from the comparison pixel.

Examples:

Note that the images as shown in the browser are GIFs; the actual rgba output is converted to GIF such that the browser can display it. Warning; Web browsers running on less than a 16 bit display (less than 65K colors) will almost certainly substitute colors wildly and/or dither the below images. This will degrade the image quality considerably.

"rgbaautocrop text.rgba"
text.rgba rgbaautocrop text.rgba stdout