ppmcolormask
Create bitmap mask from color selection
TLDR
Create mask for color
$ ppmcolormask [color] [input.ppm] > [mask.pbm]
Mask for red$ ppmcolormask red [input.ppm] > [mask.pbm]
Mask for hex color$ ppmcolormask "#ff0000" [input.ppm] > [mask.pbm]
Mask for RGB value$ ppmcolormask "rgb:ff/00/00" [input.ppm] > [mask.pbm]
SYNOPSIS
ppmcolormask color [ppmfile]
DESCRIPTION
ppmcolormask creates a bitmap mask from a PPM image where matching pixels are white (1) and non-matching are black (0). Useful for selecting regions by color.
Part of Netpbm toolkit.
PARAMETERS
color
Target color (name, hex, or rgb format).
EXAMPLES
$ # Mask white pixels
ppmcolormask white image.ppm > white_mask.pbm
# Mask specific color
ppmcolormask "#00ff00" image.ppm > green_mask.pbm
# Use mask to replace color
ppmcolormask blue original.ppm > mask.pbm
pnmpaste replacement.ppm 0 0 original.ppm -and mask.pbm > result.ppm
# Chain with conversion
jpegtopnm photo.jpg | ppmcolormask red | pnmtopng > red_mask.png
ppmcolormask white image.ppm > white_mask.pbm
# Mask specific color
ppmcolormask "#00ff00" image.ppm > green_mask.pbm
# Use mask to replace color
ppmcolormask blue original.ppm > mask.pbm
pnmpaste replacement.ppm 0 0 original.ppm -and mask.pbm > result.ppm
# Chain with conversion
jpegtopnm photo.jpg | ppmcolormask red | pnmtopng > red_mask.png
COLOR FORMATS
$ Named: red, green, blue, white, black...
Hex: #rrggbb or #rgb
RGB: rgb:rr/gg/bb
Hex: #rrggbb or #rgb
RGB: rgb:rr/gg/bb
CAVEATS
Exact color match only. For range matching, use pamfunc or similar. Output is PBM bitmap.
HISTORY
ppmcolormask is part of Netpbm by Jef Poskanzer, providing color-based masking functionality.
SEE ALSO
pammasksharpen(1), pnmcomp(1), pgmtopbm(1), netpbm(1)