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ppmchange !!!ppmchange NAME SYNOPSIS DESCRIPTION OPTIONS SEE ALSO AUTHOR ---- !!NAME ppmchange - change all pixels of one color to another in a portable pixmap !!SYNOPSIS __ppmchange__ [[ __-closeness__ ''closeness_percent'' ] [[ __-remainder__ ''remainder_color'' ] [[ ''oldcolor newcolor'' ] ... [[''ppmfile''] !!DESCRIPTION Reads a portable pixmap as input. Changes all pixels of ''oldcolor'' to ''newcolor''. You may specify up to 256 oldcolor/newcolor pairs on the command line. __ppmchange__ leaves all colors not mentioned unchanged, unless you specify the __-remainder__ option, in which case they are all changed to the single specified color. You can specify that colors similar, but not identical, to the ones you specify get replaced by specifying a The colors can be specified in five ways: o A name, assuming that a pointer to an X11-style color names file was compiled in. o An X11-style hexadecimal specifier: rgb:r/g/b, where r g and b are each 1- to 4-digit hexadecimal numbers. o An X11-style decimal specifier: rgbi:r/g/b, where r g and b are floating point numbers between 0 and 1. o For backwards compatibility, an old-X11-style hexadecimal number: #rgb, #rrggbb, #rrrgggbbb, or #rrrrggggbbbb. o For backwards compatibility, a triplet of numbers separated by commas: r,g,b, where r g and b are floating point numbers between 0 and 1. (This style was added before MIT came up with the similar rgbi style.) If a pixel matches two different ''oldcolor''s, __ppmchange__ replaces it with the ''newcolor'' of the leftmost specified one. !!OPTIONS __-closeness__ ''closeness_percent'' ''closeness'' is an integer per centage indicating how close to the color you specified a pixel must be to get replaced. By default, it is 0, which means the pixel must be the exact color you specified. A pixel gets replaced if the distance in color between it and the color you specified is less than or equal to ''closeness''. The This is probably simpler than what you want most the time. You probably would like to change colors that have similar chrominance, regardless of their intensity. So if there's a red barn that is variously shadowed, you want the entire barn changed. But because the shadowing significantly changes the color according to __ppmchange__'s distance formula, parts of the barn are probably about as distant in color from other parts of the barn as they are from green grass next to the barn. Maybe __ppmchange__ will be enhanced some day to do chrominance analysis. __-remainder__ ''color'' __ppmchange__ changes all pixels which are not of a color for which you specify an explicit replacement color on the command line to color ''color''. An example application of this is __ppmchange -remainder=black red red__ to lift only the red portions from an image, or __ppmchange -remainder=black red white | ppmtopgm__ to create a mask file for the red portions of the image. !!SEE ALSO pgmtoppm(1), ppmcolormask(1), ppm(5) !!AUTHOR Wilson H. Bent. Jr. (whb@usc.edu) with modifications by Alberto Accomazzi (alberto@cfa.harvard.edu) ----
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ppmchange(1)
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pbmfilters(1)
pbmtext(1)
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Man1p
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