>I've taken a look and unfortunately there's no way I can use it. I need the >program to run under Win32 with as few dependencies as possible, and I cannot >translate a 100's lines long Bash program and one that makes many calls to >"convert" to something more Windows friendly. I'd rather use gimp-console >instead if that's all I can. > >> In IM, you can control the brightness using the -modulate function >> (as well as saturation and hue) and IM also has a -contrast function. >> (My script however, does not use either, but goes at it a more direct >> way by building a lookup table to adjust brightness and contrast) >> >> see http://www.imagemagick.org/script/command-line-options.php >> > >I find the relevant documentation confusing. > >I'd like a more specific answer please.
If you can, you can use my scripts under cygwin on Windows or under PHP exec. Otherwise, I am sorry I cannot help (other than to suggest you recommend to the IM folk to convert my script to am IM function). -modulate B,S,H or -modulate L,S,H allows you to adjust the Brightness/Lightness, Saturation and Hue (HSB or HSL colorspaces). 100 means no change. Increase or decrease it for brighter or darker. see http://www.imagemagick.org/Usage/color/#color_mods -contrast increase contrast some amount (unknown) and +contrast decrease the contrast (again unknown). That is all there is about it. But you can use -level and +level to adjust contrast, via a linear transformation. See http://www.imagemagick.org/Usage/color/#level and http://www.imagemagick.org/Usage/color/#level_plus or you can use -function polynomial "a,b" to create a linear transformation with a as slope and b as intercept. slope is like contrast and intercept is like brightness. see http://www.imagemagick.org/Usage/transform/#function_polynomial you can also use -evaluate add and also -evaluate multiply to do similar, but -function polynomial is better as it does it in one step and so avoids clipping between operations. see http://www.imagemagick.org/Usage/transform/#evaluate My bcimage script is similar to creating the linear transformation and then converting it to a lookup table so it can be used efficiently by -clut. But it is possible to do the calculations I have to set up the a and b coefficients and then just use -function polynomial. Fred _______________________________________________ Magick-users mailing list [email protected] http://studio.imagemagick.org/mailman/listinfo/magick-users
