Anthony Thyssen scripsit: > Mikolaj Machowski on wrote... >| Hello, >| >| How to simulate Curves tool from GUI programs? >| >| I suppose there is some smart meddling with fx option but I would be >| grateful for any hints. >| > Yes and with the help of an external script (which uses gnuplot > underneath), > http://www.imagemagick.org/Usage/scripts/im_fx_curves
Thanks but something doesn't work. I tried to use it as explained to get line going through 10,0 and 90,100 points but in with -d option I get line going through 0,50 and 50,100 with output: 1,000*u+0,000 >| Specifically I am interested in effects like described here: >| >| http://www.outbackphoto.com/workflow/wf_81/essay.html >| > > That is not a 'curve' but a linear change. Though not a typical one as > you are doing a contrast change rather than a color limit change. > > However given the two points the curves technique will still give you > the linear equation for the adjustment. > > At this time there is no IM contrast option with specific arguments to > control the contrast adjustment. There are some automatic ones simular > to normalize, but no non-normalizing linear contrasting functions. > > The closest would be a curved contrast adjustment known as > -sigmodial-contrast. Somewhere is typo: in my docs distributed with IM 6.3.0-3 in docs is option called "sigmoidal-contrast". Also this whole trick is to *avoid* contrast change. As explained in tutorial operating on HSB changes contrast, but in L*a*b* it doesn't happen. m. _______________________________________________ Magick-users mailing list [email protected] http://studio.imagemagick.org/mailman/listinfo/magick-users
