On 5/8/07, Mark Probst <mark.probst@xxxxxxxxx> wrote: > Hi! > > I'm trying to implement a B/W processing application using Gegl, > similar to my B/W Photoshop workflow: > > http://schani.wordpress.com/2006/05/23/my-digital-bw-workflow/ > > There are several operations that I need which, as far as I can tell > (I'm completely new to Gegl), are not supported, directly or > indirectly: > > * Channel Mixer. What it does is it generates a B/W image out of a > color image by calculating a weighted sum of the color channels. There is no real equivalent to a Channel Mixer operation at the moment. > * Gradient curves. I want to give the user a curve control to modify > the contrast of the image, like the "Curve" filter in GIMP/Photoshop. There is no curves control either, the closest would be levels. Both of these are point operations and would live in the gegl/operations/color/ dir. The Channel Mixer is probably the one that would be easiest to implement. For a curves operation the main issue is how to pass the curve to the operation, there currently is no operations in GEGL that take an array of values as a parameter; thus you should probably bypass the gegl-chant mechanisms and write all the needed boilerplate yourself gegl/color/remap.c is an example of one operation that does this for other reasons. When it comes to how an array of values are best expressed, there probably are some examples in GIMP plug-ins. /Øyvind K. -- «The future is already here. It's just not very evenly distributed» -- William Gibson http://pippin.gimp.org/ http://ffii.org/ _______________________________________________ Gegl-developer mailing list Gegl-developer@xxxxxxxxxxxxxxxxxxxxxx https://lists.XCF.Berkeley.EDU/mailman/listinfo/gegl-developer
