/ by Matt
We’ve had a bit of a problem to solve over the last weeks, to do with texture painting on the Macs here. GIMP is one of the few open source image editors available on Mac OS X, and it works pretty well, but with one major issue - it doesn’t support tablet pressure sensitivity, which is vital for texture painting. GIMP is based on the GTK+ toolkit, which has not yet been ported to run on Mac OS X natively, so GIMP uses Apple’s open source implementation of X11, which does not pass tablet events through to applications.
We got in touch with some GIMP developers, who were quite helpful, giving us ideas of how to proceed, with a developer contact at Wacom sharing some hints as well. Unfortunately all the options (hacking GIMP, or X11, or paying a developer to work on a proper Mac OS X version of GTK+) were not very nice, leaving us without much luck. I then remembered a post on drunkenblog mentioning a little open source Mac application called Seashore.
Seashore takes the GIMP core and wraps it up in a lovely native Mac (Cocoa) user interface, and to our joy, it supports tablet sensitivity. It uses the GIMP native .XCF file format which is great - we can run both applications side by side, using Seashore for painting and if we need any extra filters or functionality that’s in GIMP, it’s just a quick save and reload away. Seashore is really early in development, and strangely enough the GIMP developers didn’t seem to know about it at all.
The code is in CVS at sourceforge, it seems pretty clean, and the filter/plug-in system seems pretty good too. There are a couple of other features that we’d like extended, such as having the tablet pressure affect size as well as opacity, which hasn’t been implemented yet. If there are any Cocoa-savvy programmers out here that would like to help us out in our mission to improve open source graphics software in production, here’s how you can get eternal fame, glory, and a warm fuzzy feeling inside :)