boite_a_spam@club-internet.fr (2004-04-04 at 1212.03 -0400):

I would like to create an "electrical switch" out of a given rectangle[1]. The perspective transform tool only allows a rectangle to be transformed into a quadrilateral, so I can get the following "approximations" ([2], [3] and [4]), but it would be nice in that case to be able to have the round shape that I have in mind (and that I hope you guessed :o). Any tricks to do that?

The simplest, get a 3d app to do it. :]

In GIMP you can use map object filter, with cylinder shape, or curve bend to get the round profile. In both cases I think you will have to retouch with perspective tool, so the straight edges are not parallel. If you think it is too complex to do it directly, start with the button flat, distort it to get -_- and when done rotate it to get the _-^ shape.

Another way I can think of is polar coords filter, but that one requires steps in a separate image. You should use a really big square image as discardable work place, and paint the final result roughly and near the bottom, then convert in reverse (to polar option off), and see where you get a rectangle or square. Place a copy your good version there, and convert forward (to polar on) and cut the result to paste it back in your normal image. This temp image has to be really big to hide imperfections of polar coords filter (scale down the area to cut).

GSR