On Sun, Oct 03, 2010 at 09:32:13PM +0200, Thorsten Wilms wrote:
A solution could be to put this functionality into a tool/effect. You choose the Wallpaper group, then you create the base tile area that will have the right shape (similar to rectangle/star/polygon tools). There could be automatic selection of geometry covered by the base tile area. If you start with a selection, the base tile area could be created centered on it, automatically.
It's worth noting that the number of sensible parameters varies a lot for the different groups.
Types P1 and P2 can work with any parallelogram (which is currently pretty awkward in the Inkscape interface).
Types PM, PG, CM, PMM, PMG, PGG, and CMM all based on a rectangle-like structure, although the base tile area is sometimes a little different.
Types P4, P4m, and P4g are based on a square structure. The base tile is best thought of as a 45-45-90 right triangle.
Types P6, P6m, P3, P3m1, and P31m are based on an equilateral triangle; the base tile is either an equilateral triangle or a 30-60-90 right triangle (depending on the type).
For a usable interface, you should probably be able to directly manipulate the base tile in the view window. An interface with handles wouldn't be hard, of course; but you have to give the appropriate number of handles, which varies depending on the type.
A further generalization that's worth including is incorporating scale and more general rotations. For the types that have at least one fixed direction (P1, PG, CM, PM) you can pick a center of the symmetry and have extra scalings and rotations around that center. This is easiest to understand in the case of frieze groups: You can wrap a frieze pattern around a circle in a natural way. This would generalize the present star tool.
--Dylan