Drawing in H2 and S2 before finessing with Ipe

Dear all,

If in addition to drawing figures in the Euclidean plane you also
sometime want to draw on the sphere or in the conformal model of the
hyperbolic plane, you may be interested in gfDraw.
http://www.dgp.toronto.edu/~ghali/software/gfdraw/index.html

gfDraw lets you draw points, lines, segments, polygons, and Bézier
curves, split polygons, and compute convex hulls and Delaunay
triangulations in H2, E2, and S2.

You can use gfDraw to generate the initial drawing in H2 or S2
before finessing with Ipe:
1- Press the 'PDF' button to produce a PDF file.
2- Use 'pdftoipe' to generate the Ipe file.
3- Finish editing using Ipe.

The main idea behind gfDraw is to develop geometric algorithms as only
generic recipes. One then plugs in a geometry to produce concrete
algorithms. gfDraw is currently supported on OS X and Qt 4.7.x-4.8.x.

I hope you like it. Please send your feedback.

Sherif