From: Andre Wobst <wobsta@us...>  20040728 06:23:26

Hi, On 27.07.04, Magnus Lie Hetland wrote: > So, here is a version which uses André's linear equation stuff > (although I've switched to numarray  it's what I use; and numarray > 1.0 is out now, so... Hooray for that :). Hey, isn't that something for tryimportexcept? No isinstance available ... ;) > So, presto, we've got a bidirectional thingy. Note that the angle in > the transform is still a constant, though. As André pointed out, if > the angle is to be a variable, we'd end up getting equations with > sin() and cos(), and that's not exactly pleasant. Well, I have to look at MetaPost at some point. Don't we really want to create a transformation by setting 3 2d input and output points? This is a linear problem. How is it in MetaPost? Is it allowed to define write P = t*p where the points P and p are not defined as well as t is not defined? What does MetaPost with such an equation? Does it store it for later evaluation (for example until p and P becomes known)? And what about having several transformations: P = t2*t1*p? And what about restricting a transformation to a rotation, for example? I should take a look at MetaPost/MetaFont at some point. André  by _ _ _ Dr. André Wobst / \ \ / ) wobsta@..., http://www.wobsta.de/ / _ \ \/\/ / PyX  High quality PostScript figures with Python & TeX (_/ \_)_/\_/ visit http://pyx.sourceforge.net/ 