[Ipe-discuss] Isometric circles in IPE

[Otfried Cheong]

On 06/01/2011 02:15 AM, Villads wrote:
> Thank you for a very nice editor! Does anybody knows of a good way to
> draw isometric circles in IPE? The easiest way would be if one could
> just draw a circle inside a square an then transform the square and
> circle into its isometric equivalent, but as far as I can find out, the
> stretch-function only does stretching in one direction at a time?

An isometric transformation of a circle is still a circle - I guess you 
mean affine transformations?  So the question is really on what is the 
best way to draw ellipses, and I agree that I haven't really found the 
best way yet.

The normal way is to draw a circle, then stretch it, and finally rotate 
it. Stretch does stretch in both directions at the same time, but only 
axis-parallel - such a restriction is unavoidable as the mouse has only 
two degrees of freedom.

However, sometimes this is not the best way to draw an ellipse, but I 
know no better general interface.  It would be nice to have a tool that 
takes the two foci and a third point, but that is still often not the 
right approach.

Cheers,
  Otfried