On 10/4/07, Ted Drain <ted...@jp...> wrote: > John, > I think that the problem isn't doing the inversion - it's keeping > it. Calling set_xlim() to invert is fine - but it never seems to > stay that way. There is a lot of code (resizing, autoscaling, > labelling, etc) that has a tendency to flip the axis back to it's > 'un-inverted' state. The idea behind having a flag on the axis > itself is so that other code can check that easily to see what the > state of the axis is. > > We do a lot of plots that require an inverted axis and we've had tons > of problems keeping the axis inverted (which is where the idea for > the flag came from). It seems like people forget that this is > possible and add code that assumes that xmin < xmax which then ends > up flipping the axis back to it's "normal" state (this happens in the > aspect ratio code for example). I see -- I missed James' original email describing the motivation for this flag because it was in spam quarantine (I think he posted from a non-subscribed address). As I was just clearing out the spam, I noticed it, and now better understand what you are trying to do. It seems like a reasonable use case. If I am reading this right, there is no way to support this kind of behavior *and* not break existing code. If we want to go this route, I don't mind breaking existing code as long as we do it cleanly. Eg, I think xmin and xmax should always be in order (calls to set_xlim(xmax, xmin) would raise a helpful exception like "call ax.invert_xaxis instead") and we would need to make sure that the viewlim are still reversed per Michael's request. And we would need a clean way to toggle back. In this view: ax.xaxis_invert() # turns inversion on and off ax.get_xlim() # always returns xmin, xmax ax.set_xlim(blah) # requires xmin<xmax and viewlim behave as before. This would also satisfy Eric's point that xmin and xmax are poorly named. The one thing I find potentially confusing about Jame's original post is that set_xlim can be out of order (xmin>xmax) while get_xlim always returns ordered values. For the record, I almost never use inverted axes so we should hear more from those who do.... JDH