Zoom GUI in fltk backend

[John W. Eaton]

On 23-Jul-2009, Shai Ayal wrote:

| I attach a changeset incorporating Soren's and my precious patch. It
| implements the following behavior for the fltk backend:
| Keyboard Shortcuts (operate on the current axes):
| a - autoscale
| g - toggle grid
| 
| Mouse (operate on the axes below the mouse pointer)
| left drag - pan
| mouse wheel - zoom
| right drag - rectangle zoom
| left double click - autoscale
| 
| It laso chages the help buttons label from "H" to "?" which might help
| people realize what it is.
| Hopefully this compromise will satisfy all (Probably, as compromises
| go, it'll just annoy everyone). Maybe in the future there will be some
| mechanism to customize the backend, so everyone can be happy

The rectangle zoom doesn't seem to work for me.  Instead of zooming,
clicking and dragging the right mouse button draws a series of
rectangles which don't go away when the mouse button is released, and
no zoom occurs (see the attached screenshot).  I assume it works for
you, so do you have any clues about how to debug this problem?  I'm
using libfltk1.1-dev (v 1.1.9-6) on a Debian AMD64 system.  Does
anyone else see this problem?

I checked it in anyway, since the other features work, and I'm not
sure whether this is a library problem, or some other problem.

Thanks,

jwe