Re: Zooming in Object Graphics

["Mark Hadfield" <m.hadfield(at)niwa.cri.nz>]

"David Fanning" <davidf@dfanning.com> wrote in message
MPG.14aab41f9ee42b1c989cc6@news.frii.com">news:MPG.14aab41f9ee42b1c989cc6@news.frii.com...
> Well, I'm not convinched. But, Im' shure sober Mark
> Hatfield alreaady hash somethin like thish already...

"sober Mark Hatfield"? What!?

As a matter of fact, I am sober. It's 10 am here & I haven't had time to
drink any egg nog yet. Egg nog isn't all that appealing in the middle of
summer anyway.

Yeah I do have something like thish, it's called an MGH_Plot.

The basic idea is that when the user selects a new data range in the X
direction, the X axes are recalculated so that they span the new data range,
but with no change in the normalised range. This requires a change in
XCOORD_CONV and this new value is passed on to all the atoms that are
associated with that X axis. Pretty much what you said, David (before the
egg nog) and there's no changing the viewplane rectangle.

It's just a prejudice of mine, but I like to keep the viewplane rectangle
dimensions close to 2 x 2 and also try to ensure that a square in normalised
coordinates on the viewplane is square on the window or printer page.

Those who have looked at any of my code will not be surprised to hear that
MGH_Plot calls on a whole heap of other classes in my object library and
there's some really neat stuff in there with "master-slave" relationships
between the axes and atoms that I won't explain because I've forgotten how
it works. But if you want to take a look go to:

http://katipo.niwa.cri.nz/~hadfield/gust/software/idl/

This URL looks a bit odd right now because the sysadmin fiddled with the
Apache settings.

---
Mark Hadfield
m.hadfield@niwa.cri.nz  http://katipo.niwa.cri.nz/~hadfield/
National Institute for Water and Atmospheric Research
PO Box 14-901, Wellington, New Zealand