New zoom functions (was: Re: [GRASS5] The status of 5.0)

[Carl Worth]

On Mar 25, Helena Mitasova wrote:
 
 > Just as a small example from my own experience: I really hated the
 > new d.zoom (because I cannot tell left from right and I aways
 > clicked the wrong button). However, just recently I had to use some
 > old version of GRASS with the old d.zoom.  Well, enough to say, I
 > don't hate the new d.zoom anymore. What a tedious work it was to do
 > zooming in old versions of GRASS

I've never used any GRASS prior to 5, so I won't comment on that.

However, I'm constantly frustrated by the 3-button d.zoom
function. The meaning of the buttons keeps changing and I regularly
get it wrong.

Also, I'm starting work to make GRASS more usable on handheld
computers, (using Compaq iPAQs running Linux right now). The iPAQ has
a touchscreen, (ie. a one-button pointer), so I need to come up with
something new.

I'm thinking of writing:

	d.zoomin
	d.zoomout

each of which would allow the user to draw a rectangular region for
zooming using button 1.  I think a very small rectangle should be
interpreted as a "click" and just zoom in/out a fixed factor such as
2X.

Any thoughts?

I guess the only important things missing would be a way to
undo/cancel a zoom, but some higher-level GUI, (which I am also
starting on), should probably handle that.

-Carl

-- 
Carl Worth                                        
USC Information Sciences Institute                 cworth at east.isi.edu
3811 N. Fairfax Dr. #200, Arlington VA 22203		  703-812-3725