[GRASS5] Zoom

[Carl Worth]

On Apr 22, Radim Blazek wrote:
 > BTW: How do you use d.zoom on handheld? Do you have your special
 > version of d.zoom for one button or do you use aditional buttons 
 > on handheld?

When I first put GRASS on my handheld, I planned to write a new
d.zoom.

However, I then found an application which needed fairly high
framerate animation of dynamic data on top of maps, (including
real-time plotting of several mobile GPS units). With that I found
several limitations in GRASS:

	o It couldn't redraw my maps fast enough.

	o I didn't see an obvious way to store/query the
	  time-dependent data I had.

	o No translucency support in display.

	o No pixmap support for point data.

So, what I ended up doing is writing a custom X application that
handles its own mouse events, reads the dynamic data from a PostgreSQL
database, and draws the animation. Meanwhile, GRASS draws to the
window's background using the XDRIVER_WINDOW mechanism.

This isn't an ideal solution, (much of it was motivated by
deadlines). Instead, I'd like to go back and fix the limitations in
GRASS. The big feature that would be nice would be good layer support
to handle the refresh rate needs I have.

On the other hand, the code I now have in hand might just make a good
base for a real GRASS user-interface, so I want to start generalizing
it into that, rather than the custom application I currently have.

-Carl

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