[GRASS-dev] animation missing pnmscale

[Michael Barton]

On 9/9/07 7:02 AM, "Glynn Clements" <glynn at gclements.plus.com> wrote:

> Also, I don't think that those options can be combined, so you would
> have to zoom the image first then subsample the zoomed image. One
> consequence is that it may not be practical to get the exact size
> required (the zoom factor needs to be reasonably small to avoid
> creating a huge intermediate image).

I played around with TclTk rescaling a little when initially working out how
to display GRASS maps in a Tcltk canvas and was disappointed in how it
worked--especially quality.

> 
> If the lack of pnmscale is the only issue, I can create a local
> version.

This would be especially good for Windows users. Maybe just build it into
r.out.ppm???

> 
> The main question is whether the Tcl/Tk version is fast enough to act
> as a replacement for xganim. When I originally posted it, the comments
> suggested that the speed difference was enough that xganim needed to
> be retained.
> 

I was wondering this too. I'd originally thought that the best way to go
about this was to render all the maps to PPM first, and then display the
animation in a second step. But I was able to get the TclTk animation
running without scaling so that I could continue to get the rest of it
working. I'm surprised at how fast it runs. The maps I'm testing are very
simple. Is the speed of r.out.ppm affected by the amount of non-null data or
just the total number of cells? If the latter, then it may well be quite
fast enough. 

Michael
__________________________________________
Michael Barton, Professor of Anthropology
Director of Graduate Studies
School of Human Evolution & Social Change
Center for Social Dynamics & Complexity
Arizona State University

phone: 480-965-6213
fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton