[GRASSGUI] managing layer and properties

[Michael Barton]

Here is a chance to rethink how map display is presented to users in the
GUI.

In the TclTk GUI, there is pretty much one layer type for each d.* command.
This works, but is complicated to maintain the various options panels. So
here are a couple thoughts on how to make this better.

Glynn suggested that we simply use the autogenerated options dialog for each
d.* command and make these better as needed. In fact, I've committed a
version of gismutils.py that does just that (although it doesn't yet work
for setting any options in layers.). In this way, we would still have a
layer type for each d.* command we want to include, but would not have to
individually maintain an options panel for each as the commands and their
options are changed in the future. We'd need to put considerably more effort
into mapform.py, especially for how it presented complex d.* commands like
d.vect, to make it less daunting.

An alternative is to have only one raster and one vector properties panel.
Each panel would offer the range of display options for raster and vector
maps accordingly. For example, the raster panel would have options for
draping color over shaded relief maps, combining rgb/his maps, displaying
cell values or flow arrows. We could maintain a separate, attached canvas
for raster or thematic vector legends. The user would only add a raster or a
vector map, then decide on how to display it.

This would simplify some aspects of the UI. But it would be some effort to
build these metacontrols. If we went this way, we would need to simplify how
render.py works. Currently, the actual commands are supplied in render.py.
If we went with a combined property window for rasters and vectors, this
metacontrol should generate the actual command, depending on how the user
wants to display a map (e.g., use d.rast, d.rgb, d.his, etc.). This is more
the way that arcgis and qgis present to the user. Although the control would
be complex, it offers more chance for custom explanations and help.

Anyway, I want to run this by you for my overnight.

Michael


__________________________________________
Michael Barton, Professor of Anthropology
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