[udig-devel] Geowidgets news: Eclipse-based CRS widget, M1 in preparatio

[Matthias Basler <Matthias.Basler@xxxxxxxxxxx>]

Hi developers

Here are last week's news:

1. Eclipse-based CRSwidget:
After having worked some time on the new map framework and having thus learned
how to work with JFace I thought it a good time to test this with the CRS
assembly widgets which were up to now only available in Swing. SWT turned out
very inconvenient, JFace had much better (and model-driven) widgets to use.
However the first results were not too convincing. Then I remembered that uDig
used the "Properties view" for things like I imagined.

Unfortunately the PropertySheetViewer is not part of JFace, but lives in
"org.eclipse.ui.views". Moreover it's not a public class. :-( However I managed
to break out five classes (PropertySheetViewer and four of its dependent
classes) and include copies of them in GeoWidgets, edited slightly so they
became public (or I made some methods public). This gave me a
PropertySheetViewer that would work outside Eclipse and which I could utilize
for testing in GeoWidgets. It still depends on the plugin
"org.eclipse.ui.views" for its model, but this is desirable, since the model
must be compatible to the "original" Eclipse PropertySheetViewer, in order to
get directly used in Eclipse or uDig.

I managed to build a standalone widget for the selection of CRS, Ellipsoids, and
all that stuff. It is nested like it's Swing counterpart, but thanks to the
compactness of the PropertySheetViewer takes much less space. It works,
although it needs some time to mature, i.e. become fail save even with very
dumb users that insert negative semi-major axes and such. ;-)
(Also still missing: custom coordinate systems and projections.)

The property view based widget shares its model with its Swing counterpart, but
I had to realize that it was a rather naive idea of mine to expect that it
might be possible to share ANYTHING UI-related between Swing and a SWT, JFace
and/or property view based solutions. All four use completely different
concepts and UI models for very similar things like managing a tree structure.
Plus they have different capabilities each. So in the end it turns out that I
have to write a new widget separately for Swing/JFace each time. Hopefully I
can at least share some code WITHIN different Swing resp. JFace widgets.

2. M1 in preparation

The new widget and the new introduced dependencies will be the motivation to
create the 1.0.M1 release, which I hope to have on Sourceforge on Tuesday
before I go on holiday hiking in the Alps. Also I hope to have some
documentation (other than the Javadoc) ready until then.

After that I hope to continue work on maps, legend views and map panes. My first
attempts on that terrain will not yet be included in M1.

Matthias Basler
c9bama@xxxxxxxxxxx

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