[PATCH] OpenLayers

[stoecker]

Hi,

I tried yesterday to decide what's the best way to support Yahoo!

imagery with firefox 3 (or rather without ff 2). First I checked out
the OpenLayers plugin from Francisco Santos and tried to see what was
left to be done in it. I like the idea of the plugin but there seem
to be unresolved design issues.

Firstly, it does a switch from firefox to a java based browser for
downloading. Aside from the size of the file, this browser is slower
for me and causes josm to hang for a couple of seconds when loading
yahoo for the first time. On the other hand scrolling the mapview
doesn't spawn new processes like it would be with firefox so it's
smoother. Perhaps it could be put into a thread of its own.

Then the first thing that I found annoying was lack of progress
indication when downloading, so the first patch attached makes the
layer contents be displayed progressively as they're loaded. Then
there's the issue with positioning and scalling the layer contents -
the code to do this is disabled with a "TODO wrong calculations"
comment. I found the calculations are actually correct but the whole
idea of chaging the map view according to the layer requirements is
bad. In this case it causes infinite recurrency because updating the
view causes the open layer update (possibly download of new tiles) and
a map view update again. Then it also implies restricting josm map
view to only the zoom levels supported by the openlayer, I think this
will be absolutely unusable.

So I had an idea to reuse GeorefImage from WMSPlugin and store the
openlayer contents and scale and position them when necessary. But
then I checked out the latest WMSPlugin and found that some yahoo
imagery support was added there with seemingly all the things I
needed, even the download is done in a separate thread and tiles are
downloaded automatically. I installed gnome-web-photo 0.5 and it
basically works, with firefox 3 and wmsplugin, but the tiles were
displayed wrongly. It took a lot of wrapping my head around it to
understand out why (basically firefox 3 / gnome-web-photo alwyas
return images enlarged to some constant window width and we have no
way to communicate the downloaded yahoo image width from browser back
to josm). I managed to work around it and while there are new gecko
processes spawned all the time (like with ywms) it is quite usable and
works with firefox 3. The third attached patch is the work around.

[anonymous]

Applied.