qgis preferences in a python plugin

Question

I'm developing a qgis python plugin. This plugin changes the default UI windows displayed (which I've already managed to do) and creates a few new tabs and such. Recently, it was requested that I modify some of the options within qgis. These are what they want me to modify:

Under Settings -> Options -> CRS ... modify the preference to Always start new projects with this CRS. They want me to change that to a specific CRS. They also want me to change several settings under the general tab and the map tools tab.

I have no idea where these preferences live in the API and/or how I can change them. I don't think I need specifics, but if you could give me a general idea of where to look, it would be much appreciated. Thanks!

Answer 1

I figured out the answer here. This mailing list entry: http://lists.osgeo.org/pipermail/qgis-developer/2012-October/022627.html and this http://qt-project.org/doc/qt-5.0/qtcore/qsettings.html were helpful. I ended up going into the windows registry to figure out the names of the options (since that's where they're set when you use store QSettings natively in Windows. It was under HKEY_USERS/myid/Software/QuantumGIS. In there, I just experimented by turning things on and off to figure out what needed to be changed in the plugin. I did that like this.

settings = QSettings(QSettings.NativeFormat, QSettings.UserScope, 'QuantumGIS', 'QGis')
settings.setValue('/Projections/projectDefaultCrs', 'EPSG:2278')

Hope this helps someone else.