Btw., the legend code is quite old and probably needs a complete
redesign to make it easier maintainable. I think it would be good to do
this before exposing all the things in the legend to plugins (but I
don't know if there is any volunteer for it?).
Regards,
Marco
On 08.10.2012 17:58, Giuseppe Sucameli wrote:
Hi,
On Fri, Oct 5, 2012 at 11:28 AM, Massimo <[email protected]> wrote:
I propose another solution based on QDomDocument similar to the one
adopted into the QgsLegend::writeProject method.
Massimo has made a pull request [1] to add a
groupLayerHierarchy method that returns a QDomDocument.
Here's my opinion (see the pull request comments):
A QDomDocument is good when you want to export/import
data (e.g between different QGis installations) and we already
have a such QDomDocument, i.e. the project file.
I totally agree with Martin, we need to implement some
classes to give plugin devs the opportunity to work on the
legend using an API.
Furthermore I don't understand why having a new xml
document with it's own tags/elements.
The QgsProject.write(...) calls the QgsLegend.writeXml(...)
to write all the stuff needed to re-create the legend tree,
so we could just expose the QgsLegend.writeXml().
BTW, in the meantime the API is developed you could
save a temporary project file and parse it.
Note: you need to restore the project filename after done
because the QgsProject.write(QFileInfo) changes it.
Here's XML elements you need to know to get legend
info from project file:
*<legend>* is the legend root tag.
It can contains both *legendlayer* and *legendgroup* elements.
A legend layer can contains more sublayers,
it has the following structure:
<legendlayer name="mylayer1" checked="Qt::Checked">
<filegroup>
<legendlayerfile id="mylayer120121008125355262" />
</filegroup>
</legendlayer>
where the *filegroup* elem contains the sublayers with their id.
Group info is stored into a *legendgroup* element,
it can contains both *legendlayer* and *legendgroup* elements:
<legendgroup name="mygroup1" checked="Qt::Checked">
<legendlayer name="mylayer1">...</legendlayer>
<legendgroup name="mygroup2" checked="Qt::Checked">
<legendlayer name="mylayer2">...</legendlayer>
</legendgroup>
</legendgroup>
Regards.
[1] https://github.com/qgis/Quantum-GIS/pull/265
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