[QGIS-Developer] Get the Canvas CRS in Expression

[René-Luc Dhont]

Hi Dev,

I need to get the canvas CRS in an expression.

It's possible to get the layer CRS with the method layer_property

It's possible to get some data of the map like map_center, 
map_extent_height, map_scale but I didn't find how to get the map_crs.

It will be useful for exemple to only display the labels of features 
nearest the center point. If the layer and the map are not in the same 
CRS, the distance between features can't be used.

Do I have to update QGIS sources or a way to get the canvas CRS allready 
exists ?

Regards,

René-Luc