[Qgis-user] variables in postgis filters

[Sandro Santilli]

On Sat, Apr 02, 2016 at 07:39:47AM -0700, ralfwessels wrote:
> Hi,
> 
> ....I haven't looked at how the QuickOSM plugin deals with the issue, 
> does it update the layer definition on every pan and zoom operations ? 
> 
> No, the QuickOSm-Plugin is not updateing on every pan or zoom - it just
> loads the object for the current map extent (if this is not to big though).
> But as a first step this would be ok to load data from PostGIS tables.
> 
> So if the QuickOSM Plugin uses the current map extents, thsee must be
> accessible somehow.

Any plugin can subscribe to receive notifications about canvas
updates and can fetch information about the canvas (extent, scale).

--strk;