Hi All,
I use mapCanvas().setRenderFlag( False ) before loading a (potentially) large number of layers using the 'Load Them All' plugin [1]. I acknowledge I needed to toggle such flag years ago (the plugin was mainly developed in 2012) and still use it. For another plugin (private according to requirements from a company), I use heavy PostGIS layers in a Processing workflow. As I don't want the canvas to show anything in the meantime (I'm only interested in getting progress bar updates in QgsMessageBar), I use the setRenderFlag(False) and only ask canvas to show all needed layers, including results, after all processing is done. Does it make sense or could I avoid toggling the flag? Regards, Germán ---- [1] http://plugins.qgis.org/plugins/loadthemall/ 2017-02-28 6:49 GMT-05:00 Tim Sutton <[email protected]>: > Hi > > On 28 Feb 2017, at 12:00 PM, Matthias Kuhn <[email protected]> wrote: > > Hi Tim > > On 02/28/2017 10:42 AM, Tim Sutton wrote: > > One reason to keep it: For us the use case has often been when you are > doing first set up of a project and you are dropping a bunch of large > layers yet. You want to set up scale dependent visibility and rules > first without waiting for time consuming renders, then enable rendering > when everything is added. I know we can also use the option to make > layers not visible when they are first added to the canvas so I reckon > that use case can be worked around easily enough. > > > Sorry if I'm missing something, but why is it important that in this > case nothing is rendered? I imagine you can just configure scale > dependent rendering, while ignoring that something is rendered in the > background. And once you apply the changed config, rendering will > restart with the same net-time and net-result (but less clicks). > > > > Hmm probably not so important if it is rendering nicely in a side thread > and esc cancels rendering efficiently. Anyway it seems that others like > Giovanni and Denis are quite invested in the feature so probably it is more > useful to understand their needs as I could easily see it go and not be too > worried... > > Regards > > Tim > > > > Matthias > > > — > > > > > > > > > > *Tim Sutton* > > *Co-founder:* Kartoza > *Project chair:* QGIS.org > > Visit http://kartoza.com to find out about open source: > > Desktop GIS programming services > Geospatial web development > GIS Training > Consulting Services > > *Skype*: timlinux > *IRC:* timlinux on #qgis at freenode.net > > Kartoza is a merger between Linfiniti and Afrispatial > > > _______________________________________________ > Qgis-developer mailing list > [email protected] > List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer > Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer > -- ----------- |\__ (:>__)( |/ Soluciones Geoinformáticas Libres http://geotux.tuxfamily.org/ http://twitter.com/GeoTux2 http://about.me/germancarrillo <http://gis.stackexchange.com/users/4972/germ%c3%a1n-carrillo>
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