On 11 July 2017 at 19:22, Neumann, Andreas <[email protected]> wrote: > Hi Martin, > > Sounds interesting. Of course this is not urgent. We now need to concentrate > on all the stuff that requires refactoring and API changes in the master > branch. > > But it would really be nice, if such rendering improvements could be > introduced in a future 3.x version. Maybe something for the next QGIS grants > program?
Andreas - do you compile master builds? I'd love it if you could give the branch from https://github.com/qgis/QGIS/pull/4777 a test and give feedback on the open questions in that PR. I suspect you'll be pleased with the behavior with that change. Full credit for the changes goes to Sourcepole - I've just forward ported the feature from their fork and modernised the code for 3.0. Nyall > > Andreas > > On 2017-07-11 10:48, Martin Dobias wrote: > > Hi Andreas > > On Tue, Jul 11, 2017 at 9:38 AM, Neumann, Andreas <[email protected]> > wrote: > > Hi Martin, > > I noticed that loading and redraw only happens when the mouse button is > released after the panning operation. While I understand the reasoning for > this (definitely on the safe side and no unnecessary redraws), I wonder, if > for WMTS, loading and display could already happen while panning and the > mouse button isn't yet released, e.g. triggered whenever a certain threshold > of panning distance (e.g. in percent of the last extent) was surpassed. > > This would be even nicer than the current behaviour. Or are there technical > reasons, not to do that? Google maps works like this. It redraws while > panning. > > > Good news - there are no technical reasons that would prohibit us from > such improvement. Background rendering could start earlier, we just > need to add logic for such behavior. There is already a pending pull > request from Nyall to render adjacent parts of map canvas once > rendering of the visible area has finished - that may already be a > sufficient solution - I have not had time to play with it yet though. > Maybe these two approaches (render on map dragging, render outside of > current view) can be combined somehow for the best UX while keeping > overhead of extra rendering low. > > We could even think about moving more towards tile-based approach to > rendering of map canvas, with the advantage of being able to cache map > tiles from previous canvas redraws for the same scale. This would > allow instant appearance of areas previously rendered with lower CPU > use at the expense of consuming more memory and having more > complicated logic for labeling. > > Regards > Martin > > _______________________________________________ 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
