Hi > On 22 Jul 2020, at 08:48, Nyall Dawson <[email protected]> wrote: > > On Wed, 22 Jul 2020 at 17:39, Andreas Neumann <[email protected]> wrote: >> >> Hi Nyall, >> >> Thanks for your reply. >> >> Thanks for explaining the issue about the enforced rasterization of the line >> pattern fills. Any rough estimate how much the speed penalty would be when >> one would implement the line pattern fill purely as vector? > > Hard to say upfront -- it's going to depend on the size (pixels) of > the features, and the number of lines in the fill pattern. Gut feeling > is that it's unlikely to be noticeable for individual users, but > costly enough to be an issue for server. Somewhere in the middle > there! > >> Also - would it be possible to "enforce" vector only rendering of line and >> point pattern fills - not only for export, but also for server or canvas >> rendering? As an example, when generating raster tiles, it would be nice to >> get a higher quality (even on server output) at the expense of speed. When a >> Mapproxy is harvesting tiles from a QGIS server, it would be nice if there >> could be a parameter in the GetMap request that enforces higher quality >> vector rendering at the expense of a lower performance. > > Hm -- maybe we should add a project level setting for "rendering > quality". There's actually quite a few more shortcuts we could > potentially take if someone just cares about fast rendering vs high > quality rendering (e.g. rendering shapeburst fills at a lower > resolution). So potentially we could add a setting "rendering quality" > with options like "Prioritise speed over > quality"/"Balanced"/"Prioritize quality over speed". (I think layout > exports should ALWAYS use the highest quality render though, so they'd > ignore this setting)
I’m imagining a checkbox in the status bar here next to the enable / disable render one that toggles ‘draft’ mode versus ‘awesome mode’….I love that QGIS has advanced so far that we are even having this discussion :-) Regards Timi > > Nyall > > >> >> Thanks, >> >> Andreas >> >> On 2020-07-22 08:32, Nyall Dawson wrote: >> >> On Fri, 17 Jul 2020 at 19:34, Andreas Neumann <[email protected]> wrote: >> >> >> Hi, >> >> In our efforts to improve cartographic quality, I'd also like to discuss, if >> we could somehow improve the quality of the line-pattern fills, and/or the >> antialiasing quality of the qt renderer. A very small change in angle can >> change the quality of a line-pattern fill in QGIS pretty or very ugly. >> >> Also: even if all buildings in the following rendering have the same >> distance between lines, some look much "denser" than others. Have a look at >> the attached file where I labeled some line fills as ugly and pretty. >> >> Is there something that QGIS could do to improve the "prettyness" of line >> pattern fills, or would this have to change in the qt library? >> >> Thanks if you have any thoughts on this topic, >> >> >> Sorry for the delayed reply! >> >> This is a long-standing issue in QGIS' polygon fill support. See >> https://github.com/qgis/QGIS/issues/16100 (filed 2013). Basically, the >> line pattern symbol type uses a trick to speed up the rendering of >> features by first making a small tiled raster image of the line >> pattern, and then painting the polygons using this raster brush. It's >> nice and fast, and works well for canvas/server renders, but is far >> from ideal for high quality exports. It's also an issue if you try to >> use data defined settings on the line sub symbol -- because the >> pattern is generated using the tiled image, you won't see the expected >> results if you try to make the appearance of individual lines in the >> pattern vary. >> >> For reference, up until 3.14 the point pattern fill had the same >> limitation. For 3.14 point pattern fills were improved to now export >> the fill as vector markers (the same raster brush approach is still >> used for canvas renders, where speed is more important vs quality). >> >> What we need to do is implement a similar fix as was done for the >> point pattern fill, and render each individual line in a line pattern >> fill as a proper vector line (during layout exports, or when we detect >> that the line subsymbol has data defined properties set). Hopefully >> something we can do for 3.16... >> >> Nyall >> >> >> >> >> Andreas >> >> _______________________________________________ >> 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 >> >> > _______________________________________________ > 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 — Tim Sutton Co-founder: Kartoza Honorary PSC Member and Ex-Project chair: QGIS.org <http://qgis.org/> Visit http://kartoza.com <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 I'd love to connect. Here's my calendar link <https://calendly.com/timlinux/30min> to make finding time easy.
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