[Qgis-developer] Progress bar or continuous feature display when displaying large datasets (feature request)

[Andreas Neumann]

Hi Stefan,

I believe that the progressive rendering and the render cache don't work
well together. Tim could probably comment on that since he worked on the
rendering cache.

You are right that with the rendering cache set to off there are sometimes
"useless" redraws.

So somehow the combination of progressive rendering and rendering cache
would have to be fixed.

Andreas


On Thu, February 11, 2010 9:56 pm, Stefan Keller wrote:
> Thanks Andreas - mea culpa - did'nt realize this. To me following
> suggestion remains:
>
> 1. Why is'nt this Rendering Behavior ("Number of Features to draw
> before updating the display") the default?
>
> In addition, I recognized the following:
>
> 2. The Rendering behavior is void when option flag "Use display cache
> if possible to speed up display" is on. I think, the options dialog
> should reflect this relationship and disable "Rendering behavior".
>
> 3. When in main window and switching "Layer visibility" off, another
> redraw is issued - only for making objects disappear right after
> completing the drawing - and this (useless) redrawing might take a
> long time.
>
> Just my 5 cents. -Stefan
>
> 2010/2/10 Andreas Neumann <a.neumann at carto.net>:
>> Hi Stefan,
>>
>> Continuous feature drawing is already possible, but is disabled by
>> default, as in the overall, it slows down rendering.
>>
>> If you want to enable it:
>>
>> Settings --> Options --> Rendering & SVG --> Rendering behavior -->
>> "Number of Features to draw before updating the display" --> set it to >
>> 0
>> (e.g. 10000).
>>
>> Andreas
>>
>> On Wed, February 10, 2010 8:35 pm, Stefan Keller wrote:
>>> I'm currently working on a geodatabase benchmark proposal (look for
>>> "HSR Texas Database Benchmark") and consequently dealing with large
>>> datasets.
>>> When displaying these large datasets in QGIS I often get trapped in
>>> thinking, the process would never end because there's "just" a wait
>>> cursor.
>>> As a feature request I would suggest that there could be a continuous
>>> feature display (as in uDig :->) or at least a progress bar (if
>>> datasource makes this info available).
>>> Just my 5 cents. -Stefan
>>> _______________________________________________
>>> Qgis-developer mailing list
>>> Qgis-developer at lists.osgeo.org
>>> http://lists.osgeo.org/mailman/listinfo/qgis-developer
>>>
>>
>>
>> --
>> Andreas Neumann
>> http://www.carto.net/neumann/
>> http://www.svgopen.org/
>>
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>


-- 
Andreas Neumann
http://www.carto.net/neumann/
http://www.svgopen.org/