[Qgis-developer] rendering current line in Grass digitizer is very slow

[Radim Blazek]

GRASS edit in 0.8 is using QgsRubberBand (XOR rendering
does not work anymore IIRC) and it is probably slow because
it is not designed for complex graphics.
I dont know if it can be improved.

Radim


On 7/7/06, Maciek Sieczka <werchowyna at epf.pl> wrote:
> Hi,
>
> Lines in Grass digitizer are being drawn really slowly on pretty fast
> computers [1]. The more vertices the line has, the slower the
> rendering. The bug affects only the line being currently digitized, ie.
> if you just try to modify an existing one by moving or adding
> single vertices rendering is fast. But when you digitize a long line,
> with each vertex added the rendering speed decreases.
>
> To reproduce:
>
> 1. Open a Grass vector in Grass digitizer.
> 2. Start a new line (or boundary) by putting the first vertex. See how
> smoothly the line is drawn as you move the cursor with mouse.
> 3. Now digitize 10, 100, 300 etc. vertices. See how much slower the
> rendering gets with each vertex put. Note the slow-down does not depend
> on the zoom level or the amount of features being displayed. The only
> "reason" for the slow-down is the amount of vertices you have put in
> the line being currently digitized.
>
> Is this a known issue? Is my description clear? Could it be fixed?
>
> Using SVN 0.8 of yesterday, Ubuntu Breezy and Dapper.
>
> Maciek
>
> [1]
> PM 1,86 GHz, ATI X700 128MB, propriearty drivers, direct rendering on
> AMD 3200, NVIDIA GX400 64MB, propriearty drivers, direct rendering on
>
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