[GRASS-dev] wxpython gui: speed of display

[Moritz Lennert]

On Wed, August 16, 2006 16:13, Glynn Clements wrote:
>
> Moritz Lennert wrote:
>
>> While we are working on a new wxpython prototype, I would like to
>> mention raise the issue of speed of display (which is also valid for
>> gis.m).
>>
>> When I display a vector map with 65961 boundaries and 20464 areas, it
>> takes about 10 seconds to display it with type=area and fcol=none (ca
>> 13s with no parameters set). In ArcView under Windows this takes only
>> max 3s.
>>
>> I was wondering where the difference comes from. Is it the passage
>> through g.composite ? Is it the fact that we are not dealing with simple
>> features ? Something else ?
>
> It's unlikely to be related to g.pnmcomp. For a start, the time taken
> by g.pnmcomp depends only on the size and number of the images being
> composited, not the contents of the images.
>
> It's more likely that most of the time is taken by d.vect. Try running
> d.vect directly (using the PNG driver), and timing that. Also, try
> using GRASS_RENDER_IMMEDIATE=TRUE to see if that makes a noticeable
> difference.

It halves the rendering time:

GRASS 6.3.cvs (BELGIQUE):~ > echo $GRASS_RENDER_IMMEDIATE
FALSE
GRASS 6.3.cvs (BELGIQUE):~ > d.mon start=PNG
PNG: GRASS_TRUECOLOR status: FALSE
PNG: collecting to file: map.png,
     GRASS_WIDTH=640, GRASS_HEIGHT=480
Graphics driver [PNG] started
GRASS 6.3.cvs (BELGIQUE):~ > date;d.vect ssbel01 fcol=none type=area;date
jeudi 17 août 2006, 00:35:08 (UTC+0200)
jeudi 17 août 2006, 00:35:14 (UTC+0200)
GRASS 6.3.cvs (BELGIQUE):~ > d.mon stop=PNG
Monitor 'PNG' terminated
GRASS 6.3.cvs (BELGIQUE):~ > export GRASS_RENDER_IMMEDIATE=TRUE
GRASS 6.3.cvs (BELGIQUE):~ > date;d.vect ssbel01 fcol=none type=area;date
jeudi 17 août 2006, 00:35:29 (UTC+0200)
PNG: GRASS_TRUECOLOR status: FALSE
PNG: collecting to file: map.png,
     GRASS_WIDTH=640, GRASS_HEIGHT=480
jeudi 17 août 2006, 00:35:32 (UTC+0200)

How could I test this with the wxpython gui ?

Moritz

P.S. I won't be around for a week. So I'll have to wait for the end of
next week to test this more.