[GRASS-dev] [GRASS GIS] #2033: Moving g.pnmcomp to lib/display to improve render performance of wxGUI

[Markus Neteler]

(back on this in the list rather than cluttering the ticket)

On Wed, Aug 7, 2013 at 9:42 PM, GRASS GIS <trac at osgeo.org> wrote:
> #2033: Moving g.pnmcomp to lib/display to improve render performance of wxGUI
...

I still hope that the command line wx0 can be brought to speed as x0
is for GRASS 6.

Some questions wrt to the comments sent by Soeren:

>   * Moving the code of g.pnmcomp, d.vect, d.rast ... d.* into the display
>  library for speedup reason is not meaningful. It might be meaningful when
>  we decide to implement the d.* modules as Python modules that communicate
>  with the wx display using sockets instead of files to call the rendering
>  backend.

What estimate of work would it be needed to implement a prototype for this?

> Well, the same can be achieved by implementing python wrapper
>  modules around the display modules ... so it might be not meaningful at
>  all.
>
>   * The current wxGUI rendering approach using PPM and g.pnmcomp seems to
>  be the most efficient considering the fact that the cairo driver is not
>  yet available in the windows version of grass7.

Meanwhile this has been fixed (see r57542). Is g.pnmcomp still the
only choice? To me it looks like slow.


> It seems to me that using
>  PIL will not provide a large speedup benefit over g.pnmcmop especially for
>  large images.

(the latter happens on large monitors)

>   * A small speedup can be achieved when calling the d.* modules in
>  parallel in the GUI, especially when several maps need to be re-rendered.
>
>   * IMHO the only way to speedup the rendering is to make d.rast and d.vect
>  faster.

Would also a quite different approach be possible? I have somehow the
idea that generating tmp files on disk is slower than writing into the
graphics card's memory :-)

thanks
Markus

> --
> Ticket URL: <http://trac.osgeo.org/grass/ticket/2033#comment:10>
> GRASS GIS <http://grass.osgeo.org>
>
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