[GRASS-dev] [GRASS GIS] #2403: cairo driver fails to create surface

[GRASS GIS]

#2403: cairo driver fails to create surface
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 Reporter:  martinl                     |       Owner:  martinl    
     Type:  defect                      |      Status:  assigned   
 Priority:  major                       |   Milestone:  7.0.0      
Component:  Display                     |     Version:  unspecified
 Keywords:  cairo, resolution, surface  |    Platform:  Linux      
      Cpu:  x86-64                      |  
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Comment(by martinl):

 Replying to [comment:7 glynn]:

 > The PNG driver resamples each row and stores it directly in the image.

 Thanks for the hint. Could you please review
 attachment:cairo_down_sampling.diff which do down-sampling for Cairo in
 similar as already does PNG driver?

 Down-sampling has of course a significant speed effect when rendering
 larger rasters using their original region, eg.

 {{{
 g.region rast=dmt -p
 ...
 rows:       11682
 cols:       18913
 cells:      220941666
 ...

 # cairo: no down-sampling
 time GRASS_RENDER_IMMEDIATE=cairo d.rast dmt
 real    0m40.797s

 # cairo: down-sampling (patch applied)
 time GRASS_RENDER_IMMEDIATE=cairo d.rast dmt
 real    0m1.400s
 }}}

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Ticket URL: <http://trac.osgeo.org/grass/ticket/2403#comment:8>
GRASS GIS <http://grass.osgeo.org>