[GRASS-dev] Re: [GRASS GIS] #937: cairo driver: d.legend colors all broken

[GRASS GIS]

#937: cairo driver: d.legend colors all broken
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  Reporter:  hamish   |       Owner:  grass-dev at lists.osgeo.org
      Type:  defect   |      Status:  new                      
  Priority:  major    |   Milestone:  7.0.0                    
 Component:  Display  |     Version:  svn-trunk                
Resolution:           |    Keywords:  cairo, d.legend          
  Platform:  Linux    |         Cpu:  x86-64                   
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Comment (by glynn):

 Replying to [ticket:937 hamish]:

 > in grass7 d.legend is pretty broken if you use the Cairo driver. The
 color table seems out of sync or corrupted.
 >
 > If you use the PNG driver it's fine.

 I can't reproduce this.

 > ps- with the PNG driver I notice the bottom right corner pixel of the
 legend is wrong. Line-end wants to be closed?

 The path is closed, but the PNG driver's line-drawing code doesn't draw
 the last pixel. It's a boundary condition caused by trying to draw lines
 exactly along the boundaries between pixels, rather than through their
 centres. d.legend really needs either a 0.5 pixel offset for the lines, or
 drawing successively smaller filled rectangles rather than stroking
 outlines and hoping that they align exactly with the contents.

-- 
Ticket URL: <https://trac.osgeo.org/grass/ticket/937#comment:1>
GRASS GIS <http://grass.osgeo.org>