[GRASS-dev] Re: [GRASS GIS] #72: PNG driver: boundary rendering is off by one pixel

[GRASS GIS]

#72: PNG driver: boundary rendering is off by one pixel
----------------------+-----------------------------------------------------
  Reporter:  hamish   |       Owner:  grass-dev at lists.osgeo.org   
      Type:  defect   |      Status:  new                         
  Priority:  blocker  |   Milestone:  6.3.0                       
 Component:  Tcl      |     Version:  svn-trunk                   
Resolution:           |    Keywords:  gis.m, rendering, PNG_DRIVER
----------------------+-----------------------------------------------------
Changes (by hamish):

  * keywords:  gis.m, rendering => gis.m, rendering, PNG_DRIVER
  * priority:  minor => blocker
  * summary:  gis.m: boundary rendering is off by one pixel => PNG driver:
              boundary rendering is off by one pixel

Comment:

 Hi,

 This seems to be a generic problem with the PNG driver and 'd.vect
 rend=c'.

 {{{
 #spearfish
 g.region n=4928610 s=4919190 w=596700 e=598860 res=30
 d.mon x0
 d.vect fields type=area
 d.out.file offby1

 qiv offby1.png
 }}}


 It was there last time I rand the rendering tests, but I guess I missed
 that the error was still there. Using xmag on the tiny peninsula in the
 rend=c image shows the problem too:
 http://bambi.otago.ac.nz/hamish/grass/bugs/d.vect/dec2008/dvect_render_fill_PNGdriver.png


 As noted here:
   http://article.gmane.org/gmane.comp.gis.grass.devel/23833
 "PNG driver: only 'g' lines up correctly. 'c' isn't so bad, it looks ok in
 the y, but off by one in the x (boundary line 1px to the right vs fill).
 [exploring with xmag]"



 thanks,
 Hamish

-- 
Ticket URL: <http://trac.osgeo.org/grass/ticket/72#comment:2>
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