[GRASS-dev] Re: [GRASS GIS] #72: PNG driver: boundary rendering is
off by one pixel
GRASS GIS
trac at osgeo.org
Fri Dec 5 01:03:13 EST 2008
#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: 6.4.0
Component: default | Version: svn-develbranch6
Resolution: | Keywords: d.vect, rendering, PNG_DRIVER
Platform: Unspecified | Cpu: Unspecified
--------------------------+-------------------------------------------------
Comment (by hamish):
Replying to [comment:13 glynn]:
> If you want quality, I would expect both the cairo and PS drivers
> to produce better results overall than either PNG or XDRIVER.
both are less WYSIWYG. Cairo thickens and antialiases lines, and PS driver
in 6.4 is limited by 6.4, and needs to be passed through pstoimg or
ghostscript to get the web/presentation image which has its own
rasterization quirks.
> You might also run into problems with the distinction between
> polylines and multiple line segments (caps versus joins) being
> visible.
unrelated, but ps.map's region box command has that problem,
obvious once you set the width a bit wider.
I ran some 'd.vect rend=' tests with the latest 6.4svn (w/ Polygon.c
commit). screenshots & scripts here:
http://bambi/hamish/grass/bugs/d.vect/dec2008/
{{{
results for render mode trials 5 Dec 2008
coastline
=========
6.3.0
-----
xdriver: R, C perfect; G near perfect; D, L off (x+y)
pngdriver: R, C off (x); G perfect; D off (y); L off(x+y)
6.4.svn 20081205 (with Polygon.c patch)
-------
xdriver: R, C, G perfect; D, L off (x+y)
pngdriver: R, C off (x); G perfect; D, L off (x)
gis.m: off (x)
inter-version
-------------
xdriver- results mostly unchanged (fixed 1 pixel in G)
pngdriver- D,L slightly improved
boxes
=====
6.4svn xdriver: D, L off (x+y)
6.4svn png driver: all look good.
6.4svn gis.m: looks good
}}}
Hamish
--
Ticket URL: <https://trac.osgeo.org/grass/ticket/72#comment:14>
GRASS GIS <http://grass.osgeo.org>
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