[mapserver-users] Draw roads WITHOUT anti-aliasing

[Rahkonen Jukka (MML)]

Hi,

I suppose that the amount of antialiasing with AGG is set with "gamma" parameter.  Mapserver supports that at least for polygons as documented in http://www.mapserver.org/mapfile/outputformat.html but you could try if using gamma=0.0 has an effect on lines as well. It may be that it does not because search 
https://github.com/mapserver/mapserver/search?utf8=%E2%9C%93&q=gamma&type=
seems to find only something that is tied to polygon outlines
https://github.com/mapserver/mapserver/blob/branch-7-0/renderers/agg/include/agg_renderer_outline_aa.h


 If gamma does not work for lines then it could be worth making a feature request for adding a new formatoption "GAMMA_LINE=[].

Couple of Mapnik links dealing with the same issue:
http://gis.19327.n8.nabble.com/Turning-off-anti-aliasing-td5339458.html
http://mapnik.org/mapnik-reference/#3.0.6/line-gamma-method

-Jukka Rahkonen-



-----Alkuperäinen viesti-----
Lähettäjä: mapserver-users [mailto:mapserver-users-bounces at lists.osgeo.org] Puolesta Eichner, Andreas - SID
Lähetetty: 18. lokakuuta 2017 9:57
Vastaanottaja: Erik H <erik.h11.01 at gmail.com>
Kopio: mapserver-users at lists.osgeo.org
Aihe: Re: [mapserver-users] Draw roads WITHOUT anti-aliasing

Damn... missed attaching the images.

> -----Ursprüngliche Nachricht-----
> Von: mapserver-users [mailto:mapserver-users-bounces at lists.osgeo.org] 
> Im Auftrag von Eichner, Andreas - SID
> Gesendet: Mittwoch, 18. Oktober 2017 08:28
> An: Erik H
> Cc: mapserver-users at lists.osgeo.org
> Betreff: Re: [mapserver-users] Draw roads WITHOUT anti-aliasing
> 
> Hi,
> 
> I just meant that it seems to be pretty easy to implement aliased 
> rendering with AGG.
> Simply changing the typedef in line 91 of mapagg.cpp from
> 
>   typedef mapserver::renderer_scanline_aa_solid<renderer_base>
> renderer_scanline;
> 
> to
> 
>   typedef mapserver::renderer_scanline_bin_solid<renderer_base>
> renderer_scanline;
> 
> turns of anti-aliased rendering. I've attached the output of "shp2img 
> -m line_simple.map" from the msautotests.
> An additional member in class AGG2Renderer for the aliased rasterizer 
> and conditionally passing one or the other to render_scanlines() 
> depending on some value of strokeStyleObj might be enough.
> 
> Regards
> 
> > -----Ursprüngliche Nachricht-----
> > Von: Erik H [mailto:erik.h11.01 at gmail.com]
> > Gesendet: Dienstag, 17. Oktober 2017 17:34
> > An: Eichner, Andreas - SID
> > Cc: Richard Greenwood; mapserver-users at lists.osgeo.org
> > Betreff: Re: [mapserver-users] Draw roads WITHOUT anti-aliasing
> >
> > As for Andreas' remark about 'simply the use of another scanline 
> > rasterizer.' - I'm sorry but I'm not much of a C++ developer. If I
> have
> > to do rasterizing, I'd skip MapServer altogether and generate the 
> > PNG
> in
> > Java.
> >
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