Sounds like a reasonable approach to me. What will the option look like to the user? Will it be a vendor parameter in an SLD? Or what did you have in mind?
Andrea Aime wrote: > Hi all, > I'm writing to build some consensus on how to handle a > compatibility breaking change. > > Years ago, way before my involvement in GeoServer, I > introduced a rendering optimization for lines. The > observation was that if the line width was less than > 1.5 pixels, setting it to 0 flat would make the rendering > quite a bit faster (30%+ if my memory serves me right) > and the visual result would have been the same. > > Now, at the time I was not using antialiasing, as it > made rendering times untolerable on my Athlon 700Mhz, > and I did not notice how that optimization affected > antialiased rendering. > > These days more than one people complains that they > cannot control the thickness of thin lines. No wonder, > it's the above optimization kicking in. > And with antialiasing rendering on, well, you can > tell a difference between line withs of 0.5, 1, > and 1.5 pixels (just to make an example). > > So, what can we do? Kicking off the optimization > the hard way does not seem like a good option to me. > People have been creating styles based on the current > behaviour, changing it would change the way maps > are rendered. > To give you some examples, here are maps that > have been rendered with the optimization on (the > current behaviour) and off (the proposed change). > > USA population: > default: http://www.flickr.com/photos/29313...@n03/3217765574/sizes/o/ > opt off: http://www.flickr.com/photos/29313...@n03/3217765474/sizes/o/ > > USA population, with hatch fills: > default: http://www.flickr.com/photos/29313...@n03/3216912511/sizes/o/ > opt off: http://www.flickr.com/photos/29313...@n03/3216912387/sizes/o/ > > Tasmania: > default: http://www.flickr.com/photos/29313...@n03/3217765504/sizes/o/ > opt off: http://www.flickr.com/photos/29313...@n03/3216912443/sizes/o/ > > As you can see the rendering changes, in some cases, significantly. > It's still possible to get back the old "thin line" rendering, you > just have to go and specify a thinner line with, such as 0.5, in the > SLD. > > What I'm proposing is to create an option that allows to toggle > the optimization on and off at the renderer level, and at the > SLDStyleFactory level (since this is where the optimization > really kicks in). For the 2.5.x series, we leave > the option on by default, so no change in rendering occurs > unless you tell the code otherwise. > > For the trunk series, I'd say that we should turn the > optimization off by default, but leave the toggle around for > one more release cycle, after which, we remove it completely. > > How does this sound? > Cheers > Andrea > -- Justin Deoliveira OpenGeo - http://opengeo.org Enterprise support for open source geospatial. ------------------------------------------------------------------------------ This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword _______________________________________________ Geotools-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-devel
