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 -- Andrea Aime OpenGeo - http://opengeo.org Expert service straight from the developers. ------------------------------------------------------------------------------ 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
