On 26 March 2011 11:51, Andrea Aime <[email protected]> wrote: > Hi, > the major bluder in http://jira.codehaus.org/browse/GEOT-3484 > made me think again about how to test map rendering. > > So far what we have is largely insufficient, as it's not really comparing > the maps we're generating wit a known to be good result. > > I have thought long about this topic and explored different possibilities. > Comparing the rendered image with a known to be good sample was > the first thing we tried... and I still bear the scars of that approach. > What happened back then is that we were comparing images pixel > by pixel, and fail at the slightest difference. > Unfortunately that fell apart pretty soon due to differences in how > the antialiasing and font rendering was performed on different platforms.
I remember it well :-) > > There is no much to discuss here, pPixel by pixel exact comparison > is dumb, we want the test to fail if a human would notice the difference > in maps, if the difference is actually relevant, not otherwise. > > Yet, probably better to have tests using it than not having tests > like we do now. Replicating it in Java is unfortunately hard. Some googling threw up glean and Piglit (http://www.winehq.org/pipermail/wine-devel/2009-September/078607.html) which are in C++ and The Batik tests (http://xmlgraphics.apache.org/batik/dev/test.html) which is Java and claims to handle variations (not sure how). Anyway I think this is a good idea and I'll continue thinking about the best way to do it. Ian -- Ian Turton ------------------------------------------------------------------------------ Enable your software for Intel(R) Active Management Technology to meet the growing manageability and security demands of your customers. Businesses are taking advantage of Intel(R) vPro (TM) technology - will your software be a part of the solution? Download the Intel(R) Manageability Checker today! http://p.sf.net/sfu/intel-dev2devmar _______________________________________________ Geotools-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-devel
