I'll add that without fuzzing, it would very hard for us to do things like switch from a Moz2D backend to another or change the way we do drawing (like enabling tiling), because these things mean some rounding happens in slightly different ways and anti-aliasing is particularly sensitive to this. For example with some drawing backends going from drawing into a non-tiled surface with no offset into drawing into tiles with an offset for each tile will typically produces very tiny differences in the anti-aliasing which can't be seen with the naked eye and should not be considered as bugs. So I recommend supporting fuzzing reftests as well.
Nical On Tue, Oct 27, 2015, at 01:52 AM, Robert O'Callahan wrote: > Many Webkit layout tests use DRT (DumpRenderTree), which dumps the layout > object tree and compares against reference text files. These became > difficult to maintain as the layout engine evolved and such tests are not > portable to any other engine. Testing display list dumps sounds like it > would have similar downsides. > > Unsurprisingly I recommend making reftests fuzzy if that's what you need. > I > think our approach has worked pretty well: the annotation fuzzy(A, B) > means > that at most B pixels differ, and those pixels differ by at most A in any > color channel. This seems to be a good mix of convenience and precision. > I > resisted allowing fuzziness for a long time for roughly the same reason > as > Lars --- too tempting --- but I haven't been able to say "I told you > so!". > > Rob > -- > lbir ye,ea yer.tnietoehr rdn rdsme,anea lurpr edna e hnysnenh hhe > uresyf > toD > selthor stor edna siewaoeodm or v sstvr esBa kbvted,t > rdsme,aoreseoouoto > o l euetiuruewFa kbn e hnystoivateweh uresyf tulsa rehr rdm or rnea > lurpr > .a war hsrer holsa rodvted,t nenh hneireseoouot.tniesiewaoeivatewt sstvr > esn > _______________________________________________ > dev-servo mailing list > dev-servo@lists.mozilla.org > https://lists.mozilla.org/listinfo/dev-servo _______________________________________________ dev-servo mailing list dev-servo@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-servo
