Reftests? -- Dirk
On Mon, Jun 6, 2011 at 11:00 PM, Hao Zheng <zheng...@chromium.org> wrote: > Unfortunately, even for SVG or images, different drawing > implementations will lead to different pixel results. Like this Skia > bug, http://code.google.com/p/skia/issues/detail?id=179 , which caused > most pages using SkFixed calculation, e.g. round-corner, gradient, > svg, etc., produce different rendered image on different platforms. So > I think there are many subtle, if possible, issues to make pixels > consistent across all platforms. > > On Tue, Jun 7, 2011 at 1:23 PM, Eric Seidel <e...@webkit.org> wrote: >> So are we saying it's impossible to have matching results across all >> platforms if a test involves any text (in any font)? >> >> I know it's certainly possible to have pixel-results for tests which >> do not involve text match across all platforms (like SVG or images or >> css styling, etc.) >> >> Or is all this just theory? >> >> -eric >> >> On Mon, Jun 6, 2011 at 8:09 PM, Hao Zheng <zheng...@chromium.org> wrote: >>> Yes, actually in Skia, Chromium/Linux uses a noop gamma implementation >>> in SkFontHost_gamma_none.cpp; however, if you use a substantial >>> implementation in SkFontHost_gamma.cpp, there will be much image >>> mismatch on Chromium/Linux for every font including Ahem. The slight >>> differences are on font fringe. >>> And I think if other WebKit is not using Skia at all, there will >>> surely be even more differences. >>> >>> As the gamma implementation on Clank is desired, we should not fix >>> this bug. Just file the bug to record this difference. >>> >>> On Fri, Jun 3, 2011 at 2:30 AM, Tony Chang <t...@chromium.org> wrote: >>>> Perhaps, but in practice, it's not enough. Here's an ahem pixel test that >>>> is slightly different on Mac and Chromium Linux: >>>> http://trac.webkit.org/browser/trunk/LayoutTests/platform/mac/fast/block/basic/010-expected.png >>>> http://trac.webkit.org/browser/trunk/LayoutTests/platform/chromium-linux/fast/block/basic/010-expected.png >>>> >>>> Also, I think it would be hard to tell by examining the HTML if a test uses >>>> another font. For example, the line height of an empty block might depend >>>> on the default font that isn't specified (does <pre></pre> render the same >>>> height on all platforms?). >>>> On Thu, Jun 2, 2011 at 10:44 AM, Adam Barth <aba...@webkit.org> wrote: >>>>> >>>>> I thought the whole point of Ahem was to avoid those problems. >>>>> >>>>> Adam >>>>> >>>>> >>>>> On Thu, Jun 2, 2011 at 1:29 AM, Hao Zheng <zheng...@chromium.org> wrote: >>>>> > Actually, even the same Ahem font will be rendered differently on >>>>> > different platform, depending on the font drawing library, the >>>>> > anti-aliasing algorithm, subpixel, tiny float-point calculation diff >>>>> > on different arch. >>>>> > >>>>> > On Thu, Jun 2, 2011 at 3:30 AM, Eric Seidel <e...@webkit.org> wrote: >>>>> >> I know that Ahem is safe to use across multiple platforms (the font >>>>> >> metrics >>>>> >> will be the same). Do we know if there are any other fonts for which >>>>> >> this >>>>> >> is true? >>>>> >> I'd like to make the style-bot yell at people when they use pixel tests >>>>> >> with >>>>> >> non-safe fonts. Right now that list would only include ahem. >>>>> >> -eric >>>>> >> _______________________________________________ >>>>> >> webkit-dev mailing list >>>>> >> webkit-dev@lists.webkit.org >>>>> >> http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev >>>>> >> >>>>> >> >>>>> > _______________________________________________ >>>>> > webkit-dev mailing list >>>>> > webkit-dev@lists.webkit.org >>>>> > http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev >>>>> > >>>>> _______________________________________________ >>>>> webkit-dev mailing list >>>>> webkit-dev@lists.webkit.org >>>>> http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev >>>> >>>> >>> _______________________________________________ >>> webkit-dev mailing list >>> webkit-dev@lists.webkit.org >>> http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev >>> >> > _______________________________________________ > webkit-dev mailing list > webkit-dev@lists.webkit.org > http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev > _______________________________________________ webkit-dev mailing list webkit-dev@lists.webkit.org http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev
