I've encountered an obscure rendering difference between Uniscribe/DirectWrite as in IE11 on Windows 7 and HarfBuzz 0.98+. It shows up in my test cases in http://homepage.ntlworld.com/richard.wordingham/lanna/renderer_test.htm.
On HarfBuzz-based browsers, the word meaning 'to lead' in the section headed 'Ligature NAA' displays in the 'text' column as a connected glyph with a small circle above it. In the Firefox browser, both on Linux and Windows 7, when I hack this to the 3-letter ASCII string "nAM" the small circle moves up and rightwards so much that it is severely clipped in Firefox. However, when I display the same page in IE11 on Windows 7, the string displays as the original Tai Tham text does on Firefox. I can reproduce the bad display using the command hb-view --features=ss02,abvs,blws,pstf,blwf ~/.fonts/dalekh.ttf nAMn (The extra letter 'n' of the string extends the display so as to see the small circle.) Is it worth investigating the difference from Windows? There is a fairly complicated sequence of transforms, which probably ought to be reduced for the investigation. I suspect it depends on the inheritability of the base/mark difference. I could change the font to remove the effect; it's purpose is to render the incorrect sequence <U+1A36, U+1A63, U+1A76> differently to the correct sequence <U+1A36, U+1A76, U+1A63> by positioning marks above on the two halves of the ligature differently. Richard. _______________________________________________ HarfBuzz mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/harfbuzz
