<html> <head> <base href="https://bugs.documentfoundation.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - Enabling pair kerning breaks rendering of many common fonts" href="https://bugs.documentfoundation.org/show_bug.cgi?id=142940#c7">Comment # 7</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - Enabling pair kerning breaks rendering of many common fonts" href="https://bugs.documentfoundation.org/show_bug.cgi?id=142940">bug 142940</a> from <a class="email" href="mailto:adam.m.fontenot+docfo@gmail.com" title="adam.m.fontenot+docfo@gmail.com">adam.m.fontenot+docfo@gmail.com</a> <pre>(In reply to Ming Hua from <a href="show_bug.cgi?id=142940#c3">comment #3</a>) > I don't know much about text rendering so all I can add is a screenshot with > 7.2.0 Beta1 on Windows 10, showing similar differences with or without pair > kerning. Thanks for your effort to get this looked at. The issue with using Windows as a comparison is that by default Windows hints so strongly that much of the subpixel nuance is lost anyway. I actually find the screenshot you posted very difficult to read because of the amount of distortion to the glyph shapes. IIRC, the developers of Microsoft Word agree with me, and they actually wrote their own text rendering engine for Word so that they don't have to use ClearType. (It's been a long time since I looked at anything Windows related, I could be misremembering.) (In reply to V Stuart Foote from <a href="show_bug.cgi?id=142940#c5">comment #5</a>) > Cross platform we went to harfbuzz at 5.3.0.3; any improvement to sub-pixel > rendereing needed to improve font provided hinting for kerning will only > come with resolution of <a class="bz_bug_link bz_status_NEW " title="NEW - Use floating point for glyph positioning in VCL" href="show_bug.cgi?id=103322">bug 103322</a> This was indeed what I was worried about. My thinking, though, is that this bug shouldn't depend on that one. If LibreOffice doesn't support rendering at arbitrary subpixel offsets, then pair kerning (which depends heavily on being able to render at precise offsets) is sort of useless / broken. As far as I can tell, in LibreOffice's present state, pair kerning is effectively adding or subtracting a small random value from the desired glyph offset, which then gets rounded by the renderer into whole pixels. It's really not surprising that the result is frequently worse than no pair kerning at all. For that reason, it seems to make sense to consider disabling it until bug 103322 is fixed. Can anyone show that having it enabled confers any definite advantage to font rendering under Linux at present? My screenshots of LibreOffice's rendering would seem to suggest that the results of having it enabled are uniformly worse.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the assignee for the bug.</li> </ul> </body> </html>