W3C home > Mailing lists > Public > www-style@w3.org > November 2008

RE: [webfonts] pixel-perfection

From: Sergey Malkin <sergeym@windows.microsoft.com>
Date: Sun, 2 Nov 2008 14:46:31 -0800
To: Håkon Wium Lie <howcome@opera.com>, Boris Zbarsky <bzbarsky@MIT.EDU>
CC: "www-style@w3.org" <www-style@w3.org>
Message-ID: <684BC3F674EB9647A19C0B7FB3EAAF7C11CB60CF7F@NA-EXMSG-W601.wingroup.windeploy.ntdev.microsoft.com>
Håkon Wium Lie wrote:

> So, it seems -- also based on Philippe Wittenbergh's screenshot [1] --
> that Gecko's behavior is platform-dependent. Perhaps the problem is
> system-related, rather than browser-related? Could it be that the
> Starburst font triggers different behavior on Windows and Mac? And
> that Safari differs on Windows because it takes with it parts of the
> Mac system to Windows?

There are three different sets of metrics in OpenType font, they are used separately, in combination, or with heuristics by different systems/applications. I tried to take Starburst and calculate expected rendering in case browsers use different metrics.

Safari rendering matches "typo" and "mac" font metrics. This is what MacOS uses. GDI(Windows) is returning "Win" metrics, and this matches behavior of two other browsers. If browser is using whatever is provided by font system on hosting OS, this would explain difference in its behavior on Windows and Mac.

Different in appearance for is result of different distribution between ascender and descender in two sets of metrics. There is nothing wrong (by OpenType spec) in having them different, but if designer wants similar behavior for the font in different applications, metrics are better to be synchronized.

Thanks,
Sergey

Received on Sunday, 2 November 2008 22:47:15 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 27 April 2009 13:55:16 GMT