Bug 97972 – Mathematical characters shown as missing glyphs (empty squares)

• Component: WebCore Misc.
• Status: RESOLVED MOVED

[Samuel]

When accessing a webpage that contains some mathematical characters, a missing glyph square is shown. 

To reproduce it, view http://en.wikipedia.org/wiki/Mathematical_Alphanumeric_Symbols and go to the different tables showing glyphs of different Unicode characters.

The actual result is that an empty square is shown instead of most characters (see captured attachment). 

The expected result would properly render the different characters (attached capture from MSIE 9.0.10).

=== Detailed description ===

The bug happens when the character is missing from all the font families or generic fonts indicated by the webpage creator in the corresponding style declarations. In particular, in the above example, a "font-family: sans-serif" declaration applies to the whole page. The table includes characters from the range U+1D400 ... U+1D7FF, but they are shown as empty squares instead. The only characters correctly rendered are indeed those shadowed in pink, noting they come from a different range. This is not exclusive to sans-serif, as the same happens with other font families that do not include glyphs for those characters.

This happens when using any WebKit browser: the last nightly build r129884 (version 534+), Safari 5.1.7 (version 534.57.2), and Chrome 22 (version 537.4). In contrast, in a non-webkit browser, they appear correctly rendered. In MSIE and Firefox, we may see they have been rendered as Cambria Math glyphs (coming with Windows 7 by default), which is not a sans-serif font, yet it includes the characters here needed.

Moreover, this is not the usual behaviour of webkit either. If we view a page which includes, for instance, characters from the Cherokee syllabary (see attached capture), they are rendered using a specialized font (Plantagenet Cherokee).

[Samuel]

Created attachment 166371 [details]
Capture of WebKit faulty rendering of the example webpage

[Samuel]

Created attachment 166372 [details]
Capture of correct rendering on MSIE 9.0

[Samuel]

Created attachment 166373 [details]
Capture of the correct rendering of Cherokee on Webkit

Cherokee is another script purportedly unsupported by the fonts specified by CSS, yet it is correctly rendered, so it must be something specific to Mathematical Alphanumeric.

[Samuel]

Update: the same happens in Safari on an iPad2 (534.46): Cherokee Syllabary is correctly rendered but Mathematical Alphanumerical is not. Yet in this case I am not sure if this is a problem of the characters available in the iPad fonts or the same webkit bug.

[Alexey Proskuryakov]

FWIW, this page renders correctly for me in Safari 6.0.1 on Mac.

[Alexey Proskuryakov]

<rdar://problem/12406590>

[Samuel]

It also renders ok for me on Chrome 21 (Webkit 537.1) on Ubuntu 11.

From which I understand this is not a webkit-wide bug, but a platform-specific one which appears repeatedly on different ports of webkit (Chrome on Win, but on on Ubuntu, Safari on iPad 2, but not on Mac...).

[Brent Fulgham]

The fix for this issue was needed outside the WebKit project, therefore this is being resolved as 'Moved'.

This should now be fixed in shipping software.