1422602 - ability of Firefox to replace missing fonts

Status: RESOLVED INVALID

(Core :: Layout: Text and Fonts, defect)

Description

[milenhh]

User Agent: Mozilla/5.0 (Windows NT 10.0; rv:53.0) Gecko/20100101 Firefox/53.0
Build ID: 20170518000419

Steps to reproduce:

please check this thread
https://webcompat.com/issues/13844


Actual results:

https://webcompat.com/issues/13844


Expected results:

missing font to be replaced

Comment 1

[Jonathan Kew [:jfkthame]]

As was already explained in https://webcompat.com/issues/13532, this is behaving as expected. If you choose the option to use your preferred fonts instead of those specified by the web page, that's exactly what Firefox does. In cases where the site was depending on a particular icon font, that may result in "bad" display.

In the example of https://www.ricardo.ch/ from https://webcompat.com/issues/13532, there are (at least) two icon fonts involved, the "RicardoCategory" font which provides the icons to the left of the various category titles, and the "Material Icons" font which is used for the right-arrow symbols to the right of the category titles, as well as on various other buttons etc. In this example, the RicardoCategory icons still work even when "Allow pages to choose their own fonts" is deselected, because this font uses Private Use Area codepoints that are not likely to be supported in the default fonts selected in the browser options; as a result, we still end up with RicardoCategory as the only available font that supports those character codes.

On the other hand, the Material Icons font is encoded to use strings of English text, and then form ligatures that are actually the icon glyphs. Here, the regular ASCII characters used are naturally present in the default font you've chosen in the browser options, and therefore that's the font we use -- exactly as requested by the preference setting.

In short: working as designed. Not a browser webcompat issue; if anything, it's a web authoring issue: using ligature-based icon fonts is a poor design choice, because it means that if the intended font is unavailable (for any reason -- in this case because the user has forced the browser to prefer its default fonts) the layout will be severely broken.