My grand project to compile a database of cross-platform LC font metrics is
slowly progressing, though rather hindered by bugs in LC.
In particular fontNames() produces inconsistent results between Mac and Windows
(and is not available in Linux) and worse can produce incorrect results on the
Mac.
To demonstrate, start using font file Akshar[wght].ttf, which is one of the
Google opentype fonts. This file includes 5 style variations, which are
certainly all quite different fonts in appearance. The naming and style
conventions for fonts are so complex that the bug is understandable — but its
still a bug.
On the Mac, fontNames() produces
Akshar Light
Akshar Light
Akshar Light Medium
Akshar Light SemiBold
Akshar Light Bold
This is a bug: the first two are supposed to be references to quite different
variations (a Regular and Light version of Akshar). Since they have the same
name one of them cannot be accessed by setting textFont. This list does not
match the MacOS knowledge of the font.
On Windows, fontNames() produces
Akshar
This is perhaps not a bug, but gives no way to access the 4 non-Regular
versions of the font; the variations would be accessed by a Windows user or app
by setting a style variation, but this cannot be done in LC. It also does not
match what the Windows system knows about the fonts in the family..
If you look at Akshar[wght].ttf in the Mac Font Book application, you find that
the system says the name of the font family is Akshar, with fonts
Akshar Regular
Akshar Light
Akshar Medium
Akshar SemiBold
Akshar Bold
If you look at Akshar[wght].ttf in the Windows Font Manager application, you
find that the system says the name of the font family is Akshar Light, with
fonts
Akshar
Akshar Light
Akshar Medium
Akshar SemiBold
Akshar Bold
Using Linux the Fonts application (Ubuntu) the family name appears as Akshar,
Light (note the comma) and with named variations
Regular, Light, Bold, Medium, SemiBold
The LC function fontNames() is not implemented in Linux but there is a shell
command fc-list which explains a lot. After parsing a little we get
Akshar,Akshar Light
Akshar,Akshar Light:style=Regular
Akshar,Akshar Light:style=Bold
Akshar,Akshar Light:style=Medium
Akshar,Akshar Light:style=SemiBold
Akshar,Akshar Light:style=Light,Regular
The items before the colon are alternative names for the font. The first line
with no styles attached give the family names – 2 alternative names, Mac uses
#2, Win uses #1. So fonts can have many names, often including non-Roman script
names. They also can have multiple styles, many being international names of
English style names. Akshar is actually a comparatively straightforward case.
Which names should be returned by fontNames() for each platform is clearly a
difficult problem.
Apart from the bug in the Mac version of fontNames(), there may be problems,
which I cannot yet pin down, with using custom fonts in Windows as well. A
stack which works in the IDE crashes as a standalone, the error dialog
returning a seemingly irrelevant line for the source of the error so likely it
is in the engine somewhere and almost certainly to do with fontNames.
Furthermore even in the IDE there may be a problem with stop using font file,
as it does not seem to clear the font cache after multiple use, which means
fontNames() returns stale values.
Finally of course there is fontStyles(), which has been dead for years on the
Mac, and even when it did work returned only plain, italic, bold, bold-italic
instead of the actual available font style variations — and even if it did
would be useless because you can’t set such styles within LC. A vast number of
modern fonts are just inaccessible from LC.
Neville Smythe
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