From: Gary P. Grosso (ggrosso@arbortext.com)
Date: Fri Dec 03 2004 - 10:10:44 CST
Hi Antoine, others,
Questions about OpenType vs TrueType come up often in my work, so perhaps the list will suffer a couple of questions in that regard.
First, I see an "O" icon, not an "OT" icon in Windows' "Fonts folder" for some fonts and a "TT" icon for others. Nothing looks like "OT" to me, so are we talking about the same thing?
Next, if I double-click on one of the "fonts" (files), I get a window which shows a sample of the font, at the top of which is the font name, followed by either "(OpenType)" or "(TrueType)". Can I believe what that says as indicative of whether this is truly OpenType or TrueType?
Mostly how this comes up is we have customers ask if we support OpenType fonts, to which I reply with some variation of "it depends". I usually say the OpenType spec is complex, but we handle all the commonly-used fonts we know of, and follow it by saying that they can look in their Fonts folder (at the icon) to see some examples of OpenType fonts. So that is the background for my questions.
Thanks,
Gary
> -----Original Message-----
> From: unicode-bounce@unicode.org [mailto:unicode-bounce@unicode.org] On Behalf
> Of Antoine Leca
> Sent: Friday, December 03, 2004 9:26 AM
> To: unicode@unicode.org
> Subject: Re: current version of unicode-font
>
> On Friday, December 03, 2004 13:10, Cristian Secarã va escriure:
> >
> > However, the .ttf fonts that ship with their products are showing an
> > OT icon. I don't know how it's done technically.
>
> Technically, it is done by including a (valid) 'DSIG' (digital signature)
> subtable into the font file, that is a table whose only aim is to guarantee
> that the fontfile has been unaltered (using cryptographic seals as used for
> certificated e-mails).
>
> The interesting thing is that while the specification for this 'DSIG' table
> is part of OpenType, it is completely unrelated to what people usually
> associates with this technology, that is the possibility to have complex
> script and advanced typography support (see my previous post for details,
> since I did the mistake myself ;-).) Neither it is related to the fact (also
> introduced by the OpenType specifications) to have the outlines and hints
> stored in Postscript format (rather than the traditional TrueType format)
>
> As a result, having the nice-looking OT on a font is misleading, it just
> means the designer have paid Verisign for a class 3 certificate and signed
> its font. And last but not least it ensures you the font has not been
> modified (I am hoping Windows is actually checking the seal, but when I
> thought a bit more I am not 100% sure, since this is a process that is
> somewhat time-consuming, and it does not appear to me that Windows is less
> quick to draw the content of this folder...)
>
>
> Antoine
>
--- Gary Grosso Arbortext, Inc. Ann Arbor, MI, USA
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