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Re: EOT-Lite File Format

From: Thomas Lord <lord@emf.net>
Date: Thu, 30 Jul 2009 16:08:29 -0700
To: John Daggett <jdaggett@mozilla.com>
Cc: www-font <www-font@w3.org>
Message-Id: <1248995309.6257.84.camel@dell-desktop.example.com>
On Tue, 2009-07-28 at 17:15 -0700, John Daggett wrote:

> EOT-Lite header validation:

> 1. Check that MagicNumber is 0x504C.
> 2. Check that the version number is either 0x00010000, 0x00020001, or 0x00020002.
> 2. Check that Flag bits TTEMBED_TTCOMPRESSED and TTEMBED_XORENCRYPTDATA are not set.
> 
> If any of these checks fail, the font is not loaded.  The font is
> activated by loading the data at offset (EOTSize - FontDataSize) of
> length (FontDataSize) as a normal OpenType font.

[Regarding your second item #2 as #3, as presumably
intended.]

When you say "the font is not loaded" do 
you mean MUST, MAY, or SHOULD?

If EOT-lite becomes the recommendation, is the 
previously discussed patent de-encumberence of MTX
included in the deal?

(My opinion is that if check #3 fails a browser
SHOULD (but is not obligated to) render the font
and MTX has to be included in the deal.  Otherwise
we have a sneaky back door in which liability concerns
are imposed on browser makers.)

Similarly, all three checks should be stated affirmatively
rather than negatively.  If the magic number and version
numbers check out and if the flag bits of interest are 0
then the browser MUST render the font.  That is importantly
different from "MUST NOT" in the case where those checks
don't pass.

-t
Received on Thursday, 30 July 2009 23:09:10 GMT

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