W3C home > Mailing lists > Public > public-webfonts-wg@w3.org > November 2010

two minor comments on the meta-data section

From: David Singer <singer@apple.com>
Date: Fri, 5 Nov 2010 14:13:21 +0100
Message-Id: <BB25D8DE-5C80-4ECC-856E-DAD6A90765D2@apple.com>
To: WOFF Working Group <public-webfonts-wg@w3.org>
The text:

If present, the metadata MUST be compressed; it is never stored in uncompressed form.


The extended metadata MUST be well-formed XML encoded in UTF-8 or UTF-16. The use of UTF-8 encoding is recommended.

The schema for the extended metadata XML is described below. If the extended metadata does not match this schema, it is invalid. A conforming user agent MUST ignore invalid metadata, as if the block were not present.

The point:

It's not defined what 'valid' means;  a sentence is needed 'valid metadata matches the schema and is compressed' or 'valid metadata matches the schema' (which would allow UAs to process uncompressed but otherwise OK data)

The text:

The metadata block MUST follow immediately after the last font table. As font tables MUST be padded with null bytes to a 4-byte boundary, the beginning of the metadata block will always be 4-byte aligned. If the metadata block is followed by a private data block (see below), the end of the metadata block MUST be padded with null bytes to a 4-byte boundary. If the metadata block is not followed by a private data block, it MUST either be padded with null bytes to the next 4-byte boundary, or contain no additional padding after the end of the block.

The point:

Earlier we learn that the padding is only allowed *between* tables and must not follow the last one.  This paragraph suggests twice the contrary (that 'font tables must be padded', and at the end saying if it's not followed by private data, it must be padded -- but not if it's not followed by anything?).

David Singer
Multimedia and Software Standards, Apple Inc.
Received on Friday, 5 November 2010 13:14:02 UTC

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