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Re: [css3-text] text-transform: uppercase; and cpsp OpenType Feature

From: John Daggett <jdaggett@mozilla.com>
Date: Wed, 7 Sep 2011 00:24:03 -0700 (PDT)
To: fantasai <fantasai.lists@inkedblade.net>
Cc: www-style@w3.org, www-font@w3.org
Message-ID: <626873282.86741.1315380243398.JavaMail.root@zimbra1.shared.sjc1.mozilla.com>
[cross posting to www-font]

fantasai wrote:

> One of the issues marked in the latest draft of CSS3 Text is whether the
> cpsp OpenType feature should be turned on for combinations of
>    text-transform: uppercase; letter-spacing: normal;
> 
> This does seem to be the recommendation in the OpenType spec:
>    http://www.microsoft.com/typography/otspec/features_ae.htm#cpsp

A quick search of typophile returns some interesting discussions
related to this feature [1]. The capital spacing feature is a feature
registered by Adobe and it's functionality mimic's InDesign behavior. 
In InDesign, if you apply allcaps to a specific run of text, the
letters are uppercased and the feature is enabled.  However, this
suffers from the problem that normal textruns of all uppercase letters
can't access this feature.

In the context of text-transform enabling capital spacing, that would
mean the two lines below would render differently, the first one with
capital spacing, the second line without:

  .ex1 { text-transform: uppercase; }

  <p class="t1">abc</p>
  <p>ABC</p>

I think that *if* we want to support this feature it would be better
to support it using an extra value for font-variant-caps.  Support
wouldn't be automatic but there also wouldn't be odd differences in
text-transform'ed text versus simple strings of capital letters.

I should also point out that you can currently achieve similar results using:

  .ex2 { text-transform: uppercase; letter-spacing: 0.2em; }

One note about the OpenType feature tag list, what's described as
"default" in the description of individual feature tags may not in
actuality be a true, general default.  This feature is an *optional*
feature that is which is applied in certain contexts (e.g. when the
allcaps setting is enabled in InDesign).

Cheers,

John

[1] http://typophile.com/node/15849
Received on Wednesday, 7 September 2011 07:24:31 GMT

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