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RE: 7.16.2 "letter-spacing"

From: Paul Grosso <pgrosso@arbortext.com>
Date: Wed, 19 Mar 2003 12:03:09 -0600
Message-Id: <4.3.2.7.2.20030319115611.01c682e0@172.27.10.30>
To: www-xsl-fo@w3.org

At 17:50 2003 03 19 +0000, Dave Pawson wrote:
>At 09:55 19/03/2003 -0600, Paul Grosso wrote:
>
>>Sorry I wasn't clearer.
>
>No problem Paul.
>   I'll keep asking till I understand it :-)
>
>
>>letter-spacing affects all fo:characters (and leaders
>>and page-numbers).
>
>'All' other than the one on which it is explictly specified?

All.  Every FO has a value for letter-spacing, and every
fo:character is affected by letter-spacing.  (Most of them
have the default value.)

>>  Remember that all FOs always have a
>>value for all properties, either because the property
>>in question is explicitly specified on that FO or because
>>it has an inherited or defaulted value.
>
>I'm happy with that.
>
>
>>More below.
>>
>>At 15:37 2003 03 19 +0000, David.Pawson@rnib.org.uk wrote:
>>>Paul said:
>>>> The discussion at
>>>> http://www.w3.org/TR/xsl/slice7.html#letter-spacing
>>>> explains how letter-spacing affects the space-start and
>>>> space-end traits of the fo:character.
>>>>
>>>> What the spec doesn't make clear in section 7.16.2  is that letter-spacing
>>>applies
>>>> only to the fo:character, fo:leader, and fo:page-number FOs
>>>> (as you discover if you search through the various FO descriptions
>>>> for applicable properties).
>>>
>>>I'm nearly happy with that Paul, but *which* character(s) is my question.
>>>I'm using
>>><fo:character../><fo:character../><fo:character../>
>>
>>All characters.  Every fo:character has some value for letter-spacing.
>
>OK, but if inheritance is 'down' the hierarchy, in the example given,
>this is the current one plus none?

Right.  There is no 'down' from fo:character.




>>> What I'm trying to do is use a negative
>>>value to get a character to appear more to the start direction
>>>than it normally would, rather than using a combining diaresis,
>>>which works nicely to produce, say a u umlaut.
>>
>>Then you don't want letter-spacing, you want to set the space-start
>>of that character to a negative value.
>
>OK, I'm on home territory :-) I.e. I got it wrong.
>
>>  While letter-spacing might
>>work in that it affects the fo:character's space-start, space-start
>>is much more likely to be implemented than letter-spacing, so you
>>are making your life unnecessarily difficult.
>
>Heck I'm used to that Paul!!
>   I must admit, the idea of using negative values is not
>   home ground for me!
>
>
>>>    <fo:block font-family="ArialUnicodeMS">
>>> <fo:inline>Some more standard inline text to test a different way.
>>>&#x20;<fo:character character="A" letter-spacing="-0.8 * 1em" />
>>><fo:character character="&#x02DA;"
>>>
>>>vertical-align="50%"/> </fo:inline></fo:block>
>>
>>In that case, it only affects the middle fo:character since
>>the other two have the default value of letter-spacing (which
>>is zero).  And how it affects that middle letter is by changing
>>its start-space as described in the spec.
>
>I'd request then that the rec be clarified?
>  Since its spaces we are talking about, and for any fo:character,
>these occur either side of the char in question, I found it
>quite elusive..... (and AH and XEP implement it differently)
> so perhaps it could be more clearly explained?

Most likely the spec could be clearer.

>My 'trial and error' was tending to show
>that it impacted the space following the actual char on which
>it was specified, but perhaps I'm the odd one in deducing that.

I simplified.  It can affect both space-start and space-end.
See the spec at
http://www.w3.org/TR/xsl/slice7.html#letter-spacing
and read the part that starts "the space-start and space-end 
traits are each set to a value as follows:".

paul
Received on Wednesday, 19 March 2003 13:09:17 GMT

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