Re: [xsl] Calculating the size of a string

["G. Ken Holman" <gkholman@xxxxxxxxxxxxxxxxxxxx>]

At 2012-08-15 07:13 -0400, Philip Vallone wrote:
> I have an xml input that will be processed into a FO file, via Saxon 
> and Apache's FOP (1.0). The resulting string will eventually be 
> output to a fo:table-cell. FOP does a decent job of hyphenating, 
> however it is not perfect. If I have a string input like this:
>
> <pnr>PN-THIS.IS.A.LONG.PN12.23.56</pnr>
>
> The output on PDF looks like this:
>
> PN-
> THIS.IS.A.LONG.PN12.23.56
>
> the problems is that my cell is very small. I would like to have it 
> look like this:
>
> PN-THIS.IS.A.
> LONG.PN12.
> 23.56
>
> I found a workaround, where if I include spaces in the string, I get 
> better results:
>
> <pnr>PN-THIS.IS.A.LONG. PN12.23. 56</pnr>
>
> However, this requires changing the input, which I don't want to do. 
> I can not use string-length because the size of the space can vary 
> depending on the characters used. For example, 'WWWWW', is bigger 
> than 'iiiii' in actual size. Both return a string-length of 5, but 
> are not the same size. So, I've written a java extension that will 
> return the size of the Rectangle2D width. I have an idea of where 
> the 'line' break should be (140 the width of the framing rectangle), 
> but I am not sure how to translate the width into a function in xslt 
> to add the spaces.
>
> Any ideas?

Yes, if you look on page 317 of my XSL-FO book (you can download it 
in full for free) at:

  http://www.CraneSoftwrights.com/training/#pfux
  (use the "Try and Buy free trial A4/US download" links)

... you'll see an example of this where I recommend to students to 
inject the string with Unicode zero-width spaces:  &#x200b

That way if the string fits, you see no visual difference, but if the 
string does not fit, it breaks more likely where you have injected 
the zero-width spaces.

I needed to solve this problem for URIs.

Of course your space method and my zero-width-space method still 
presents the problem that if the user uses copy and paste from the 
printed material, those characters are embedded in the copied 
content.  In my case I typically make the URI linkable so that users 
will be more tempted to simply click on it than use copy and paste.

I hope this helps.

. . . . . . . . . . . Ken

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