[xsl] formatting lines to a fixed width.

[Kamal Bhatt <kbhatt@xxxxxxxxx>]

Hi
I am outputting a field to plain text and I need to ensure that a fixed 
width is maintained. To help me with this I "borrowed" some code from 
www.dpawson.co.uk/xsl/sect2/N7240.html#d9312e433 . (BTW, if he is 
around, thanks to Mr. Pawson for maintaining this website, it has been a 
great resource).

I had to modify it, however, as it did not take two things into account. 
Firstly, it assumes that all lines need to be split, secondly it assumes 
a normalised string, that is, one without any newlines.

I fixed the first of these, but I am having problems with the second. 
Here is my modified version of the code. Basically, I assume that if the 
substring contains a newline then I should move through it in a forward 
direction until I find the newline. The ouput I am looking for is 
something like this:

title:[TAB]Blah BLah BLah blah blah blah blah
[TAB]
[TAB]BLAH BLAH

with input text:
<Text>Blah BLah BLah blah blah blah blah

BLAH BLAH</Text>


<xsl:template name="text-print">
   <xsl:param name="txt"/>
   <xsl:param name="width"/>
   <xsl:param name="title"/>
   <xsl:param name="first"/>
   <xsl:param name="text-pos"/>
   <xsl:param name="space-padding"/>

   <xsl:param name="space-pad">
   <xsl:call-template name="repeat-chars">
       <xsl:with-param
        name="rep-chars"><xsl:text>&space;</xsl:text></xsl:with-param>
       <xsl:with-param name="times" select="$space-padding"/>
       <xsl:with-param name="str"></xsl:with-param>
   </xsl:call-template>
   </xsl:param>
   <xsl:if test="$txt">
   <xsl:variable name="real-width">
       <xsl:call-template name="tune-width">
       <xsl:with-param name="txt" select="$txt"/>
       <xsl:with-param name="width" select="$width - $space-padding"/>
       <xsl:with-param name="def" select="$width - $space-padding"/>
       </xsl:call-template>
   </xsl:variable>

   <xsl:choose>
       <xsl:when test="$first = 'true' and $text-pos = 1">
       <!-- TEXT OUTPUT BEGINS -->
       <xsl:value-of select="$title"/>:<xsl:text>&tab;</xsl:text>
       <xsl:value-of select="$space-pad"/>
       <xsl:value-of select="substring($txt, 1, $real-width)"/>
       <xsl:text>&newln;</xsl:text>
       <!-- TEXT OUTPUT ENDS -->
       </xsl:when>
       <xsl:otherwise>
       <!-- TEXT OUTPUT BEGINS -->
       <xsl:text>&tab;</xsl:text>
       <xsl:value-of select="$space-pad"/>
       <xsl:value-of select="substring($txt, 1, $real-width)"/>
       <xsl:text>&newln;</xsl:text>
       <!-- TEXT OUTPUT ENDS -->
       </xsl:otherwise>
   </xsl:choose>
   <xsl:call-template name="text-print">
       <xsl:with-param name="txt"
               select="substring($txt, $real-width + 1)"/>
       <xsl:with-param select="$width" name="width"/>
       <xsl:with-param name="first">false</xsl:with-param>
       <xsl:with-param name="title" select="$title"/>
       <xsl:with-param name="space-padding" select="$space-padding"/>
   </xsl:call-template>
  </xsl:if>
</xsl:template>

<xsl:template name="repeat-chars">
   <xsl:param name="rep-chars"/>
   <xsl:param name="times"/>
   <xsl:param name="str"/>
   <xsl:choose>
   <xsl:when test="$times &gt; 0">
       <xsl:call-template name="repeat-chars">
           <xsl:with-param name="rep-chars" select="$rep-chars"/>
       <xsl:with-param name="times" select="$times - 1"/>
       <xsl:with-param name="str" select="concat($str, $rep-chars)"/>
       </xsl:call-template>
   </xsl:when>
   <xsl:otherwise>
       <xsl:value-of select="$str"/>
   </xsl:otherwise>
   </xsl:choose>   
</xsl:template>

<xsl:template name="tune-width">
   <xsl:param name="txt"/>
   <xsl:param name="width"/>
   <xsl:param name="def"/>
   <xsl:variable name="newln"><xsl:text>&newln;</xsl:text></xsl:variable>

   <xsl:if test="string-length($txt) &lt; $width">
       <xsl:value-of select="string-length($txt)"/>
   </xsl:if>
  
   <xsl:if test="contains(substring($txt, 1, $def), $newln)">
      <xsl:choose>
              <xsl:when test="substring($txt, $width, 1) = $newln">
           <xsl:value-of select="$width"/>
           </xsl:when>       
       <xsl:otherwise>
           <xsl:variable name="new-width">
           <xsl:choose>
                <!-- This indicates that this is the first time in -->
               <xsl:when test="$def = $width">1</xsl:when>
           <xsl:otherwise>
                <xsl:value-of select="$width + 1"/>
           </xsl:otherwise>    
           </xsl:choose>   
       </xsl:variable>   

       <xsl:call-template name="tune-width">
           <xsl:with-param name="txt"   select="$txt"/>
           <xsl:with-param name="width" select="$new-width"/>
           <xsl:with-param name="def"   select="$def"/>
       </xsl:call-template>
       </xsl:otherwise>   
   </xsl:choose>
   </xsl:if>   

   <xsl:choose>
   <xsl:when test="$width = 0">
        <xsl:value-of select="$def"/>
   </xsl:when>
   <xsl:otherwise>
        <xsl:choose>
        <xsl:when test="substring($txt, $width, 1) = ' '">
            <xsl:value-of select="$width"/>
        </xsl:when>
        <xsl:otherwise>
            <xsl:call-template name="tune-width">
             <xsl:with-param name="txt" select="$txt"/>
             <xsl:with-param name="width" select="$width - 1"/>
             <xsl:with-param name="def" select="$def"/>
            </xsl:call-template>
        </xsl:otherwise>
        </xsl:choose>
      </xsl:otherwise>
  </xsl:choose>
</xsl:template>

Cheers.

Kamal