<rect height="50" width="1.5" x="$x" y="0.0"/>...
but fop doesn't want assign the value of $x in "rec" tag
It's not FOP, its the XSLT processor. Use <rect height="50" width="1.5" x="{$x}" y="0.0"/>
This is called "attribute value template", look up details in an XSLT book, a tutorial or the XSL FAQ.
XSLT questions like this are better asked on the XSL list: http://www.mulberrytech.com/xsl/xsl-list/
J.Pietschmann
