fo:external-graphic src="data:image/png;base64, ..." as attribute

Question

I have a sniplet in my xslt like:

    <fo:block>
    <fo:external-graphic src="data:image/png;base64, //base64 code//" />
    </fo:block>

Not to clutter my main stylesheet, i have created another xslt that have the base64 image as parameter like:

     <xsl:param name="logo">data:image/png;base64, //base64 code//</xsl:param>

If i change my main stylesheet to:

    .
    .
    <xsl:include href="image.xsl" />
    .
    .
    <fo:block>
    <fo:external-graphic>
    <xsl:attribute name="src"><xsl:value-of select="$logo" /></xsl:attribute>
    </fo:external-graphic>
    </fo:block>

1st i get a heap-size error and after using -Xmx4096m i get a parse error.. When i have the base64 image embedded in the main stylesheet, i don't need the 4gb heap and the pdf i make have the image as intented.

Using Apache FOP 1.1 and sorry for my english, not my main language..

Answer 1

You are trying to use an attribute value template, I think. Use { and } to indicate that $logo is not a literal value, but a variable or parameter.

<fo:external-graphic src="{$logo}" />

Like this it is even more concise, since you do not have to type xsl:value-of.

Otherwise, $logo is stored as literal text content. Read about attribute value templates here.

---

To illustrate this:

Stylesheet

<?xml version="1.0" encoding="utf-8"?>

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:fo="http://www.w3.org/1999/XSL/Format">

   <xsl:output method="xml" indent="yes"/>

   <xsl:template match="/">
      <xsl:param name="logo">data:image/jpg;base64,/9j/4AAQSkZJRgABAQEASABIAAD/4QNaRXhpZgAATU0AKgAAAAgADQEPAAIAAAAGAAAAqgEQ</xsl:param>

      <fo:external-graphic src="{$logo}"/>
   </xsl:template>

</xsl:stylesheet>

Output

<?xml version="1.0" encoding="utf-8"?>
<fo:external-graphic xmlns:fo="http://www.w3.org/1999/XSL/Format" src="data:image/jpg;base64,/9j/4AAQSkZJRgABAQEASABIAAD/4QNaRXhpZgAATU0AKgAAAAgADQEPAAIAAAAGAAAAqgEQ"/>