乘 <xsl:value-of> -1的结果

Question

Novice/beginner XSL user here.

I have something like the following template in my XSLT document:

<xsl:template name="getpoint"> <xsl:param name="nodenum"/> <xsl:value-of select="//nodeCoord[nodeNumber=$nodenum]/nodeXCoord"/> <xsl:text>,</xsl:text> <xsl:value-of select="//nodeCoord[nodeNumber=$nodenum]/nodeYCoord"/> </xsl:template>

The full XSLT document is being used to produce an SVG graphic. However, I wish to flip the browser's Y coordinate system upside down since my source data assumes a traditional coordinate system.

My question is very simple: how do I multiply nodeYCoord by -1 and have that result sent to the browser instead of the value produced by the <xsl:value-of> element?

EDIT: Please do not provide alternative methods on how to flip the Y coordinate system. I have researched this, and for my specific application I am pretty certain this is the best way to go about it (assuming I can make it work).

Answer 1

My question if very simple: how do I multiply nodeYCoord by -1 and have that result sent to the browser instead of the value produced by the <xsl:value-of> element?

And the answer is very simple, too: use the minus sign. Instead of:

<xsl:value-of select="//nodeCoord[nodeNumber=$nodenum]/nodeYCoord"/>

write:

<xsl:value-of select="-//nodeCoord[nodeNumber=$nodenum]/nodeYCoord"/>

Please do not provide alternative methods on how to flip the Y coordinate system. I have researched this, and for my specific application I am pretty certain this is the best way to go about it (assuming I can make it work).

Perhaps you should take another look at it.

Answer 2

Save your value to a variable and then use it in an xpath expression

<xsl:variable name="yval" select="//nodeCoord[nodeNumber=$nodenum]/nodeYCoord/text()"/>
<xsl:value-of select="-1 * $yval"/>