The other day, I experimented with saving InVision prototypes as interactive PDFs in Lucee CFML. And, while very few people will have an interest in such a technique, it’s gotten me thinking a lot about how I might use PDFs more effectively. One thing I started to wonder about is how CFDocument handles repeated Image URLs. The answer to this would certainly influence how I would implement different types of PDF content: whether I crop images in a pre-processing step, generating unique image URLs per cropping; or, whether I should just use overflow:hidden in order to simulate cropping on a repeated image URL. To explore this, I created a simple demo in which I can dynamically repeat an image in a CFDocument tag using Lucee CFML 5.3.4.80.
This demo is super simple. All I’m doing is passing in a URL parameter, pageCount, and then using CFLoop to generate N-number of pages all with the same img tag and src attribute:
<!--- We can use the URL to drive the number of pages generated in the PDF. --->
<cfparam name="url.pageCount" type="numeric" default="1" />
<cfdocument
format="pdf"
filename="./images.pdf"
overwrite="true"
localurl="true"
orientation="portrait"
pagetype="a4"
margintop="0.5"
marginright="0.5"
marginbottom="0.5"
marginleft="0.5">
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8" />
<style type="text/css">
p img {
border: 3px solid #ff3366 ;
width: 600px ;
}
</style>
</head>
<body>
<cfoutput>
<cfloop index="i" from="1" to="#url.pageCount#" step="1">
<p>
<!---
This IMAGE file is going to be used on N-number of pages. We can
look at the size (bytes on disk) of the generated file to see if
the repeated image is "reused" intelligently.
--->
<img src="file:///#expandPath( "./goose-duck.jpg" )#" />
</p>
<cfdocumentitem type="pagebreak" />
</cfloop>
</cfoutput>
</body>
</html>
</cfdocument>
<!--- Now that the file has been generated, let's look at the file-size. --->
<cfoutput>
Page Count: #url.pageCount#
<br />
File Size: #numberFormat( getFileInfo( "./images.pdf" ).size )#
</cfoutput>
#coldfusion #artificial intelligence
