How can I scale an image with ColdFusion without losing resolution?

Question

Server Config:

• Windows Server 2003
• IIS 6
• ColdFusion 8 Standard Edition
• Java Version 6 Update 18

I have a ColdFusion application that allows users to upload images that will be added to an existing PDF. When the images are added to the PDF, they have to fit within a minimum/maximum height and width, so the uploaded image needs to be scaled to fit.

For instance, let's say the minimum height and width for a given image is 100x100, and the maximum height and width is 200x200, and the user uploads an image that is 500x1000. I use the logic below to scale that image down without skewing the image (it keeps its original shape) to 100x200. For an image smaller than the minimum, it is scaled up (in the example above, a 50x50 image would be scaled up to 100x100).

The problem I'm noticing is that when ColdFusion scales the image using its built-in functions, it reduces the resolution to 72dpi. Is there a way to prevent this loss of resolution, as the images are being added to PDFs which need to be print-quality?

Here's the [scaled-down] code I'm using to scale the images:

<cfscript>
    imagePath = "/uploads/image.tif";
    scaledWidth = 100;
    scaledHeight = 100;
    scaledImage = ImageNew(imagePath);
    ImageSetAntialiasing(scaledImage, "on");
    ImageScaleToFit(scaledImage, scaledWidth, scaledHeight);
</cfscript>

Answer 1

I think you may want to skip scaling the image at all and add the original image to the pdf document. Then have whatever pdf creation tool you are using "resize" and position the image on the document canvas. Similar to setting width and height on images in html to something other than its native resolution. I have not had to add images to PDFs docs like you described but this post might point you in the right direction:

Adding a dynamic image to a PDF using ColdFusion and iText