Creating a Print Monitor / Print Handler

Question

I'm having trouble getting started with building a Print Monitor / Print Handler for Windows using Visual Studio 2012 Ultimate with WDK 8. Basically, this is what I am trying to accomplish:

• Create a print monitor (something an application can print to) that will generate a file with the content that should be printed (like the default XPS printer or a PDF printer), and then invokes the print handler
• Create a print handler that will parse the generated file and do certain actions with it (check to see if certain text is present, upload the file online, etc)

I feel like the print handler part should not be too hard, but starting with the print monitor is what I'm stuck at. What would I do within VS12? I see options for "Printer Driver V4", "Printer Driver V4 Property Bag", and "Printer XPS Render Filter". Should I use one of those templates, and, if so, what would I do within them? Anything pointing me in the right direction would be appreciated!

EDIT:

Just some more clarification - I only need the text from the print output, but I've read from various sources that getting text-only output leads to no output at all from sources like Firefox, etc since they print text as glyphs.

I will be using the print handler to parse the text for keywords and then upload that information to a web server in a specific format. The print monitor just needs to capture and save the text information from whatever application is printing.

Answer 1

As you pointed out in your comments, some applications such as Firefox print using glyph indices instead of characters. In fact, quite a few do and it's becoming more common. What you need is a print driver. The good news is Microsoft has already written it for you and provided you with sample source code in the WDK. Start by reviewing this to understand your options. The Unidriver is perhaps a little simpler but the Postscript driver has the advantage of generating output that can readily be transformed to PDF or other formats that retain text information (as opposed to raster page images that lose all text information). As far as I'm concerned, don't even think about XPS; it's just an all around disaster.

To handle glyph indices, what you'll need to do is add code to the driver's OEMTextOut function that uses the font's cmap tables to translate glyph indices back into character codes. I'm unaware of any public domain libraries that parse font files, so you'll likely have to write your own code to do this. (Hint: If you support only OpenType/TrueType fonts, you'll cover 99% of all printing applications).

Getting the Microsoft sample code to build, install and run is mostly straightforward, but if you're new to the WDK and installing print drivers, plan on spending a week or more on just that. The glyph index translation part is far more complex and you should plan on spending a lot more time on that.