Oh! I just have to type "r/cpp" instead of "cpp". Sorry... works just the wrong default value. Awesome function!
Looks like this no longer works?
I get a proper pdf with those inputs: https://api.blockspring.com/results/8bc25e917b803df569c28a282cb187bc
What is inside of $content? Is there any html? Copy/paste that into the form on this page, what do you see?