Hi
I am an Adops analyst, trafficker, campaign manager, Adops-WebApp developer and banner developer.
Adserver Knowledge: DFP, DBM, DCM, Chango, AppNexus, emmidiate etc...
Scripting Knowledge: PHP, Javascript, JQ, Ajax, Json, Basic python etc..
Me too have faced many issues with cross-domain policy while serving rich-media banners(expandable) and had found solutions for different seniors in real time.
I have analysed your project and their difficulties. Before moving into POC I would like to have some more details regarding this project.
My View:
1. Up to me this project will be only 98% automated and 2% some manual work. This is because there is no perfect client side code to take prints exactly. We need to to do some edits before we send them to client.
2. If the database of prints are going to be stored in the same domain of website then things will be much better and easier. If not means need to analyse many thinks like, where to host the Web-App, Security hazards, Administration , etc.
3. I think you can also prefer using Add-on to achieve this. Submitting the campaign Id in a form and displaying the ad and taking manual screenshot will provide more perfect output. This is just my suggestion.
Fell free to contact me over here or through my personal mail ajaykudukka on gmail.
Thanks
Ajay