Support Prawn PDF output

[800a7b32]

We are implementing QRBills into a rails application that uses Prawn for generating PDFs.

Right now, for us to be able to use this gem without any modification means we have to output the bill to HTML, then convert it using IMGKit etc into a PNG image (for the whole bill slip) before placing the image into our Prawn output.

What we want is the entire bill slip (not just the qr_code) to output in a format supported by Prawn (e.g. png). We really want to avoid having to manually design the entire bill slip by hand incase the design standards change in the future.

[800a7b32]

we will be working on implementing support for native Prawn outputs shortly

[800a7b32]

@damoiser see #27

[andreacanonica]

@damoiser hi hi - I am also trying to implement your QRBills with Prawn PDF. I am just a beginner - at the moment I manage to get the SVG string. Could you please explain me how to get directly an image for Prawn PDF?