The closest I've gotten is from blockchain.info
https://blockchain.info/qr?data=1Agb153xWsbqS9vt8gP4vBFKHkAchLMdSX&size=200
I can't find any documentation for other parameters like 'amount' though?
I did find a service that does a generate a QR code with an amount. I just have never heard of them before (trust?). And am not sure what to put for 'error correction level' or 'code square size' given this code will be displayed on a website.
There are many ways you can generate a QR code!
IMO, the most trusted way to generate a QR code is through google!
You can simply make an tag with this link:
https://chart.googleapis.com/chart?chs=250x250&cht=qr&chl= 12kQMUkB9QJu9X5JP9H9M2qMUmrGtDakkV
Im not sure what you mean by "trust". You dont really need to worry about trust since these are just the public keys, and not the private keys.
I hope this helps! (My BTC address is in the QR code!)