user48450: Not trusting those already available QR code generators available, I would want to program my own. The idea is to input a Bitcoin key ( private or public ) and the program would simply generate the corresponding QR code image as the output. Of course, this program would be run from an offline computer has to preserve a maximum security.
I haven't found any useful source of information about the procedure needed for my project. I've got fare experience in programming BASIC VBA C C++. I can probably figure out some Java or Python codes.
Essentially , I am looking for a tutorial showing the main procedure to input a Bitcoin key and construct the actual QR code.

user140302: You're mentioning private keys, which are obviously not supposed to be shared while the purpose of QR code is to share information.
A QR Code is the transformation of a string into a 2D picture. It could be URL or whatever text. There is no specification for Bitcoin about QR Code.
If you'd like to share a public address for payment purposes, you just have to generate the QR Picture using the public address, some exchange applications support it.
Edit: QR Code generation libraries exists for most of programming languages.

48450: <p>Not trusting those already available QR code generators available, I would want to program my own. The idea is to input a Bitcoin key ( private or public ) and the program would simply generate the corresponding QR code image as the output. Of course, this program would be run from an offline computer has to preserve a maximum security.</p>
<p>I haven't found any useful source of information about the procedure needed for my project. I've got fare experience in programming BASIC VBA C C++. I can probably figure out some Java or Python codes.</p>
<p>Essentially , I am looking for a tutorial showing the main procedure to input a Bitcoin key and construct the actual QR code.</p>
 140302: <p>You're mentioning private keys, which are obviously not supposed to be shared while the purpose of QR code is to share information.</p>
<p>A QR Code is the transformation of a string into a 2D picture. It could be URL or whatever text. There is no specification for Bitcoin about QR Code.</p>
<p>If you'd like to share a public address for payment purposes, you just have to generate the QR Picture using the public address, some exchange applications support it.</p>
<p>Edit: QR Code generation libraries exists for most of programming languages.</p>
