I would like to write a visual force page that dynamically generates a QR code and serves it up as an image to the browser based on parameters in the URL. This is not currently possible due to the way VF encodes data.
Examples of people asking for this:
"Visualforce emits text, not binary data. As such, the output result ends up running through a UTF-8 parser. UTF-8 disallows certain combinations of bits, such as 0xFF 0xFF. Basically, when 0x80 is set in a byte, the remainder of the 0x7F bits tell the UTF-8 stream how many more bytes to read, and each byte after must start with 0x80 with 0x40 bit set to zero, or the entire multibyte entity is also invalid."
"I can't convert blob into binary strings the only encoding for binary data in salesforce is base64"