问题
I need to build a QR-code for my url as small as possible - it is short enough to use shorteners (and I don't want to be dependent to their reliability).
HTTP: // SUBDOM.DOMAIN.EU
8-bit byte mode is too place-wasting, I can reach Version 2 there, but Version 1 in alphanumeric mode.
- Is there a way how to set alphanumeric mode to use only lower-case letters instead of upper-case?
- May using upper-case in URL cause problem in any browser / platform? (I tested it in Firefox, IE but I am afraid, that it is only inner case conversion.)
EDIT:
I didn't explicitely mentioned, that my adress is only subdomain and domain name, that is case-insensitive, according to for example
http://www.enterthenet.com/webgeek-stuff-web-names-and-case-sensitivity/
Addresses of this type, without page names, can be written with upper-case and use alphanumeric mode (Version 1 = 25 characters for compared to 17 chars in 8-bit byte mode on level L)
I have found different recommendations about minimum size of one dot from 0,4 mm to 0,76 mm. I need the QR-code 16 × 16 mm big and Version 1 (21×21) exactly matches the upper recommendation level.
回答1:
(Aside: version 1 is actually harder to read in some cases than version 2 because it lacks an alignment pattern. I would not be afraid of using version 2.)
Set alphanumeric mode, in what tool? Maybe, probably, but depends on your tool.
Alphanumeric mode only encodes upper-case.
URLs are case sensitive, so no you may not in general upper-case a URL. It is nothing to do with the browser.
来源：https://stackoverflow.com/questions/9767503/using-alphanumeric-mode-to-encode-url-in-qr-code