 Software Center and find the OpenJDK Java 7 runtime; on openSUSE 12.3, the matching package goes by the name java-1_7_0-openjdk.
The ZIP archive of the portable QR code generator is available from the project’s Downloads page (to download, click on the Herunterladen link under the .zip entry). Unzip the file on your hard drive, open a terminal window, change to the directory with the extracted files, and run the command:
$ java -jar QRCodeGen.jar
The main window appears, and a small preview window (Figure 5) shows you the QR code.
In the main window, look at the top edge first. Depending on the data you want to store in the code, click on the appropriate tab; that is, to save a URL, open the URL tab, and for an address, use VCard v4.
In the selected tab, the program displays appropriate fields. For an address, you will see more tabs that group the information, but you only need to fill out the required fields. If you do not want to specify a phone number, simply ignore the Telephone tab. If the address is already in a vCard file, you can import it by clicking Read VCard.
Once you have entered the data to encode, click on Generate. The results appear in the preview window. Plain text (in the Text tab) and geographic coordinates (in the Geo URI tab) are exceptions; the preview shows the code during entry.
You can define the size of the QR codes, as well as the error correction level at the bottom left under QR Code options section. In contrast to the previously featured tools, the Portable QR code generator allows you to specify the dimensions for the final image.
If you set Requested size (pixel) to 400, the resulting QR code image is 400 screen pixels wide. However, if you want to specify the size of each dot in the code, set Mode to Module size, then in Module size (pixel) define the number of pixels to form a dot. Additionally, you can select a specific Character encoding (see the “Character Encoding” box).
To the right, in the QR Code details panel, you will see some statistics that reveal, among other things, how many bytes of payload (Data byes) the QR code currently displayed contains. To check the text that the Portable QR code generator actually dumped into the QR code, look at the bottom of the window; the details are in the Data field.
You can copy the generated QR code to the clipboard (Edit | Copy QR Code to clipboard) or save a PNG format image file with File | Save As.
KDE users have an easy way to convert text into QR code: Copy some text to the clipboard, click the Klipper tool (the scissors) in the system section of the control bar at the bottom, and select Show Barcode. Unfortunately, the interface does not let you save the QR code shown on the left side (Figure 6) or copy it to the clipboard. Your only workaround is to grab a screenshot with KSnapshot. For a single QR code this will still be faster than installing one of the other tools.
A possible alternative is the slightly older KBarcode4-light. To use it, first install PyQt via the package manager. On openSUSE 12.3 and Ubuntu, it resides in the python-qt4 package. Next, unpack the KBarcode4-light archive, which you downloaded off the web. In the src subdirectory, run the python kbarcode.py command.
In the window that now appears (Figure 7), select the QR Code item in the Encoding drop-down, then type the text to encode in Value, and press Generate. The resulting QR code appears at the bottom. Pressing Save as PDF lets you save the code in a text file.
Theoretically, it’s possible to export the QR code as an image file, but clicking Save on modern distributions only leads to an error message in the terminal. Another alternative is to click Copy and then paste the Clipboard contents into another program. The options offered in the Basic Options and Extra Options tabs are useless for QR codes.
Although dozens of apps are out there for reading QR codes with smartphones, only a few fairly rudimentary programs exist for Linux. If you have QtQR installed, press Decode in the bottom right corner of the main window. The program either accepts the QR code a