Customizing the Look of Your Distro | Hacking Knoppix (ExtremeTech)

You have the software you want, but you still need to make things look fun and inviting for the kiddies. You can make some changes that will improve the look of your new distro.

Getting a Desktop Background

The normal desktop background is OK, but the kids would get a kick out of something that's a bit cooler. First you need to find an image. If you're making this distro for a particular individual who has a favorite picture, by all means, use that; but if you would instead like to find something online, you'll find a few ideas in this section and the accompanying sidebar, "Searching for Cool Wallpaper." Just make sure that any images you decide to use are freely available or licensed in such a way that you can use them without any problems.

There's a particular image from the Astronomy Picture of the Day site that it is beautiful and thought-provoking, qualities you should always look for in a good photograph. Titled "Earth at Night," the photo (shown in Figure 11-1) was chosen as Picture of the Day in 2000. You can find it at http://antwrp.gsfc.nasa.gov/apod/ap001127.html.

image from book
Figure 11-1: Earth at Night
C. Mayhew and R. Simmon (NASA/GSFC), NOAA/ NGDC, DMSP Digital Archive

The composite photograph gives you a powerful sense of humanity's presence on the globe, perfect for a discussion with an intelligent kid. Where are there lights? Why? Where are there fewer lights? Why is that? Geography, history, environmentalism: It can all be taught using this one image.

The 386KB image's 2400 × 1200 dimensions won't work with Knoppix. Instead, it needs to be 1024 × 768. Open the image in the GIMP (examined in Chapter 1) and change the image's dimensions. Yes, the image will be a bit distorted, but it's not that bad, and it actually is closer to the Gall-Peters projection that some geographers find more accurate.

Note

For more information on the various ways to picture the spherical earth on a flat surface, see Gall-Peters projection (http://en.wikipedia.org/wiki/Gall-Peters_projection), Mercator projection (http://en.wikipedia.org/wiki/Mercator_projection), and Map projection (http://en.wikipedia.org/wiki/Map_projection).

Alternately, you can use the GIMP to change the size of the image's width, but keep your dimensions proportional. Then change the size of the image's canvas to 1024 × 768, center the image vertically, and give the blank areas at the top and bottom of the canvas a color, like the deep navy of the photo or black.

Once you have the image you want, copy it into the appropriate location in the Knoppix file system structure:

 $ cp knoppix.jpg /home/scott/knoppixuncompressed/usr/local/lib/

Now when your distro finishes loading, the kids using it will have an amazing image in front of their eyes.

Changing the Boot Screen

Long before the desktop background screen shows up, the boot screen makes its appearance. That's where you can present the user with the name of your distro. This is clearly an important consideration: Your custom distro's name should be short, snappy, descriptive, and somehow cool. For example, St. Louis is the home of the world-famous Arch, and that's what sparked the name Archix for this chapter's example kid distro. It seemed like a fun name to use.

Creating a boot screen isn't nearly as easy as making a desktop background image. First, open the GIMP and create a blank image that's 640 × 480 pixels in size. Paste in a photo or some other graphic that you like (the example uses a photo of the Arch taken from one of its legs). Then use the Text tool to insert text blocks that describe your distro, welcome new users, and let them know to press Enter to boot the CD. Don't be afraid to use a little color to spice things up (a little orange, a popular color with kids, could give a little zing to the text showing your distro's name).

To finalize things for Knoppix, save your image as a PPM file (the example is, cleverly enough, archix.ppm). Then set it to use only 16 colors, which is required by Knoppix. This may chew up your image quite a bit, and greatly limit the quality of your boot screen, but you have no choice. It must be 16 colors. To limit the color palette, select Image → Mode → Indexed, choose Generate Optimum Palette, and then set Maximum Number of Colors to 16. The boot screen shown in Figure 11-2 isn't exactly a work of art, but it's clear and neat enough for kids to enjoy.

image from book
Figure 11-2: The boot screen for Archix utilizes the famous St. Louis Arch.

Searching for Cool Wallpaper

There are loads of Websites from which you can get terrific pictures to use as wallpaper for your distro. Here are some sites to check out:

Common Content — http://commoncontent.org/. A catalog of works licensed using Creative Commons.
Flickr — http://flickr.com. The best photo-sharing site in the world. In particular, see http://flickr.com/creativecommons/, which contains Flickr photos available under a Creative Commons license.
Stock.XCHNG — http://sxc.hu/. 100,000+ stock photos taken by 9,000+ individuals
The Open Photo Project — http://openphoto.net/. 2,395 photos taken by 2,158 users, and all photos are released under a Creative Commons license.
Astronomy Picture of the Day — http://antwrp.gsfc.nasa.gov/apod/. Gorgeous, stunning astronomy photos available for personal, noncommercial, nonpublic fair use.

On the command line, convert the ppm to lss16, the format that Knoppix uses for a boot screen. The name must be logo.16, so don't use anything else:

 $ ppmtolss16 < archix.ppm > logo.16

Now move the image to its correct location in the Knoppix filesystem:

 # cp logo.16 /home/scott/knoppixiso/boot/isolinux/

You've customized the images that people will now associate with your distro. There's still more you could do, but this is enough to give you some ideas to tackle on your own.