The Tiles Teachpack

This teachpack provides a variety of functions for manipulating graphical images. To use it, you'll need to

To download and install

This should be done once on your home computer, and you'll never have to do it again (unless I come up with an improved version). If you do it on a classroom computer, the teachpack may be uninstalled before the next time you come to class, so you'll have to do it again (unless I can persuade the Computing Center to install it permanently).

The easy way

Start DrScheme, go to the "File" menu, choose "Install .plt file...", make sure you're in the "Web" tab rather than the "File" tab, type the URL "" into the blank, and hit "OK". It should be downloaded and installed.

However, on some computers this doesn't seem to work: you get messages like "gnu-unzip: bad header" and "not an unpackable distribution archive". If that happens, try...

The second easiest way

Right-click on the link tiles.plt, choose "Save file as...", and save it somewhere on your computer. Wherever you put it, it should appear with a red-white-and-blue DrScheme logo. If so, double-click on it and it should install automatically (perhaps showing a black window for a few seconds).

If the file appears with some other kind of logo, try...

The third easiest way

Once you've saved the tiles.plt file somewhere on your computer, start DrScheme, choose "File->Install .plt file...", click the "File" tab, then the "Browse" button, navigate to wherever you put the file, select it, and hit "OK". You should get a bunch of messages ending with "Done setting up."

If that doesn't work, talk to me.

To load in DrScheme

When you start DrScheme, you can tell it you want to use these added functions, and it'll remember that for the next time you start DrScheme on the same computer... unless somebody else using the same computer tells it not to use this teachpack, in which case you'll need to go through these steps again.

Go to the "Language" menu in DrScheme and choose "Add Teachpack", select "", click "Open", and then click the "Run" button. You should see a message saying "Teachpack: ..." in the interactions window. The next time you start DrScheme, it should remember this unless you choose "Language->Clear Teachpack" to remove the teachpack.

What does it do?

You can copy-and-paste images from a Web browser into DrScheme and use them just like any other value: you can store them in a variable, etc. This teachpack includes several useful functions for manipulating images:

It also includes a number of useful functions for creating images from scratch: It also includes functions to find out information about an image:

There are numerous other, more obscure, functions provided; to learn about them, start DrScheme, choose "Help -> Help Desk", and search for "" (my "" teachpack is an enhancement of the built-in "", including all the same functions and a few improvements).

Last modified:
Stephen Bloch /