The Tiles and SB-World Teachpacks

These teachpacks provide a variety of functions for manipulating and animating graphical images. To use them, you'll need to

download them to your computer,
install them in the right place in your computer, and
load them in DrScheme.

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). You shouldn't need to do this at all on a classroom computer.

Right-click on this link and choose "Save Link" (or the equivalent on your browser). Save the file someplace like the desktop; we'll clean that up later.
Do the same with this link.
Start DrScheme.
If it doesn't say "Language: Beginning Student", go to the "Language" menu, then "Choose Language", then "How to Design Programs", then select "Beginning Student". Click the "Run" button.
If it says anything about "Teachpacks" on the line below "Language: Beginning Student", go to the "Language" menu and "Clear All Teachpacks". Click "Run".
Go to the "Language" menu, "Add Teachpack", then "Add Teachpack to List", then browse to wherever you put the two files. Double-click one of them and click "OK".
Repeat the previous step with the other file.
Click "Run". You should see
Welcome to DrScheme, version 371 [3m].
Language: Beginning Student custom.
Teachpacks: 371-tiles.ss and 371-sb-world.ss
If the two teachpacks are listed in the other order, that doesn't matter.
You should now be able to delete the two files from the desktop or wherever you put them.

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", and you should see both 371-tiles.ss and 371-sb-world.ss on the right-hand side. Click one of these, then "OK". Repeat with the other teachpack. Click the "Run" button. You should see a message saying "Teachpack: 371-tiles.ss and 371-sb-world.ss" 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 do they 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. The 371-tiles.ss teachpack includes several useful functions for manipulating images:

```
image-above: image image ... -> image
```
Combines two or more images into one, putting the first above the second (above the third, ...).
```
image-above-align-right: image image ... -> image
```
Just like image-above, but lines up the right-hand edges of all the images.
```
image-above-align-left: image image ... -> image
```
Just like image-above, but lines up the left-hand edges of all the images.
```
image-beside: image image ... -> image
```
Combines two or more images into one, putting the first to the left of the second (to the left of the third, ...).
```
image-beside-align-top: image image ... -> image
```
Just like image-beside, but lines up the top edges of all the images.
```
image-beside-align-bottom: image image ... -> image
```
Just like image-beside, but lines up the bottom edges of all the images.
```
reflect-vert : image -> image
```
flips an image top-to-bottom.
```
reflect-horiz : image -> image
```
flips an image left-to-right.
```
reflect-main-diag : image -> image
```
flips an image top-right to bottom-left.
```
reflect-other-diag : image -> image
```
flips an image top-left to bottom-right.
```
rotate-cw : image -> image
```
rotates an image 90 degrees clockwise.
```
rotate-ccw : image -> image
```
rotates an image 90 degrees counter-clockwise.
```
rotate-180 : image -> image
```
rotates an image 180 degrees.

The 371-tiles.ss teachpack also includes the image.ss teachpack (which comes standard with DrScheme, so you don't need to worry about installing it). This provides a variety of other functions useful for building and manipulating images in DrScheme. To learn about them, start DrScheme, choose "Help -> Help Desk", and search for "image.ss".

The 371-sb-world.ss teachpack provides several functions related to animation:

```
run-animation : number(width) number(height) world
number(tick interval) handler ... -> true
```
This is the most important function in the 371-sb-world.ss teachpack. You give it the width and height of your desired animation window, the initial world, how many seconds between "ticks", and possibly some "handlers", and it will run an animation for you. For details, see Chapter 7 of my textbook.
```
run-saveable-animation: ...
```
Just like run-animation, except that it records the sequence of events and allows you to save it as an animated GIF picture.

nw:rectangle : number(width) number(height) string("outline" or
"solid" string(color-name) -> scene

Just like rectangle, but puts the "pinhole" in the top left corner.

More To Come...

Last modified:

Stephen Bloch / sbloch@adelphi.edu