Drawbox (Freeware)

Drawbox is a lightweight, lighthearted package for graphics programming in C++.  It is especially designed for student programmers, though others may find it useful.  It is cross-platform, supporting both Macintosh and Windows, so that students can use whatever computer they have at school, and take their work home to whatever computer they have there.

The programmer's interface is carefully designed for quick-start, low-overhead programming.  All you need to get started is one #include and a main function, and the very first line of that function can be a drawing command.  No visible setup required.  There is only one window, and it does not need to be specified or named; it is implicit.

Drawbox is an open-source effort.  Programmers who want to add to the package itself are welcomed to do so; please send fixes and improvements back to ken@sparklight.com to be added to the main distribution.  I would love to find someone interested in doing a port to Linux.

This package is being maintained and improved in an ongoing way. Work is in progress to make quick, frequent releases possible. If you find bugs, please report them to: ken@sparklight.com.

If you teach programmers, or if you've been wanting to do some lighthearted graphics programming yourself, download Drawbox and give it a try!

Download (Macintosh .sea, 1.5 MB)
Download (Macintosh .hqx, 1.9 MB)
Download (Windows .EXE , 1.8 MB)

The archive you download actually contains the code and projects for a dual build, Macintosh and Windows. See the Setup directory for an easy way to remove what you don't need. If you actually want to use the dual build, download and unpack on a Macintosh to preserve file type information.

I'm interested in having a small core of highly-involved testers, who plan to use the package and interact with me a lot. If you feel like being one of those, please speak up! Or if you are a less involved user, but would like to be on the mailing list for announcements of new releases, please speak up.

Why another graphics package?

How fondly I remember the days of my first computer, and Apple II+. You could just sit down, write a few lines of Basic, and it would start drawing graphics for you. But with the advent of Macintosh, now followed by all other modern operating systems, the age of the GUI/window system has come. A lot of research went into the original Macintosh interface design, and it and its offspring have made programs much more user-friendly. But not programmer-friendly. In Windows it takes upwards of 40 lines of code, just to create a window that can interact with the system in a half-decent way. And then you're ready to start doing graphics.

Drawbox is an attempt to bring back programmer-friendly graphics. No setup required, except one simple #include, and you're ready to go. I expect it to grow with time, to accommodate more of the typical window-system things--but never compromising the ability to do simple things simply, with very low overhead.

Another virtue, though less of a priority, is low overhead in space. Drawbox can produce executables as small as 100K.

What's in the name?

When a professional enters upon the project of programming in a new system, especially where graphics are involved, he is faced with the vast and complex world of an operating system. It has historical quirks, numerous system dependencies, and various data structures that the programmer must initialize and use, although they are really only needful for complex programs, not simple ones.

The beginning student must be protected from all this. We need to build a "sandbox," a safe, confined environment in which the student can enjoy graphics while being protected from the quirks and the complexity. Drawbox is such a box, designed for students of beginning to intermediate skill.

Drawbox Resources for Teachers

Marine Biology Case Study

Part 1: a fish swims back and forth randomly in a tank, making a "bump" sound whenever it collides with the wall of the tank. Statistics are reported as in the standard Case Study. An optional advanced version shows several fish swimming at once, each at a different depth and carrying out its own random walk.

Part 2: several fish, each with its own color and number to identify it, swim randomly in a two-dimensional tank.

Download (Macintosh .sit) Download (Windows PC ZIP)

Executables for quick preview: Fish; MultiFish; Fish2 (Macintosh .sit) Fish; MultiFish; Fish2 (Windows PC ZIP)

(Note: this exercise revealed a minor bug in the display of numbers in the Windows version of Drawbox, which affects Part 2. It impairs the visual quality but not the accuracy of the output. This will be fixed after Christmas family visits are over!)

 

SortWatcher

A very visual sorting algorithm simulator, using colors as the sort keys. Includes most of the AP required algorithms; you can also program more algorithms into it with a handy object-oriented interface. SortWatcher page.

SortWatcher came out of my teaching work in an AP Computer Science course, during the spring of 2000. It is a visualization based on the use of colors (in their natural spectral order) to illustrate sort keys; this has the result that as well as being beautiful, it very easily shows when sorting is complete or nearly complete.

SortWatcher is flexible. You can specify the number of array elements it will work on, and you can specify several aspects of the speed of execution.

It is also extensible, designed for use in a class exercise. It comes with several well-known sorting algorithms already built in, so you may simply run it to illustrate them. But its true intended use is to assign different algorithms to different individuals or teams in the class, to let each come up with their own visualized implementation of the algorithm. When all is done, they can all be assembled together into one grand improved "class showcase" SortWatcher program, with a button for each student-implemented algorithm in its button bar.

Download (Macintosh .sit)
Download (Windows PC ZIP)
These files provided to the public without restriction.

Support for new visualized algorithms is provided through three simple classes: VisInt stands in for int, or other type of the elements to be sorted VisVector stands in for apvector<int>, or other type of the array to be sorted VisIndex stands in for int, wherever int is used as an index into the array. Each of these types can be used just like the type it stands in for, except in the constructor, where some extra visual information must be provided. The whole framework makes it quite easy to adapt a sorting program based on apvector<int>, into a visual sorting module under SortWatcher.

If you, the teacher, are assigning such an exercise, you may wish to strip out most of the provided algorithms, before making it available to students. To do so, just look in Algorithms.txt and reverse the process (Step 5) of installing an algorithm.

 

An Introduction to Recursion

CheckerCheckerBoardBoard starts out looking like a 3x3 checkerboard. Click on any square, and it changes state. But you will soon find that every square has three states, not two: blue, yellow, and other. And what is other?? A recursive image of the whole! But that is for the student to figure out, while playing with it.

I envision this little program as a first demonstration of recursion, in a visual form. But it may also be useful as a programming exercise, to ask the student to replicate it. The program takes good advantage of the Drawbox Rect class, which makes it very easy to subdivide a rectangle into an array of equal sub-rectangles.

Download (single source file)

(Note: students will try to use large numbers of squares, thinking to get a cooler image. Discourage this, because it doesn't work. The best numbers are 5 and under, because they allow for deep recursion.)