CS 241 Lab 1: Clicking on Windows

This first assignment is intended more as a warm-up exercise, to bring you back up to speed on programming from last semester (or perhaps even earlier, for some of you). If you find it especially difficult, see me: it may be that you are mis-interpreting my intent, or that I can help out in some other way.

Note: this is not necessarily a GUI (graphical user interface) assignment! Some students may not have seen GUI code yet. We may enhance the assignment at some point to include graphics, but most GUI systems using actual windows (or panels, etc.) would make this assignment trivial by doing the work for you. However, if you want to do a GUI version, do so by drawing framed rectangles on your own, i.e., not using windows from a library.

The assignment is a little simulation of a windowing system (by default textual): you should imagine some over-lapping rectangles on the screen, representing windows in a modern GUI, on any of which a user might click. When a window (i.e., a rectangle) is clicked on, it would be brought to the front (and all windows re-drawn). In order to simulate the window ordering, we will just write out the names of the windows in order, from top to bottom ... but in a picture form, they might look like one of these (depending on the GUI used):

To get the original window data, you should read the lines of a text file: each line will contain four positive integers representing the upper-left corner (x and y coordinates) and the width and height. These will be followed on the same line by a name (text string) for the window (you might want to trim the string to eliminate stray spaces from the beginning and end).

Your program should proceed as follows:

• Phase 1: read in the window coordinate data from the file and create an appropriate structure to hold the windows. You should report on the initial ordering of the windows by dumping out a listing, in order from top to bottom, just to verify the data was read correctly.
• Phase 2: read user "clicks" from the console, one per line as a pair of positive integer coordinates, promoting each selected window to the front, and leaving the others in the same relative order. (This phase continues indefinitely, until there is no more data.) Each time you read a click, you should report on the new relative ordering of the windows to verify that the correct window was promoted.

Of course, some windows might remain completely obscured, and thus not selectable, or even visible. Oh well.

Regarding implementation:

• Think in terms of classes: a window class, a window-list class, etc. (you might want to use a Python list for the latter).
• Use standard Python techniques such as a __str__(…) method for the window-list printing, in order to make your job easier.
• Use the prompted input function to read the data from the user.

I will release some sample input data files in the next few days, but you should develop your own for testing.

PS: when and if we do modify the program to use some real graphics, you would want it to be as easy as possible to "upgrade" your code to work in that new environment. The use of objects, classes and other standard Java techniques should help here, but you should think consciously about this issue as you design your program (and in general when you design any program). Building programs that are robust in the face of such changes is a difficult skill to learn, but one that you should definitely begin to cultivate now.

Some hints and samples!

Finally, here are some hints about program design and some sample data and output.

• The first page and second page of a sample program design;
• Some sample data (you can use this in your program demos, but you also should develop a set of your own windows);
• Some sample output of a program run.

Note! When demoing your program, it will be helpful to know which windows are where in your own data, so please document this somehow: a quick sketch with a few numbers will do … but you should probably have these from designing your data anyway!