Introduction to Xwindows

This lab will introduce you to the Xwindows environment. With Xwindows, a program can interact with the user in a graphical environment. Programming with Xwindows is a bit different from the programming you are probably used to, since it presents an interface to the user, and user interaction generates events. Use the Xwindow.h and Xwindow.cc files with your programs. These files are available on the Qubit server, under the /home/cscmcw/csc4110 directory:

-rw-r--r-- 1 mweeks staff 1312  Mar 10 16:52 Xhello.cc
-rw-r--r-- 1 mweeks staff 1481  Mar 10 16:50 Xhello_iPAQ.cc
-rw-r--r-- 1 mweeks staff 12700 Mar 10 16:51 Xwindow.cc
-rw-r--r-- 1 mweeks staff 5027  Mar 10 16:51 Xwindow.h
-rw-r--r-- 1 mweeks staff 9984  Mar 10 16:49 Xwindow.o
-rw-r--r-- 1 mweeks staff 7626  Mar 10 16:51 Xwindow_demo.cc
-rw-r--r-- 1 mweeks staff 5255  Mar 10 16:51 Xwindow_demo2.cc
-rw-r--r-- 1 mweeks staff 12719 Mar 10 16:50 Xwindow_iPAQ.cc
-rw-r--r-- 1 mweeks staff 5269  Mar 10 16:50 Xwindow_iPAQ.h

Under Linux on the PC, compile the library file using:
    g++ Xwindow.cc -c
Once this is done, you can compile your program with:
    g++ YourProgram.cc -L/usr/X11R6/lib -lX11 Xwindow.o -o YourProgram
Of course, you only have to compile the library code once. To run your program, type "./YourProgram" at the command prompt. Note that the "./" is used to specify that you want to run the file called "YourProgram" found in the current directory.

Your task is to demonstrate some basic Xwindows calls:

• open an Xwindow
• draw graphics on the window
• report mouse movement
• report mouse-button presses
• report keyboard presses

When your code works, port it to the iPAQ. The main difference is that you need to use the Skiff cross-compiler, which should be in the Linux PCs in the Lab. I will supply special files "Xwindow_iPAQ.h" and "Xwindow_iPAQ.cc" to use. Actually, the default screen size is changed; everything else should be the same. Make sure you use the right ".h" file. To compile, use the following commands.
For the library file:
 /skiff/local/bin/arm-linux-g++ Xwindow_iPAQ.cc -c

 /skiff/local/bin/arm-linux-g++ YourProgram.cc -L/skiff/local/arm-linux/lib/X11 -lX11 Xwindow_iPAQ.o -o YourProgram_iPAQ

If this does not work, make sure that the cross-compiler is where it is supposed to be. Note that appending "_iPAQ" to your program's name is not a requirement, but it will help you remember which file is which. Next, download the code to the iPAQ. You can do this with the wireless card, or by sync'ing the iPAQ to the host machine. If your choose to use the wireless card, an easy way to use it is to put the file under your public_html directory. On the iPAQ, you would type "wget http://yamacraw.cs.gsu.edu/~youraccount/YourProgram_iPAQ". Then "chmod 777 YourProgram_iPAQ" to change the file's permissions. Finally, you can run it with "./YourProgram_iPAQ" from the iPAQ's command prompt.

Write-up what you did IN YOUR OWN WORDS. Do not simply re-word the directions, but explain what is going on. Avoid listing steps. Use outside sources as appropriate, and be certain to cite your sources. Turn in one report per person. Make sure everyone is present for the lab.
 

Questions:
1. What is X-windows? Research it, describe it, and be sure to cite sources in your answer. (This should be at least 2 pages.)
2. How big is the executable file on the Host PC? How big is it on the iPAQ?
3. Re-compile your program for both Host PC and iPAQ. Use the "-S" option to generate the assembly language listing. How many commands does your program take on the Host PC? How many on the iPAQ? Which is larger, and why?
4. Why do we develop the program on the Host PC first, instead of testing it on the iPAQ every time?
5. How could you give some events priority over others?