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Scratching that programming itch

Joe Barr starts building an online bridge game with GTK/GNOME and glade

(LinuxWorld) ¡ª It's a bad itch. I've had it for years. For a short period, back in 1988 and 1989, I had a fix for it. But that didn't last. Now, thanks to an unlikely pair (Nick Petreley and Whil Hentzen), it's back. Let me explain.

In the late 1980s, I used to hang out on Portal, which was sort of a step-sister of The Well, a popular online watering hole at the time. Remember, these were the days before easy Internet access from anywhere to anywhere. Our rag-tag band of migrant online addicts used a flat-rate service called PC Pursuit to connect to Portal. It made it affordable to hang out online. In those days, CompuServe and The Source were getting $7 or $8 an hour for connect time. That made the Portal/PC Pursuit arrangement all the more attractive.

We would gather each evening to chat, argue and play games. The favorite game was Trivia. Ms_Missie would run the game and keep score. The competition was intense. Of course, we had ringers in the game, too, such as the woman who edited the puzzle column for New York Magazine. It was very tough to beat her. One day, as we chatted, a few of us discovered that we had enough bridge players for a table or two. That was the trigger. I had to write an online bridge game.

I had experience writing communications software using BASIC, so that is what I used to write the game. I even found a public domain comm driver written for C. I hacked that to make it work with BASIC.

Unfortunately, the application was hard-coded to connect to Portal via PC Pursuit. That turned out to be its downfall. It worked well enough to deal the cards for us, count the tricks and keep score. But when Sprint bought PC Pursuit, Peter Naleszkiewicz announced the end of the pricing that made it a good deal for folks like us. That was the end of our Portal community, and that was also the end of the bridge game.

New world, same old itch

The world has changed a lot since then. Everything is connected to the Internet, and access is usually unmetered. I don't run DOS any longer, unless you count that cool emulator called dosbox. But the itch remains. I think you can see where this is leading. I have decided to scratch that same itch again: I'm writing a bridge game, this time for online play over the Internet and on Linux.

Why do I blame Petreley and Hentzen for this? Simple. They got me thinking about Linux development. Petreley's analysis of Linux developers started it. And because I haven't coded any real Linux apps (unless I count that toy I created with Kylix), I began to feel a small twitch where the itch used to be. When Whil Hentzen told me a couple of weeks ago that developing applications for Linux is the sweet spot for software development these days, it pushed me over the edge. The itch is back. I have to scratch it.

I haven't gotten very far on the project yet, at least not in terms of coding. But I have found some good tools to use and some good code to start with. C is my language of choice, so I looked around on Freshmeat.org for existing card-games written in C and licensed under the GPL. I found one that seems a perfect match: NetSpades. It's GPL'd, it's written in very clean C, and it has many of the parts I need already in place. A server handles the connections between players, and each player runs a client. Thanks to Brent Hendricks for creating this game and making his code available under the GPL.

Because I am fonder of C than I am of C++, I've decided to use the GTK/GNOME approach rather than KDE. That's another way of saying that I can at least limp around in C, but not in C++.

I was going to call the game NetBridge to give the creator of NetSpades more credit for its heritage, but that term is already overloaded in usage. GNUBridge, on the other hand, returned zero hits on a Google Web search.

Building GNUBridge

There is an excellent tutorial for learning how to use GTK+ (the Gimp Toolkit) on the GTK.org Web site. There's another one at LinuxHeadquarters.com. They are both excellent. They cover all the basics you need to know: callbacks, widget creation and so on. I've spent some time bouncing back between the two of them recently. I would copy and paste sample code from into gedit, save it and then run gcc from the command line as they said to do. Everything worked that way, but I began to think I needed better tools. I started looking for an IDE. Freshmeat.org led me to Anjuta, so I downloaded the RPM version and installed it. Anjuta correctly placed itself in my RHL 9 menu tree during the install. It looks to be an excellent IDE, although I have to admit I haven't logged much time in it yet.

I did get as far as using the wizard to create a new project. The wizard allows you to select the programming language (C, C++ or both), application type (GTK, GNOME, libglade, etc.) and give the project a name. It creates a empty template and makefile for you, so you can start adding code and debugging it immediately. I decided to copy one of the example programs from the GTK tutorial in place of the main.c template created by the Anjuta wizard.

I clicked on Build from the Anjuta toolbar, and it compiled the code. When I clicked on Build ¡ú Execute, however, I got an error message. It turned out that particular bit of example code wanted you to enter a 1, 2 or 3 as a command-line argument. If you don't, you get the error message. I noticed an option for "Set Program Params" under Build, clicked on it, entered a 1, then clicked Execute. This time it ran, producing the window you see below. Anjuta is definitely a step up from using gedit and CLI make.

Anjuta IDE

As nice as Anjuta is, it didn't provide the instant gratification of a drag-and-drop window designer. I wanted something like Kylix, but without the licensing encumbrances. As I went through the GTK+ tutorials and learned how to build containers to stuff widgets into, I thought how nice it would be to have a GUI generating the code for me. I set off in search of one.

That's how I found glade, and I didn't even have to install it.

GUIs the glade way

Both glade and glade-2 were already on my system as part of my stock Red Hat 9 workstation installation. I spent some time feeling my way around both versions of glade. It does generate code, and it does allow me to create a GUI interface more quickly than I could by coding it manually. However, I am not sure how or if I will end up using it for GNUBridge.

One experienced GTK programmer told me not to use the C code glade generates, but instead to use the XML GUI parts and load them via libglade. Another programmer, closer to my level of GTK-programming experience than the first, said he found glade's C code useful in another way. He examined the generated code to see how he should manually code the same widgets. At the moment, that's how I am leaning towards using glade. That may change, however, as I investigate the libglade option.

So that's it for now. There will be more on this project in the future. I've got a great starting point in NetSpades. I've got a nice-looking IDE to work with in Anjuta. And I may or may not have a helpful GUI-builder in glade. I mentioned above that I hadn't gotten very far in terms of coding, but I feel that given what I have to start with, I'm more than half-way finished already.

Any advice from experienced GTK developers out there will be gratefully accepted. For all you other tired, old dinosaurs out there who have to this point only coded on mainframes, minis or DOS/Windows PCs, I have a question for you:

When are you going to start scratching your own itch and develop an application for Linux?

More Stories By Joe Barr

Joe Barr is a freelance journalist covering Linux, open source and network security. His 'Version Control' column has been a regular feature of Linux.SYS-CON.com since its inception. As far as we know, he is the only living journalist whose works have appeared both in phrack, the legendary underground zine, and IBM Personal Systems Magazine.

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