From 3913d1778318cd0c6bfb871148d38abb33ec7fd3 Mon Sep 17 00:00:00 2001 From: nasr Date: Wed, 28 Jan 2026 13:13:40 +0100 Subject: checkpoint --- xlib-tutorial/index.html | 116 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 116 insertions(+) create mode 100644 xlib-tutorial/index.html (limited to 'xlib-tutorial/index.html') diff --git a/xlib-tutorial/index.html b/xlib-tutorial/index.html new file mode 100644 index 0000000..5e57eaf --- /dev/null +++ b/xlib-tutorial/index.html @@ -0,0 +1,116 @@ + + +Xlib programming: a short tutorial + + + + +

Xlib programming: a short tutorial

+ +I haven't found anything very satisfying on the Web as an Xlib +tutorial. Many of them are too much Motif-oriented for my +taste. Furthermore, I answer questions about X programming almost +daily, so I've started to put together some small coursewares. + +

Important note:

the example programs are written in C++, but +this is mainly for the ability to declare variables anywhere. + +
+ +Let's begin with a short story: the eternal story of the newbie at +Xlib writing his/her first program. + +

+ + +"Ok, I've to open a connection to the X server (whatever this means), +with XOpenDisplay, then create a window with XCreateWindow, then draw +a line with XDrawLine. Then, the program sleeps for ten seconds so I +can see the result. Sounds easy." + + +

+ +The poor newbie writes the program. And nothing happens. He then +calls his wizard friend. + +

+ + +-"Did you perform an XFlush after you've done everything ?
+- No, why ?
+- The requests stay in the client," wizard doubletalk, thinks the +poor newbie, " if you +don't." + + +

+ +The poor newbie changes the program. And nothing happens. He then +calls his wizard friend. + +

+ + +-"Did you map your window ?
+- Did I do what ???
+- Creating a window doesn't make it appear on the screen. You've to + map it with XMapWindow first. + + +

+ +The poor newbie changes the program. The window appears with nothing +in it (like this). The poor newbie then calls +his wizard friend. + +

+ + +-"Did you wait for a MapNotify before drawing your line ?" (more wizard doubletalk)
+- "No, why ?
+- X has a stateless drawing model, the content of the window may be lost + when the window isn't on the screen." (overflow, why can't these + wizard guys speak just like you and me ?) "You've to wait for a MapNotify + before drawing." + + +

+ +The poor newbie changes the program. Things are getting more and more +complex. Not as easy as it first seemed. A loop gets the events until a +MapNotify. The window appears with nothing +in it. The poor newbie then calls his wizard friend. + +

+ + +-"I got it, did you select the StructureNotifyMask on your window ?
+- ???
+- Just do it, and everything'll be fine. + + +

+ +The poor newbie fixes the program. And the miracle happens ! A line in the +window. Until now, the program looks like this +(it is actually slighty more complex than the dialog may let you think). + +

+ +Now you've learned at least 2 things: + +

+ +Now, if you want to learn more and get a deeper understanding of the +program, go to next lesson. + +

More about X.

+ + +
Christophe Tronche, ch.tronche@computer.org
+ + -- cgit v1.3