added extra demo

x/displaylist.cpp

 /*
 CS 349 Code Examples: X Windows and XLib
 
-    displaylist     Demos Displayable class and display list
+    displaylist     Demos Displayable class and display list technique
 
 - - - - - - - - - - - - - - - - - - - - - -
 

x/multiwindow.cpp

+/*
+CS 349 Code Examples: X Windows and XLib
+
+    multiwindow     Opens and draws into two windows
+
+  					usage:
+
+  					to create sibling window:
+
+  					   ./muliwindow sib  
+  					
+  					to create child window:
+
+  					   ./multiwindow child
+
+- - - - - - - - - - - - - - - - - - - - - -
+
+See associated makefile for compiling instructions
+
+*/
+
+#include <iostream>
+#include <list>
+#include <cstdlib>
+#include <unistd.h>
+
+/*
+ * Header files for X functions
+ */
+#include <X11/Xlib.h>
+#include <X11/Xutil.h>
+
+using namespace std;
+
+const int Border = 5;
+
+
+/*
+ * Information to draw on the window.
+ */
+struct XInfo {
+	Display	 *display;
+	int		 screen;
+	Window	 window;
+	GC		 gc[3];
+};
+
+
+/*
+ * Function to put out a message on error exits.
+ */
+void error( string str ) {
+  cerr << str << endl;
+  exit(0);
+}
+
+
+void drawPointsInCorners(XInfo &xinfo) {
+	Display  *display = xinfo.display;
+	Window   win = xinfo.window;
+	GC       gc = xinfo.gc[1];
+
+	XWindowAttributes windowInfo;
+	XGetWindowAttributes(display, win, &windowInfo);
+	unsigned int height = windowInfo.height;
+	unsigned int width = windowInfo.width;
+
+	/* draw one pixel near each corner of the window */
+	XDrawPoint(display, win, gc, 5, 5);
+	XDrawPoint(display, win, gc, 5, height-5);
+	XDrawPoint(display, win, gc, width-5, 5);
+	XDrawPoint(display, win, gc, width-5, height-5);
+}
+
+void drawStuff(XInfo &xinfo, int gcIndex, int x, int y) {
+	Display  *display = xinfo.display;
+	Window   win = xinfo.window;
+	GC       gc = xinfo.gc[gcIndex];
+
+
+	/* draw two intersecting lines, one horizontal and one vertical, */
+	/* which intersect at point "x,y".                            */
+	XDrawLine(display, win, gc, x, y-30, x, y+200);
+	XDrawLine(display, win, gc, x-30, y, x+200, y);
+
+	/* now use the XDrawArc() function to draw a circle whose diameter */
+	/* is 30 pixels, and whose center is at location 'x,y'.         */
+	XDrawArc(display, win, gc, x-(30/2), y-(30/2), 30, 30, 0, 360*64);
+
+	{
+		XPoint points[] = {
+				{x+200, y+50},
+				{x+250, y+80},
+				{x+200, y+80},
+				{x+200, y+50}
+			};
+		int npoints = sizeof(points)/sizeof(XPoint);
+
+		/* draw a small triangle at the top-left corner of the window. */
+		/* the triangle is made of a set of consecutive lines, whose   */
+		/* end-point pixels are specified in the 'points' array.       */
+		XDrawLines(display, win, gc, points, npoints, CoordModeOrigin);
+	}
+
+	/* draw a rectangle whose top-left corner is at 'x+120,y+50', its width is */
+	/* 50 pixels, and height is 60 pixels.                                  */
+	XDrawRectangle(display, win, gc, x+120, y+50, 50, 60);
+
+	/* draw a filled rectangle of the same size as above, to the left of the */
+	/* previous rectangle.                                                   */
+	XFillRectangle(display, win, gc, x+60, y+50, 50, 60);
+}
+
+
+
+
+/*
+ * Initialize X and create a window
+ */
+void initX(int argc, char *argv[], XInfo &xInfo, Window root, int x, int y, int width, int height) {
+	XSizeHints hints;
+	unsigned long white, black;
+
+	white = XWhitePixel( xInfo.display, xInfo.screen );
+	black = XBlackPixel( xInfo.display, xInfo.screen );
+
+	hints.x = x;
+	hints.y = y;
+	hints.width = width;
+	hints.height = height;
+	hints.flags = PPosition | PSize;
+
+	xInfo.window = XCreateSimpleWindow(
+		xInfo.display,				// display where window appears
+		root, 						// window's parent in window tree
+		hints.x, hints.y,			// upper left corner location
+		hints.width, hints.height,	// size of the window
+		Border,						// width of window's border
+		black,						// window border colour
+		white );					// window background colour
+
+	XSetStandardProperties(
+		xInfo.display,		// display containing the window
+		xInfo.window,		// window whose properties are set
+		"x2_simpleDrawing",	// window's title
+		"SD",				// icon's title
+		None,				// pixmap for the icon
+		argv, argc,			// applications command line args
+		&hints );			// size hints for the window
+
+	/*
+	 * Create Graphics Contexts
+	 */
+	int i = 0;
+	xInfo.gc[i] = XCreateGC(xInfo.display, xInfo.window, 0, 0);
+	XSetForeground(xInfo.display, xInfo.gc[i], BlackPixel(xInfo.display, xInfo.screen));
+	XSetBackground(xInfo.display, xInfo.gc[i], WhitePixel(xInfo.display, xInfo.screen));
+	XSetFillStyle(xInfo.display, xInfo.gc[i], FillSolid);
+	XSetLineAttributes(xInfo.display, xInfo.gc[i],
+	                     1, LineSolid, CapButt, JoinRound);
+
+	i = 1;
+	xInfo.gc[i] = XCreateGC(xInfo.display, xInfo.window, 0, 0);
+	XSetForeground(xInfo.display, xInfo.gc[i], BlackPixel(xInfo.display, xInfo.screen));
+	XSetBackground(xInfo.display, xInfo.gc[i], WhitePixel(xInfo.display, xInfo.screen));
+	XSetFillStyle(xInfo.display, xInfo.gc[i], FillSolid);
+	XSetLineAttributes(xInfo.display, xInfo.gc[i],
+	                     7, LineSolid, CapRound, JoinMiter);
+
+	i = 2;
+	xInfo.gc[i] = XCreateGC(xInfo.display, xInfo.window, 0, 0);
+	XSetForeground(xInfo.display, xInfo.gc[i], BlackPixel(xInfo.display, xInfo.screen));
+	XSetBackground(xInfo.display, xInfo.gc[i], WhitePixel(xInfo.display, xInfo.screen));
+	XSetFillStyle(xInfo.display, xInfo.gc[i], FillSolid);
+	XSetLineAttributes(xInfo.display, xInfo.gc[i],
+	                     7, LineOnOffDash, CapButt, JoinBevel);
+
+
+	XSelectInput(xInfo.display, xInfo.window,
+		ButtonPressMask | KeyPressMask | ExposureMask);
+
+	/*
+	 * Put the window on the screen.
+	 */
+	XMapRaised( xInfo.display, xInfo.window );
+
+}
+
+void repaintWindow1(XInfo xinfo) {
+	drawPointsInCorners(xinfo);
+	drawStuff(xinfo, 0, 30, 50);
+	drawStuff(xinfo, 1, 180, 200);
+	drawStuff(xinfo, 2, 330, 350);
+}
+
+
+void repaintWindow2(XInfo xinfo) {
+	drawStuff(xinfo, 0, 30, 50);
+}
+
+/*
+ * Start executing here.
+ *	 First initialize window.
+ *	 Next loop responding to events.
+ *	 Exit forcing window manager to clean up - cheesy, but easy.
+ */
+int main ( int argc, char *argv[] ) {
+	XInfo xInfo1;
+	XInfo xInfo2;
+	bool isSibling = true;
+
+	if (argc != 2) {
+		error("Usage: ./multiwindow [sib|child]");
+	} else if (strcmp(argv[1], "sib") == 0) {
+		isSibling = true;
+	} else if (strcmp(argv[1], "child") == 0) {
+		isSibling = false;
+	} else {
+		error("Usage: ./multiwindow [sib|child]");		
+	}
+
+
+   /*
+	* Display opening uses the DISPLAY	environment variable.
+	* It can go wrong if DISPLAY isn't set, or you don't have permission.
+	*/
+	Display * display = XOpenDisplay( "" );
+	if ( !display )	{
+		error( "Can't open display." );
+	}
+
+   /*
+	* Find out some things about the display you're using.
+	*/
+	int screen = DefaultScreen( display );
+	xInfo1.display = display;
+	xInfo1.screen = screen;
+
+	// create window 1
+	initX(argc, argv, xInfo1, DefaultRootWindow( display ), 100, 100, 800, 600);
+
+	// create window 2
+	xInfo2.display = display;
+	xInfo2.screen = screen;
+
+	if (isSibling)
+		// make window 2 a sibling of window 1
+		initX(argc, argv, xInfo2, DefaultRootWindow( display ), 50, 50, 250, 125);
+	else
+		// make window 2 a child of window 1
+		initX(argc, argv, xInfo2, xInfo1.window, 50, 50, 250, 125);
+
+	XFlush(display);
+	sleep(1);	// let server get set up before sending drawing commands
+
+	// need to repaint both windows
+	repaintWindow1(xInfo1);
+	repaintWindow2(xInfo2);
+
+	XEvent event;
+
+	while( true ) {
+		XNextEvent( display, &event );
+		switch( event.type ) {
+			case ButtonPress:
+				if (event.xany.window == xInfo1.window)
+					cout << "Got button press in window 1!\n";
+				else if (event.xany.window == xInfo2.window)
+					cout << "Got button press in window 2!\n";
+				break;
+			case KeyPress:
+				if (event.xany.window == xInfo1.window)
+					cout << "Got key press in window 1!\n";
+				else if (event.xany.window == xInfo2.window)
+					cout << "Got key press in window 2!\n";
+				break;
+			case Expose:
+				// only repaint window which sent the expose
+				if (event.xany.window == xInfo1.window)
+					repaintWindow1(xInfo1);
+				else if (event.xany.window == xInfo2.window)
+					repaintWindow2(xInfo2);
+				break;
+		}
+	}
+
+	/* flush all pending requests to the X server. */
+	XFlush(display);
+
+	XCloseDisplay(display);
+}