#include <decw$include/Xlib.h>
#include <decw$include/Xutil.h>
#include <stdlib.h>

#define FontName\
    "-Adobe-New Century Schoolbook-Medium-R-Normal--*-140-*-*-P-*-ISO8859-1"
#define WindowName "Sample Xlib Program"

Display *dpy;
Window window1,window2;
GC gc;
Screen *screen;
int state = 0;
char *message[]= {
    "Click here to exit",
    "Click HERE to exit!"
    };

static void doInitialize( );
static int doDefineColor( );
static void doCreateWindows( );
static void doCreateGraphicsContext( );
static void doLoadFont( );
static void doExpose( );
static void doMapWindows( );
static void doHandleEvents( );
static void doButtonPress( );

/********************** The main program *******************************/

static int main()
{          
    doInitialize( );
    doHandleEvents( );
}                                        

/***************** doInitialize **************************/
static void doInitialize( )
{
    dpy = XOpenDisplay(0);	
    if (!dpy){
        printf("Display not opened!\n");
        exit(-1);
    }
    screen = XDefaultScreenOfDisplay(dpy);

    XSynchronize(dpy, 1);

    doCreateWindows( );

    doCreateGraphicsContext( );

    doLoadFont( );

    doMapWindows( );  
} 

/******* doCreateWindows *********/
static void doCreateWindows( )
{   
    int window1W = 400;
    int window1H = 300;
    int window1X = (XWidthOfScreen(screen)-window1W)>>1;
    int window1Y = (XHeightOfScreen(screen)-window1H)>>1;
    int window2X = 50;
    int window2Y = 75;
    int window2W = 300;
    int window2H = 150;
    XSetWindowAttributes xswa;
                   
    /* Create the window1 window */

    xswa.event_mask = ExposureMask | ButtonPressMask;
    xswa.background_pixel = doDefineColor(1);

    window1 = XCreateWindow(dpy, XRootWindowOfScreen(screen),
		window1X, window1Y, window1W, window1H, 0,
		XDefaultDepthOfScreen(screen), InputOutput,
		XDefaultVisualOfScreen(screen), CWEventMask | CWBackPixel, &xswa);

    XStoreName(dpy, window1, WindowName);

    /* Create the window2 window */                 

    xswa.event_mask = ExposureMask | ButtonPressMask;
    xswa.background_pixel = doDefineColor(2);

    window2 = XCreateWindow(dpy, window1, window2X, window2Y, window2W, 
        window2H, 4, XDefaultDepthOfScreen(screen), InputOutput,
	    XDefaultVisualOfScreen(screen), CWEventMask | CWBackPixel, &xswa);
}
    

/******** Create the graphics context *********/    
static void doCreateGraphicsContext( )
{                                                
    XGCValues xgcv;
    
    xgcv.foreground = doDefineColor(3);
    xgcv.background = doDefineColor(2);

    gc = XCreateGC(dpy, window2, GCForeground | GCBackground, &xgcv);   
}

/******* Load the font for text writing ******/
static void doLoadFont( )
{
    Font font;

    font = XLoadFont(dpy, FontName);
    XSetFont(dpy, gc, font);
}
    
/******* Create color ************************/
static int doDefineColor(n)
int n;
{
    int pixel;
    XColor exact_color,screen_color;
    char *colors[] = {
	"dark slate blue",
	"light grey",
	"firebrick"
	};
                                                      
    if ((XDefaultVisualOfScreen(screen))->class == TrueColor 
        ||  (XDefaultVisualOfScreen(screen))->class == PseudoColor
        ||  (XDefaultVisualOfScreen(screen))->class == DirectColor
        ||  (XDefaultVisualOfScreen(screen))->class == StaticColor)

        if (XAllocNamedColor(dpy, XDefaultColormapOfScreen(screen),
            colors[n-1], &screen_color, &exact_color))
                return screen_color.pixel; 
        else
	        printf("Color not allocated!");
     else 
        switch (n) {
            case 1:		return XBlackPixelOfScreen(screen); break; 
	    	case 2:		return XWhitePixelOfScreen(screen); break;
            case 3:		return XBlackPixelOfScreen(screen); break;
        }
}   
                                             
/******** doMapWindows ***********/
static void doMapWindows( )                                           
{
    XMapWindow(dpy, window1);
    XMapWindow(dpy, window2);        
}

/****************** doHandleEvents ***********************/
static void doHandleEvents( )
{
    XEvent event;         

    for ( ; ; ) {
	XNextEvent(dpy, &event);
	switch (event.type) { 
            case Expose:		doExpose(&event); break;
	    case ButtonPress: 		doButtonPress(&event); break;
        }
    }                                           
}

/***** Write the message in the window *****/
static void doExpose(eventP)
XEvent *eventP;
{
    /* If this is an expose event on our child window, then write the text. */

    if (eventP->xexpose.window != window2) return;
    XClearWindow(dpy, window2);
    XDrawImageString(dpy, window2, gc, 75, 75, message[state], 
		strlen(message[state]));
}

/***************** doShutdown ***************************/
static void doButtonPress(eventP)
XEvent *eventP;
{                               
    if (eventP->xexpose.window != window2) {
        state = 1;
	XDrawImageString(dpy, window2, gc, 75, 75, message[state], 
		strlen(message[state]));
	return;
    }

    /* Unmap and destroy windows */
    XUnmapWindow(dpy, window1);
    XDestroyWindow(dpy, window1);
    XCloseDisplay(dpy);    

    sys$exit (1);
}