/* The zurburt example ... basic X application template */

/* to compile:

   cc zurburt_handout.c genrand.c -L/usr/X11R6/lib -lm -lX11 -o zurburt
*/

#include <X11/Xlib.h> 
#include <X11/Xutil.h>
#include <X11/Xos.h>
#include <stdio.h>

#define NUM_MI 5
#define MI_W 160
#define MI_H 40
#define MI_BSZ 1

char *choice [] = {"choice1", "choice2", "choice3", "choice4", "zurburt"};

Display *dpy;
Window rootw, win, menu, mi [NUM_MI];
GC win_gc, menu_gc, mi_gc [NUM_MI];

void flip_video ();
void take_action ();
void write_menu_label ();

main (int argc, char **argv)

{
   XSizeHints whisper;
   XEvent report;
   XGCValues values;
   XFontStruct *font;
   XFontStruct *font2;
   unsigned long bp, wp, valuemask;
   int screen, width, height, bsz;
   int i;

   /* open (NULL) means get display name from environment 
      variable DISPLAY, set by xterm */

   if((dpy = XOpenDisplay (NULL)) == NULL) {
	fprintf (stderr, "can't open\n");
	exit (1);
   }

   screen = DefaultScreen (dpy);
   width = 500;
   height = 400;
   bp = BlackPixel (dpy, screen);
   wp = WhitePixel (dpy, screen);
   rootw = RootWindow (dpy, screen);

   /* create output window with black border and white background;
      upper left corner will be at (400,100); border size at this level 
      is overriden by window manager, so just make it 0 */

   bsz = 0;
   win = XCreateSimpleWindow (dpy, rootw, 400, 100, width, height, bsz, bp, wp);
   menu = XCreateSimpleWindow (dpy, rootw, 200, 50, MI_W, MI_H * NUM_MI, bsz, bp, wp);

   /* individual menu items will overlay menu window */
   bsz = MI_BSZ;

   for (i = 0; i < NUM_MI; i++) {
      mi [i] = XCreateSimpleWindow (dpy, menu, 0, MI_H * i, MI_W - bsz, MI_H - bsz, 
                                    bsz, bp, wp);
   }

   /* whisper some hints to the window manager; suggest that it use the indicated 
      position, width, and height for window placement */

   whisper.flags = PSize|PPosition;
   XSetWMNormalHints (dpy, win, &whisper);
   XSetWMNormalHints (dpy, menu, &whisper);

   /* indicate which events are important;
      NOTE: buttonpress in menu (window) will determine which mi (subwindow);
            so, don't recognize buttonpress in subwindow */

   XSelectInput (dpy, win, ExposureMask | KeyPressMask | StructureNotifyMask);
   XSelectInput (dpy, menu, ButtonPressMask | ButtonReleaseMask | KeyPressMask |
                            StructureNotifyMask);

   for (i = 0; i < NUM_MI; i++) 
      XSelectInput (dpy, mi [i], ExposureMask);

   /* set up graphics contexts and get the fonts ...
      but if you ask for one that isn't there ... BLAMO! */

   valuemask = 0;
   font = XLoadQueryFont (dpy, "9x15");

   for (i = 0; i < NUM_MI; i++) {
      mi_gc [i] = XCreateGC (dpy, mi [i], valuemask, &values);
      XSetFont (dpy, mi_gc[i], font -> fid);
      XSetForeground (dpy, mi_gc [i], bp);
   }

   font2 = XLoadQueryFont (dpy, "10x20");

   win_gc = XCreateGC (dpy, win, valuemask, &values);
   XSetFont (dpy, win_gc, font2 -> fid);
   XSetForeground (dpy, win_gc, bp);

   menu_gc = XCreateGC (dpy, menu, valuemask, &values);
   XSetFont (dpy, menu_gc, font2 -> fid);
   XSetForeground (dpy, menu_gc, bp);

   XMapWindow (dpy, win);
   XMapWindow (dpy, menu);

   for (i = 0; i < NUM_MI; i++) 
      XMapWindow (dpy, mi [i]);

   /* wait on expose from main window and expose from menu items;
      if you try to draw before this, you go down in flames */

   for (i = 0; i <= NUM_MI; i++) {
      XNextEvent (dpy, &report);

      while (report.type != Expose) {
         fprintf (stderr, "waiting...\n");
         XNextEvent (dpy, &report);
      }
   }

   for (i = 0; i < NUM_MI; i++) 
      write_menu_label (i);

   while (1) {
      XNextEvent (dpy, &report);

      switch (report.type) {
         case Expose:
               for (i = 0; i < NUM_MI; i++) 
                  write_menu_label (i);

               break;

         case KeyPress:
               XUnloadFont (dpy, font -> fid);
               XUnloadFont (dpy, font2 -> fid);
               XFreeGC (dpy, win_gc);

               for (i = 0; i < NUM_MI; i++)
                  XFreeGC (dpy, mi_gc [i]);

               XCloseDisplay (dpy);
               exit (0);

         case ButtonPress:
               for (i = 0; i < NUM_MI; i++) {
                  if (report.xbutton.subwindow == mi [i]) 
                     break;
               }

               flip_video (i, wp, bp);

               /* wait for ham-handed user to let go of the button */

               XNextEvent (dpy, &report);

               while (report.type != ButtonRelease) {
                  XNextEvent (dpy, &report);
               }

               flip_video (i, bp, wp);
               take_action (i);
               break;

         default:
               break;
      }
   }
}


void flip_video (item, fore, back)

int item;
unsigned long fore, back;

{
   XSetForeground (dpy, mi_gc [item], fore);
   XSetWindowBackground (dpy, mi [item], back);
   XClearWindow (dpy, mi [item]);

   write_menu_label (item);
}


void write_menu_label (i)

int i;

{
   XDrawString (dpy, mi [i], mi_gc [i], 2 * MI_BSZ, MI_H / 2, choice [i], 
                strlen (choice [i]));
}


/* trivial action */

void take_action (i)

int i;

{
   XClearWindow (dpy, win);
   XDrawString (dpy, win, win_gc, 300, 300, choice [i], strlen (choice [i]));
}