/*
This should compile using:

gcc X11_testAPI.c-o X11_test -I /usr/include/X11 -L /usr/X11/lib -lX11
*/

// X11 header files.
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/Xos.h>

// Declare X11 globals
Display *display;        /* X11 display type */
int screen;              /* X11 - client screen */
Window win;              /* X11 Window type */
GC gc;                   /* X11 GC (graphic context) type */

/**
Function declarations.
*/
void window_init();
void close_window();
void redraw();

/**
Main
*/
int main()
{
    window_init();

	// Basic setup for events and keypress keys
	XEvent event;          /* XEvent declaration. */
	KeySym key;		       /* KeyPress event key  */
	char text[255];		   /* Buffer for KeyPress events */
	_Bool run = 1;

    while(run)
	{
		XNextEvent(display, &event);

		if (event.type==Expose && event.xexpose.count==0)
		{
		/* The window was exposed, redraw it */
		    redraw();
		}
		
	    XSetForeground(display, gc, 100); // 100 is a color
	    XFillRectangle(display, win, gc, 30, 30, 200, 200);
	}
} /* END MAIN */

/**
Function definitions.
*/

/* window_init creates and manages a window and it's structures.*/
void window_init()
{
    unsigned long black, white;

  	display=XOpenDisplay((char *)0);

   	screen=DefaultScreen(display);

	black=BlackPixel(display, screen),

	white=WhitePixel(display, screen);

   	win=XCreateSimpleWindow(display,DefaultRootWindow(display),
	        50, 50, 500, 500, 5, black, white);

	XSetStandardProperties(display, win, "zeta","zeta", None, NULL, 0, NULL);

    // NOTE: At minimum, we have to select the ExposureMask in order for draw
		//  functions to produce output (draw) to the window.
	XSelectInput(display, win, ExposureMask|ButtonPressMask|KeyPressMask);

    gc=XCreateGC(display, win, 0, 0);

	XSetBackground(display, gc, white);

	XSetForeground(display, gc, black);

	XClearWindow(display, win);

	XMapRaised(display, win);
};

void close_window()
{
	XFreeGC(display, gc);

	XDestroyWindow(display, win);

	XCloseDisplay(display);
};

void redraw()
{
	XClearWindow(display, win);
};