#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <X11/Xlib.h>
#include <X11/xpm.h>
#include <math.h>

/* include ufo2_xpm */
#include "ufo2.xpm"

#define WIN_W 512
#define WIN_H 512
#define WIN_X 100
#define WIN_Y 100
#define BORDER 4

#ifndef M_PI
#define M_PI 3.14159265358979
#endif

#define deg2rad(x) (x * M_PI / 180.0)

typedef struct _Pixmaps
{
    Pixmap pix;
    Pixmap mask;
} Pixmaps;

static void update(Display *dpy, Drawable win, GC gc, double ang, Pixmaps pixs);

/* get a color value from a color name */
static unsigned long
get_color(Display *dpy, char *colorname)
{
    Colormap cmap;
    XColor near_color, true_color;

    cmap = DefaultColormap(dpy, DefaultScreen(dpy));
    XAllocNamedColor(dpy, cmap, colorname, &near_color, &true_color);
    return near_color.pixel;
}

int main(void)
{
    Display *dpy;
    Window root;
    Window win;
    int screen;
    XEvent evt;
    unsigned long black, white;
    GC gc;
    Pixmaps pixs;
    int busy_loop;
    double ang;

    /* open display */
    dpy = XOpenDisplay(NULL);
    root = DefaultRootWindow(dpy);
    screen = DefaultScreen(dpy);

    /* get color black and white */
    white = WhitePixel(dpy, screen);
    black = BlackPixel(dpy, screen);

    /* create window */
    win = XCreateSimpleWindow(dpy, root,
                              WIN_X, WIN_Y, WIN_W, WIN_H, BORDER,
                              black, white);

    XSelectInput(dpy, win, KeyPressMask | ExposureMask);

    XMapWindow(dpy, win);

    /* wait display window */
    do
    {
        XNextEvent(dpy, &evt);
    } while (evt.type != Expose);

    XMoveWindow(dpy, win, WIN_X, WIN_Y);

    /* create graphics context */
    gc = XCreateGC(dpy, win, 0, 0);
    XSetGraphicsExposures(dpy, gc, False);

    /* load image */
    if (XpmCreatePixmapFromData(dpy, win, ufo2_xpm,
                                &pixs.pix, &pixs.mask, NULL))
    {
        fprintf(stderr, "Error not load xpm.");
        return 1;
    }

    ang = 0;

    busy_loop = 1;
    while (busy_loop)
    {
        /* event */
        while (XPending(dpy))
        {
            XNextEvent(dpy, &evt);
            switch (evt.type)
            {
                /*
            case Expose:
                if (evt.xexpose.count == 0)
                {
                }
                break;
                */
            case KeyPress:
                busy_loop = 0;
                break;
            default:
                break;
            }
        }

        update(dpy, win, gc, ang, pixs);
        ang += 1.0;
        if (ang >= 360)
            ang -= 360;

        XFlush(dpy);
        usleep(16 * 1000); /* wait */
    }

    XFreePixmap(dpy, pixs.pix);
    XFreePixmap(dpy, pixs.mask);
    XFreeGC(dpy, gc);
    XDestroyWindow(dpy, win);
    XCloseDisplay(dpy);
    return 0;
}

/* update and draw */
static void
update(Display *dpy, Drawable win, GC gc, double ang, Pixmaps pixs)
{
    XWindowAttributes xgwa;
    int scrw, scrh;
    int r, x, y, w, h;
    int r2, x2, y2, w2, h2;

    /* get window attributes */
    XGetWindowAttributes(dpy, win, &xgwa);
    scrw = xgwa.width;  /* window width */
    scrh = xgwa.height; /* window height */

    w = 96;
    h = 96;
    r = 200;
    x = r * cos(deg2rad(ang)) + (scrw / 2) - (w / 2);
    y = r * sin(deg2rad(ang)) + (scrh / 2) - (h / 2);

    w2 = 128;
    h2 = 128;
    r2 = 128;
    x2 = r2 * cos(deg2rad(-ang)) + (scrw / 2) - (w2 / 2);
    y2 = r2 * sin(deg2rad(-ang)) + (scrh / 2) - (h2 / 2);

    /* clear window */
    XClearWindow(dpy, win);

    /* draw shape */
    XSetForeground(dpy, gc, get_color(dpy, "blue"));
    XFillRectangle(dpy, win, gc, x - 8, y - 8, w + 16, h + 16);

    XSetForeground(dpy, gc, get_color(dpy, "cyan"));
    XFillArc(dpy, win, gc, x, y, w, h, 0, 360 * 64);

    /* draw image (Pixmap) */
    XSetClipMask(dpy, gc, pixs.mask);                        /* set clip mask */
    XSetClipOrigin(dpy, gc, x2, y2);                         /* set clip origin */
    XCopyArea(dpy, pixs.pix, win, gc, 0, 0, w2, h2, x2, y2); /* copy Pixmap */
    XSetClipMask(dpy, gc, None);                             /* reset clip */
}