--- a/src/Makefile.am	Fri Sep 24 16:00:04 2010 +0800
+++ b/src/Makefile.am	Sun Oct 03 16:54:26 2010 +0800
@@ -38,6 +38,10 @@
 libmbfly_la_SOURCES += X_supp.c
 endif
 
+if DFB_BACKEND
+libmbfly_la_SOURCES += dfb_supp.c
+endif
+
 libmbfly_la_LDFLAGS =
 
 if CAIRO_GRAPH_ENGINE

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/dfb_supp.c	Sun Oct 03 16:54:26 2010 +0800
@@ -0,0 +1,1011 @@
+// -*- indent-tabs-mode: t; tab-width: 8; c-basic-offset: 4; -*-
+// vim: sw=4:ts=8:sts=4
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <X11/Xlib.h>
+#include <X11/Xutil.h>
+#include <cairo-xlib.h>
+#include "mb_graph_engine.h"
+#include "mb_redraw_man.h"
+#include "mb_timer.h"
+#include "mb_X_supp.h"
+#include "config.h"
+
+#ifdef XSHM
+/* \sa http://www.xfree86.org/current/mit-shm.html */
+#include <sys/ipc.h>
+#include <sys/shm.h>
+#include <X11/extensions/XShm.h>
+#endif
+
+#define ERR -1
+#define OK 0
+
+#define ONLY_MOUSE_MOVE_RAW 1
+
+/*! \ingroup xkb
+ * @{
+ */
+struct _X_kb_info {
+    int keycode_min, keycode_max;
+    int ksym_per_code;
+    KeySym *syms;
+    subject_t *kbevents;
+    ob_factory_t *ob_factory;
+};
+
+/* @} */
+#define MAX_MONITORS 200
+typedef struct {
+    int type;
+    int fd;
+    mb_eventcb_t f;
+    void *arg;
+}  monitor_t;
+
+struct _X_MB_runtime {
+    Display *display;
+    Window win;
+    Visual *visual;
+    mbe_surface_t *surface, *backend_surface;
+    mbe_pattern_t *surface_ptn;
+    mbe_t *cr, *backend_cr;
+    redraw_man_t *rdman;
+    mb_tman_t *tman;
+    mb_img_ldr_t *img_ldr;
+    int w, h;
+
+    X_kb_info_t kbinfo;
+    monitor_t monitors[MAX_MONITORS];
+    int n_monitor;
+
+#ifndef ONLY_MOUSE_MOVE_RAW
+    /* States */
+    shape_t *last;
+#endif
+
+#ifdef XSHM
+    XImage *ximage;
+    XShmSegmentInfo shminfo;
+#endif
+
+    /*
+     * Following variables are used by handle_single_x_event()
+     */
+    int last_evt_type;	       /* Type of last event */
+    int eflag;
+    int ex1, ey1, ex2, ey2;    /* Aggregate expose events */
+    int mflag;
+    int mx, my;		       /* Position of last motion event */
+    int mbut_state;	       /* Button state of last motion event */
+};
+
+#ifdef XSHM
+static void
+XSHM_update(X_MB_runtime_t *xmb_rt) {
+    GC gc;
+
+    gc = DefaultGC(xmb_rt->display, DefaultScreen(xmb_rt->display));
+    if(xmb_rt->ximage) {	/* support XSHM */
+	XShmPutImage(xmb_rt->display,
+		     xmb_rt->win,
+		     gc,
+		     xmb_rt->ximage,
+		     0, 0, 0, 0,
+		     xmb_rt->w, xmb_rt->h, 0);
+    }
+}
+#endif
+
+/*! \defgroup xkb X Keyboard Handling
+ *
+ * Accept keyboard events from X server and delivery it to
+ * application through observer pattern.  There is a subject,
+ * per X-connection, for that.
+ * @{
+ */
+static int keycode2sym(X_kb_info_t *kbinfo, unsigned int keycode) {
+    int sym_idx;
+    int sym;
+
+    sym_idx = kbinfo->ksym_per_code * (keycode - kbinfo->keycode_min);
+    sym =  kbinfo->syms[sym_idx];
+    return sym;
+}
+
+static int X_kb_init(X_kb_info_t *kbinfo, Display *display,
+		     redraw_man_t *rdman) {
+    int n_syms;
+    ob_factory_t *factory;
+    int r;
+
+    r = XDisplayKeycodes(display,
+			 &kbinfo->keycode_min,
+			 &kbinfo->keycode_max);
+    if(r == 0)
+	return ERR;
+
+    n_syms = kbinfo->keycode_max - kbinfo->keycode_min + 1;
+    kbinfo->syms = XGetKeyboardMapping(display, kbinfo->keycode_min,
+				       n_syms,
+				       &kbinfo->ksym_per_code);
+    if(kbinfo->syms == NULL)
+	return ERR;
+
+    factory = rdman_get_ob_factory(rdman);
+    kbinfo->kbevents = subject_new(factory, kbinfo, OBJT_KB);
+    if(kbinfo->kbevents == NULL)
+	return ERR;
+    /*! \todo Make sure ob_factory is still need. */
+    kbinfo->ob_factory = factory;
+
+    return OK;
+}
+
+static void X_kb_destroy(X_kb_info_t *kbinfo) {
+    subject_free(kbinfo->kbevents);
+    XFree(kbinfo->syms);
+}
+
+/*! \brief Accept X keyboard events from handle_x_event() and dispatch it.
+ */
+static void X_kb_handle_event(X_kb_info_t *kbinfo, XKeyEvent *xkey) {
+    unsigned int code;
+    int sym;
+    X_kb_event_t event;
+
+    code = xkey->keycode;
+    sym = keycode2sym(kbinfo, code);
+    if(xkey->type == KeyPress)
+	event.event.type = EVT_KB_PRESS;
+    else if(xkey->type == KeyRelease)
+	event.event.type = EVT_KB_RELEASE;
+    event.event.tgt = event.event.cur_tgt = kbinfo->kbevents;
+    event.keycode = code;
+    event.sym = sym;
+
+    subject_notify(kbinfo->kbevents, &event.event);
+}
+
+/* @} */
+
+static unsigned int get_button_state(unsigned int state) {
+    unsigned int but = 0;
+
+    if(state & Button1Mask)
+	but |= MOUSE_BUT1;
+    if(state & Button2Mask)
+	but |= MOUSE_BUT2;
+    if(state & Button3Mask)
+	but |= MOUSE_BUT3;
+
+    return but;
+}
+
+static unsigned int get_button(unsigned int button) {
+    switch(button) {
+    case Button1:
+	return MOUSE_BUT1;
+    case Button2:
+	return MOUSE_BUT2;
+    case Button3:
+	return MOUSE_BUT3;
+    }
+    return 0;
+}
+
+/*! \brief Notify observers of the shape at specified
+ *	position for mouse event.
+ *
+ * Observers of parent shapes may be called if the subject is not
+ * with SUBF_STOP_PROPAGATE flag.  The subject of mouse event
+ * for a shape is returned by sh_get_mouse_event_subject().
+ */
+static void notify_coord_or_shape(redraw_man_t *rdman,
+				   mb_obj_t *obj,
+				   co_aix x, co_aix y, int etype,
+				   unsigned int state,
+				   unsigned int button) {
+    mouse_event_t mouse_event;
+    subject_t *subject;
+
+    mouse_event.event.type = etype;
+    mouse_event.x = x;
+    mouse_event.y = y;
+    mouse_event.but_state = state;
+    mouse_event.button = button;
+
+    if(IS_MBO_SHAPES(obj))
+	subject = sh_get_mouse_event_subject((shape_t *)obj);
+    else
+	subject = coord_get_mouse_event((coord_t *)obj);
+
+    subject_notify(subject, (event_t *)&mouse_event);
+}
+
+/*! \brief Handle motion event.
+ */
+static void
+handle_motion_event(X_MB_runtime_t *rt) {
+    redraw_man_t *rdman = rt->rdman;
+    int x, y;
+    int state;
+    shape_t *shape;
+    coord_t *root;
+    int in_stroke;
+    
+    x = rt->mx;
+    y = rt->my;
+    state = rt->mbut_state;
+    
+    shape = find_shape_at_pos(rdman, x, y,
+			      &in_stroke);
+#ifdef ONLY_MOUSE_MOVE_RAW
+    if(shape != NULL) {
+	notify_coord_or_shape(rdman, (mb_obj_t *)shape,
+			      x, y, EVT_MOUSE_MOVE_RAW, state, 0);
+    } else {
+	root = rdman_get_root(rdman);
+	notify_coord_or_shape(rdman, (mb_obj_t *)root,
+			      x, y, EVT_MOUSE_MOVE_RAW, state, 0);
+    }
+#else
+    if(shape != NULL) {
+	if(rt->last != shape) {
+	    if(rt->last)
+		notify_coord_or_shape(rdman, rt->last, x, y,
+				      EVT_MOUSE_OUT, state, 0);
+	    notify_coord_or_shape(rdman, shape, x, y,
+				  EVT_MOUSE_OVER, state, 0);
+	    rt->last = shape;
+	} else
+	    notify_coord_or_shape(rdman, shape, x, y,
+				  EVT_MOUSE_MOVE, state, 0);
+    } else {
+	if(rt->last) {
+	    notify_coord_or_shape(rdman, rt->last, x, y,
+				  EVT_MOUSE_OUT, state, 0);
+	    rt->last = NULL;
+	}
+    }
+#endif
+    
+    rt->mflag = 0;
+}
+
+/*! \brief Redraw exposed area.
+ */
+static void
+handle_expose_event(X_MB_runtime_t *rt) {
+    redraw_man_t *rdman = rt->rdman;
+    int ex1, ey1, ex2, ey2;
+
+    ex1 = rt->ex1;
+    ey1 = rt->ey1;
+    ex2 = rt->ex2;
+    ey2 = rt->ey2;
+    
+    rdman_redraw_area(rdman, ex1, ey1, (ex2 - ex1), (ey2 - ey1));
+    
+    rt->eflag = 0;
+}
+
+/*! \brief Handle single X event and maintain internal states.
+ *
+ * It keeps internal state in rt to improve performance.
+ */
+static void
+handle_single_x_event(X_MB_runtime_t *rt, XEvent *evt) {
+    redraw_man_t *rdman = rt->rdman;
+    XMotionEvent *mevt;
+    XButtonEvent *bevt;
+    XExposeEvent *eevt;
+    XKeyEvent *xkey;
+    int x, y, w, h;
+
+    shape_t *shape;
+
+    unsigned int state, button;
+    int in_stroke;
+
+    if(evt->type != MotionNotify && rt->mflag)
+	handle_motion_event(rt);
+
+    switch(evt->type) {
+    case ButtonPress:
+	bevt = (XButtonEvent *)evt;
+	x = bevt->x;
+	y = bevt->y;
+	state = get_button_state(bevt->state);
+	button = get_button(bevt->button);
+
+	shape = find_shape_at_pos(rdman, x, y,
+				  &in_stroke);
+	if(shape)
+	    notify_coord_or_shape(rdman, (mb_obj_t *)shape,
+				  x, y, EVT_MOUSE_BUT_PRESS,
+				  state, button);
+	break;
+
+    case ButtonRelease:
+	bevt = (XButtonEvent *)evt;
+	x = bevt->x;
+	y = bevt->y;
+	state = get_button_state(bevt->state);
+	button = get_button(bevt->button);
+
+	shape = find_shape_at_pos(rdman, x, y,
+				  &in_stroke);
+	if(shape)
+	    notify_coord_or_shape(rdman, (mb_obj_t *)shape,
+				  x, y, EVT_MOUSE_BUT_RELEASE,
+				  state, button);
+	break;
+
+    case MotionNotify:
+	mevt = (XMotionEvent *)evt;
+	rt->mx = mevt->x;
+	rt->my = mevt->y;
+	rt->mbut_state = get_button_state(mevt->state);
+	rt->mflag = 1;
+	break;
+
+    case KeyPress:
+    case KeyRelease:
+	xkey = &evt->xkey;
+	X_kb_handle_event(&rt->kbinfo, xkey);
+	break;
+
+    case Expose:
+	eevt = &evt->xexpose;
+	x = eevt->x;
+	y = eevt->y;
+	w = eevt->width;
+	h = eevt->height;
+
+	if(rt->eflag) {
+	    if(x < rt->ex1)
+		rt->ex1 = x;
+	    if(y < rt->ey1)
+		rt->ey1 = y;
+	    if((x + w) > rt->ex2)
+		rt->ex2 = x + w;
+	    if((y + h) > rt->ey2)
+		rt->ey2 = y + h;
+	} else {
+	    rt->ex1 = x;
+	    rt->ey1 = y;
+	    rt->ex2 = x + w;
+	    rt->ey2 = y + h;
+	    rt->eflag = 1;
+	}
+	break;
+    }
+}
+
+/*! \brief Call when no more event in an event iteration.
+ *
+ * No more event means event queue is emplty.  This function will
+ * perform some actions according current internal state.
+ */
+static void
+no_more_event(X_MB_runtime_t *rt) {
+    if(rt->mflag)
+	handle_motion_event(rt);
+    if(rt->eflag)
+	handle_expose_event(rt);
+}
+
+/*! \brief Dispatch all X events in the queue.
+ */
+static void handle_x_event(X_MB_runtime_t *rt) {
+    Display *display = rt->display;
+    XEvent evt;
+    int r;
+
+    /* XXX: For some unknown reason, it causes a segmentation fault to
+     *      called XEventsQueued() after receiving first Expose event
+     *      and before redraw for the event.
+     */
+    while(XEventsQueued(display, QueuedAfterReading) > 0) {
+	r = XNextEvent(display, &evt);
+	if(r == -1)
+	    break;
+
+	handle_single_x_event(rt, &evt);
+    }
+    no_more_event(rt);
+    
+#ifdef XSHM
+    XSHM_update(rt);
+#endif
+    XFlush(display);
+}
+
+/*! \brief Handle connection coming data and timeout of timers.
+ *
+ * \param display is a Display returned by XOpenDisplay().
+ * \param rdman is a redraw manager.
+ * \param tman is a timer manager.
+ *
+ * The display is managed by specified rdman and tman.  rdman draws
+ * on the display, and tman trigger actions according timers.
+ */
+void X_MB_handle_connection(void *be) {
+    X_MB_runtime_t *rt = (X_MB_runtime_t *) be;
+    Display *display = rt->display;
+    redraw_man_t *rdman = rt->rdman;
+    mb_tman_t *tman = rt->tman;
+    int fd;
+    mb_timeval_t now, tmo;
+    struct timeval tv;
+    fd_set rfds,wfds;
+    int nfds;
+    int r, r1,i;
+
+    handle_x_event(rt);
+
+    fd = XConnectionNumber(display);
+    nfds = fd + 1;
+    while(1) {
+	FD_ZERO(&rfds);
+	FD_ZERO(&wfds);
+	FD_SET(fd, &rfds);
+        for(i=0;i<rt->n_monitor;i++) {
+	    if (rt->monitors[i].type == MONITOR_READ)
+		FD_SET(rt->monitors[i].fd, &rfds);
+	    else if (rt->monitors[i].type == MONITOR_WRITE)
+		FD_SET(rt->monitors[i].fd, &wfds);
+        }
+
+	get_now(&now);
+	r = mb_tman_next_timeout(tman, &now, &tmo);
+
+	if(r == 0) {
+	    tv.tv_sec = MB_TIMEVAL_SEC(&tmo);
+	    tv.tv_usec = MB_TIMEVAL_USEC(&tmo);
+	    r1 = select(nfds, &rfds, NULL, NULL, &tv);
+	} else
+	    r1 = select(nfds, &rfds, NULL, NULL, NULL);
+
+	if(r1 == -1) {
+	    perror("select");
+	    break;
+	}
+
+	if(r1 == 0) {
+	    get_now(&now);
+	    mb_tman_handle_timeout(tman, &now);
+	    rdman_redraw_changed(rdman);
+#ifdef XSHM
+	    XSHM_update(rt);
+#endif
+	    XFlush(display);
+	} else if(FD_ISSET(fd, &rfds)){
+	    handle_x_event(rt);
+	} else {
+            for(i=0;i<rt->n_monitor;i++) {
+	        if (rt->monitors[i].type == MONITOR_READ) {
+		    if (FD_ISSET(rt->monitors[i].fd, &rfds))
+		    	rt->monitors[i].f(rt->monitors[i].fd,rt->monitors[i].arg);
+		} else if (rt->monitors[i].type == MONITOR_WRITE) {
+		    if (FD_ISSET(rt->monitors[i].fd, &wfds))
+			rt->monitors[i].f(rt->monitors[i].fd,rt->monitors[i].arg);
+		}
+            }
+	}
+    }
+}
+
+#define ERR -1
+#define OK 0
+
+static int X_init_connection(const char *display_name,
+			     int w, int h,
+			     Display **displayp,
+			     Visual **visualp,
+			     Window *winp) {
+    Display *display;
+    Window root, win;
+    Visual *visual;
+    int screen;
+    XSetWindowAttributes wattr;
+    int depth;
+    int x, y;
+    int draw_root = 0;
+    const char *disp_name;
+    char disp_buf[32];
+    int cp;
+    int r;
+
+    /*
+     * Support drawing on the root window.
+     */
+    disp_name = display_name;
+    if(strstr(display_name, ":root") != NULL) {
+	draw_root = 1;
+	cp = strlen(display_name) - 5;
+	if(cp >= 32)
+	    cp = 31;
+	memcpy(disp_buf, display_name, cp);
+	disp_buf[cp] = 0;
+	disp_name = disp_buf;
+    }
+
+    display = XOpenDisplay(disp_name);
+    if(display == NULL)
+	return ERR;
+
+    screen = DefaultScreen(display);
+    root = DefaultRootWindow(display);
+    visual = DefaultVisual(display, screen);
+    depth = DefaultDepth(display, screen);
+    wattr.override_redirect = False;
+    x = 10;
+    y = 10;
+    if(draw_root)
+	win = RootWindowOfScreen(ScreenOfDisplay(display, screen));
+    else {
+	win = XCreateWindow(display, root,
+			    x, y,
+			    w, h,
+			    1, depth, InputOutput, visual,
+			    CWOverrideRedirect, &wattr);
+	r = XMapWindow(display, win);
+	if(r == -1) {
+	    XCloseDisplay(display);
+	    return ERR;
+	}
+    }
+
+    XSelectInput(display, win, PointerMotionMask | ExposureMask |
+		 ButtonPressMask | ButtonReleaseMask |
+		 KeyPressMask | KeyReleaseMask);
+    XFlush(display);
+
+    *displayp = display;
+    *visualp = visual;
+    *winp = win;
+
+    return OK;
+}
+
+#ifdef XSHM
+static void
+xshm_destroy(X_MB_runtime_t *xmb_rt) {
+    XShmSegmentInfo *shminfo;
+
+    shminfo = &xmb_rt->shminfo;
+
+    if(xmb_rt->shminfo.shmaddr) {
+	XShmDetach(xmb_rt->display, shminfo);
+    }
+
+    if(xmb_rt->ximage) {
+	XDestroyImage(xmb_rt->ximage);
+	xmb_rt->ximage = NULL;
+    }
+
+    if(shminfo->shmaddr) {
+	shmdt(shminfo->shmaddr);
+	shminfo->shmaddr = NULL;
+    }
+
+    if(shminfo->shmid) {
+	shmctl(shminfo->shmid, IPC_RMID, 0);
+	shminfo->shmid = 0;
+    }
+}
+
+static void
+xshm_init(X_MB_runtime_t *xmb_rt) {
+    Display *display;
+    Visual *visual;
+    XImage *ximage;
+    int screen;
+    int depth;
+    int support_shm;
+    int mem_sz;
+    XShmSegmentInfo *shminfo;
+    int surf_fmt;
+
+    display = xmb_rt->display;
+    visual = xmb_rt->visual;
+    shminfo = &xmb_rt->shminfo;
+
+    support_shm = XShmQueryExtension(display);
+    if(!support_shm)
+	return;
+
+    screen = DefaultScreen(display);
+    depth = DefaultDepth(display, screen);
+
+    if(depth != 24 && depth != 32)
+	return;
+
+    xmb_rt->ximage = XShmCreateImage(display, visual, depth,
+				     ZPixmap, NULL, shminfo,
+				     xmb_rt->w, xmb_rt->h);
+    ximage = xmb_rt->ximage;
+
+    mem_sz = ximage->bytes_per_line * ximage->height;
+    shminfo->shmid = shmget(IPC_PRIVATE, mem_sz, IPC_CREAT | 0777);
+    if(shminfo->shmid == -1) {
+	xshm_destroy(xmb_rt);
+	return;
+    }
+
+    shminfo->shmaddr = shmat(shminfo->shmid, 0, 0);
+    ximage->data = shminfo->shmaddr;
+
+    shminfo->readOnly = 0;
+
+    XShmAttach(display, shminfo);
+
+    switch(depth) {
+    case 24: surf_fmt = CAIRO_FORMAT_RGB24; break;
+    case 32: surf_fmt = CAIRO_FORMAT_ARGB32; break;
+    }
+
+    xmb_rt->backend_surface =
+	mbe_image_surface_create_for_data((unsigned char *)ximage->data,
+					  surf_fmt,
+					  xmb_rt->w,
+					  xmb_rt->h,
+					  ximage->bytes_per_line);
+    if(xmb_rt->backend_surface == NULL)
+	xshm_destroy(xmb_rt);
+}
+#endif /* XSHM */
+
+/*! \brief Initialize a MadButterfy runtime for Xlib.
+ *
+ * This one is very like X_MB_init(), except it accepts a
+ * X_MB_runtime_t object initialized with a display connected to a X
+ * server and an opened window.
+ *
+ * Following field of the X_MB_runtime_t object should be initialized.
+ *   - w, h
+ *   - win
+ *   - display
+ *   - visual
+ */
+static int
+X_MB_init_with_win_internal(X_MB_runtime_t *xmb_rt) {
+    mb_img_ldr_t *img_ldr;
+    int w, h;
+
+    w = xmb_rt->w;
+    h = xmb_rt->h;
+
+#ifdef XSHM
+    xshm_init(xmb_rt);
+#endif
+
+    xmb_rt->surface =
+	mbe_image_surface_create(MB_IFMT_ARGB32, w, h);
+
+    xmb_rt->surface_ptn =
+	mbe_pattern_create_for_surface(xmb_rt->surface);
+
+    if(xmb_rt->backend_surface == NULL) /* xshm_init() may create one */
+	xmb_rt->backend_surface =
+	    mbe_xlib_surface_create(xmb_rt->display,
+				    xmb_rt->win,
+				    xmb_rt->visual,
+				    w, h);
+
+    xmb_rt->cr = mbe_create(xmb_rt->surface);
+    xmb_rt->backend_cr = mbe_create(xmb_rt->backend_surface);
+
+    mbe_set_source(xmb_rt->backend_cr, xmb_rt->surface_ptn);
+
+    xmb_rt->rdman = (redraw_man_t *)malloc(sizeof(redraw_man_t));
+    redraw_man_init(xmb_rt->rdman, xmb_rt->cr, xmb_rt->backend_cr);
+    // FIXME: This is a wired loopback reference. This is inly required when we need
+    //        to get the xmb_rt->tman for the animation. We should relocate the tman
+    //	      to the redraw_man_t instead.
+    xmb_rt->rdman->rt = xmb_rt;
+
+    xmb_rt->tman = mb_tman_new();
+
+    img_ldr = simple_mb_img_ldr_new("");
+    xmb_rt->img_ldr = img_ldr;
+    rdman_set_img_ldr(xmb_rt->rdman, img_ldr);
+    memset(xmb_rt->monitors,0,sizeof(xmb_rt->monitors));
+
+#ifndef ONLY_MOUSE_MOVE_RAW
+    xmb_rt->last = NULL;
+#endif
+
+    X_kb_init(&xmb_rt->kbinfo, xmb_rt->display, xmb_rt->rdman);
+
+    return OK;
+}
+
+/*! \brief Initialize a MadButterfy runtime for Xlib.
+ *
+ * It setups a runtime environment to run MadButterfly with Xlib.
+ * Users should specify width and height of the opening window.
+ */
+static int X_MB_init(X_MB_runtime_t *xmb_rt, const char *display_name,
+		     int w, int h) {
+    int r;
+
+    memset(xmb_rt, 0, sizeof(X_MB_runtime_t));
+
+    xmb_rt->w = w;
+    xmb_rt->h = h;
+    r = X_init_connection(display_name, w, h, &xmb_rt->display,
+			  &xmb_rt->visual, &xmb_rt->win);
+    if(r != OK)
+	return ERR;
+
+    r = X_MB_init_with_win_internal(xmb_rt);
+
+    return r;
+}
+
+/*! \brief Initialize a MadButterfly runtime for a window of X.
+ *
+ * Runtimes initialized with this function should be destroyed with
+ * X_MB_destroy_keep_win().
+ */
+static int
+X_MB_init_with_win(X_MB_runtime_t *xmb_rt,
+		   Display *display, Window win) {
+    XWindowAttributes attrs;
+    int r;
+
+    r = XGetWindowAttributes(display, win, &attrs);
+    if(r == 0)
+	return ERR;
+    
+    memset(xmb_rt, 0, sizeof(X_MB_runtime_t));
+
+    xmb_rt->display = display;
+    xmb_rt->win = win;
+    xmb_rt->visual = attrs.visual;
+    xmb_rt->w = attrs.width;
+    xmb_rt->h = attrs.height;
+
+    r = X_MB_init_with_win_internal(xmb_rt);
+
+    return r;
+}
+
+static void X_MB_destroy(X_MB_runtime_t *xmb_rt) {
+    if(xmb_rt->rdman) {
+	redraw_man_destroy(xmb_rt->rdman);
+	free(xmb_rt->rdman);
+    }
+
+    if(xmb_rt->tman)
+	mb_tman_free(xmb_rt->tman);
+
+    if(xmb_rt->img_ldr)
+	MB_IMG_LDR_FREE(xmb_rt->img_ldr);
+
+    if(xmb_rt->cr)
+	mbe_destroy(xmb_rt->cr);
+    if(xmb_rt->backend_cr)
+	mbe_destroy(xmb_rt->backend_cr);
+
+    if(xmb_rt->surface)
+	mbe_surface_destroy(xmb_rt->surface);
+    if(xmb_rt->surface_ptn)
+	mbe_pattern_destroy(xmb_rt->surface_ptn);
+    if(xmb_rt->backend_surface)
+	mbe_surface_destroy(xmb_rt->backend_surface);
+
+    if(xmb_rt->display)
+	XCloseDisplay(xmb_rt->display);
+
+    X_kb_destroy(&xmb_rt->kbinfo);
+}
+
+/*! \brief Destroy a MadButterfly runtime initialized with
+ *	X_MB_init_with_win().
+ *
+ * Destroying a runtime with this function prevent the window and
+ * display associated with the runtime being closed.
+ */
+static void
+X_MB_destroy_keep_win(X_MB_runtime_t *xmb_rt) {
+    Display *display;
+    Window win;
+
+    display = xmb_rt->display;
+    xmb_rt->display = NULL;
+    win = xmb_rt->win;
+    xmb_rt->win = 0;
+
+    X_MB_destroy(xmb_rt);
+    
+    xmb_rt->display = display;
+    xmb_rt->win = win;
+}
+
+void *X_MB_new(const char *display_name, int w, int h) {
+    X_MB_runtime_t *rt;
+    int r;
+
+    rt = O_ALLOC(X_MB_runtime_t);
+    if(rt == NULL)
+	return NULL;
+
+    r = X_MB_init(rt, display_name, w, h);
+    if(r != OK) {
+	free(rt);
+	return NULL;
+    }
+
+    return rt;
+}
+
+/*! \brief Create a new runtime for existed window for X.
+ *
+ * The object returned by this function must be free with
+ * X_MB_free_keep_win() to prevent the window from closed.
+ */
+void *X_MB_new_with_win(Display *display, Window win) {
+    X_MB_runtime_t *rt;
+    int r;
+
+    rt = O_ALLOC(X_MB_runtime_t);
+    if(rt == NULL)
+	return NULL;
+
+    r = X_MB_init_with_win(rt, display, win);
+    if(r != OK) {
+	free(rt);
+	return NULL;
+    }
+
+    return rt;
+}
+
+void X_MB_free(void *rt) {
+    X_MB_destroy((X_MB_runtime_t *) rt);
+    free(rt);
+}
+
+/*! \brief Free runtime created with X_MB_new_with_win().
+ */
+void
+X_MB_free_keep_win(void *rt) {
+    X_MB_destroy_keep_win((X_MB_runtime_t *) rt);
+    free(rt);
+}
+
+subject_t *X_MB_kbevents(void *rt) {
+    X_MB_runtime_t *xmb_rt = (X_MB_runtime_t *) rt;
+    return xmb_rt->kbinfo.kbevents;
+}
+
+redraw_man_t *X_MB_rdman(void *rt) {
+    X_MB_runtime_t *xmb_rt = (X_MB_runtime_t *) rt;
+    return xmb_rt->rdman;
+}
+
+mb_tman_t *X_MB_tman(void *rt) {
+    X_MB_runtime_t *xmb_rt = (X_MB_runtime_t *) rt;
+    return xmb_rt->tman;
+}
+
+ob_factory_t *X_MB_ob_factory(void *rt) {
+    X_MB_runtime_t *xmb_rt = (X_MB_runtime_t *) rt;
+    ob_factory_t *factory;
+
+    factory = rdman_get_ob_factory(xmb_rt->rdman);
+    return factory;
+}
+
+mb_img_ldr_t *X_MB_img_ldr(void *rt) {
+    X_MB_runtime_t *xmb_rt = (X_MB_runtime_t *) rt;
+    mb_img_ldr_t *img_ldr;
+
+    img_ldr = xmb_rt->img_ldr;
+
+    return img_ldr;
+}
+
+void X_MB_add_event(void *rt, int type, int fd, mb_eventcb_t f,void *arg)
+{
+    X_MB_runtime_t *xmb_rt = (X_MB_runtime_t *) rt;
+    int i;
+
+    for(i=0;i<xmb_rt->n_monitor;i++) {
+        if (xmb_rt->monitors[i].type == type && xmb_rt->monitors[i].fd == fd) {
+	    xmb_rt->monitors[i].f = f;
+	    xmb_rt->monitors[i].arg = arg;
+	    return;
+	}
+    }
+    for(i=0;i<xmb_rt->n_monitor;i++) {
+        if (xmb_rt->monitors[i].type == 0) {
+	    xmb_rt->monitors[i].type = type;
+	    xmb_rt->monitors[i].fd = fd;
+	    xmb_rt->monitors[i].f = f;
+	    xmb_rt->monitors[i].arg = arg;
+	    return;
+	}
+    }
+    if (i == MAX_MONITORS) return;
+    xmb_rt->monitors[i].type = type;
+    xmb_rt->monitors[i].fd = fd;
+    xmb_rt->monitors[i].f = f;
+    xmb_rt->monitors[i].arg = arg;
+    i++;
+    xmb_rt->n_monitor=i;
+}
+
+void X_MB_remove_event(void *rt, int type, int fd)
+{
+    X_MB_runtime_t *xmb_rt = (X_MB_runtime_t *) rt;
+    int i;
+    for(i=0;i<xmb_rt->n_monitor;i++) {
+        if (xmb_rt->monitors[i].type == type && xmb_rt->monitors[i].fd == fd) {
+	    xmb_rt->monitors[i].type = 0;
+	    return;
+	}
+    }
+}
+mb_backend_t backend = { X_MB_new,
+			 X_MB_free,
+			 X_MB_add_event,
+			 X_MB_remove_event,
+			 X_MB_handle_connection,
+			 X_MB_kbevents,
+			 X_MB_rdman,
+			 X_MB_tman,
+			 X_MB_ob_factory,
+			 X_MB_img_ldr
+		};
+/*! \defgroup x_supp_nodejs_sup Export functions for supporting nodejs plugin.
+ *
+ * These functions are for internal using.
+ * @{
+ */
+/*! \brief Exported for nodejs plugin to call handle_x_event.
+ */
+void _X_MB_handle_x_event_for_nodejs(void *rt) {
+    handle_x_event((X_MB_runtime_t *)rt);
+}
+
+/*! \brief Get X connect for nodejs plugin.
+ */
+int _X_MB_get_x_conn_for_nodejs(void *rt) {
+    return XConnectionNumber(((X_MB_runtime_t *)rt)->display);
+}
+
+/*! \brief Flush buffer for the X connection of a runtime object.
+ */
+int _X_MB_flush_x_conn_for_nodejs(void *rt) {
+    X_MB_runtime_t *xmb_rt = (X_MB_runtime_t *)rt;
+#ifdef XSHM
+    XSHM_update(xmb_rt);
+#endif
+    return XFlush(xmb_rt->display);
+}
+
+/*! \brief Handle single X event.
+ */
+void
+_X_MB_handle_single_event(void *rt, void *evt) {
+    X_MB_runtime_t *xmb_rt = (X_MB_runtime_t *)rt;
+    
+    handle_single_x_event(xmb_rt, (XEvent *)evt);
+}
+
+/*! \brief Called at end of an iteration of X event loop.
+ */
+void
+_X_MB_no_more_event(void *rt) {
+    X_MB_runtime_t *xmb_rt = (X_MB_runtime_t *)rt;
+    
+    no_more_event(xmb_rt);
+}
+
+/* @} */