#include <X11/Xlib.h>
#include <X11/extensions/shape.h>
#include <stdio.h>
#include <stdlib.h>
#include <memory.h>

/* 丸いマスクを作る */
char *maru_shape( int r) 
{
	int i, j;
	int r2 = r * 2;
	int rd = r * r;
	int w = (r2 + 7) / 8;
	char *ret = (char*)calloc(1, r2 * w);
	for (i = 0; i < r2; i++) {
		int m = i * w;
		int l1 = (i - r) ; l1 *= l1;
		for (j = 0; j < r2; j++) {
			int l2 = (j - r) ; l2 *= l2;
			if (l1 + l2 <= rd) {
				ret[m + j / 8] |= 1 << (j % 8);
			}
		}
	}
	return ret; 
}
/* ウィンドウのタイトルバーを消す */
void change_prop(Display *display, Window window) 
{ 
#define MWM_HINTS_FUNCTIONS    (1L << 0)
#define MWM_HINTS_DECORATIONS   (1L << 1)
#define MWM_HINTS_INPUT_MODE    (1L << 2)
#define MWM_FUNC_MOVE           (1L << 2)
#define MWM_INPUT_MODELESS      0
   struct {
      long flags;
      long functions;
      long decorations;
      long inputmode;
   } prop;
   prop.flags=MWM_HINTS_FUNCTIONS|MWM_HINTS_DECORATIONS|MWM_HINTS_INPUT_MODE;
   prop.decorations=0;
   prop.functions=MWM_FUNC_MOVE;
   prop.inputmode=MWM_INPUT_MODELESS;
   Atom a=XInternAtom(display,"_MOTIF_WM_HINTS",0);
   XChangeProperty( display, window, a, a, 32, PropModeReplace, (unsigned char*)&prop, 4);
}
/* BMPファイルを読みこんで画像データなどを返します。*/
char *loadbmpfile(const char *filename, int *width, int *height, int *bitcount, int *linelen)
{
	char *bmpdata;
    int i, j, k, size;
    int off, hs, w = 0, h = 0, bcnt = 0;
    int line;
    int pl = 0, bicomp = 0, clrused;
    char bm[3];
    FILE *fi = fopen(filename,"rb");
    bcnt = 0;
	if (fi) {
	    fread(bm, 1, 2, fi);
    	fread(&i , 4, 1, fi);//fsize
	    fread(&i , 2, 2, fi);
    	fread(&off , 4, 1, fi);//offset
	    fread(&hs , 4, 1, fi);//hdsize
	    if (hs == 40) {
	        fread(&w , 4, 1, fi);//width
	        fread(&h , 4, 1, fi);//height
	        fread(&pl , 2, 1, fi);//planes
	        fread(&bcnt , 2, 1, fi);//bitcount
	        fread(&bicomp, 4, 1, fi);//biComp
	        fread(&i , 4, 1, fi);//biSizeImage
	        fread(&i , 4, 1, fi);//biXPixPerMeter
	        fread(&i , 4, 1, fi);//biYPixPerMeter
	        fread(&clrused , 4, 1, fi);//biClrUsed
	        fread(&i , 4, 1, fi);//biClrImpotant
	    } else {
	        fread(&w , 2, 1, fi);//width
		    fread(&h , 2, 1, fi);//height
	        fread(&pl , 2, 1, fi);//planes
	        fread(&bcnt , 2, 1, fi);//bitcount
	    }
	    line = w * (bcnt / 8);
	    line = ((line + 3) / 4) * 4;
		size = line * h;
		if (size < 0) size = -size; 
    	bmpdata = (char*)malloc(size);
    	fread(bmpdata, 1, size, fi);

    	fclose(fi);
	}
    *bitcount = bcnt;
    *width = w;
    *height = h;
    *linelen = line;
    return bmpdata;
}
/* BMPファイルを読みこんでXImageを返す */
XImage *load_bmp(Display *d, const char *filename, int *imwidth, int *imheight) {
	char *bmpdata;
    int scrn = DefaultScreen(d);
    int depth = XDefaultDepth(d, 0);
    Colormap cmap = DefaultColormap(d, scrn);
    int width, height, bitcount, linelen, bpp;
    XImage *img;
    char *data;
    XColor color;
    int i, j, h;
	bmpdata = loadbmpfile(filename, &width, &height, &bitcount, &linelen);
	bpp = depth >= 24 ? 4 : 2;
	h = height;
	if (height < 0) height = -height;
	data = (char*)malloc(height * width * bpp);
	for (i = 0; i < height; i++) {
		int k = h < 0 ? i * linelen : (height - i -1) * linelen;
		int m = i * width * bpp;
		for (j = 0; j < width; j++) {
			int r = k + j*(bitcount/8);
			int s = m + j * bpp;
			memcpy(data+s, bmpdata+r, bpp);
		}
	}
	free(bmpdata);
	img = XCreateImage( d, CopyFromParent, depth, ZPixmap,
    		0, data, width, height, bpp*8, bpp*width );
    *imwidth = width;
    *imheight = height;
	return img;
}
/* XImageから1pixel=1byte のマスクを作成します */
char *make_shape( XImage *img )
{
	char *data = img->data;
	int bpp = img->bitmap_pad / 8;
	int width = img->width;
	int wlen = (width + 7) / 8;
	int height = img->height;
	int size = wlen * height;
	int i, j;
	char * ret;
	ret = malloc(size);
	if (ret == NULL) {
		fprintf( stderr, "cannot malloc\n" );
		exit( 1 );
	}
	memset( ret, 0, size );
	for( i = 0; i < height; i++ ){
		for( j = 0; j < width; j++ ){
			int m = i * wlen;
			int p = i * width;
			for( j = 0; j < width; j++ ){
				if (memcmp(data, data + (p + j) * bpp, bpp)) {
					ret[m + j / 8] |= 1 << (j % 8);
				}
			}
		}
	}
	return ret;
}
int main()
{
	Display *dsp;
    Window win, sub;
    char *mask1, *mask2;
    Pixmap pm1, pm2;
	int screen, width, height;
    int iwidth, iheight, iwidth2, iheight2;
    GC  gc;
    XImage *image1, *image2;
	int drag = 0, rx = 0, cx = 0;
	/* ディスプレイ */
	dsp = XOpenDisplay( NULL );
	/* イメージを読み込む */
	image1 = load_bmp(dsp, "ameya2.bmp", &iwidth, &iheight);
    image2 = load_bmp(dsp, "balloon.bmp", &iwidth2, &iheight2);
	/* 画面サイズ */
	screen = DefaultScreen(dsp);
	width = DisplayWidth(dsp, screen);
	height = DisplayHeight(dsp, screen);
    /* ウィンドウを生成 */
    win = XCreateSimpleWindow( dsp, RootWindow(dsp, 0),
							  0, 0, 100, 100, 0,
							  BlackPixel(dsp,0), WhitePixel(dsp,0) );
    sub = XCreateSimpleWindow( dsp, RootWindow(dsp, 0),
							  0, 0, 100, 100, 0,
							  BlackPixel(dsp,0), WhitePixel(dsp,0) );
	/* イメージからマスクを作り、ウィンドウの形に設定 */
    mask1 = make_shape(image1);
    pm1 = XCreateBitmapFromData( dsp, RootWindow(dsp,0), mask1, iwidth, iheight);
    mask2 = make_shape(image2);
    pm2 = XCreateBitmapFromData( dsp, RootWindow(dsp,0), mask2, iwidth2, iheight2);
    free(mask1);
    free(mask2);
    XShapeCombineMask( dsp, win, ShapeBounding, 0, 0, pm1, ShapeSet);
    XShapeCombineMask( dsp, sub, ShapeBounding, 0, 0, pm2, ShapeSet);
    /* タイトルバーとサイズボックスなし */
    change_prop(dsp, win);
    change_prop(dsp, sub);
    /* 表示 */
    XMapWindow( dsp, win );
    XMapWindow( dsp, sub );
    /* デスクトップに立つ */
    XMoveResizeWindow( dsp, win, 0, height - iheight, iwidth, iheight);
    XMoveResizeWindow( dsp, sub, iwidth, height - iheight - iheight2/3, iwidth2, iheight2);	cx = 0;
	/* グラフックコンテクスト */
	gc = DefaultGC(dsp, 0);
	/* イベントマスク */
	XSelectInput( dsp, win, ExposureMask | ButtonPressMask | ButtonReleaseMask | PointerMotionMask);
	XSelectInput( dsp, sub, ExposureMask );
	XFlush( dsp );
	/* アプリループ */
	while (1) {
		XEvent event;
		XNextEvent( dsp, &event );
		switch( event.type ){
		case Expose: /* 再描画など */
			if (event.xany.window == win) {
				if (event.xexpose.count == 0) {
					/* ここで再描画の度にイメージを描画する */
					XPutImage( dsp, win, gc, image1, 0, 0, 0, 0, iwidth, iheight );
				}
			} else if (event.xany.window == sub) {
				if (event.xexpose.count == 0) {
					XPutImage( dsp, sub, gc, image2, 0, 0, 0, 0, iwidth2, iheight2 );
				}
			}
			break;
		case ButtonPress:
			drag = 1;
			rx = ((XButtonEvent*)&event)->x;
			break;
		case ButtonRelease:
			if (drag) {
				drag = 0;
			}
      		break;
		case MotionNotify:
			if (drag) {
				cx += ((XButtonEvent*)&event)->x - rx;
				XMoveWindow(dsp, win, cx, height - iheight);
			}
      		break;
		}
	}
	XCloseDisplay( dsp );
}