X11 Xlib截屏问题及深入分析三 —— 源码实现2

接上一篇文章《X11 Xlib截屏问题及深入分析二 —— 源码实现》，链接为：

X11 Xlib截屏问题及深入分析二 —— 源码实现1_蓝天居士的博客-CSDN博客

前一篇文章列出了XOpenDisplay和XCloseDisplay函数的源码，本篇列出其余几个函数的源码实现。

• XCreateSimpleWindow源码

XCreateSimpleWindow函数对应的源码在src/CrWindow.c中，如下所示：

Window XCreateSimpleWindow(
    register Display *dpy,
    Window parent,
    int x,
    int y,
    unsigned int width,
    unsigned int height,
    unsigned int borderWidth,
    unsigned long border,
    unsigned long background)
{
    Window wid;
    register xCreateWindowReq *req;
 
    LockDisplay(dpy);
    GetReqExtra(CreateWindow, 8, req);
    req->parent = parent;
    req->x = x;
    req->y = y;
    req->width = width;
    req->height = height;
    req->borderWidth = borderWidth;
    req->depth = 0;
    req->class = CopyFromParent;
    req->visual = CopyFromParent;
    wid = req->wid = XAllocID(dpy);
    req->mask = CWBackPixel | CWBorderPixel;
 
    {
	register CARD32 *valuePtr = (CARD32 *) NEXTPTR(req,xCreateWindowReq);
	*valuePtr++ = background;
	*valuePtr = border;
    }
 
    UnlockDisplay(dpy);
    SyncHandle();
    return (wid);
    }

• XMapWindow源码

XMapWindow函数对应的源码在src/MapWindow.c中，如下所示：

int
XMapWindow (
	register Display *dpy,
	Window w)
{
	register xResourceReq *req;
	LockDisplay (dpy);
        GetResReq(MapWindow, w, req);
	UnlockDisplay (dpy);
	SyncHandle();
	return 1;
}

•  XGetImage源码

XGetImage函数对应的源码在src/GetImage.c中，如下所示： 

XImage *XGetImage (
     register Display *dpy,
     Drawable d,
     int x,
     int y,
     unsigned int width,
     unsigned int height,
     unsigned long plane_mask,
     int format)	/* either XYPixmap or ZPixmap */
{
	xGetImageReply rep;
	register xGetImageReq *req;
	char *data;
	unsigned long nbytes;
	XImage *image;
	int planes;
	LockDisplay(dpy);
	GetReq (GetImage, req);
	/*
	 * first set up the standard stuff in the request
	 */
	req->drawable = d;
	req->x = x;
	req->y = y;
	req->width = width;
	req->height = height;
	req->planeMask = plane_mask;
	req->format = format;
 
	if (_XReply (dpy, (xReply *) &rep, 0, xFalse) == 0 ||
	    rep.length == 0) {
		UnlockDisplay(dpy);
		SyncHandle();
		return (XImage *)NULL;
	}
 
	if (rep.length < (INT_MAX >> 2)) {
	    nbytes = (unsigned long)rep.length << 2;
	    data = Xmalloc(nbytes);
	} else
	    data = NULL;
	if (! data) {
	    _XEatDataWords(dpy, rep.length);
	    UnlockDisplay(dpy);
	    SyncHandle();
	    return (XImage *) NULL;
	}
        _XReadPad (dpy, data, nbytes);
        if (format == XYPixmap) {
	    image = XCreateImage(dpy, _XVIDtoVisual(dpy, rep.visual),
		Ones (plane_mask &
		    (((unsigned long)0xFFFFFFFF) >> (32 - rep.depth))),
		format, 0, data, width, height, dpy->bitmap_pad, 0);
	    planes = image->depth;
	} else { /* format == ZPixmap */
            image = XCreateImage (dpy, _XVIDtoVisual(dpy, rep.visual),
		rep.depth, ZPixmap, 0, data, width, height,
		    _XGetScanlinePad(dpy, (int) rep.depth), 0);
	    planes = 1;
	}
 
	if (!image) {
	    Xfree(data);
	} else {
            if (planes < 1 || image->height < 1 || image->bytes_per_line < 1 ||
                INT_MAX / image->height <= image->bytes_per_line ||
                INT_MAX / planes <= image->height * image->bytes_per_line ||
                nbytes < planes * image->height * image->bytes_per_line) {
                XDestroyImage(image);
                image = NULL;
            }
	}
	UnlockDisplay(dpy);
	SyncHandle();
	return (image);
}

• XPutImage源码

 XPutImage函数对应的源码在src/PutImage.c中，如下所示： 

int
XPutImage (
    register Display *dpy,
    Drawable d,
    GC gc,
    register XImage *image,
    int req_xoffset,
    int req_yoffset,
    int x,
    int y,
    unsigned int req_width,
    unsigned int req_height)
 
{
    long width = req_width;
    long height = req_height;
    int dest_bits_per_pixel, dest_scanline_pad;
 
    if (req_xoffset < 0) {
	width += req_xoffset;
	req_xoffset = 0;
    }
    if (req_yoffset < 0) {
	height += req_yoffset;
	req_yoffset = 0;
    }
    if ((req_xoffset + width) > image->width)
	width = image->width - req_xoffset;
    if ((req_yoffset + height) > image->height)
	height = image->height - req_yoffset;
    if ((width <= 0) || (height <= 0))
	return 0;
 
    if ((image->bits_per_pixel == 1) || (image->format != ZPixmap)) {
	dest_bits_per_pixel = 1;
	dest_scanline_pad = dpy->bitmap_pad;
    } else {
	register int n;
	register ScreenFormat *format;
 
	dest_bits_per_pixel = image->bits_per_pixel;
	dest_scanline_pad = image->bitmap_pad;
	for (n = dpy->nformats, format = dpy->pixmap_format; --n >= 0; format++)
	    if (format->depth == image->depth) {
		dest_bits_per_pixel = format->bits_per_pixel;
		dest_scanline_pad = format->scanline_pad;
	    }
	if (dest_bits_per_pixel != image->bits_per_pixel) {
	    XImage img;
	    register long i, j;
	    /* XXX slow, but works */
	    img.width = width;
	    img.height = height;
	    img.xoffset = 0;
	    img.format = ZPixmap;
	    img.byte_order = dpy->byte_order;
	    img.bitmap_unit = dpy->bitmap_unit;
	    img.bitmap_bit_order = dpy->bitmap_bit_order;
	    img.bitmap_pad = dest_scanline_pad;
	    img.depth = image->depth;
	    img.bits_per_pixel = dest_bits_per_pixel;
	    img.bytes_per_line = ROUNDUP((dest_bits_per_pixel * width),
					 dest_scanline_pad) >> 3;
	    img.data = Xmallocarray(height, img.bytes_per_line);
	    if (img.data == NULL)
		return 0;
	    _XInitImageFuncPtrs(&img);
	    for (j = height; --j >= 0; )
		for (i = width; --i >= 0; )
		    XPutPixel(&img, i, j, XGetPixel(image, req_xoffset + i,
						    req_yoffset + j));
	    LockDisplay(dpy);
	    FlushGC(dpy, gc);
	    PutSubImage(dpy, d, gc, &img, 0, 0, x, y,
			(unsigned int) width, (unsigned int) height,
			dest_bits_per_pixel, dest_scanline_pad);
	    UnlockDisplay(dpy);
	    SyncHandle();
	    Xfree(img.data);
	    return 0;
	}
    }
 
    LockDisplay(dpy);
    FlushGC(dpy, gc);
 
    PutSubImage(dpy, d, gc, image, req_xoffset, req_yoffset, x, y,
		(unsigned int) width, (unsigned int) height,
		dest_bits_per_pixel, dest_scanline_pad);
 
    UnlockDisplay(dpy);
    SyncHandle();
#ifdef USE_DYNAMIC_XCURSOR
    if (image->bits_per_pixel == 1 &&
	x == 0 && y == 0 &&
	width == image->width && height == image->height &&
	gc->values.function == GXcopy &&
	(gc->values.plane_mask & 1))
    {
	_XNoticePutBitmap (dpy, d, image);
    }
#endif
    return 0;
}

至此，几个接口函数的源码就已经全部列出了。从下一篇文章起开始进行代码分析。