Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ames!pasteur!cory.Berkeley.EDU!dheller
From: dheller@cory.Berkeley.EDU (Dan Heller)
Newsgroups: comp.windows.x
Subject: Re: XGetImage from an unmapped Window - how to?
Summary: XCreatPixmap, XGetImage
Message-ID: <4086@pasteur.Berkeley.Edu>
Date: 25 Jun 88 19:01:29 GMT
References: <154@cyclopes.UUCP>
Sender: news@pasteur.Berkeley.Edu
Reply-To: dheller@cory.Berkeley.EDU.UUCP (Dan Heller)
Organization: University of California, Berkeley
Lines: 22

In article <154@cyclopes.UUCP> stergios@cyclopes.UUCP (Stergios Marinopoulos) writes:
	Is there a way to  XGetImage from an  unmapped window?  The  man  page
	states "If the drawable is a window, the window must be mapped, ...."

	My motivation  is this: create an unmapped  window, render stuff  into
	it, store that image, delete the window, and flash the image back some
	time later through the use of XPutImage.

Don't create a window -- create a pixmap.  Since it is a drawable, you can
create a pixmap (it isn't mapped to the screen), draw into it, then use
the image from the pixmap.

Note; I'm not sure of args here cuz I don't have any xcode handy at the moment.

    Pixmap pix = XCreatePixmap(dpy, rootwin, size, etc...)
    XImage *image;

    XDrawLine(dpy, pix, gc, ...
    image = XGetImage(dpy, pix, ...
    XDestroyPixmap(pix);

Dan Heller