redhat man page for blitspin

XScreenSaver(1) 					      General Commands Manual						   XScreenSaver(1)

NAME
       blitspin - rotate a bitmap in an interesting way

SYNOPSIS
       blitspin  [-display  host:display.screen]  [-foreground	color]	[-background  color] [-window] [-root] [-mono] [-install] [-visual visual]
       [-bitmap filename] [-delay usecs] [-delay2 usecs]

DESCRIPTION
       The blitspin program repeatedly rotates a bitmap by 90 degrees by using logical operations: the bitmap is divided into quadrants,  and  the
       quadrants  are shifted clockwise.  Then the same thing is done again with progressively smaller quadrants, except that all sub-quadrants of
       a given size are rotated in parallel.  So this takes O(16*log2(N)) blits of size NxN, with the limitation that the image  must  be  square,
       and the size must be a power of 2.

OPTIONS
       blitspin accepts the following options:

       -window Draw on a newly-created window.	This is the default.

       -root   Draw on the root window.

       -mono   If on a color display, pretend we're on a monochrome display.

       -install
	       Install a private colormap for the window.

       -visual visual
	       Specify which visual to use.  Legal values are the name of a visual class, or the id number (decimal or hex) of a specific visual.

       -bitmap filename
	       The  file  name	of a bitmap to rotate.	It need not be square: it will be padded with the background color.  If unspecified or the
	       string (default), a builtin bitmap is used.

	       If support for the XPM library was enabled at compile-time, the specified file may be in XPM format as well as XBM, and thus may be
	       a color image.

	       The *bitmapFilePath resource will be searched if the bitmap name is not a fully-qualified pathname.

       -grab-screen
	       If  this  option  is specified, then the image which is spun will be grabbed from the portion of the screen underlying the blitspin
	       window, or from the system's video input, or from a random file on disk, as indicated by  the  grabDesktopImages,  grabVideoFrames,
	       and chooseRandomImages options in the ~/.xscreensaver file; see xscreensaver-demo(1) for more details.

       -delay microseconds
	       How long to delay between steps of the rotation process, in microseconds.  Default is 500000, one-half second.

       -delay2 microseconds
	       How  long  to  delay  between  each  90-degree  rotation, in microseconds.  Default is 500000, one-half second.	DISPLAY to get the
	       default host and display number.

ENVIRONMENT
       XENVIRONMENT to get the name of a resource file that overrides the global resources stored in the RESOURCE_MANAGER property.

SEE ALSO
       X(1), xscreensaver(1), xscreensaver-demo(1), xscreensaver-getimage(1)

COPYRIGHT
       Copyright (C) 1992, 1993, 1997, 2001 by Jamie Zawinski.	Permission to use, copy, modify, distribute, and sell this software and its  docu-
       mentation  for  any purpose is hereby granted without fee, provided that the above copyright notice appear in all copies and that both that
       copyright notice and this permission notice appear in supporting documentation.	No representations are made about the suitability of  this
       software for any purpose.  It is provided "as is" without express or implied warranty.

AUTHOR
       Jamie Zawinski <jwz@jwz.org>, 17-aug-92.

       Based on SmallTalk code which appeared in the August 1981 issue of Byte magazine.

X Version 11							     24-Nov-97							   XScreenSaver(1)