1blitspin(6x)                  XScreenSaver manual                 blitspin(6x)
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NAME

6       blitspin - rotate a bitmap in an interesting way
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SYNOPSIS

9       blitspin  [-display  host:display.screen]  [-foreground  color] [-back‐
10       ground color] [-window] [-root]  [-mono]  [-install]  [-visual  visual]
11       [-bitmap filename] [-delay usecs] [-delay2 usecs] [-duration secs]
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DESCRIPTION

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

23       blitspin accepts the following options:
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25       -window Draw on a newly-created window.  This is the default.
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27       -root   Draw on the root window.
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29       -mono   If on a color display, pretend we're on a monochrome display.
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31       -install
32               Install a private colormap for the window.
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34       -visual visual
35               Specify  which  visual  to use.  Legal values are the name of a
36               visual class, or the id number (decimal or hex) of  a  specific
37               visual.
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39       -bitmap filename
40               The file name of a bitmap to rotate.  It need not be square: it
41               will be padded with the background color.   If  unspecified  or
42               the string (default), a builtin bitmap is used.
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44               If support for the XPM library was enabled at compile-time, the
45               specified file may be in XPM format as well as  XBM,  and  thus
46               may be a color image.
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48               The  *bitmapFilePath  resource  will  be searched if the bitmap
49               name is not a fully-qualified pathname.
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51       -grab-screen
52               If this option is specified, then the image which is spun  will
53               be  grabbed from the portion of the screen underlying the blit‐
54               spin window, or from the system's video input, or from a random
55               file  on disk, as indicated by the grabDesktopImages, grabVide‐
56               oFrames, and chooseRandomImages options in the  ~/.xscreensaver
57               file; see xscreensaver-demo(1) for more details.
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59       -delay microseconds
60               How  long  to  delay  between steps of the rotation process, in
61               microseconds.  Default is 500000, one-half second.
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63       -duration seconds
64               How long to run before loading a new image.  Default  120  sec‐
65               onds.
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67       -delay2 microseconds
68               How long to delay between each 90-degree rotation, in microsec‐
69               onds.  Default is 500000, one-half second.  DISPLAY to get  the
70               default host and display number.
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72       -fps    Display the current frame rate and CPU load.
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ENVIRONMENT

75       XENVIRONMENT  to  get  the  name  of a resource file that overrides the
76       global resources stored in the RESOURCE_MANAGER property.
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SEE ALSO

79       X(1), xscreensaver(1), xscreensaver-demo(1), xscreensaver-getimage(1)
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82       Copyright © 1992, 1993, 1997, 2001 by Jamie  Zawinski.   Permission  to
83       use,  copy, modify, distribute, and sell this software and its documen‐
84       tation for any purpose is hereby granted without fee, provided that the
85       above  copyright  notice  appear in all copies and that both that copy‐
86       right notice and this permission notice appear in supporting documenta‐
87       tion.   No representations are made about the suitability of this soft‐
88       ware for any purpose.  It  is  provided  "as  is"  without  express  or
89       implied warranty.
90

AUTHOR

92       Jamie Zawinski <jwz@jwz.org>, 17-aug-92.
93
94       Based on SmallTalk code which appeared in the August 1981 issue of Byte
95       magazine.
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99X Version 11               5.15-3.fc14 (18-Oct-2011)              blitspin(6x)
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