1blitspin(6x) XScreenSaver manual blitspin(6x)
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6 blitspin - rotate a bitmap in an interesting way
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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]
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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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23 blitspin accepts the following options:
24 -window Draw on a newly-created window. This is the default.
26 -root Draw on the root window.
28 -mono If on a color display, pretend we're on a monochrome display.
30 -install
32 Install a private colormap for the window.
33 -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.
38 -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.
43 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.
47 The *bitmapFilePath resource will be searched if the bitmap
49 name is not a fully-qualified pathname.
50 -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.
58 -delay microseconds
60 How long to delay between steps of the rotation process, in
61 microseconds. Default is 500000, one-half second.
62 -delay2 microseconds
64 How long to delay between each 90-degree rotation, in microsec‐
65 onds. Default is 500000, one-half second. DISPLAY to get the
66 default host and display number.
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69 XENVIRONMENT to get the name of a resource file that overrides the
70 global resources stored in the RESOURCE_MANAGER property.
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73 X(1), xscreensaver(1), xscreensaver-demo(1), xscreensaver-getimage(1)
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76 Copyright © 1992, 1993, 1997, 2001 by Jamie Zawinski. Permission to
77 use, copy, modify, distribute, and sell this software and its documen‐
78 tation for any purpose is hereby granted without fee, provided that the
79 above copyright notice appear in all copies and that both that copy‐
80 right notice and this permission notice appear in supporting documenta‐
81 tion. No representations are made about the suitability of this soft‐
82 ware for any purpose. It is provided "as is" without express or
83 implied warranty.
84
86 Jamie Zawinski <jwz@jwz.org>, 17-aug-92.
87 Based on SmallTalk code which appeared in the August 1981 issue of Byte
89 magazine.
90X Version 11 5.05-3 (06-Apr-2008) blitspin(6x)