1penrose(6x) XScreenSaver manual penrose(6x)
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6 penrose - draws quasiperiodic tilings
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9 penrose [-display host:display.screen] [-foreground color] [-background
10 color] [-window] [-root] [-mono] [-install] [-visual visual] [-ncolors
11 integer] [-delay microseconds] [-size integer] [-ammann] [-no-ammann]
12 [-fps]
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16 The penrose program draws quasiperiodic tilings.
17 See Onoda, Steinhardt, DiVincenzo and Socolar in Phys. Rev. Lett. 60,
19 #25, 1988 or Strandburg in Computers in Physics, Sep/Oct 1991.
20 This implementation uses the simpler version of the growth algorithm,
22 i.e., if there are no forced vertices, a randomly chosen tile is added
23 to a randomly chosen vertex (no preference for those 108 degree
24 angles).
25 There are two essential differences to the algorithm presented in the
27 literature: First, we do not allow the tiling to enclose an untiled
28 area. Whenever this is in danger of happening, we just do not add the
29 tile, hoping for a better random choice the next time. Second, when
30 choosing a vertex randomly, we will take one that lies withing the
31 viewport if available. If this seems to cause enclosures in the forced
32 rule case, we will allow invisible vertices to be chosen.
33 Tiling is restarted whenever one of the following happens: there are no
35 incomplete vertices within the viewport or the tiling has extended a
36 window's length beyond the edge of the window horizontally or verti‐
37 cally or forced rule choice has failed 100 times due to areas about to
38 become enclosed.
39 Although quasiperiodic tilings are produced, the tiles themselves are
41 not penrose tiles (darts and kites). In contrast to penrose tiles,
42 these tiles can be arranged to form a periodic tiling.
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46 penrose accepts the following options:
47 -window Draw on a newly-created window. This is the default.
49 -root Draw on the root window.
51 -mono If on a color display, pretend we're on a monochrome display.
53 -install
55 Install a private colormap for the window.
56 -visual visual
58 Specify which visual to use. Legal values are the name of a
59 visual class, or the id number (decimal or hex) of a specific
60 visual.
61 -ncolors integer
63 How many colors should be used (if possible). Default 64. The
64 colors are chosen randomly.
65 -size integer
67 How big the tiles should be. Default 40 pixels.
68 -delay milliseconds
71 How long (in 1/1,000,000'ths of a second) to wait between draw‐
72 ing each tile. Default 10,000 or .01 seconds.
73 -ammann
76 -no-ammann
78 Whether Ammann lines should be added.
79 -fps Display the current frame rate and CPU load.
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84 DISPLAY to get the default host and display number.
85 XENVIRONMENT
87 to get the name of a resource file that overrides the global
88 resources stored in the RESOURCE_MANAGER property.
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91 X(1), xscreensaver(1), xlock(1)
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94 Copyright © 1996 by Timo Korvola.
95 Permission to use, copy, modify, and distribute this software and its
97 documentation for any purpose and without fee is hereby granted, pro‐
98 vided that the above copyright notice appear in all copies and that
99 both that copyright notice and this permission notice appear in sup‐
100 porting documentation.
101
103 Timo Korvola <tkorvola@dopey.hut.fi>, 1996.
104 Ability to run standalone or with xscreensaver added by Jamie Zawinski
106 <jwz@jwz.org>, 10-May-97.
107X Version 11 5.15-3.fc14 (18-Oct-2011) penrose(6x)