XScreenSaver(1) XScreenSaver(1) NNAAMMEE attraction - interactions of opposing forces SSYYNNOOPPSSIISS aattttrraaccttiioonn [-display _h_o_s_t_:_d_i_s_p_l_a_y_._s_c_r_e_e_n] [-foreground _c_o_l_o_r] [-background _c_o_l_o_r] [-window] [-root] [-mono] [-install] [-visual _v_i_s_u_a_l] [-points _i_n_t] [-threshold _i_n_t] [-mode balls | lines | polygons | splines | filled-splines | tails ] [-size _i_n_t] [-segments _i_n_t] [-delay _u_s_e_c_s] [-color-shift _i_n_t] [-radius _i_n_t] [-vx _i_n_t] [-vy _i_n_t] [-glow] [-noglow] [-orbit] [-viscosity _f_l_o_a_t] [-mouse] [-no-mouse] [-mouse-size] DDEESSCCRRIIPPTTIIOONN The _a_t_t_r_a_c_t_i_o_n program has several visually different modes of operation, all of which are based on the interac- tions of a set of control points which attract each other up to a certain distance, and then begin to repel each other. The attraction/repulsion is proportional to the distance between any two particles. OOPPTTIIOONNSS _a_t_t_r_a_c_t_i_o_n accepts the following options: --wwiinnddooww Draw on a newly-created window. This is the default. --rroooott Draw on the root window. --mmoonnoo If on a color display, pretend we're on a monochrome display. --iinnssttaallll Install a private colormap for the window. --vviissuuaall _v_i_s_u_a_l 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. --ppooiinnttss iinntteeggeerr How many control points should be used, or 0 to select the number randomly. Default 0. Between 3 and 15 works best. --tthhrreesshhoolldd iinntteeggeerr The distance (in pixels) from each particle at which the attractive force becomes repulsive. Default 100. --mmooddee bbaallllss || lliinneess || ppoollyyggoonnss || ttaaiillss || sspplliinneess || ffiilllleedd-- sspplliinneess In _b_a_l_l_s mode (the default) the control points are drawn as filled circles. The larger the circle, X Version 11 14-Jun-97 1 XScreenSaver(1) XScreenSaver(1) the more massive the particle. In _l_i_n_e_s mode, the control points are connected by straight lines; the effect is something like _q_i_x. In _p_o_l_y_g_o_n_s mode, the control points are connected by straight lines, and filled in. This is most interesting in color. In _s_p_l_i_n_e_s mode, a closed spline is interpolated from the control points. In _f_i_l_l_e_d_-_s_p_l_i_n_e_s mode, the splines are filled in instead of being outlines. This is most interest- ing in color. In _t_a_i_l_s mode, the path which each particle fol- lows is indicated by a worm-like trail, whose length is controlled by the _s_e_g_m_e_n_t_s parameter. --ssiizzee iinntteeggeerr The size of the balls in pixels, or 0, meaning to select the sizes randomly (the default.) If this is specified, then all balls will be the same size. This option has an effect in all modes, since the ``size'' of the balls controls their mass. --sseeggmmeennttss iinntteeggeerr If in _l_i_n_e_s or _p_o_l_y_g_o_n_s mode, how many sets of line segments or polygons should be drawn. Default 100. This has no effect in _b_a_l_l_s mode. If _s_e_g_- _m_e_n_t_s is 0, then no segments will ever be erased (this is only useful in color.) --ddeellaayy mmiiccrroosseeccoonnddss How much of a delay should be introduced between steps of the animation. Default 10000, or about 0.01 seconds. --ccoolloorr--sshhiifftt iinntt If on a color display, the color of the line seg- ments or polygons will cycle through the color map. This specifies how many lines will be drawn before a new color is chosen. (When a small num- ber of colors are available, increasing this value will yield smoother transitions.) Default 3. This has no effect in _b_a_l_l_s mode. --rraaddiiuuss The size in pixels of the circle on which the points are initially positioned. The default is slightly smaller than the size of the window. --ggllooww This is consulted only in _b_a_l_l_s mode. If this is X Version 11 14-Jun-97 2 XScreenSaver(1) XScreenSaver(1) specified, then the saturation of the colors of the points will vary according to their current acceleration. This has the effect that the balls flare brighter when they are reacting to each other most strongly. In _g_l_o_w mode, all of the balls will be drawn the same (random) color, modulo the saturation shifts. In non-glow mode, the balls will each be drawn in a random color that doesn't change. --nnooggllooww Don't do ``glowing.'' This is the default. --vvxx ppiixxeellss --vvyy ppiixxeellss Initial velocity of the balls. This has no effect in --oorrbbiitt mode. --oorrbbiitt Make the initial force on each ball be tangential to the circle on which they are initially placed, with the right velocity to hold them in orbit about each other. After a while, roundoff errors will cause the orbit to decay. --vvmmuulltt ffllooaatt In orbit mode, the initial velocity of the balls is multiplied by this; a number less than 1 will make the balls pull closer together, and a larger number will make them move apart. The default is 0.9, meaning a slight inward pull. --vviissccoossiittyy ffllooaatt This sets the viscosity of the hypothetical fluid through which the control points move; the default is 1, meaning no resistance. Values higher than 1 aren't interesting; lower values cause less motion. One interesting thing to try is attraction -viscosity 0.8 -points 75 \ -mouse -geometry =500x500 Give it a few seconds to settle down into a stable clump, and then move the mouse through it to make "waves". --mmoouussee This will cause the mouse to be considered a con- trol point; it will not be drawn, but it will influence the other points, so you can wave the mouse and influence the images being created. X Version 11 14-Jun-97 3 XScreenSaver(1) XScreenSaver(1) --nnoo--mmoouussee Turns off --mmoouussee. --mmoouussee--ssiizzee iinntteeggeerr In --mmoouussee mode, this sets the mass of the mouse (analagously to the --ssiizzee parameter.) EENNVVIIRROONNMMEENNTT DDIISSPPLLAAYY to get the default host and display number. XXEENNVVIIRROONNMMEENNTT to get the name of a resource file that overrides the global resources stored in the RESOURCE_MAN- AGER property. SSEEEE AALLSSOO XX(1), xxssccrreeeennssaavveerr(1) CCOOPPYYRRIIGGHHTT Copyright (C) 1992, 1993, 1997 by Jamie Zawinski. Permis- sion to use, copy, modify, distribute, and sell this soft- ware and its documentation 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 pro- vided "as is" without express or implied warranty. AAUUTTHHOORR Jamie Zawinski , 13-aug-92. Viscosity and mouse support by Philip Edward Cutone, III. X Version 11 14-Jun-97 4