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 xmartin(1)                                                       xmartin(1)
                                20 July 1991



 NAME
      xmartin - set X root window to Martin hopalong pattern

 SYNOPSIS
      xmartin  [options]
      xmartin+  [options]

 DESCRIPTION
      Xmartin sets the X root window to a hopalong pattern.  Xmartin+ is an
      optional front end.  The hopalong algorithm was attributed to Barry
      Martin of Aston University (Birmingham, England) in  A. K. Dewdney's
      Computer Recreations column in the September 1986 Scientific American.
      The cp1 sine sculpture functions were published by Clifford Pickover
      in the January 1991 Algorithm. The rr1 function was developed by
      Renaldo Recuerdo of the Santa Cruz Operation.

 OPTIONS
      -f function
           Requests a specific hopalong function: martin1, martin2, ejk1,
           ..., ejk6, rr1, or cp1. By default, a function is selected at
           random. xmartin+ allows tailoring probabilities that a function
           will be selected. (See FRONT END below.)

           Note: cp1 is actually a family of roughly 2.8e19 functions with
           the highest-order exponent ranging from 1 to 16 and requested by
           -f cp1,order. Within a cp1 order, there are 16**order function
           permutations. A specific permutation is requested by -f
           cp1,order,xn,yn, where xn and yn are integers from 0 to
           (4**order)-1.

      -a  -b  -c -d -x -y { r | r:r | r::r }
           Sets the corresponding hopalong parameter to the real value r or
           to a random value in the range r:r or r::r. Two colons indicate a
           plus-or-minus range. For example, -100:1e3 means a value between
           -100 and 1000, while 1::3 means a value between 1 and 3 or
           between -1 and -3.  abcd are constants, while xy are the
           coordinates of the starting point for the calculation.  By
           default, random values are assigned for abcd. The ranges for
           default random values can be tailored with the xmartin+ front end
           described below.

      -p n -P n
           Sets maximum points to calculate to n. -p sets the maximum for
           in-range (i.e. on display) points. -P sets the total points to
           calculate. Defaults: -p: 25% of pixels in server display (or
           tile).  -P: 3 times the -p value. Values of 100 or less are
           interpreted as percent of pixels in display or tile.

      -dynam [ nd ]
           Sets the number of points calculated before display.  Default is
           -dynam 1024 (128 if -tile is selected.)



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 xmartin(1)                                                       xmartin(1)
                                20 July 1991



      -static
           Display after all points calculated.

      -tile [ XxY ]
           Requests that the root window be tiled with a pattern smaller
           than the entire display. XxY, if present, requests a specific
           tiling pattern. For example, -tile 3x4 requests a tile size of
           1/3 the display width and 1/4 the display height. A random XxY is
           used if not supplied.  This option substantially reduces
           calculation time and memory requirements for the pattern.

      -perturb [ n[,v] ]
           Perturbs the calculation every n points by offsetting the current
           x and y values by v. If v or n are not supplied, random values
           are used.

      -coord { xy | yx | ra | ar }
           Coordinate mode. Calculation (x,y) interpreteted as (x,y), (y,x),
           (radius,angle), or (angle,radius). Default is xy except for -f
           cp1, where one of the four is selected at random.

      -zoom z
           Multiplies calculation coordinates by z before display. Thus, z >
           1 magnifies, and z < 1 reduces. Defaults to an appropriate value
           for the selected function.

      -move d,p
           Moves the  pattern p pixels in the direction d. The direction d
           is either a compass degree heading (0 = north, 90 = east, 180 =
           south, etc), or the common abbreviations ('n', 'sw', 'nnw', etc.)
           Thus, for example, -move ne,300 moves the pattern 300 pixels
           toward the upper right corner.

      -recall
           Recalls hopalong parameters (-f, -a, -b, -c, -d, -x, -y, -zoom,
           -move, -tile, -perturb) from the last pattern before processing
           any other arguments. Thus, for example, -recall -zoom 0.5
           -perturb will zoom out and add random perturbation to the
           previous pattern. The recall parameters are saved in
           $HOME/.xmartin. A pattern generated with -recall is not itself
           saved.

      -bg color[,intensity]
           Requests a specific background color for the pattern. If present,
           intensity (a value from 0.0 to 1.0) specifies the color
           intensity.  For example, -bg blue,0.20 yields a very dark blue
           background. By default, random low intensity color backgrounds
           are used (see RESOURCES below.)

      -nc n
           For color or grayscale displays, sets the number of points to



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 xmartin(1)                                                       xmartin(1)
                                20 July 1991



           calculate before changing colors. (Default: 1/16th of -P value,
           except for -f cp1 on color displays, where the default is the -P
           value.)

      -nrc Non-random color sequence.

      +rv -rv
           Requests black-on-white or white-on-black patterns respectively.
           -rv (white-on-black) is the default for monochrome displays.

      -mono
           Forces white-on-black for a grayscale or color displays.

      -v   Prints xmartin version and patch level.

 FRONT END
      On systems with perl installed, the xmartin+ front end may be used to
      invoke xmartin with probabilities and parameters tailored to your
      preferences, or to save or request interesting parameter sets by name.
      Tailored parameters and recorded values are stored in $HOME/.xmartin+.
      If you don't have  a .xmartin+ file, one with comments and examples is
      created.

      -q   Prints table of .xmartin+ entry names, weights, and comments.

      -demo
           Executes each entry once.

      -n name [-n name] ...
           Requests pattern(s) by name. (Also -f)

      -repeat [seconds]
           Generates patterns indefinitely (until ^C), pausing the requested
           number of seconds between each pattern. Thus xmartin+ -repeat 300
           -tile will generate a random tiled background about every 5
           minutes.

      -save
           Saves the exact hopalong parameters for the previous pattern in
           the .xmartin+ file so it can be recalled later with xmartin+ -n
           name. You will be prompted for the name and a brief comment.

      -file file
           Requests a file other than ~/.xmartin+.

      All xmartin parameters (except -recall) are also accepted, so you can
      add to or alter options generated by xmartin+.

 RESOURCES
      For color or grayscale displays, xmartin honors the following resource
      for background color:



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 xmartin(1)                                                       xmartin(1)
                                20 July 1991



      xmartin*background: color[,intensity]

      Intensity, if present, is a real number from 0.0 to 1.0 which
      indicates the intensity of the color desired (default: 1.0). Another
      permissable value for this resource is random (the default) which
      selects one of the 16 background resources below.

      For color displays, xmartin honors the following resources for
      foreground and random background colors (shown with default values):

      xmartin*Color1: red
      xmartin*Color2: green
      xmartin*Color3: blue
      xmartin*Color4: yellow
      xmartin*Color5: magenta
      xmartin*Color6: cyan
      xmartin*Color7: coral
      xmartin*Color8: slate blue
      xmartin*Color9: orange red
      xmartin*Color10: spring green
      xmartin*Color11: orange
      xmartin*Color12: steel blue
      xmartin*Color13: pink
      xmartin*Color14: violet
      xmartin*Color15: firebrick
      xmartin*Color16: gold

      xmartin*bgColor1: black
      xmartin*bgColor2: white,.20
      xmartin*bgColor3: white,.25
      xmartin*bgColor4: white,.30
      xmartin*bgColor5: white,.35
      xmartin*bgColor6: blue,.20
      xmartin*bgColor7: blue,.25
      xmartin*bgColor8: blue,.30
      xmartin*bgColor9: red,.25
      xmartin*bgColor10: red,.30
      xmartin*bgColor11: red,.35
      xmartin*bgColor12: green,.25
      xmartin*bgColor13: green,.30
      xmartin*bgColor14: cyan,.20
      xmartin*bgColor15: cyan,.25
      xmartin*bgColor16: cyan,.30

      For grayscale displays, xmartin honors the following resources for
      foreground and random background shades (shown with default values):

      xmartin*Gray1: white
      xmartin*Gray2: white,.96
      xmartin*Gray3: white,.92
      xmartin*Gray4: white,.88



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 xmartin(1)                                                       xmartin(1)
                                20 July 1991



      xmartin*Gray5: white,.84
      xmartin*Gray6: white,.80
      xmartin*Gray7: white,.76
      xmartin*Gray8: white,.72
      xmartin*Gray9: white,.68
      xmartin*Gray10: white,.64
      xmartin*Gray11: white,.60
      xmartin*Gray12: white,.56
      xmartin*Gray13: white,.52
      xmartin*Gray14: white,.48
      xmartin*Gray15: white,.44
      xmartin*Gray16: white,.40

      xmartin*bgGray1: black
      xmartin*bgGray2: white,.02
      xmartin*bgGray3: white,.04
      xmartin*bgGray4: white,.06
      xmartin*bgGray5: white,.08
      xmartin*bgGray6: white,.10
      xmartin*bgGray7: white,.12
      xmartin*bgGray8: white,.14
      xmartin*bgGray9: white,.16
      xmartin*bgGray10: white,.18
      xmartin*bgGray11: white,.20
      xmartin*bgGray12: white,.22
      xmartin*bgGray13: white,.24
      xmartin*bgGray14: white,.26
      xmartin*bgGray15: white,.28
      xmartin*bgGray16: white,.30

      Foreground colors and grays are used in the order above if -nrc is
      used. Otherwise they are used in a random order.  Color is changed
      every -nc n points during the calculation.

 ALGORITHMS
      The basic algorithm for all patterns is:

           {pick initial x,y and constants A,B,...}
           while(not enough points) {
              x1 = X1(x,y);
              y1 = Y1(x,y);
              x = x1; y=y1;
              plot(x,y);
              }


      martin1:
      x1 = y  - ( (x<0) ? sqrt(fabs(B*x-C)) : -sqrt(fabs(B*x-C)) );
      y1 = A - x;

      martin2:



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 xmartin(1)                                                       xmartin(1)
                                20 July 1991



      x1 = y  - sin(x);
      y1 = A - x;

      ejk1:
      x1 = y  - ( (x>0) ? (B*x-C) : -(B*x-C) );
      y1 = A - x;

      ejk2:
      x1 = y  - ( (x<0) ? log(fabs(B*x-C)) : -log(fabs(B*x-C)) );
      y1 = A - x;

      ejk3:
      x1 = y  - ( (x>0) ? (sin(B*x)-C) : -(sin(B*x)-C) );
      y1 = A - x;

      ejk4:
      x1 = y  - ( (x>0) ? (sin(B*x)-C) : -sqrt(fabs(B*x-C)) );
      y1 = A - x;

      ejk5:
      x1 = y  - ( (x>0) ? (sin(B*x)-C) : -(B*x-C) );
      y1 = A - x;

      ejk6:
      x1 = y  - asin(fmod(B*x, 1.0));
      y1 = A - x;

      rr1:
      x1 = y  - ( (x<0) ? -pow(fabs(B*x-C), D) : pow(fabs(B*x-C), D) );
      y1 = A - x;

      cp1:
      x1 = sin(p1) + sin(p2)*sin(p2) + sin(p3)*sin(p3)*sin(p3) + ...
      y1 = sin(q1) + sin(q2)*sin(q2) + sin(q3)*sin(q3)*sin(q3) + ...

      Each pn or qn is either A*x, A*y, B*x, or B*y.


 BUGS
      On some systems, certain parameter combinations cause xmartin to abort
      with a floating point exception. (The neuron pattern defined by
      xmartin+ is an example.)

 AUTHOR
      Ed Kubaitis, Computing Services Office, University of Illinois.









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