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<html>
<head>
<title>
PLOT_TO_PS - PostScript Graphics Creation
</title>
</head>
<body bgcolor="#EEEEEE" link="#CC0000" alink="#FF3300" vlink="#000055">
<h1 align = "center">
PLOT_TO_PS <br> PostScript Graphics Creation
</h1>
<hr>
<p>
<b>PLOT_TO_PS</b>
is a FORTRAN90 program which
reads a text file of
plot commands and creates a PostScript file.
</p>
<p>
I often use this utility to make simple graphics illustrations.
</p>
<h3 align = "center">
Commands:
</h3>
<p>
<dl>
<dt>
<b>ARC</b> X Y R ANGLE1 ANGLE2
</dt>
<dd>
draw the circular arc from ANGLE1 to ANGLE2, for a circle
of radius R and center (X,Y).
</dd>
<dt>
<b>ARROW</b> X1 Y1 X2 Y2
</dt>
<dd>
draw an arrow from (X1,Y1) to (X2,Y2).
</dd>
<dt>
<b>CIRCLE</b> X Y R
</dt>
<dd>
draw a circle of radius R and center (X,Y).
</dd>
<dt>
<b>CIRCLE_FILL</b> X Y R
</dt>
<dd>
draw a circle of radius R and center (X,Y) and fill it with
the current fill color.
</dd>
<dt>
<b>DEBUG</b>
</dt>
<dd>
switch the debugging state.
</dd>
<dt>
<b>DRAWTO</b> X Y
</dt>
<dd>
draw a line from the current point to (X,Y).
</dd>
<dt>
<b>ELLIPSE</b> X Y R1 R2 ANGLE
</dt>
<dd>
draw an ellipse centered at (X,Y) with axes lengths R1 and R2,
an an angle ANGLE.
</dd>
<dt>
<b>ELLIPSE_FILL</b> X Y R1 R2 ANGLE
</dt>
<dd>
draw an ellipse centered at (X,Y) with axes lengths R1 and R2,
an an angle ANGLE, and fill it with the current color.
</dd>
<dt>
<b>ENDFILE</b>
</dt>
<dd>
indicate the end of the file.
</dd>
<dt>
<b>ENDPAGE</b>
</dt>
<dd>
indicate the end of this "page" or image.
</dd>
<dt>
<b>FILE</b> NAME
</dt>
<dd>
specifies the name of the output file.
</dd>
<dt>
<b>FILL_GRAY</b> GRAY
</dt>
<dd>
sets the fill color to the given shade of gray.
</dd>
<dt>
<b>FILL_RGB</b> R G B
</dt>
<dd>
sets the fill color to the given RGB color.
</dd>
<dt>
<b>FONT_SIZE</b> H
</dt>
<dd>
sets the font size to the given height.
</dd>
<dt>
<b>GRID</b> X1 Y1 X2 Y2 N1 N2
</dt>
<dd>
draws an N1 by N2 grid in the box from (X1,Y1) to (X2,Y2).
</dd>
<dt>
<b>HIST_FAT</b> W
</dt>
<dd>
sets the width of histogram bars to W.
</dd>
<dt>
<b>HISTOGRAM</b> (followed by X,Y pairs, then END)
</dt>
<dd>
processes histogram data.
</dd>
<dt>
<b>LABEL</b> text
</dt>
<dd>
prints the text at the current position and current font size
and current line color.
</dd>
<dt>
<b>LABEL_SLANT</b> ANGLE
</dt>
<dd>
sets a slant angle for a label.
</dd>
<dt>
<b>LINE</b> X1 Y1 X2 Y2
</dt>
<dd>
draws a line from (X1,Y1) to (X2,Y2).
</dd>
<dt>
<b>LINE_GRAY</b> GRAY
</dt>
<dd>
sets the line color to the given gray shade.
</dd>
<dt>
<b>LINE_RGB</b> R G B
</dt>
<dd>
sets the line color to the given RGB color.
</dd>
<dt>
<b>LINE_WIDTH</b> N
</dt>
<dd>
sets the line width. 1 is the finest.
</dd>
<dt>
<b>LINETO</b> X Y
</dt>
<dd>
draws a line from the current point to (X,Y). Same as DRAWTO.
</dd>
<dt>
<b>MOVETO</b> X Y
</dt>
<dd>
moves to (X,Y) without drawing.
</dd>
<dt>
<b>PAGE</b>
</dt>
<dd>
begins a new page or image.
</dd>
<dt>
<b>POINT</b> X Y
</dt>
<dd>
draws a point at (X,Y).
</dd>
<dt>
<b>POINT_LIST</b> (followed by X,Y pairs, then END)
</dt>
<dd>
draws a point at each of the (X,Y) pairs that follow.
</dd>
<dt>
<b>POLYGON</b> (followed by X,Y pairs, then END)
</dt>
<dd>
draws a outlined polygon by connecting the (X,Y) pairs that follow.
</dd>
<dt>
<b>POLYGON_FILL</b> (followed by X,Y pairs, then END)
</dt>
<dd>
draws a filled polygon by connecting the (X,Y) pairs that follow.
</dd>
<dt>
<b>RADIUS</b> X Y R ANGLE
</dt>
<dd>
for the circle of radius R and center (X,Y), draw the
radial line at angle ANGLE.
</dd>
<dt>
<b>SECTOR</b> X Y R ANGLE1 ANGLE2
</dt>
<dd>
draws the sector of a circle centered at (X,Y) with radius R,
from ANGLE1 to ANGLE2.
</dd>
<dt>
<b>SECTOR_FILL</b> X Y R ANGLE1 ANGLE2
</dt>
<dd>
draws the sector of a circle centered at (X,Y) with radius R,
from ANGLE1 to ANGLE2, and fills it with current color.
</dd>
<dt>
<b>SPACE</b> X1 Y1 X2 Y2
</dt>
<dd>
defines the coordinate space to use in the current page.
</dd>
<dt>
<b>SQUARE</b> X Y R
</dt>
<dd>
draws a square centered at (X,Y) with radius R.
</dd>
<dt>
<b>SQUARE_FILL</b> X Y R
</dt>
<dd>
draws a square centered at (X,Y) with radius R and fills it.
</dd>
<dt>
<b>STAR</b> X Y R
</dt>
<dd>
draws a star centered at (X,Y) with radius R.
</dd>
<dt>
<b>STAR_CIRCLE</b> X Y R
</dt>
<dd>
draws open circles at the ten vertices of a star centered at (X,Y)
with radius R.
</dd>
<dt>
<b>STAR_DISK</b> X Y R
</dt>
<dd>
draws filled disks at the ten vertices of a star centered at (X,Y)
with radius R.
</dd>
<dt>
<b>TRIANGLE</b> X1 Y1 X2 Y2 X3 Y3
</dt>
<dd>
draws a triangle with the given vertices.
</dd>
<dt>
<b>TRIANGLE_FILL</b> X1 Y1 X2 Y2 X3 Y3
</dt>
<dd>
draws a triangle with the given vertices, and fills it with
the current color.
</dd>
</dl>
</p>
<h3 align = "center">
Licensing:
</h3>
<p>
The computer code and data files described and made available on this web page
are distributed under
<a href = "../../txt/gnu_lgpl.txt">the GNU LGPL license.</a>
</p>
<h3 align = "center">
Related Data and Software:
</h3>
<p>
<a href = "../../f_src/grf_to_eps/grf_to_eps.html">
GRF_TO_EPS</a>,
a FORTRAN90 program which
converts a GRF file to
<a href = "../../data/eps/eps.html">EPS format</a>;
</p>
<p>
<a href = "../../m_src/points_01_plot/points_01_plot.html">
POINTS_01_PLOT</a>,
a MATLAB program which
reads an ASCII file containing points
in the unit square, and makes an Encapsulated PostScript image;
</p>
<p>
<a href = "../../f_src/ps_write/ps_write.html">
PS_WRITE</a>,
a FORTRAN90 library which
implements PostScript graphics routines
that is used by <b>PLOT_TO_PS</b>.
</p>
<p>
<a href = "../../f_src/triangulation_plot/triangulation_plot.html">
TRIANGULATION_PLOT</a>,
a FORTRAN90 program which
makes a PostScript image of a triangulation of points.
</p>
<p>
<a href = "../../f_src/vector_plot/vector_plot.html">
VECTOR_PLOT</a>,
a FORTRAN90 program which
plots velocity fields and the velocity direction fields.
</p>
<p>
<a href = "../../f_src/voronoi_plot/voronoi_plot.html">
VORONOI_PLOT</a>,
a FORTRAN90 program which
plots the Voronoi neighborhoods of points in the 2D unit square,
using L1, L2 or LInfinity norms;
</p>
<p>
<a href = "../../m_src/xy_display/xy_display.html">
XY_DISPLAY</a>,
a MATLAB program which
reads XY information defining points in 2D,
and displays an image in a MATLAB graphics window;
</p>
<p>
<a href = "../../cpp_src/xy_display_opengl/xy_display_opengl.html">
XY_DISPLAY_OPENGL</a>,
a C++ program which
reads XY information defining points in 2D,
and displays an image using OpenGL.
</p>
<p>
<a href = "../../m_src/xyl_display/xyl_display.html">
XYL_DISPLAY</a>,
a MATLAB program which
reads XYL information defining points and lines in 2D,
and displays an image in a MATLAB graphics window.
</p>
<p>
<a href = "../../cpp_src/xyl_display_opengl/xyl_display_opengl.html">
XYL_DISPLAY_OPENGL</a>,
a C++ program which
reads XYL information defining points and lines in 2D,
and displays an image using OpenGL.
</p>
<p>
<a href = "../../m_src/xyz_display/xyz_display.html">
XYZ_DISPLAY</a>,
a MATLAB program which
reads XYZ information defining points in 3D,
and displays an image in the MATLAB graphics window.
</p>
<p>
<a href = "../../cpp_src/xyz_display_opengl/xyz_display_opengl.html">
XYZ_DISPLAY_OPENGL</a>,
a C++ program which
reads XYZ information defining points in 3D,
and displays an image using OpenGL.
</p>
<h3 align = "center">
Reference:
</h3>
<p>
<ol>
<li>
Henry McGilton, Mary Campione,<br>
PostScript by Example,<br>
Addison-Wesley,<br>
ISBN: 0-201-63228-4
</li>
</ol>
</p>
<h3 align = "center">
Source Code:
</h3>
<p>
<ul>
<li>
<a href = "plot_to_ps.f90">plot_to_ps.f90</a>, the source code;
</li>
<li>
<a href = "plot_to_ps.sh">plot_to_ps.sh</a>,
commands to compile the source code;
</li>
</ul>
</p>
<h3 align = "center">
Examples and Tests:
</h3>
<p>
Note that the program creates a PostScript file, but that,
for display on this web page, we have used the ImageMagick
program <b>convert</b> to convert them to
PNG files.
</p>
<p>
<b>123</b> is an attempt to make a plot of "1, 2, 3"
<ul>
<li>
<a href = "123.plot">123.plot</a>, the input;
</li>
<li>
<a href = "123.png">123.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>AREA_BASIS</b> illustrates how the barycentric coordinates
of a point in a triangle can be defined by the relative areas
of subtriangles:
<ul>
<li>
<a href = "area_basis.plot">area_basis.plot</a>, the input;
</li>
<li>
<a href = "area_basis.png">area_basis.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>BILL_020</b> is a figure for page 20 of Bill's book, a plot
of a typical linear basis function for a grid of triangular
elements arranged in a hexagonal grid:
<ul>
<li>
<a href = "bill_020.plot">bill_020.plot</a>, the input;
</li>
<li>
<a href = "bill_020.png">bill_020.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>BILL_020_RECTANGLE</b> is a version of <b>BILL_020</b> in which
the elements of interest are included in a rectangular grid.
<ul>
<li>
<a href = "bill_020_rectangle.plot">bill_020_rectangle.plot</a>, the input;
</li>
<li>
<a href = "bill_020_rectangle.png">bill_020_rectangle.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>BILL_055</b> is a figure for page 55 of Bill's book:
<ul>
<li>
<a href = "bill_055.plot">bill_055.plot</a>, the input;
</li>
<li>
<a href = "bill_055.png">bill_055.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>BILL_060</b> is a figure for page 60 of Bill's book:
<ul>
<li>
<a href = "bill_060.plot">bill_060.plot</a>, the input;
</li>
<li>
<a href = "bill_060.png">bill_060.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>BILL_061</b> is a figure for page 61 of Bill's book:
<ul>
<li>
<a href = "bill_061.plot">bill_061.plot</a>, the input;
</li>
<li>
<a href = "bill_061.png">bill_061.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>BURGERS_EQUATION</b> is a 2D grid of points for a discretized
Burgers equation, with red nodes for initial condition, green for
boundaries, and gray for initially unknown:
<ul>
<li>
<a href = "burgers_equation.plot">burgers_equation.plot</a>, the input;
</li>
<li>
<a href = "burgers_equation.png">burgers_equation.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>CENTER_OF_MASS</b> plots the center of mass of 6 weighted points:
<ul>
<li>
<a href = "center_of_mass.plot">center_of_mass.plot</a>, the input;
</li>
<li>
<a href = "center_of_mass.png">center_of_mass.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>CENTROID</b> plots the centroid of 6 (equally weighted) points:
<ul>
<li>
<a href = "centroid.plot">centroid.plot</a>, the input;
</li>
<li>
<a href = "centroid.png">centroid.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>CHEBYSHEV</b> illustrates the determination of the Chebyshev points.
<ul>
<li>
<a href = "chebyshev.plot">chebyshev.plot</a>, the input;
</li>
<li>
<a href = "chebyshev.png">chebyshev.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>CIRCLE</b> is a plot of a circle:
<ul>
<li>
<a href = "circle.plot">circle.plot</a>, the input;
</li>
<li>
<a href = "circle.png">circle.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>CLIMB</b> is an illustration for a trigonometry problem, without
which, our students, upon hearing that a train climbed 1 mile up
a slope, would draw a diagram in which the <i>horizontal</I>
distance was 1 mile:
<ul>
<li>
<a href = "climb.plot">climb.plot</a>, the input;
</li>
<li>
<a href = "climb.png">climb.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>COMPONENTS_**</b> illustrate the connected components algorithm.
<ul>
<li>
<a href = "components_01.plot">components_01.plot</a>, the input;
</li>
<li>
<a href = "components_01.png">components_01.png</a>,
a PNG image.
</li>
<li>
<a href = "components_02.plot">components_02.plot</a>, the input;
</li>
<li>
<a href = "components_02.png">components_02.png</a>,
a PNG image.
</li>
<li>
<a href = "components_03.plot">components_03.plot</a>, the input;
</li>
<li>
<a href = "components_03.png">components_03.png</a>,
a PNG image.
</li>
<li>
<a href = "components_04.plot">components_04.plot</a>, the input;
</li>
<li>
<a href = "components_04.png">components_04.png</a>,
a PNG image.
</li>
</ul>
</p>
<p>
<b>CONVEX_HULL</b> illustrate the computation of the convex hull.
<ul>
<li>
<a href = "convex_hull_edge0.plot">convex_hull_edge0.plot</a>, the input;
</li>
<li>
<a href = convex_hull_edge0.png">convex_hull_edge0.png</a>,
the resulting PNG file.
</li>
<li>
<a href = "convex_hull_edge1.plot">convex_hull_edge1.plot</a>, the input;
</li>
<li>
<a href = "convex_hull_edge1.png">convex_hull_edge1.png</a>,
the resulting PNG file.
</li>
<li>
<a href = "convex_hull_edge2.plot">convex_hull_edge2.plot</a>, the input;
</li>
<li>
<a href = convex_hull_edge2.png">convex_hull_edge2.png</a>,
the resulting PNG file.
</li>
<li>
<a href = "convex_hull_edge3.plot">convex_hull_edge3.plot</a>, the input;
</li>
<li>
<a href = "convex_hull_edge3.png">convex_hull_edge3.png</a>,
the resulting PNG file.
</li>
<li>
<a href = "convex_hull_edge4.plot">convex_hull_edge4.plot</a>, the input;
</li>
<li>
<a href = convex_hull_edge4.png">convex_hull_edge4.png</a>,
the resulting PNG file.
</li>
<li>
<a href = "convex_hull.plot">convex_hull.plot</a>, the input;
</li>
<li>
<a href = "convex_hull.png">convex_hull.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>CRESCENT</b> illustrates the construction of a crescent shape
from two circles.
<ul>
<li>
<a href = "crescent.plot">crescent.plot</a>, the input;
</li>
<li>
<a href = "crescent.png">crescent.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>DIATOM</b> fills in a region by plotting lots of points in it:
<ul>
<li>
<a href = "diatom.plot">diatom.plot</a>, the input;
</li>
<li>
<a href = "diatom.png">diatom.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>DOUBLE_CIRCLE</b> is a plot of intersecting circles:
<ul>
<li>
<a href = "double_circle.plot">double_circle.plot</a>, the input;
</li>
<li>
<a href = "double_circle.png">double_circle.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>EGYPTIAN</b> illustrates an odd fact about Egyptian mathematics:
<ul>
<li>
<a href = "egyptian.plot">egyptian.plot</a>, the input;
</li>
<li>
<a href = "egyptian.png">egyptian.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>FEM_MESH_1D</b> illustrates the construction of nodes and elements for
a 1D finite element mesh:
<ul>
<li>
<a href = "fem_mesh_1d.plot">fem_mesh_1d.plot</a>, the input;
</li>
<li>
<a href = "fem_mesh_1d.png">fem_mesh_1d.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>ELL</b> illustrates the construction of nodes and elements for
a 2D finite element mesh on an L-shaped region:
<ul>
<li>
<a href = "ell_region.plot">ell_region.plot</a>, the region.
</li>
<li>
<a href = "ell_region.png">ell_region.png</a>,
the resulting PNG file.
</li>
<li>
<a href = "ell_nodes.plot">ell_nodes.plot</a>, the nodes.
</li>
<li>
<a href = "ell_nodes.png">ell_nodes.png</a>,
the resulting PNG file.
</li>
<li>
<a href = "ell_elements.plot">ell_elements.plot</a>, the elements.
</li>
<li>
<a href = "ell_elements.png">ell_elements.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>GRAPH_DIJKSTRA</b> illustrates a graph used to demonstrate
Dijkstra's shortest path algorithm.
<ul>
<li>
<a href = "graph_dijkstra.plot">graph_dijkstra.plot</a>, the input;
</li>
<li>
<a href = "graph_dijkstra.png">graph_dijkstra.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>GRAPH_DISCONNECTED</b> illustrates a disconnected graph
<ul>
<li>
<a href = "graph_disconnected.plot">graph_disconnected.plot</a>, the input;
</li>
<li>
<a href = "graph_disconnected.png">graph_disconnected.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>GRAPH_MST</b> illustrates a graph suitable for the minimum spanning
tree problem, with 10 nodes and 17 links labeled with lengths.
<ul>
<li>
<a href = "graph_mst.plot">graph_mst.plot</a>, the input;
</li>
<li>
<a href = "graph_mst.png">graph_mst.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>GRAPH_MST2</b> illustrates a graph suitable for the minimum spanning
tree problem, with 13 nodes and 21 links labeled with lengths.
<ul>
<li>
<a href = "graph_mst2.plot">graph_mst2.plot</a>, the input;
</li>
<li>
<a href = "graph_mst2.png">graph_mst2.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>GRAPH_MST_TREE</b> illustrates one spanning tree for the
<b>GRAPH_MST</b> graph.
<ul>
<li>
<a href = "graph_mst_tree.plot">graph_mst_tree.plot</a>, the input;
</li>
<li>
<a href = "graph_mst_tree.png">graph_mst_tree.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>GRAPH_MST_TREE_MINIMAL</b> illustrates the minimal spanning tree for the
<b>GRAPH_MST</b> graph.
<ul>
<li>
<a href = "graph_mst_tree_minimal.plot">graph_mst_tree_minimal.plot</a>, the input;
</li>
<li>
<a href = "graph_mst_tree_minimal.png">graph_mst_tree_minimal.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>GRAPH_PATHS</b> is a graph on which we can ask the question
of whether you can reach node A from node B.
<ul>
<li>
<a href = "graph_paths.plot">graph_paths.plot</a>, the input;
</li>
<li>
<a href = "graph_paths.png">graph_paths.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>GRAPH_SIMPLE</b> illustrates a simple graph with 5 nodes and
4 links on a 3x3 bit of graph paper.
<ul>
<li>
<a href = "graph_simple.plot">graph_simple.plot</a>, the input;
</li>
<li>
<a href = "graph_simple.png">graph_simple.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>GRAPH_TSP</b> illustrates a graph suitable for the minimum spanning
tree problem or the traveling salesman problem,
with 5 nodes and 10 links labeled with lengths.
<ul>
<li>
<a href = "graph_tsp.plot">graph_tsp.plot</a>, the input;
</li>
<li>
<a href = "graph_tsp.png">graph_tsp.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>GRID_CLIFF</b> is a small finite element grid for Gene Cliff:
<ul>
<li>
<a href = "grid_cliff.plot">grid_cliff.plot</a>, the input;
</li>
<li>
<a href = "grid_cliff.png">grid_cliff.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>GRID_CLIFF2</b> illustrates how portions of the grid in
<b>GRID_CLIFF</b> might be assigned to separate processors:
<ul>
<li>
<a href = "grid_cliff2.plot">grid_cliff2.plot</a>, the input;
</li>
<li>
<a href = "grid_cliff2.png">grid_cliff2.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>HEAT_EQUATION</b> illustrates how a discretized version of the
1D time dependent heat equation might be set up and solved.
<ul>
<li>
<a href = "heat_equation.plot">heat_equation.plot</a>, the input;
</li>
<li>
<a href = "heat_equation.png">heat_equation.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>HISTOGRAM</b> makes a histogram:
<ul>
<li>
<a href = "histogram.plot">histogram.plot</a>, the input;
</li>
<li>
<a href = "histogram.png">histogram.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>HORIZON</b> illustrates the problem of determining the distance to
the horizon:
<ul>
<li>
<a href = "horizon.plot">horizon.plot</a>, the input;
</li>
<li>
<a href = "horizon.png">horizon.png</a>,
the resulting PNG file.
</li>
</ul>
</p>
<p>
<b>HULL</b> shows some points and their convex hull:
<ul>
<li>
<a href = "hull.plot">hull.plot</a>, the input;
</li>
<li>