Provided by: triangle-bin_1.6-6_amd64 bug

NAME

       showme - showme [-bfw_Qh] input_file

DESCRIPTION

       Show Me A Display Program for Meshes and More.  Version 1.6

COPYRIGHT

       Copyright  1996  Jonathan  Richard  Shewchuk   (bugs/comments to jrs@cs.cmu.edu) School of
       Computer  Science  /  Carnegie  Mellon  University  5000  Forbes  Avenue   /   Pittsburgh,
       Pennsylvania   15213-3891  Created  as  part of the Archimedes project (tools for parallel
       FEM).  Supported in part by NSF Grant CMS-9318163 and an NSERC 1967 Scholarship.  There is
       no  warranty  whatsoever.   Use  at your own risk.  This executable is compiled for double
       precision arithmetic.

       Show Me graphically displays the contents of geometric files, especially  those  generated
       by Triangle, my two-dimensional quality mesh generator and Delaunay triangulator.  Show Me
       can also write images in PostScript form.   Show  Me  is  also  useful  for  checking  the
       consistency  of  the files you create as input to Triangle; Show Me does these checks more
       thoroughly than Triangle does.  The command syntax is:

       showme [-bfw_Qh] input_file

       The underscore indicates that a number should follow the -w switch.  input_file may be one
       of  several  types  of  file.  It must have extension .node, .poly, .ele, .edge, .part, or
       .adj.  If no extension is provided, Show Me will assume the extension .ele.  A .node  file
       represents  a set of points; a .poly file represents a Planar Straight Line Graph; an .ele
       file (coupled with a .node file) represents the elements of a mesh or the triangles  of  a
       triangulation;  an  .edge  file  (coupled  with a .node file) represents a set of edges; a
       .part file specifies a partition of a mesh; and a .adj file represents the adjacency graph
       defined by a partition.

       Command Line Switches:

       -b     Makes all PostScript output black and white.  If this switch is not selected, color
              PostScript is used for partitioned meshes and  adjacency  graphs  (.part  and  .adj
              files).

       -f     On  color  displays and in color PostScript, displays partitioned meshes by filling
              triangles with color, rather than by coloring the edges.  This switch  will  result
              in  a  clearer  picture  if  all  triangles  are reasonably large, and a less clear
              picture if small triangles are present.  (There is also a  button  to  toggle  this
              behavior.)

       -w     Followed  by  an  integer, specifies the line width used in all images.  (There are
              also buttons to change the line width.)

       -Q     Quiet:  Suppresses all explanation of what  Show  Me  is  doing,  unless  an  error
              occurs.

       -h     Help:  Displays these instructions.

       Controls:

              To  zoom  in  on  an image, point at the location where you want a closer look, and
              click the left mouse button.  To zoom out, click the right mouse button.  In either
              case,  the  point you click on will be centered in the window.  If you want to know
              the coordinates of a point, click the middle mouse button; the coordinates will  be
              printed on the terminal you invoked Show Me from.

              If you resize the window, the image will grow or shrink to match.

              There is a panel of control buttons at the bottom of the Show Me window:

       Quit:  Shuts down Show Me.

       <, >, ^, v:
              Moves the image in the indicated direction.

       Reset: Unzooms and centers the image in the window.
              When you switch from

              one  image to another, the viewing region does not change, so you may need to reset
              the new image to make it fully visible.  This often  is  the  case  when  switching
              between  Delaunay  triangulations  and  their  corresponding  Voronoi  diagrams, as
              Voronoi vertices can be far from the initial point set.

       Width+, -:
              Increases or decreases the width of all lines and points.

       Exp, +, -:
              These buttons appear only when you are viewing a partitioned

       mesh (.part file).
              `Exp' toggles between an exploded and non-exploded

       image of the mesh.
              The non-exploded image will not show the partition

       on a black and white monitor.
              `+' and `-' allow you to adjust the

              spacing between pieces of the mesh to better distinguish them.

       Fill:  This button appears only when you are viewing a partitioned mesh

       (.part file).
              It toggles between color-filled triangles and colored

       edges (as the -f switch does).
              Filled triangles look better when all

              triangles are reasonably large; colored edges look better when there are very small
              triangles present.

       PS:    Creates a PostScript file containing the image you are viewing.  If

              the  -b  switch  is  selected,  all  PostScript  output  will  be  black and white;
              otherwise, .part.ps and .adj.ps files will be color, independent of whether you are
              using  a  color  monitor.   Normally the output will preserve the properties of the
              image you see on the screen, including zoom and line width; however, if  black  and
              white  output  is  selected  (-b  switch),  partitioned meshes will always be drawn
              exploded.  The output file name depends on the image being  viewed.   If  you  want
              several  different  snapshots  (zooming  in on different parts) of the same object,
              you'll have to rename each  file  after  Show  Me  creates  it  so  that  it  isn't
              overwritten by the next snapshot.

       EPS:   Creates an encapsulated PostScript file, suitable for inclusion in

       documents.
              Otherwise, this button is just like the PS button.  (The

              only difference is that .eps files lack a `showpage' command at the end.)

              There  are  two  nearly-identical  rows  of buttons that load different images from
              disk.  Each row contains the following buttons:

       node:  Loads a .node file.

       poly:  Loads a .poly file (and possibly an associated .node file).

       ele:   Loads an .ele file (and associated .node file).

       edge:  Loads an .edge file (and associated .node file).

       part:  Loads a .part file (and associated .node and .ele files).

       adj:   Loads an .adj file (and associated .node, .ele, and .part files).

       voro:  Loads a .v.node and .v.edge file for a Voronoi diagram.

              Each row represents a different iteration number of the geometry files.  For a full
              explanation  of  iteration  numbers,  read the instructions for Triangle.  Briefly,
              iteration numbers are used to allow a  user  to  easily  represent  a  sequence  of
              related triangulations.  Iteration numbers are used in the names of geometry files;
              for instance, mymesh.3.ele is a triangle file  with  iteration  number  three,  and
              mymesh.ele has an implicit iteration number of zero.

              The  control  buttons  at  the  right  end  of  each row display the two iterations
              currently under view.  These buttons can be clicked to  increase  or  decrease  the
              iteration numbers, and thus conveniently view a sequence of meshes.

              Show  Me  keeps  each file in memory after loading it, but you can force Show Me to
              reread a set of files (for one iteration number)  by  reclicking  the  button  that
              corresponds  to  the  current  image.   This  is  convenient  if you have changed a
              geometry file.

       File Formats:

       All files may contain comments prefixed by the character '#'.
              Points,

              segments, holes, triangles, edges, and subdomains must be  numbered  consecutively,
              starting  from  either  1  or  0.   Whichever  you  choose, all input files must be
              consistent (for any single iteration number); if the nodes are numbered from 1,  so
              must be all other objects.  Show Me automatically detects your choice while reading
              a .node (or .poly) file.  Examples of these file formats are given below.

              .node files:

       First line:
              <# of points> <dimension (must be 2)> <# of attributes>

              <# of boundary markers (0 or 1)>

       Remaining lines:
              <point #> <x> <y> [attributes] [boundary marker]

              The attributes, which are typically floating-point values  of  physical  quantities
              (such  as mass or conductivity) associated with the nodes of a finite element mesh,
              are ignored  by  Show  Me.   Show  Me  also  ignores  boundary  markers.   See  the
              instructions for Triangle to find out what attributes and boundary markers are.

              .poly files:

       First line:
              <# of points> <dimension (must be 2)> <# of attributes>

              <# of boundary markers (0 or 1)>

       Following lines:
              <point #> <x> <y> [attributes] [boundary marker]

       One line:
              <# of segments> <# of boundary markers (0 or 1)>

       Following lines:
              <segment #> <endpoint> <endpoint> [boundary marker]

       One line:
              <# of holes>

       Following lines:
              <hole #> <x> <y>

              [Optional additional lines that are ignored]

              A  .poly  file  represents a Planar Straight Line Graph (PSLG), an idea familiar to
              computational geometers.  By definition, a PSLG is just a list of points and edges.
              A .poly file also contains some additional information.

              The  first  section  lists  all the points, and is identical to the format of .node
              files.  <# of points> may be set to zero to indicate that the points are listed  in
              a  separate  .node  file; .poly files produced by Triangle always have this format.
              When Show Me reads such a file, it also reads the corresponding .node file.

       The second section lists the segments.
              Segments are edges whose

       presence in a triangulation produced from the PSLG is enforced.
              Each

       segment is specified by listing the indices of its two endpoints.
              This

       means that its endpoints must be included in the point list.
              Each

              segment, like each point, may have a boundary marker, which is ignored by Show Me.

              The third section lists holes and concavities that are desired in any triangulation
              generated  from  the  PSLG.  Holes are specified by identifying a point inside each
              hole.

              .ele files:

       First line:
              <# of triangles> <points per triangle> <# of attributes>

       Remaining lines:
              <triangle #> <point> <point> <point> ... [attributes]

       Points are indices into the corresponding .node file.
              Show Me ignores

              all but the first three points of each triangle; these should be the corners listed
              in  counterclockwise order around the triangle.  The attributes are ignored by Show
              Me.

              .edge files:

       First line:
              <# of edges> <# of boundary markers (0 or 1)>

       Following lines:
              <edge #> <endpoint> <endpoint> [boundary marker]

       Endpoints are indices into the corresponding .node file.
              The boundary

              markers are ignored by Show Me.

              In Voronoi diagrams, one also finds a special kind of edge that is an infinite  ray
              with only one endpoint.  For these edges, a different format is used:

              <edge #> <endpoint> -1 <direction x> <direction y>

              The  `direction'  is  a  floating-point  vector that indicates the direction of the
              infinite ray.

              .part files:

       First line:
              <# of triangles> <# of subdomains>

       Remaining lines:
              <triangle #> <subdomain #>

              The set of triangles is partitioned by a .part file; each triangle is mapped  to  a
              subdomain.

              .adj files:

       First line:
              <# of subdomains>

       Remaining lines:
              <adjacency matrix entry>

              An  .adj  file  represents adjacencies between subdomains (presumably computed by a
              partitioner).  The first line is followed by (subdomains X subdomains) lines,  each
              containing  one  entry of the adjacency matrix.  A nonzero entry indicates that two
              subdomains are adjacent (share a point).

       Example:

              Here is a sample file `box.poly' describing a square with a square hole:

              # A box with eight points in 2D, no attributes, no boundary marker.   8  2  0  0  #
              Outer box has these vertices:

       1      0 0

       2      0 3

       3      3 0

       4      3 3

              # Inner square has these vertices:

       5      1 1

       6      1 2

       7      2 1

       8      2 2

              # Five segments without boundary markers.  5 0

       1      1 2          # Left side of outer box.

       2      5 7          # Segments 2 through 5 enclose the hole.

       3      7 8

       4      8 6

       5      6 5

              # One hole in the middle of the inner square.  1

       1      1.5 1.5

              After  this  PSLG is triangulated by Triangle, the resulting triangulation consists
              of a .node and .ele file.  Here is the former, `box.1.node', which  duplicates  the
              points of the PSLG:

       8      2   0   0  1     0  0 2    0  3 3    3  0 4    3  3 5    1  1 6    1  2 7    2  1 8
              2  2

              # Generated by triangle -pcBev box

              Here is the triangulation file, `box.1.ele'.

       8      3  0 1       1     5     6 2       5     1     3 3       2     6      8  4        6
              2     1 5       7     3     4 6       3     7     5 7       8     4     2 8       4
              8     7

              # Generated by triangle -pcBev box

              Here is the edge file for the triangulation, `box.1.edge'.

       16     0

       1      1  5

       2      5  6

       3      6  1

       4      1  3

       5      3  5

       6      2  6

       7      6  8

       8      8  2

       9      2  1

       10     7  3

       11     3  4

       12     4  7

       13     7  5

       14     8  4

       15     4  2

       16     8  7

              # Generated by triangle -pcBev box

              Here's a file `box.1.part' that partitions the mesh into four subdomains.

       8      4 1    3 2    3 3    4 4    4 5    1 6    1 7    2 8    2

              # Generated by slice -s4 box.1

              Here's a file `box.1.adj' that represents the resulting adjacencies.

              4

              9 2 2 0 2 9 0 2 2 0 9 2 0 2 2 9

       Display Speed:

              It is worthwhile to note that .edge files typically plot and print twice as quickly
              as  .ele files, because .ele files cause each internal edge to be drawn twice.  For
              the same reason, PostScript files created from edge sets  are  smaller  than  those
              created from triangulations.

       Show Me on the Web:

              To see an illustrated, updated version of these instructions, check out

              http://www.cs.cmu.edu/~quake/showme.html

       A Brief Plea:

              If  you  use Show Me (or Triangle), and especially if you use it to accomplish real
              work, I would like very much to hear  from  you.   A  short  letter  or  email  (to
              jrs@cs.cmu.edu)  describing how you use Show Me (and its sister programs) will mean
              a lot to me.  The more people I know are using my programs, the more easily  I  can
              justify spending time on improvements, which in turn will benefit you.  Also, I can
              put you on a list to receive email whenever new versions are available.

              If you use a PostScript file generated by Show Me in a publication, please  include
              an acknowledgment as well.

       -b     Black and white PostScript (default is color).

       -f     Fill triangles of partitioned mesh with color.

       -w     Set line width to some specified number.

       -Q     Quiet:  No terminal output except errors.

       -h     Help:  Detailed instructions for Show Me.

SEE ALSO

       The  full  documentation  for  showme  is maintained as a Texinfo manual.  If the info and
       showme programs are properly installed at your site, the command

              info showme

       should give you access to the complete manual.