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<BODY>
<PRE>
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</PRE>
<H2>SYNOPSIS</H2><PRE>
       <B>graph</B> <I>pathName</I> ?<I>option</I> <I>value</I>?...


</PRE>
<H2>DESCRIPTION</H2><PRE>
       The  <B>graph</B>  command  creates  a graph for plotting two-dimensional data
       (X-Y coordinates). It  has  many  configurable  components:  coordinate
       axes,  elements,  legend, grid lines, cross hairs, etc.  They allow you
       to customize the look and feel of the graph.


</PRE>
<H2>INTRODUCTION</H2><PRE>
       The <B>graph</B> command creates a new  window  for  plotting  two-dimensional
       data  (X-Y coordinates).  Data points are plotted in a rectangular area
       displayed in the center of the new window.  This is the <I>plotting</I>  <I>area</I>.
       The  coordinate axes are drawn in the margins around the plotting area.
       By default, the legend is displayed in the right margin.  The title  is
       displayed in top margin.

       The  <B>graph</B>  widget  is composed of several components: coordinate axes,
       data elements, legend, grid, cross hairs, pens, postscript, and annota-
       tion markers.

       axis      The  graph has four standard axes (x, x2, y, and y2), but you
                 can create and display any number of axes.  Axes control what
                 region  of data is displayed and how the data is scaled. Each
                 axis consists of the axis line, title, major and minor ticks,
                 and tick labels.  Tick labels display the value at each major
                 tick.

       crosshairs
                 Cross hairs are used to position the mouse  pointer  relative
                 to  the  X  and  Y  coordinate axes. Two perpendicular lines,
                 intersecting at the current location  of  the  mouse,  extend
                 across the plotting area to the coordinate axes.

       element   An  element  represents a set of data points. Elements can be
                 plotted with a symbol at each data point and lines connecting
                 the  points.  The appearance of the element, such as its sym-
                 bol, line width, and color is configurable.

       grid      Extends the major and minor ticks of the X-axis and/or Y-axis
                 across the plotting area.

       legend    The legend displays the name and symbol of each data element.
                 The legend can be drawn in any  margin  or  in  the  plotting
                 area.

       marker    Markers  are  used  annotate or highlight areas of the graph.
                 For example, you could use a polygon marker to fill  an  area
                 under  a  curve,  or a text marker to label a particular data
                 point. Markers come in various forms: text strings,  bitmaps,
                 connected  line  segments, images, polygons, or embedded wid-
                 gets.

       <B>graph</B>  <I>pathName</I> ?<I>option</I> <I>value</I>?...  The <B>graph</B> command creates a new win-
       dow <I>pathName</I> and makes it into a <B>graph</B> widget.  At the time  this  com-
       mand  is  invoked,  there  must  not exist a window named <I>pathName</I>, but
       <I>pathName</I>'s parent must exist.  Additional options may be  specified  on
       the  command line or in the option database to configure aspects of the
       graph such as its colors and font.  See the <B>configure</B>  operation  below
       for the exact details about what <I>option</I> and <I>value</I> pairs are valid.

       If successful, <B>graph</B> returns the path name of the widget.  It also cre-
       ates a new Tcl command by the same name.  You can use this  command  to
       invoke  various operations that query or modify the graph.  The general
       form is: <I>pathName</I> <I>operation</I> ?<I>arg</I>?...  Both <I>operation</I> and its  arguments
       determine  the exact behavior of the command.  The operations available
       for the graph are described in the <B>GRAPH</B> <B>OPERATIONS</B> section.

       The command can also be used to access components of the graph.   <I>path-</I>
       <I>Name</I> <I>component</I> <I>operation</I> ?<I>arg</I>?...  The operation, now located after the
       name of the component, is the function to be performed on  that  compo-
       nent. Each component has its own set of operations that manipulate that
       component.  They will be described below in their own sections.


</PRE>
<H2>EXAMPLE</H2><PRE>
       The <B>graph</B> command creates a new graph.  # Create a new graph.  Plotting
       area  is black.  graph .g -plotbackground black A new Tcl command .g is
       also created.  This command can be used to query and modify the  graph.
       For example, to change the title of the graph to "My Plot", you use the
       new command and the graph's <B>configure</B> operation.  # Change  the  title.
       .g configure -title "My Plot" A graph has several components. To access
       a particular component you use the component's name.  For  example,  to
       add  data  elements, you use the new command and the <B>element</B> component.
       # Create a  new  element  named  "line1"  .g  element  create  line1  \
            -xdata { 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 } \      -ydata {
       26.18 50.46 72.85 93.31 111.86 128.47  143.14            155.85  166.60
       175.38  }  The  element's  X-Y coordinates are specified using lists of
       numbers.  Alternately, BLT vectors could be used to hold the X-Y  coor-
       dinates.   # Create two vectors and add them to the graph.  vector xVec
       yVec xVec set { 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 }  yVec  set  {
       26.18  50.46 72.85 93.31 111.86 128.47 143.14 155.85      166.60 175.38
       } .g element create line1 -xdata xVec  -ydata  yVec  The  advantage  of
       using  vectors  is that when you modify one, the graph is automatically
       redrawn to reflect the new values.  # Change the y  coordinate  of  the
       first  point.   set <B>yVector(0)</B> 25.18 An element named e1 is now created
       in .b.  It is automatically added to the display list of elements.  You
       can  use this list to control in what order elements are displayed.  To
       query or reset the element display list, you  use  the  element's  <B>show</B>
       operation.   #  Get  the  current display list set elemList [.b element
       show] # Remove the first element so it won't be displayed.  .b  element
       show  [lrange $elemList 0 end] The element will be displayed by as many
       bars as there are data points (in this case there are ten).   The  bars
       will  be drawn centered at the x-coordinate of the data point.  All the
       bars will have the same attributes (colors, stipple, etc).   The  width
       of each bar is by default one unit.  You can change this with using the
       example, you change the scale of the Y-axis from linear  to  log  using
       the  <B>axis</B>  component.   #  Y-axis  is  log  scale.  .g axis configure y
       -logscale yes One important way axes are used is to zoom in on  a  par-
       ticular  data  region.   Zooming  is done by simply specifying new axis
       limits using the <B>-min</B> and <B>-max</B> configuration options.  .g axis  config-
       ure  x  -min  1.0  -max 1.5 .g axis configure y -min 12.0 -max 55.15 To
       zoom interactively, you link the <B>axis</B> <B>configure</B>  operations  with  some
       user  interaction  (such  as pressing the mouse button), using the <B>bind</B>
       command.  To convert between screen  and  graph  coordinates,  use  the
       <B>invtransform</B>  operation.   # Click the button to set a new minimum bind
       .g &lt;ButtonPress-1&gt; {
           %W axis configure x -min [%W axis invtransform x %x]
           %W axis configure x -min [%W axis invtransform x %y] } By  default,
       the  limits of the axis are determined from data values.  To reset back
       to the default limits, set the <B>-min</B>  and  <B>-max</B>  options  to  the  empty
       value.   # Reset the axes to autoscale again.  .g axis configure x -min
       {} -max {} .g axis configure y -min {} -max {} By default,  the  legend
       is  drawn  in the right margin.  You can change this or any legend con-
       figuration options using the <B>legend</B> component.  # Configure the  legend
       font,  color,  and  relief  .g  legend configure -position left -relief
       raised \      -font fixed -fg blue To prevent  the  legend  from  being
       displayed,  turn  on the <B>-hide</B> option.  # Don't display the legend.  .g
       legend configure -hide yes The <B>graph</B> widget has simple  drawing  proce-
       dures  called  markers.  They can be used to highlight or annotate data
       in the graph. The types of markers available are bitmaps, images, poly-
       gons,  lines, or windows.  Markers can be used, for example, to mark or
       brush points.  In this example, is a text marker that labels  the  data
       first point.  Markers are created using the <B>marker</B> component.  # Create
       a label for the first data point of "line1".   .g  marker  create  text
       -name  first_marker  -coords { 0.2 26.18 } \      -text "start" -anchor
       se  -xoffset  -10  -yoffset  -10  This  creates  a  text  marker  named
       first_marker.  It will display the text "start" near the coordinates of
       the first data point.  The <B>-anchor</B>, <B>-xoffset</B>, and <B>-yoffset</B> options  are
       used  to display the marker above and to the left of the data point, so
       that the data point isn't covered by the marker.  By  default,  markers
       are  drawn  last,  on top of data.  You can change this with the <B>-under</B>
       option.  # Draw the label before elements are drawn.  .g marker config-
       ure first_marker -under yes You can add cross hairs or grid lines using
       the <B>crosshairs</B> and <B>grid</B> components.  # Display  both  cross  hairs  and
       grid  lines.   .g crosshairs configure -hide no -color red .g grid con-
       figure -hide no -dashes { 2 2 } # Set up a binding  to  reposition  the
       crosshairs.  bind .g &lt;Motion&gt; {
           .g crosshairs configure -position @%x,%y } The crosshairs are repo-
       sitioned as the mouse pointer is moved in the graph.  The  pointer  X-Y
       coordinates define the center of the crosshairs.

       Finally, to get hardcopy of the graph, use the <B>postscript</B> component.  #
       Print the graph into file "file.ps" .g postscript output file.ps  -max-
       pect  yes  -decorations no This generates a file file.ps containing the
       encapsulated PostScript of the graph.   The  option  <B>-maxpect</B>  says  to
       scale  the  plot to the size of the page.  Turning off the <B>-decorations</B>
       option denotes that no borders or color  backgrounds  should  be  drawn
              <I>option</I>.   <I>Option</I>  may be any option described below for the <B>con-</B>
              <B>figure</B> operation.

       <I>pathName</I> <B>configure</B> ?<I>option</I> <I>value</I>?...
              Queries or modifies the configuration options of the graph.   If
              <I>option</I>  isn't  specified,  a list describing the current options
              for <I>pathName</I> is returned.   If  <I>option</I>  is  specified,  but  not
              <I>value</I>,  then  a  list  describing <I>option</I> is returned.  If one or
              more <I>option</I> and <I>value</I> pairs are specified, then for  each  pair,
              the  option  <I>option</I>  is set to <I>value</I>.  The following options are
              valid.

              <B>-aspect</B> <I>width/height</I>
                     Force a fixed aspect ratio of  <I>width/height</I>,  a  floating
                     point number.

              <B>-background</B> <I>color</I>
                     Sets  the background color. This includes the margins and
                     legend, but not the plotting area.

              <B>-borderwidth</B> <I>pixels</I>
                     Sets the width of the 3-D border around the outside  edge
                     of the widget.  The <B>-relief</B> option determines if the bor-
                     der is to be drawn.  The default is 2.

              <B>-bottommargin</B> <I>pixels</I>
                     If non-zero, overrides the computed size  of  the  margin
                     extending  below  the X-coordinate axis.  If <I>pixels</I> is 0,
                     the automatically computed size is used.  The default  is
                     0.

              <B>-bufferelements</B> <I>boolean</I>
                     Indicates  whether  an internal pixmap to buffer the dis-
                     play of data elements should  be  used.   If  <I>boolean</I>  is
                     true,  data  elements  are  drawn  to an internal pixmap.
                     This option  is  especially  useful  when  the  graph  is
                     redrawn  frequently while the remains data unchanged (for
                     example, moving a marker across the plot).  See the <B>SPEED</B>
                     <B>TIPS</B> section.  The default is 1.

              <B>-cursor</B> <I>cursor</I>
                     Specifies  the  widget's  cursor.   The default cursor is
                     crosshair.

              <B>-font</B> <I>fontName</I>
                     Specifies the font of the graph  title.  The  default  is
                     *-Helvetica-Bold-R-Normal-*-18-180-*.

              <B>-halo</B> <I>pixels</I>
                     Specifies  a  maximum distance to consider when searching
                     for the closest data point  (see  the  element's  <B>closest</B>
                     operation  below).   Data points further than <I>pixels</I> away
                     text.  <I>Justify</I>  must  be  left,  right,  or  center.  The
                     default is center.

              <B>-leftmargin</B> <I>pixels</I>
                     If non-zero, overrides the computed size  of  the  margin
                     extending from the left edge of the window to the Y-coor-
                     dinate axis.  If <I>pixels</I> is 0, the automatically  computed
                     size is used.  The default is 0.

              <B>-plotbackground</B> <I>color</I>
                     Specifies the background color of the plotting area.  The
                     default is white.

              <B>-plotborderwidth</B> <I>pixels</I>
                     Sets the width of the  3-D  border  around  the  plotting
                     area.   The  <B>-plotrelief</B> option determines if a border is
                     drawn.  The default is 2.

              <B>-plotpadx</B> <I>pad</I>
                     Sets the amount of padding to be added to  the  left  and
                     right  sides  of the plotting area.  <I>Pad</I> can be a list of
                     one or two screen distances.  If <I>pad</I>  has  two  elements,
                     the left side of the plotting area entry is padded by the
                     first distance and the right side by the second.  If  <I>pad</I>
                     is  just  one distance, both the left and right sides are
                     padded evenly.  The default is 8.

              <B>-plotpady</B> <I>pad</I>
                     Sets the amount of padding to be added  to  the  top  and
                     bottom of the plotting area.  <I>Pad</I> can be a list of one or
                     two screen distances.  If <I>pad</I> has two elements,  the  top
                     of  the plotting area is padded by the first distance and
                     the bottom by the second.  If <I>pad</I> is just  one  distance,
                     both  the  top and bottom are padded evenly.  The default
                     is 8.

              <B>-plotrelief</B> <I>relief</I>
                     Specifies the 3-D effect for the plotting  area.   <I>Relief</I>
                     specifies  how  the  interior of the plotting area should
                     appear relative to rest of the graph; for example, raised
                     means  the plot should appear to protrude from the graph,
                     relative to the surface of the  graph.   The  default  is
                     sunken.

              <B>-relief</B> <I>relief</I>
                     Specifies  the  3-D  effect for the graph widget.  <I>Relief</I>
                     specifies how the graph should appear relative to  widget
                     it  is  packed  into; for example, raised means the graph
                     should appear to protrude.  The default is flat.

              <B>-rightmargin</B> <I>pixels</I>
                     If non-zero, overrides the computed size  of  the  margin

              <B>-tile</B> <I>image</I>
                     Specifies  a  tiled  background for the widget.  If <I>image</I>
                     isn't "", the background is tiled  using  <I>image</I>.   Other-
                     wise,  the  normal  background  color  is  drawn (see the
                     <B>-background</B> option).  <I>Image</I>  must  be  an  image  created
                     using the Tk <B>image</B> command.  The default is "".

              <B>-title</B> <I>text</I>
                     Sets  the  title to <I>text</I>. If <I>text</I> is "", no title will be
                     displayed.

              <B>-topmargin</B> <I>pixels</I>
                     If non-zero, overrides the computed size  of  the  margin
                     above  the  x2  axis.   If <I>pixels</I> is 0, the automatically
                     computed size is used.  The default is 0.

              <B>-width</B> <I>pixels</I>
                     Specifies the requested width of the widget.  The default
                     is 5i.

       <I>pathName</I> <B>crosshairs</B> <I>operation</I> ?<I>arg</I>?
              See the <B>CROSSHAIRS</B> <B>COMPONENT</B> section.

       <I>pathName</I> <B>element</B> <I>operation</I> ?<I>arg</I>?...
              See the <B>ELEMENT</B> <B>COMPONENTS</B> section.

       <I>pathName</I> <B>extents</B> <I>item</I>
              Returns  the  size of a particular item in the graph.  <I>Item</I> must
              be  either  leftmargin,  rightmargin,  topmargin,  bottommargin,
              plotwidth, or plotheight.

       <I>pathName</I> <B>grid</B> <I>operation</I> ?<I>arg</I>?...
              See the <B>GRID</B> <B>COMPONENT</B> section.

       <I>pathName</I> <B>invtransform</B> <I>winX</I> <I>winY</I>
              Performs  an  inverse  coordinate transformation, mapping window
              coordinates back to graph coordinates, using the standard X-axis
              and  Y-axis.  Returns a list of containing the X-Y graph coordi-
              nates.

       <I>pathName</I> <B>inside</B> <I>x</I> <I>y</I>
              Returns 1 is the designated  screen  coordinate  (<I>x</I>  and  <I>y</I>)  is
              inside the plotting area and 0 otherwise.

       <I>pathName</I> <B>legend</B> <I>operation</I> ?<I>arg</I>?...
              See the <B>LEGEND</B> <B>COMPONENT</B> section.

       <I>pathName</I> <B>line</B> <B>operation</B> <B>arg</B>...
              The operation is the same as <B>element</B>.

       <I>pathName</I> <B>marker</B> <I>operation</I> ?<I>arg</I>?...
                        photo  Saves a Tk photo image.  <I>OutputName</I>  represents
                               the  name of a Tk photo image that must already
                               have been created.

                        wmf    Saves an Aldus Placeable Metafile.   <I>OutputName</I>
                               represents  the  filename where the metafile is
                               written.  If <I>outputName</I> is CLIPBOARD, then out-
                               put  is  written  directly to the Windows clip-
                               board.  This format  is  available  only  under
                               Microsoft Windows.

                        emf    Saves  an  Enhanced Metafile. <I>OutputName</I> repre-
                               sents the filename where the metafile is  writ-
                               ten.   If  <I>outputName</I> is CLIPBOARD, then output
                               is written directly to the  Windows  clipboard.
                               This  format  is available only under Microsoft
                               Windows.

              <B>-height</B> <I>size</I>
                        Specifies the height of the graph.  <I>Size</I> is  a  screen
                        distance.  The graph will be redrawn using this dimen-
                        sion, rather than its current window height.

              <B>-width</B> <I>size</I>
                        Specifies the width of the graph.  <I>Size</I>  is  a  screen
                        distance.  The graph will be redrawn using this dimen-
                        sion, rather than its current window width.

       <I>pathName</I> <B>transform</B> <I>x</I> <I>y</I>
              Performs a coordinate transformation, mapping graph  coordinates
              to  window  coordinates,  using  the standard X-axis and Y-axis.
              Returns a list containing the X-Y screen coordinates.

       <I>pathName</I> <B>xaxis</B> <I>operation</I> ?<I>arg</I>?...

       <I>pathName</I> <B>x2axis</B> <I>operation</I> ?<I>arg</I>?...

       <I>pathName</I> <B>yaxis</B> <I>operation</I> ?<I>arg</I>?...

       <I>pathName</I> <B>y2axis</B> <I>operation</I> ?<I>arg</I>?...
              See the <B>AXIS</B> <B>COMPONENTS</B> section.


</PRE>
<H2>GRAPH COMPONENTS</H2><PRE>
       A graph is composed of several components: coordinate axes,  data  ele-
       ments,  legend,  grid, cross hairs, postscript, and annotation markers.
       Instead of one big set of configuration  options  and  operations,  the
       graph  is  partitioned,  where each component has its own configuration
       options and operations that specifically control that aspect or part of
       the graph.

   <B>AXIS</B> <B>COMPONENTS</B>
       Four  coordinate  axes are automatically created: two X-coordinate axes
       You can have several axes. To create an axis, invoke the axis component
       and  its  create  operation.   # Create a new axis called "tempAxis" .g
       axis create tempAxis You map data elements to an axis  using  the  ele-
       ment's  -mapy and -mapx configuration options. They specify the coordi-
       nate axes an element is mapped onto.  # Now map the  tempAxis  data  to
       this  axis.   .g element create "e1" -xdata $x -ydata $y -mapy tempAxis
       Any number of axes can be displayed simultaneously. They are  drawn  in
       the  margins  surrounding  the plotting area.  The default axes x and y
       are drawn in the bottom and left margins. The axes x2 and y2 are  drawn
       in  top  and  right  margins.  By default, only x and y are shown. Note
       that the axes can have different scales.

       To display a different axis or more than one axis, you  invoke  one  of
       the  following components: <B>xaxis</B>, <B>yaxis</B>, <B>x2axis</B>, and <B>y2axis</B>.  Each com-
       ponent has a <B>use</B> operation that designates the axis  (or  axes)  to  be
       drawn  in  that corresponding margin: <B>xaxis</B> in the bottom, <B>yaxis</B> in the
       left, <B>x2axis</B> in the top, and <B>y2axis</B> in the right.  # Display  the  axis
       tempAxis  in  the left margin.  .g yaxis use tempAxis The <B>use</B> operation
       takes a list of axis names as its last argument.  This is the  list  of
       axes to be drawn in this margin.

       You  can  configure  axes in many ways. The axis scale can be linear or
       logarithmic.  The  values  along  the  axis  can  either  monotonically
       increase  or decrease.  If you need custom tick labels, you can specify
       a Tcl procedure to format the label any way you wish.  You can  control
       how  ticks are drawn, by changing the major tick interval or the number
       of minor ticks.  You can define non-uniform tick intervals, such as for
       time-series plots.


       <I>pathName</I> <B>axis</B> <B>bind</B> <I>tagName</I> ?<I>sequence</I>?  ?<I>command</I>?
              Associates  <I>command</I>  with  <I>tagName</I>  such that whenever the event
              sequence given by <I>sequence</I> occurs for an  axis  with  this  tag,
              <I>command</I> will be invoked.  The syntax is similar to the <B>bind</B> com-
              mand except that it operates on graph axes, rather than widgets.
              See  the  <B>bind</B> manual entry for complete details on <I>sequence</I> and
              the substitutions performed on <I>command</I> before invoking it.

              If all arguments are specified then a new  binding  is  created,
              replacing  any  existing  binding for the same <I>sequence</I> and <I>tag-</I>
              <I>Name</I>.  If the first character of <I>command</I> is + then <I>command</I>  aug-
              ments  an existing binding rather than replacing it.  If no <I>com-</I>
              <I>mand</I> argument is provided then the command currently  associated
              with  <I>tagName</I>  and  <I>sequence</I> (it's an error occurs if there's no
              such binding) is returned.  If both  <I>command</I>  and  <I>sequence</I>  are
              missing  then  a list of all the event sequences for which bind-
              ings have been defined for <I>tagName</I>.

       <I>pathName</I> <B>axis</B> <B>cget</B> <I>axisName</I> <I>option</I>
              Returns the current value of the  option  given  by  <I>option</I>  for
              <I>axisName</I>.  <I>Option</I> may be any option described below for the axis
              <B>configure</B> operation.
                     the  list  matching  the current event sequence will have
                     its Tcl command executed.  Implicitly  the  name  of  the
                     element is always the first tag in the list.  The default
                     value is all.

              <B>-color</B> <I>color</I>
                     Sets the color of the axis and tick labels.  The  default
                     is black.

              <B>-descending</B> <I>boolean</I>
                     Indicates whether the values along the axis are monotoni-
                     cally increasing or decreasing.  If <I>boolean</I> is true,  the
                     axis values will be decreasing.  The default is 0.

              <B>-hide</B> <I>boolean</I>
                     Indicates  if  the axis is displayed. If <I>boolean</I> is false
                     the axis will be displayed. Any  element  mapped  to  the
                     axis is displayed regardless.  The default value is 0.

              <B>-justify</B> <I>justify</I>
                     Specifies  how  the axis title should be justified.  This
                     matters only when the axis title contains more  than  one
                     line  of  text.  <I>Justify</I>  must be left, right, or center.
                     The default is center.

              <B>-limits</B> <I>formatStr</I>
                     Specifies a printf-like description to format the minimum
                     and maximum limits of the axis.  The limits are displayed
                     at the top/bottom or left/right  sides  of  the  plotting
                     area.   <I>FormatStr</I> is a list of one or two format descrip-
                     tions.  If one description is supplied, both the  minimum
                     and  maximum  limits  are  formatted in the same way.  If
                     two, the first designates  the  format  for  the  minimum
                     limit,  the  second  for  the maximum.  If "" is given as
                     either description, then the that limit will not be  dis-
                     loosely, at the outer tick intervals.  If the axis  limit
                     is  set  with  the -min or -max option, the axes are dis-
                     played tightly.  If <I>boolean</I> is true, the  axis  range  is
                     "loose".  The default is 0.

              <B>-majorticks</B> <I>majorList</I>
                     Specifies where to display major axis ticks.  You can use
                     this option to display ticks  at  non-uniform  intervals.
                     <I>MajorList</I>  is  a list of axis coordinates designating the
                     location of major ticks.  No minor ticks are  drawn.   If
                     <I>majorList</I>  is  "", major ticks will be automatically com-
                     puted. The default is "".

              <B>-max</B> <I>value</I>
                     Sets the maximum  limit  of  <I>axisName</I>.   Any  data  point
                     greater than <I>value</I> is not displayed.  If <I>value</I> is "", the
                     maximum limit is calculated using the largest data value.
                     The default is "".

              <B>-min</B> <I>value</I>
                     Sets  the  minimum limit of <I>axisName</I>. Any data point less
                     than <I>value</I> is not displayed.  If <I>value</I> is "", the minimum
                     limit  is  calculated using the smallest data value.  The
                     default is "".

              <B>-minorticks</B> <I>minorList</I>
                     Specifies where to display minor axis ticks.  You can use
                     this  option to display minor ticks at non-uniform inter-
                     vals. <I>MinorList</I> is a list of real  values,  ranging  from
                     0.0  to  1.0,  designating the placement of a minor tick.
                     No minor ticks are drawn if the <B>-majortick</B> option is also
                     set.   If  <I>minorList</I> is "", minor ticks will be automati-
                     cally computed. The default is "".

              <B>-rotate</B> <I>theta</I>
                     Specifies the how many degrees to rotate  the  axis  tick
                     labels.  <I>Theta</I> is a real value representing the number of
                     degrees to rotate the tick labels.  The  default  is  0.0
                     degrees.

              <B>-scrollcommand</B> <I>command</I>
                     Specify the prefix for a command used to communicate with
                     scrollbars for this axis, such as <I>.sbar</I> <I>set</I>.

              <B>-scrollmax</B> <I>value</I>
                     Sets the maximum limit of the  axis  scroll  region.   If
                     <I>value</I>  is  "",  the maximum limit is calculated using the
                     largest data value.  The default is "".

              <B>-scrollmin</B> <I>value</I>
                     Sets the minimum limit of axis scroll region.   If  <I>value</I>
                     is "", the minimum limit is calculated using the smallest
                     Indicates how many minor axis ticks are to be drawn.  For
                     example, if <I>number</I> is two, only one minor tick is  drawn.
                     If  <I>number</I>  is  one,  no  minor ticks are displayed.  The
                     default is 2.

              <B>-tickfont</B> <I>fontName</I>
                     Specifies the font for axis tick labels. The  default  is
                     *-Courier-Bold-R-Normal-*-100-*.

              <B>-tickformat</B> <I>formatStr</I>
                     Specifies a printf-like description to format teh axis
                     tick labels.  You can get the standard tick labels again by
                     setting <I>formatStr</I> to "".  The default is "".

              <B>-tickformatcommand</B>, <B>-command</B> <I>prefix</I>
                     Specifies a Tcl command to be invoked when formatting the
                     axis tick labels. <I>Prefix</I> is a string containing the  name
                     of  a Tcl proc and any extra arguments for the procedure.
                     This command is invoked for each major tick on the  axis.
                     Two additional arguments are passed to the procedure: the
                     pathname of the widget and the current the numeric  value
                     of  the  tick.   The procedure returns the formatted tick
                     label.  If "" is returned, no label will appear  next  to
                     the  tick.  You can get the standard tick labels again by
                     setting <I>prefix</I> to "".  The default is "".

                     The numeric value for the tick might change when using the
                     <B>-logscale</B> and <B>-tickformat</B> options.

                     Please note that this  procedure  is  invoked  while  the
                     graph  is  redrawn.  You may query configuration options.
                     But  do  not  them,  because  this  can  have  unexpected
                     results.

              <B>-ticklength</B> <I>pixels</I>
                     Sets the length of major and minor ticks (minor ticks are
                     half the length of major ticks). If <I>pixels</I> is  less  than
                     zero, the axis will be inverted with ticks drawn pointing
                     towards the plot.  The default is 0.1i.

              <B>-title</B> <I>text</I>
                     Sets the title of the axis. If <I>text</I> is "", no axis  title
                     will be displayed.

              <B>-titlealternate</B> <I>boolean</I>
                     Indicates  to  display  the  axis  title in its alternate
                     location.  Normally the axis title is centered along  the
                     axis.   This  option  places the axis either to the right
                     (horizontal axes) or above (vertical axes) the axis.  The
                     default is 0.

              <B>-titlecolor</B> <I>color</I>
                     Sets the color of the axis title. The default is black.

              <B>-titlefont</B> <I>fontName</I>
                     Specifies  the font for axis title. The default is *-Hel-
                     vetica-Bold-R-Normal-*-14-140-*.

              Axis configuration options may be also be set by the <B>option</B> com-
              mand.   The  resource class is Axis.  The resource names are the
              names  of  the  axes  (such   as   x   or   x2).    option   add
              *Graph.Axis.Color    blue  option  add  *Graph.x.LogScale   true
              option add *Graph.x2.LogScale false

       <I>pathName</I> <B>axis</B> <B>create</B> <I>axisName</I> ?<I>option</I> <I>value</I>?...
              Creates a new axis by the name <I>axisName</I>.  No axis  by  the  same
              name  can already exist. <I>Option</I> and <I>value</I> are described in above
              in the axis <B>configure</B> operation.

       <I>pathName</I> <B>axis</B> <B>delete</B> ?<I>axisName</I>?...
              Deletes the named axes. An axis is not really deleted  until  it
              is not longer in use, so it's safe to delete axes mapped to ele-
              ments.

       <I>pathName</I> <B>axis</B> <B>invtransform</B> <I>axisName</I> <I>value</I>
              Performs the inverse transformation, changing the screen coordi-
              nate  <I>value</I>  to  a graph coordinate, mapping the value mapped to

       <I>pathName</I> <B>axis</B> <B>view</B> <I>axisName</I>
              Change the viewable area of this axis. Use as an argument  to  a
              scrollbar's "<I>-command</I>".

       The  default  axes are x, y, x2, and y2.  But you can display more than
       four axes simultaneously.  You can also swap in a different  axis  with
       <B>use</B> operation of the special axis components: <B>xaxis</B>, <B>x2axis</B>, <B>yaxis</B>, and
       <B>y2axis</B>.  .g create axis temp .g create axis time ...  .g xaxis use temp
       .g  yaxis use time Only the axes specified for use are displayed on the
       screen.

       The <B>xaxis</B>, <B>x2axis</B>, <B>yaxis</B>, and <B>y2axis</B>  components  operate  on  an  axis
       location  rather than a specific axis like the more general <B>axis</B> compo-
       nent does.  They implicitly control the axis that is currently using to
       that location.  By default, <B>xaxis</B> uses the x axis, <B>yaxis</B> uses y, <B>x2axis</B>
       uses x2, and <B>y2axis</B> uses y2.  When more than one axis is displayed in a
       margin, it represents the first axis displayed.

       The  following  operations  are available for axes. They mirror exactly
       the operations of the <B>axis</B> component.  The <I>axis</I> argument must be <B>xaxis</B>,
       <B>x2axis</B>,  <B>yaxis</B>,  or <B>y2axis</B>.  This feature is deprecated since more than
       one axis can now be used a margin.  You  should  only  use  the  <B>xaxis</B>,
       <B>x2axis</B>,  <B>yaxis</B>,  and <B>y2axis</B> components with the <B>use</B> operation.  For all
       other operations, use the general <B>axis</B> component instead.

       <I>pathName</I> <I>axis</I> <B>cget</B> <I>option</I>

       <I>pathName</I> <I>axis</I> <B>configure</B> ?<I>option</I> <I>value</I>?...

       <I>pathName</I> <I>axis</I> <B>invtransform</B> <I>value</I>

       <I>pathName</I> <I>axis</I> <B>limits</B>

       <I>pathName</I> <I>axis</I> <B>transform</B> <I>value</I>

       <I>pathName</I> <I>axis</I> <B>use</B> ?<I>axisName</I>?
              Designates the axis <I>axisName</I> is to be displayed  at  this  loca-
              tion.   <I>AxisName</I>  can not be already in use at another location.
              This command returns the name of the axis currently  using  this
              location.

   <B>CROSSHAIRS</B> <B>COMPONENT</B>
       Cross  hairs  consist  of  two intersecting lines (one vertical and one
       horizontal) drawn completely across the plotting area.  They  are  used
       to  position the mouse in relation to the coordinate axes.  Cross hairs
       differ from line markers in that they are implemented using XOR drawing
       primitives.  This means that they can be quickly drawn and erased with-
       out redrawing the entire graph.

       The following operations are available for cross hairs:

              <B>-color</B> <I>color</I>
                     Sets the color of the cross hairs.  The default is black.

              <B>-dashes</B> <I>dashList</I>
                     Sets  the  dash  style  of the cross hairs. <I>DashList</I> is a
                     list of up to 11 numbers that alternately  represent  the
                     lengths  of  the dashes and gaps on the cross hair lines.
                     Each number must be between 1 and 255.   If  <I>dashList</I>  is
                     "", the cross hairs will be solid lines.

              <B>-hide</B> <I>boolean</I>
                     Indicates  whether  cross  hairs are drawn. If <I>boolean</I> is
                     true, cross hairs are not drawn.  The default is yes.

              <B>-linewidth</B> <I>pixels</I>
                     Set the width of the cross hair lines.  The default is 1.

              <B>-position</B> <I>pos</I>
                     Specifies  the  screen  position  where  the  cross hairs
                     intersect.  <I>Pos</I> must be in the form "<I>@x,y</I>", where <I>x</I> and <I>y</I>
                     are the window coordinates of the intersection.

              Cross  hairs  configuration  options  may  be also be set by the
              <B>option</B> command.  The resource name and class are crosshairs  and
              Crosshairs respectively.  option add *Graph.Crosshairs.LineWidth
              2 option add *Graph.Crosshairs.Color     red

       <I>pathName</I> <B>crosshairs</B> <B>off</B>
              Turns off the cross hairs.

       <I>pathName</I> <B>crosshairs</B> <B>on</B>
              Turns on the display of the cross hairs.

       <I>pathName</I> <B>crosshairs</B> <B>toggle</B>
              Toggles the current state of the cross hairs,  alternately  map-
              ping and unmapping the cross hairs.

   <B>ELEMENT</B> <B>COMPONENTS</B>
       A  data  element represents a set of data.  It contains x and y vectors
       containing the coordinates of the data points.  Elements  can  be  dis-
       played  with  a  symbol  at  each  data  point and lines connecting the
       points.  Elements also control the appearance of the data, such as  the
       symbol type, line width, color etc.

       When  new  data elements are created, they are automatically added to a
       list of displayed elements.   The display list controls  what  elements
       are drawn and in what order.

       The following operations are available for elements.

       <I>pathName</I> <B>element</B> <B>activate</B> <I>elemName</I> ?<I>index</I>?...
              Specifies  the data points of element <I>elemName</I> to be drawn using
              replacing  any  existing  binding for the same <I>sequence</I> and <I>tag-</I>
              <I>Name</I>.  If the first character of <I>command</I> is + then <I>command</I>  aug-
              ments  an existing binding rather than replacing it.  If no <I>com-</I>
              <I>mand</I> argument is provided then the command currently  associated
              with  <I>tagName</I>  and  <I>sequence</I> (it's an error occurs if there's no
              such binding) is returned.  If both  <I>command</I>  and  <I>sequence</I>  are
              missing  then  a list of all the event sequences for which bind-
              ings have been defined for <I>tagName</I>.

       <I>pathName</I> <B>element</B> <B>cget</B> <I>elemName</I> <I>option</I>
              Returns the current value of the  element  configuration  option
              given  by  <I>option</I>.   <I>Option</I>  may be any of the options described
              below for the element <B>configure</B> operation.

       <I>pathName</I> <B>element</B> <B>closest</B> <I>x</I> <I>y</I> ?<I>option</I> <I>value</I>?... ?<I>elemName</I>?...
              Searches for the data point closest to the window coordinates  <I>x</I>
              and  <I>y</I>.  By default, all elements are searched.  Hidden elements
              (see the <B>-hide</B> option is false) are ignored.  You can limit  the
              search  by  specifying  only the elements you want to be consid-
              ered.  <I>ElemName</I> must be the name of an element that can  not  be
              hidden.   It returns a key-value list containing the name of the
              closest element, the index of the closest data  point,  and  the
              graph-coordinates  of  the  point.  Returns "", if no data point
              within the  threshold  distance  can  be  found.  The  following
              <I>option</I>-<I>value</I> pairs are available.

              <B>-along</B> <I>direction</I>
                     Search for the closest element using the following crite-
                     ria:

                     x      Find closest element vertically from the given  X-
                            coordinate.

                     y      Find  the  closest  element  horizontally from the
                            given Y-coordinate.

                     both   Find the  closest  element  for  the  given  point
                            (using both the X and Y coordinates).

              <B>-halo</B> <I>pixels</I>
                     Specifies a threshold distance where selected data points
                     are ignored.  <I>Pixels</I> is a valid screen distance, such  as
                     2  or  1.2i.   If  this  option  isn't specified, then it
                     defaults to the value of the graph's <B>-halo</B> option.

              <B>-interpolate</B> <I>string</I>
                     Indicates whether to consider projections that lie  along
                     the  line  segments connecting data points when searching
                     for the closest point.  The default value is 0. The  val-
                     ues for <I>string</I> are described below.

                     no          Search only for the closest data point.

              <B>-activepen</B> <I>penName</I>
                     Specifies pen to use to draw active element.  If  <I>penName</I>
                     is  "", no active elements will be drawn.  The default is
                     activeLine.

              <B>-areabackground</B> <I>color</I>
                     Specifies the background color  of  the  area  under  the
                     curve.  The  background area color is drawn only for bit-
                     maps (see the <B>-areapattern</B> option).  If <I>color</I> is "",  the
                     background is transparent.  The default is black.

              <B>-areaforeground</B> <I>color</I>
                     Specifies  the  foreground  color  of  the area under the
                     curve.  The default is black.

              <B>-areapattern</B> <I>pattern</I>
                     Specifies how to fill the area under the curve.   <I>Pattern</I>
                     may  be  the  name  of  a  Tk  bitmap,  solid, or "".  If
                     "solid", then the area under the curve is drawn with  the
                     color  designated  by  the  <B>-areaforeground</B> option.  If a
                     bitmap, then the bitmap  is  stippled  across  the  area.
                     Here  the  bitmap colors are controlled by the <B>-areafore-</B>
                     <B>ground</B> and <B>-areabackground</B> options.  If <I>pattern</I> is "", no
                     filled area is drawn.  The default is "".

              <B>-areatile</B> <I>image</I>
                     Specifies  the  name of a Tk image to be used to tile the
                     area under the curve.  This option supersedes the <B>-areap-</B>
                     <B>attern</B> option.  <I>Image</I> must be a photo image.  If <I>image</I> is
                     "", no tiling is performed.  The default is "".

              <B>-bindtags</B> <I>tagList</I>
                     Specifies the binding tags for the element.  <I>TagList</I> is a
                     list of binding tag names.  The tags and their order will
                     determine how events are handled for elements.  Each  tag
                     in the list matching the current event sequence will have
                     its Tcl command executed.  Implicitly  the  name  of  the
                     element is always the first tag in the list.  The default
                     value is all.

              <B>-color</B> <I>color</I>
                     Sets the color of the traces connecting the data  points.

              <B>-dashes</B> <I>dashList</I>
                     Sets  the  dash style of element line. <I>DashList</I> is a list
                     of up  to  11  numbers  that  alternately  represent  the
                     lengths of the dashes and gaps on the element line.  Each
                     number must be between 1 and 255.  If <I>dashList</I> is "", the
                     lines will be solid.

              <B>-data</B> <I>coordList</I>
                     Specifies  the X-Y coordinates of the data.  <I>CoordList</I> is
                     Sets  the  element's label in the legend.  If <I>text</I> is "",
                     the element will  have  no  entry  in  the  legend.   The
                     default label is the element's name.

              <B>-linewidth</B> <I>pixels</I>
                     Sets  the  width  of  the  connecting  lines between data
                     points.  If <I>pixels</I> is 0,  no  connecting  lines  will  be
                     drawn between symbols.  The default is 0.

              <B>-mapx</B> <I>xAxis</I>
                     Selects  the  X-axis  to  map the element's X-coordinates
                     onto.  <I>XAxis</I> must be the name of an axis.  The default is
                     x.

              <B>-mapy</B> <I>yAxis</I>
                     Selects  the  Y-axis  to  map the element's Y-coordinates
                     onto.  <I>YAxis</I> must be the name of an axis. The default  is
                     y.

              <B>-offdash</B> <I>color</I>
                     Sets the color of the stripes when traces are dashed (see
                     the <B>-dashes</B> option).  If <I>color</I> is "", then the "off" pix-
                     els  will represent gaps instead of stripes.  If <I>color</I> is
                     defcolor, then the color will be the same as  the  <B>-color</B>
                     option.  The default is defcolor.

              <B>-outline</B> <I>color</I>
                     Sets  the  color  or  the outline around each symbol.  If
                     <I>color</I> is "", then no outline is drawn. If <I>color</I>  is  def-
                     color,  then  the  color  will  be the same as the <B>-color</B>
                     option.  The default is defcolor.

              <B>-pen</B> <I>penname</I>
                     Set the pen to use for this element.

              <B>-outlinewidth</B> <I>pixels</I>
                     Sets the width of the outline bordering each symbol.   If
                     <I>pixels</I>  is 0, no outline will be drawn. The default is 1.

              <B>-pixels</B> <I>pixels</I>
                     Sets the size of symbols.  If <I>pixels</I>  is  0,  no  symbols
                     will be drawn.  The default is 0.125i.

              <B>-scalesymbols</B> <I>boolean</I>
                     If  <I>boolean</I>  is  true,  the size of the symbols drawn for
                     <I>elemName</I> will change with scale of the X-axis and Y-axis.
                     At the time this option is set, the current ranges of the
                     axes are saved as the normalized scales (i.e scale factor
                     is  1.0)  and the element is drawn at its designated size
                     (see the <B>-pixels</B> option).   As  the  scale  of  the  axes
                     change,  the  symbol  will  be  scaled  according  to the
                     smaller of the X-axis and Y-axis scales.  If  <I>boolean</I>  is
                     dratic spline is used.  The default is <I>linear</I>.

              <B>-styles</B> <I>styleList</I>
                     Specifies what pen to use based on the range  of  weights
                     given.  <I>StyleList</I> is a list of style specifications. Each
                     style specification, in turn, is a list consisting  of  a
                     pen  name,  and  optionally  a minimum and maximum range.
                     Data points whose weight (see the <B>-weight</B>  option)  falls
                     in  this  range, are drawn with this pen.  If no range is
                     specified it defaults to the index  of  the  pen  in  the
                     list.   Note  that  this  affects only symbol attributes.
                     Line attributes, such as line  width,  dashes,  etc.  are
                     ignored.

              <B>-symbol</B> <I>symbol</I>
                     Specifies  the  symbol  for  data  points.  <I>Symbol</I> can be
                     either  square,  circle,  diamond,  plus,  cross,  splus,
                     scross,  triangle,  ""  (where  no symbol is drawn), or a
                     bitmap.  Bitmaps are specified as "<I>source</I> ?<I>mask</I>?",  where
                     <I>source</I>  is  the  name of the bitmap, and <I>mask</I> is the bit-
                     map's optional mask.  The default is circle.

              <B>-trace</B> <I>direction</I>
                     Indicates whether connecting lines  between  data  points
                     (whose  X-coordinate  values  are  either  increasing  or
                     decreasing) are drawn.   <I>Direction</I>  must  be  increasing,
                     decreasing,  or  both.   For  example,  if  <I>direction</I>  is
                     increasing, connecting lines will be drawn  only  between
                     those data points where X-coordinate values are monotoni-
                     cally increasing.  If <I>direction</I> is both, connecting lines
                     will  be  draw  between  all data points.  The default is
                     both.

              <B>-weights</B> <I>wVec</I>
                     Specifies the weights  of  the  individual  data  points.
                     This,  with the list pen styles (see the <B>-styles</B> option),
                     controls how data points are drawn.  <I>WVec</I> is the name  of
                     a  BLT vector or a list of numeric expressions represent-
                     ing the weights for each data point.

              <B>-xdata</B> <I>xVec</I>
                     Specifies the X-coordinates of the  data.   <I>XVec</I>  is  the
                     name of a BLT vector or a list of numeric expressions.

              <B>-ydata</B> <I>yVec</I>
                     Specifies  the  Y-coordinates  of  the data.  <I>YVec</I> is the
                     name of a BLT vector or a list of numeric expressions.

              Element configuration options may also be set by the <B>option</B> com-
              mand.   The  resource class is Element. The resource name is the
              name of the  element.   option  add  *Graph.Element.symbol  line
              option add *Graph.e1.symbol line

       <I>pathName</I> <B>element</B> <B>exists</B> <I>elemName</I>
              Returns  1  if an element <I>elemName</I> currently exists and 0 other-
              wise.

       <I>pathName</I> <B>element</B> <B>names</B> ?<I>pattern</I>?...
              Returns the elements matching one or more pattern.  If  no  <I>pat-</I>
              <I>tern</I> is given, the names of all elements is returned.

       <I>pathName</I> <B>element</B> <B>show</B> ?<I>nameList</I>?
              Queries  or modifies the element display list.  The element dis-
              play list designates the  elements  drawn  and  in  what  order.
              <I>NameList</I> is a list of elements to be displayed in the order they
              are named.  If there is no <I>nameList</I> argument, the  current  dis-
              play list is returned.

       <I>pathName</I> <B>element</B> <B>type</B> <I>elemName</I>
              Returns  the type of <I>elemName</I>.  If the element is a bar element,
              the commands returns the  string  "bar",  otherwise  it  returns
              "line".

   <B>GRID</B> <B>COMPONENT</B>
       Grid  lines extend from the major and minor ticks of each axis horizon-
       tally or vertically across the plotting area.  The following operations
       are available for grid lines.

       <I>pathName</I> <B>grid</B> <B>cget</B> <I>option</I>
              Returns  the current value of the grid line configuration option
              given by <I>option</I>.  <I>Option</I> may be any option described  below  for
              the grid <B>configure</B> operation.

       <I>pathName</I> <B>grid</B> <B>configure</B> ?<I>option</I> <I>value</I>?...
              Queries  or  modifies  the configuration options for grid lines.
              If <I>option</I> isn't specified, a list  describing  all  the  current
              grid  options for <I>pathName</I> is returned.  If <I>option</I> is specified,
              but not <I>value</I>, then a list describing <I>option</I>  is  returned.   If
              one  or more <I>option</I> and <I>value</I> pairs are specified, then for each
              pair, the grid line option <I>option</I> is set to <I>value</I>.  The  follow-
              ing options are valid for grid lines.

              <B>-color</B> <I>color</I>
                     Sets  the color of the grid lines.  The default is black.

              <B>-dashes</B> <I>dashList</I>
                     Sets the dash style of the grid lines. <I>DashList</I> is a list
                     of  up  to  11  numbers  that  alternately  represent the
                     lengths of the dashes and gaps on the grid  lines.   Each
                     number must be between 1 and 255.  If <I>dashList</I> is "", the
                     grid will be solid lines.

              <B>-hide</B> <I>boolean</I>
                     Indicates whether the grid should be drawn. If <I>boolean</I> is

              <B>-minor</B> <I>boolean</I>
                     Indicates  whether  the  grid  lines  should be drawn for
                     minor ticks.  If <I>boolean</I> is true, the lines  will  appear
                     at minor tick intervals.  The default is 1.

              Grid  configuration  options  may also be set by the <B>option</B> com-
              mand.  The resource name and class are  grid  and  Grid  respec-
              tively.    option   add   *Graph.grid.LineWidth   2  option  add
              *Graph.Grid.Color     black

       <I>pathName</I> <B>grid</B> <B>off</B>
              Turns off the display the grid lines.

       <I>pathName</I> <B>grid</B> <B>on</B>
              Turns on the display the grid lines.

       <I>pathName</I> <B>grid</B> <B>toggle</B>
              Toggles the display of the grid.

   <B>LEGEND</B> <B>COMPONENT</B>
       The legend displays a list of the data elements.  Each  entry  consists
       of the element's symbol and label.  The legend can appear in any margin
       (the default location is in the right margin).  It can  also  be  posi-
       tioned anywhere within the plotting area.

       The following operations are valid for the legend.

       <I>pathName</I> <B>legend</B> <B>activate</B> <I>pattern</I>...
              Selects  legend entries to be drawn using the active legend col-
              ors and relief.  All entries whose element names  match  <I>pattern</I>
              are  selected.  To be selected, the element name must match only
              one <I>pattern</I>.

       <I>pathName</I> <B>legend</B> <B>bind</B> <I>tagName</I> ?<I>sequence</I>?  ?<I>command</I>?
              Associates <I>command</I> with <I>tagName</I> such  that  whenever  the  event
              sequence  given  by <I>sequence</I> occurs for a legend entry with this
              tag, <I>command</I> will be invoked.  Implicitly the element  names  in
              the  entry  are tags.  The syntax is similar to the <B>bind</B> command
              except that it operates on legend entries, rather than  widgets.
              See  the  <B>bind</B> manual entry for complete details on <I>sequence</I> and
              the substitutions performed on <I>command</I> before invoking it.

              If all arguments are specified then a new  binding  is  created,
              replacing  any  existing  binding for the same <I>sequence</I> and <I>tag-</I>
              <I>Name</I>.  If the first character of <I>command</I> is + then <I>command</I>  aug-
              ments  an existing binding rather than replacing it.  If no <I>com-</I>
              <I>mand</I> argument is provided then the command currently  associated
              with  <I>tagName</I>  and  <I>sequence</I> (it's an error occurs if there's no
              such binding) is returned.  If both  <I>command</I>  and  <I>sequence</I>  are
              missing  then  a list of all the event sequences for which bind-
              ings have been defined for <I>tagName</I>.

              <B>-activebackground</B> <I>color</I>
                     Sets the background color for active legend entries.  All
                     legend  entries  marked  active  (see the legend <B>activate</B>
                     operation) are drawn using this background color.

              <B>-activeborderwidth</B> <I>pixels</I>
                     Sets the width of the 3-D border around the outside  edge
                     of the active legend entries.  The default is 2.

              <B>-activeforeground</B> <I>color</I>
                     Sets the foreground color for active legend entries.  All
                     legend entries marked as active (see the legend  <B>activate</B>
                     operation) are drawn using this foreground color.

              <B>-activerelief</B> <I>relief</I>
                     Specifies  the  3-D  effect  desired  for  active  legend
                     entries.  <I>Relief</I> denotes how the interior  of  the  entry
                     should appear relative to the legend; for example, raised
                     means the entry should appear to protrude from  the  leg-
                     end,  relative to the surface of the legend.  The default
                     is flat.

              <B>-anchor</B> <I>anchor</I>
                     Tells how to position the legend relative  to  the  posi-
                     tioning  point  for the legend.  This is dependent on the
                     value of the <B>-position</B> option.  The default is center.

                     left or right
                                 The anchor describes how to position the leg-
                                 end vertically.

                     top or bottom
                                 The anchor describes how to position the leg-
                                 end horizontally.

                     @x,y        The anchor specifies how to position the leg-
                                 end  relative  to  the positioning point. For
                                 example, if <I>anchor</I> is center then the  legend
                                 is centered on the point; if <I>anchor</I> is n then
                                 the legend will be drawn such  that  the  top
                                 center  point of the rectangular region occu-
                                 pied by the legend will be at the positioning
                                 point.

                     plotarea    The anchor specifies how to position the leg-
                                 end relative to the plotting area. For  exam-
                                 ple,  if  <I>anchor</I> is center then the legend is
                                 centered in the plotting area; if  <I>anchor</I>  is
                                 ne  then  the  legend will be drawn such that
                                 occupies the upper right corner of the  plot-
                                 ting area.

                     Sets  the width of the 3-D border around the outside edge
                     of the legend (if such border is being drawn; the  <B>relief</B>
                     option determines this).  The default is 2 pixels.

              <B>-font</B> <I>fontName</I>
                     <I>FontName</I>  specifies a font to use when drawing the labels
                     of each element into the legend.  The default  is  *-Hel-
                     vetica-Bold-R-Normal-*-12-120-*.

              <B>-foreground</B> <I>color</I>
                     Sets  the foreground color of the text drawn for the ele-
                     ment's label.  The default is black.

              <B>-hide</B> <I>boolean</I>
                     Indicates whether the  legend  should  be  displayed.  If
                     <I>boolean</I>  is  true,  the  legend  will  not  be draw.  The
                     default is no.

              <B>-ipadx</B> <I>pad</I>
                     Sets the amount of internal padding to be  added  to  the
                     width  of each legend entry.  <I>Pad</I> can be a list of one or
                     two screen distances.  If <I>pad</I> has two elements, the  left
                     side  of the legend entry is padded by the first distance
                     and the right side by the second.  If  <I>pad</I>  is  just  one
                     distance,  both  the  left  and  right  sides  are padded
                     evenly.  The default is 2.

              <B>-ipady</B> <I>pad</I>
                     Sets an amount of internal padding to  be  added  to  the
                     height of each legend entry.  <I>Pad</I> can be a list of one or
                     two screen distances.  If <I>pad</I> has two elements,  the  top
                     of the entry is padded by the first distance and the bot-
                     tom by the second.  If <I>pad</I> is just one distance, both the
                     top  and  bottom  of  the  entry  are padded evenly.  The
                     default is 2.

              <B>-padx</B> <I>pad</I>
                     Sets the padding to the left and right exteriors  of  the
                     legend.   <I>Pad</I>  can  be  a  list of one or two screen dis-
                     tances.  If <I>pad</I> has two elements, the left  side  of  the
                     legend is padded by the first distance and the right side
                     by the second.  If <I>pad</I> has just one  distance,  both  the
                     left  and  right sides are padded evenly.  The default is
                     4.

              <B>-pady</B> <I>pad</I>
                     Sets the padding above and below the legend.  <I>Pad</I> can  be
                     a  list  of  one or two screen distances.  If <I>pad</I> has two
                     elements, the area above the  legend  is  padded  by  the
                     first  distance and the area below by the second.  If <I>pad</I>
                     is just one distance, both the top and bottom  areas  are
                     padded evenly.  The default is 0.
                     plotting area.  If <I>boolean</I> is true, the  legend  will  be
                     drawn  on  top  of  any elements that may overlap it. The
                     default is no.

              <B>-relief</B> <I>relief</I>
                     Specifies the 3-D effect for the border around  the  leg-
                     end.   <I>Relief</I>  specifies  how  the interior of the legend
                     should appear relative to the graph; for example,  raised
                     means  the  legend  should  appear  to  protrude from the
                     graph, relative to the surface of the graph.  The default
                     is sunken.

              Legend  configuration options may also be set by the <B>option</B> com-
              mand.  The resource name and class are legend and Legend respec-
              tively.   option  add  *Graph.legend.Foreground  blue option add
              *Graph.Legend.Relief     raised

       <I>pathName</I> <B>legend</B> <B>deactivate</B> <I>pattern</I>...
              Selects legend entries to be drawn using the normal legend  col-
              ors  and  relief.  All entries whose element names match <I>pattern</I>
              are selected.  To be selected, the element name must match  only
              one <I>pattern</I>.

       <I>pathName</I> <B>legend</B> <B>get</B> <I>pos</I>
              Returns  the  name  of  the element whose entry is at the screen
              position <I>pos</I> in the legend.  <I>Pos</I> must be  in  the  form  "<I>@x,y</I>",
              where  <I>x</I> and <I>y</I> are window coordinates.  If the given coordinates
              do not lie over a legend entry, "" is returned.

   <B>PEN</B> <B>COMPONENTS</B>
       Pens define attributes (both symbol and line style) for elements.  Pens
       mirror  the  configuration options of data elements that pertain to how
       symbols and lines are drawn.  Data elements use pens to  determine  how
       they  are drawn.  A data element may use several pens at once.  In this
       case, the pen used for a particular data point is determined from  each
       element's weight vector (see the element's <B>-weight</B> and <B>-style</B> options).

       One pen, called activeLine, is automatically created.  It's used as the
       default  active  pen  for  elements.  So  you  can  change  the  active
       attributes for all elements by simply reconfiguring this pen.   .g  pen
       configure  "activeLine"  -color  green  You  can create and use several
       pens. To create a pen, invoke the pen component and its  create  opera-
       tion.   .g pen create myPen You map pens to a data element using either
       the element's <B>-pen</B> or <B>-activepen</B> options.  .g  element  create  "line1"
       -xdata $x -ydata $tempData \
           -pen myPen An element can use several pens at once. This is done by
       specifying the name of the pen in the element's  style  list  (see  the
       <B>-styles</B>  option).  .g element configure "line1" -styles { myPen 2.0 3.0
       } This says that any data point with a weight between 2.0 and 3.0 is to
       be drawn using the pen myPen.  All other points are drawn with the ele-
       ment's default attributes.

              specified,  then  for each pair, the pen option <I>option</I> is set to
              <I>value</I>.  The following options are valid for pens.

              <B>-color</B> <I>color</I>
                     Sets the color of the traces connecting the data  points.

              <B>-dashes</B> <I>dashList</I>
                     Sets  the  dash style of element line. <I>DashList</I> is a list
                     of up  to  11  numbers  that  alternately  represent  the
                     lengths of the dashes and gaps on the element line.  Each
                     number must be between 1 and 255.  If <I>dashList</I> is "", the
                     lines will be solid.

              <B>-fill</B> <I>color</I>
                     Sets the interior color of symbols.  If <I>color</I> is "", then
                     the interior of the symbol is transparent.  If  <I>color</I>  is
                     defcolor,  then  the color will be the same as the <B>-color</B>
                     option.  The default is defcolor.

              <B>-linewidth</B> <I>pixels</I>
                     Sets the width  of  the  connecting  lines  between  data
                     points.   If  <I>pixels</I>  is  0,  no connecting lines will be
                     drawn between symbols.  The default is 0.

              <B>-offdash</B> <I>color</I>
                     Sets the color of the stripes when traces are dashed (see
                     the <B>-dashes</B> option).  If <I>color</I> is "", then the "off" pix-
                     els will represent gaps instead of stripes.  If <I>color</I>  is
                     defcolor,  then  the color will be the same as the <B>-color</B>
                     option.  The default is defcolor.

              <B>-outline</B> <I>color</I>
                     Sets the color or the outline  around  each  symbol.   If
                     <I>color</I>  is  "", then no outline is drawn. If <I>color</I> is def-
                     color, then the color will be  the  same  as  the  <B>-color</B>
                     option.  The default is defcolor.

              <B>-outlinewidth</B> <I>pixels</I>
                     Sets  the width of the outline bordering each symbol.  If
                     <I>pixels</I> is 0, no outline will be drawn. The default is  1.

              <B>-pixels</B> <I>pixels</I>
                     Sets  the  size  of  symbols.  If <I>pixels</I> is 0, no symbols
                     will be drawn.  The default is 0.125i.

              <B>-symbol</B> <I>symbol</I>
                     Specifies the symbol for  data  points.   <I>Symbol</I>  can  be
                     either  square,  circle,  diamond,  plus,  cross,  splus,
                     scross, triangle, "" (where no symbol  is  drawn),  or  a
                     bitmap.   Bitmaps are specified as "<I>source</I> ?<I>mask</I>?", where
                     <I>source</I> is the name of the bitmap, and <I>mask</I>  is  the  bit-
                     map's optional mask.  The default is circle.

              Creates a new pen by the name <I>penName</I>.  No pen by the same  name
              can  already  exist.  <I>Option</I> and <I>value</I> are described in above in
              the pen <B>configure</B> operation.

       <I>pathName</I> <B>pen</B> <B>delete</B> ?<I>penName</I>?...
              Deletes the named pens. A pen is not really deleted until it  is
              not  longer  in  use, so it's safe to delete pens mapped to ele-
              ments.

       <I>pathName</I> <B>pen</B> <B>names</B> ?<I>pattern</I>?...
              Returns a list of pens matching zero or more  patterns.   If  no
              <I>pattern</I> argument is give, the names of all pens are returned.

   <B>POSTSCRIPT</B> <B>COMPONENT</B>
       The  graph can generate encapsulated PostScript output.  There are sev-
       eral configuration options you can specify to control how the plot will
       be  generated.   You  can  change the page dimensions and borders.  The
       plot itself can be scaled, centered,  or  rotated  to  landscape.   The
       PostScript output can be written directly to a file or returned through
       the interpreter.

       The following postscript operations are available.

       <I>pathName</I> <B>postscript</B> <B>cget</B> <I>option</I>
              Returns the current value of  the  postscript  option  given  by
              <I>option</I>.   <I>Option</I> may be any option described below for the post-
              script <B>configure</B> operation.

       <I>pathName</I> <B>postscript</B> <B>configure</B> ?<I>option</I> <I>value</I>?...
              Queries or modifies the  configuration  options  for  PostScript
              generation.   If  <I>option</I>  isn't specified, a list describing the
              current postscript options for <I>pathName</I> is returned.  If  <I>option</I>
              is  specified,  but  not <I>value</I>, then a list describing <I>option</I> is
              returned.  If one or more <I>option</I> and <I>value</I> pairs are  specified,
              then  for  each  pair,  the  postscript  option <I>option</I> is set to
              <I>value</I>.  The following postscript options are available.

              <B>-center</B> <I>boolean</I>
                     Indicates whether the plot  should  be  centered  on  the
                     PostScript  page.   If <I>boolean</I> is false, the plot will be
                     placed in the upper left corner of the page.  The default
                     is 1.

              <B>-colormap</B> <I>varName</I>
                     <I>VarName</I>  must be the name of a global array variable that
                     specifies a color mapping from the X color name to  Post-
                     Script.   Each  element  of <I>varName</I> must consist of Post-
                     Script code to set a particular color value  (e.g.  ``1.0
                     1.0  0.0  setrgbcolor'').  When generating color informa-
                     tion in PostScript, the array variable <I>varName</I> is checked
                     if  an element of the name as the color exists. If so, it
                     uses its value as  the  PostScript  command  to  set  the
                     Script.   Each  element  of <I>varName</I> must consist of a Tcl
                     list with one or two elements; the name and point size of
                     a  PostScript  font.  When outputting PostScript commands
                     for a particular font,  the  array  variable  <I>varName</I>  is
                     checked  to  see  if  an  element  by  the specified font
                     exists.  If there is  such  an  element,  then  the  font
                     information  contained  in  that  element  is used in the
                     PostScript output.  (If the point size  is  omitted  from
                     the  list, the point size of the X font is used).  Other-
                     wise the X font is examined in an attempt to  guess  what
                     PostScript  font to use.  This works only for fonts whose
                     foundry property is  <I>Adobe</I>  (such  as  Times,  Helvetica,
                     Courier,  etc.).   If  all  of  this  fails then the font
                     defaults to Helvetica-Bold.

              <B>-decorations</B> <I>boolean</I>
                     Indicates whether PostScript commands to  generate  color
                     backgrounds  and  3-D borders will be output.  If <I>boolean</I>
                     is false, the background will be white and no 3-D borders
                     will be generated. The default is 1.

              <B>-height</B> <I>pixels</I>
                     Sets  the  height  of  the plot.  This lets you print the
                     graph with a height different from the one drawn  on  the
                     screen.   If  <I>pixels</I>  is 0, the height is the same as the
                     widget's height.  The default is 0.

              <B>-landscape</B> <I>boolean</I>
                     If <I>boolean</I> is true, this specifies the printed area is to
                     be  rotated 90 degrees.  In non-rotated output the X-axis
                     of the printed area runs along the short dimension of the
                     page  (``portrait''  orientation);  in rotated output the
                     X-axis runs along the long dimension of the page (``land-
                     scape'' orientation).  Defaults to 0.

              <B>-maxpect</B> <I>boolean</I>
                     Indicates  to  scale  the plot so that it fills the Post-
                     Script page.  The aspect ratio  of  the  graph  is  still
                     retained.  The default is 0.

              <B>-padx</B> <I>pad</I>
                     Sets  the  horizontal padding for the left and right page
                     borders.  The borders are exterior to the plot.  <I>Pad</I>  can
                     be a list of one or two screen distances.  If <I>pad</I> has two
                     elements, the left border is padded by the first distance
                     and  the right border by the second.  If <I>pad</I> has just one
                     distance, both the left  and  right  borders  are  padded
                     evenly.  The default is 1i.

              <B>-pady</B> <I>pad</I>
                     Sets  the  vertical  padding  for the top and bottom page
                     borders. The borders are exterior to the plot.   <I>Pad</I>  can
                     The default width is 8.5i.

              <B>-width</B> <I>pixels</I>
                     Sets  the  width  of  the plot.  This lets you generate a
                     plot of a width different from that of  the  widget.   If
                     <I>pixels</I> is 0, the width is the same as the widget's width.
                     The default is 0.

              Postscript configuration options may  be  also  be  set  by  the
              <B>option</B>  command.  The resource name and class are postscript and
              Postscript respectively.  option  add  *Graph.postscript.Decora-
              tions false option add *Graph.Postscript.Landscape   true

       <I>pathName</I> <B>postscript</B> <B>output</B> ?<I>fileName</I>? ?<I>option</I> <I>value</I>?...
              Outputs  a file of encapsulated PostScript.  If a <I>fileName</I> argu-
              ment isn't present, the command returns the PostScript.  If  any
              <I>option-value</I>  pairs  are present, they set configuration options
              controlling how the PostScript is generated.  <I>Option</I>  and  <I>value</I>
              can  be  anything accepted by the postscript <B>configure</B> operation
              above.

   <B>MARKER</B> <B>COMPONENTS</B>
       Markers are simple drawing procedures used  to  annotate  or  highlight
       areas of the graph.  Markers have various types: text strings, bitmaps,
       images, connected lines, windows, or polygons.  They can be  associated
       with  a  particular  element, so that when the element is hidden or un-
       hidden, so is the marker.  By  default,  markers  are  the  last  items
       drawn,  so  that  data  elements  will  appear in behind them.  You can
       change this by configuring the <B>-under</B> option.

       Markers, in contrast to elements, don't affect the scaling of the coor-
       dinate axes.  They can also have <I>elastic</I> coordinates (specified by -Inf
       and Inf respectively) that translate into the minimum or maximum  limit
       of  the axis.  For example, you can place a marker so it always remains
       in the lower left corner of the plotting area, by using the coordinates
       -Inf,-Inf.

       The following operations are available for markers.

       <I>pathName</I> <B>marker</B> <B>after</B> <I>markerId</I> ?<I>afterId</I>?
              Changes the order of the markers, drawing the first marker after
              the second.  If no second <I>afterId</I>  argument  is  specified,  the
              marker  is  placed at the end of the display list.  This command
              can be used to control how markers are displayed  since  markers
              are drawn in the order of this display list.

       <I>pathName</I> <B>marker</B> <B>before</B> <I>markerId</I> ?<I>beforeId</I>?
              Changes  the  order  of  the  markers,  drawing the first marker
              before the second.  If no second <I>beforeId</I> argument is specified,
              the marker is placed at the beginning of the display list.  This
              command can be used to control how markers are  displayed  since
              markers are drawn in the order of this display list.
              with  <I>tagName</I>  and  <I>sequence</I> (it's an error occurs if there's no
              such binding) is returned.  If both  <I>command</I>  and  <I>sequence</I>  are
              missing  then  a list of all the event sequences for which bind-
              ings have been defined for <I>tagName</I>.

       <I>pathName</I> <B>marker</B> <B>cget</B> <I>option</I>
              Returns the current value of  the  marker  configuration  option
              given  by  <I>option</I>.   <I>Option</I> may be any option described below in
              the <B>configure</B> operation.

       <I>pathName</I> <B>marker</B> <B>configure</B> <I>markerId</I> ?<I>option</I> <I>value</I>?...
              Queries or modifies the configuration options for  markers.   If
              <I>option</I>  isn't  specified,  a list describing the current options
              for <I>markerId</I> is returned.   If  <I>option</I>  is  specified,  but  not
              <I>value</I>,  then  a  list  describing <I>option</I> is returned.  If one or
              more <I>option</I> and <I>value</I> pairs are specified, then for  each  pair,
              the marker option <I>option</I> is set to <I>value</I>.

              The  following  options are valid for all markers.  Each type of
              marker  also  has  its  own  type-specific  options.   They  are
              described in the sections below.

              <B>-bindtags</B> <I>tagList</I>
                     Specifies  the binding tags for the marker.  <I>TagList</I> is a
                     list of binding tag names.  The tags and their order will
                     determine  how  events for markers are handled.  Each tag
                     in the list matching the current event sequence will have
                     its  Tcl  command  executed.   Implicitly the name of the
                     marker is always the first tag in the list.  The  default
                     value is all.

              <B>-coords</B> <I>coordList</I>
                     Specifies  the coordinates of the marker.  <I>CoordList</I> is a
                     list of graph coordinates.   The  number  of  coordinates
                     required  is  dependent  on  the  type  of marker.  Text,
                     image, and window markers need only two  coordinates  (an
                     X-Y  coordinate).   Bitmap markers can take either two or
                     four coordinates (if four, they represent the corners  of
                     the bitmap). Line markers need at least four coordinates,
                     polygons at least six.  If <I>coordList</I> is  "",  the  marker
                     will not be displayed.  The default is "".

              <B>-element</B> <I>elemName</I>
                     Links  the  marker with the element <I>elemName</I>.  The marker
                     is drawn only if the element is also currently  displayed
                     (see  the  element's <B>show</B> operation).  If <I>elemName</I> is "",
                     the marker is always drawn.  The default is "".

              <B>-hide</B> <I>boolean</I>
                     Indicates whether the marker  is  drawn.  If  <I>boolean</I>  is
                     true, the marker is not drawn.  The default is no.

              <B>-under</B> <I>boolean</I>
                     Indicates whether the marker is  drawn  below/above  data
                     elements.   If  <I>boolean</I>  is  true, the marker is be drawn
                     underneath the data element symbols  and  lines.   Other-
                     wise,  the  marker  is  drawn on top of the element.  The
                     default is 0.

              <B>-xoffset</B> <I>pixels</I>
                     Specifies a screen distance to offset the marker horizon-
                     tally.   <I>Pixels</I>  is a valid screen distance, such as 2 or
                     1.2i.  The default is 0.

              <B>-yoffset</B> <I>pixels</I>
                     Specifies a screen distance to offset the markers  verti-
                     cally.   <I>Pixels</I>  is a valid screen distance, such as 2 or
                     1.2i.  The default is 0.

              Marker configuration options may also be set by the <B>option</B>  com-
              mand.   The resource class is either BitmapMarker,  ImageMarker,
              LineMarker, PolygonMarker, TextMarker, or WindowMarker,  depend-
              ing on the type of marker.  The resource name is the name of the
              marker.  option add  *Graph.TextMarker.Foreground  white  option
              add     *Graph.BitmapMarker.Foreground    white    option    add
              *Graph.m1.Background     blue

       <I>pathName</I> <B>marker</B> <B>create</B> <I>type</I> ?<I>option</I> <I>value</I>?...
              Creates a marker of the selected type. <I>Type</I> may be either  text,
              line,  bitmap,  image, polygon, or window.  This command returns
              the marker identifier, used as  the  <I>markerId</I>  argument  in  the
              other  marker-related  commands.   If  the <B>-name</B> option is used,
              this overrides the normal marker identifier.  If the  name  pro-
              vided  is  already  used for another marker, the new marker will
              replace the old.

       <I>pathName</I> <B>marker</B> <B>delete</B> ?<I>name</I>?...
              Removes one of more markers.  The graph  will  automatically  be
              redrawn without the marker..

       <I>pathName</I> <B>marker</B> <B>exists</B> <I>markerId</I>
              Returns 1 if the marker <I>markerId</I> exists and 0 otherwise.

       <I>pathName</I> <B>marker</B> <B>names</B> ?<I>pattern</I>?
              Returns  the  names of all the markers that currently exist.  If
              <I>pattern</I> is supplied, only those markers  whose  names  match  it
              will be returned.

       <I>pathName</I> <B>marker</B> <B>type</B> <I>markerId</I>
              Returns  the  type of the marker given by <I>markerId</I>, such as line
              or text.  If <I>markerId</I> is not a valid a marker identifier, ""  is
              returned.

   <B>BITMAP</B> <B>MARKERS</B>
       The following options are specific to bitmap markers:

       <B>-background</B> <I>color</I>
              Same as the <B>-fill</B> option.

       <B>-bitmap</B> <I>bitmap</I>
              Specifies  the  bitmap  to  be  displayed.  If <I>bitmap</I> is "", the
              marker will not be displayed.  The default is "".

       <B>-fill</B> <I>color</I>
              Sets the background color of the bitmap.  If <I>color</I> is the  empty
              string,  no  background  will be transparent.  The default back-
              ground color is "".

       <B>-foreground</B> <I>color</I>
              Same as the <B>-outline</B> option.

       <B>-mask</B> <I>mask</I>
              Specifies a mask for the bitmap to be displayed. This mask is  a
              bitmap  itself,  denoting  the  pixels that are transparent.  If
              <I>mask</I> is "", all pixels of the bitmap will be drawn.  The default
              is "".

       <B>-outline</B> <I>color</I>
              Sets  the  foreground  color of the bitmap. The default value is
              black.

       <B>-rotate</B> <I>theta</I>
              Sets the rotation of the bitmap.  <I>Theta</I> is a real number  repre-
              senting  the  angle of rotation in degrees.  The marker is first
              rotated and then placed according to its anchor  position.   The
              default rotation is 0.0.

   <B>IMAGE</B> <B>MARKERS</B>
       A  image  marker displays an image.  Image markers are created with the
       marker's <B>create</B> operation in the form:  <I>pathName</I>  <B>marker</B>  <B>create</B>  <B>image</B>
       ?<I>option</I>  <I>value</I>?...   There  may be many <I>option</I>-<I>value</I> pairs, each sets a
       configuration option for the marker.  These same <I>option</I>-<I>value</I> pairs may
       be used with the marker's <B>configure</B> operation.

       The following options are specific to image markers:

       <B>-anchor</B> <I>anchor</I>
              <I>Anchor</I> tells how to position the image relative to the position-
              ing point for the image. For example, if <I>anchor</I> is  center  then
              the  image  is  centered  on the point;  if <I>anchor</I> is n then the
              image will be drawn such that the top center point of the  rect-
              angular  region occupied by the image will be at the positioning
              point.  This option defaults to center.

       <B>-image</B> <I>image</I>
              Specifies the image to be drawn.  If <I>image</I>  is  "",  the  marker
              gaps  on  the  line.  Each number must be between 1 and 255.  If
              <I>dashList</I> is "", the marker line will be solid.

       <B>-fill</B> <I>color</I>
              Sets the background color of the line.  This color is used  with
              striped  lines  (see the <B>-fdashes</B> option). If <I>color</I> is the empty
              string, no background color is drawn (the line will  be  dashed,
              not striped).  The default background color is "".

       <B>-linewidth</B> <I>pixels</I>
              Sets the width of the lines.  The default width is 0.

       <B>-outline</B> <I>color</I>
              Sets  the  foreground  color  of  the line. The default value is
              black.

       <B>-stipple</B> <I>bitmap</I>
              Specifies a stipple pattern used to draw the line, rather than a
              solid  line.   <I>Bitmap</I>  specifies  a bitmap to use as the stipple
              pattern.  If <I>bitmap</I> is "", then the line is  drawn  in  a  solid
              fashion. The default is "".

   <B>POLYGON</B> <B>MARKERS</B>
       A polygon marker displays a closed region described as two or more con-
       nected line segments.  It is assumed the first and last points are con-
       nected.   Polygon markers are created using the marker <B>create</B> operation
       in the form: <I>pathName</I> <B>marker</B> <B>create</B> <B>polygon</B>  ?<I>option</I>  <I>value</I>?...   There
       may  be  many  <I>option</I>-<I>value</I> pairs, each sets a configuration option for
       the marker.  These same <I>option</I>-<I>value</I> pairs may be used with the  <B>marker</B>
       <B>configure</B>  command to change the marker's configuration.  The following
       options are supported for polygon markers:

       <B>-dashes</B> <I>dashList</I>
              Sets the dash style of the outline of the polygon. <I>DashList</I> is a
              list  of up to 11 numbers that alternately represent the lengths
              of the dashes and gaps on the  outline.   Each  number  must  be
              between  1  and  255.  If  <I>dashList</I> is "", the outline will be a
              solid line.

       <B>-fill</B> <I>color</I>
              Sets the fill color of the polygon.  If <I>color</I> is  "",  then  the
              interior of the polygon is transparent.  The default is white.

       <B>-linewidth</B> <I>pixels</I>
              Sets the width of the outline of the polygon. If <I>pixels</I> is zero,
              no outline is drawn. The default is 0.

       <B>-outline</B> <I>color</I>
              Sets the color of the outline of the polygon.  If the polygon is
              stippled  (see  the  <B>-stipple</B>  option), then this represents the
              foreground color of the stipple.  The default is black.

       the marker's <B>configure</B> operation.

       The following options are specific to text markers:

       <B>-anchor</B> <I>anchor</I>
              <I>Anchor</I> tells how to position the text relative to the  position-
              ing  point  for  the text. For example, if <I>anchor</I> is center then
              the text is centered on the point; if <I>anchor</I> is n then the  text
              will  be drawn such that the top center point of the rectangular
              region occupied by the text will be at  the  positioning  point.
              This default is center.

       <B>-background</B> <I>color</I>
              Same as the <B>-fill</B> option.

       <B>-font</B> <I>fontName</I>
              Specifies  the  font  of  the text.  The default is *-Helvetica-
              Bold-R-Normal-*-120-*.

       <B>-fill</B> <I>color</I>
              Sets the background color of the text.  If <I>color</I>  is  the  empty
              string,  no  background  will be transparent.  The default back-
              ground color is "".

       <B>-foreground</B> <I>color</I>
              Same as the <B>-outline</B> option.

       <B>-justify</B> <I>justify</I>
              Specifies how the text should be justified.  This  matters  only
              when  the  marker  contains  more than one line of text. <I>Justify</I>
              must be left, right, or center.  The default is center.

       <B>-outline</B> <I>color</I>
              Sets the color of the text. The default value is black.

       <B>-padx</B> <I>pad</I>
              Sets the padding to the left and right exteriors  of  the  text.
              <I>Pad</I>  can  be  a list of one or two screen distances.  If <I>pad</I> has
              two elements, the left side of the text is padded by  the  first
              distance  and the right side by the second.  If <I>pad</I> has just one
              distance, both the left and right sides are padded evenly.   The
              default is 4.

       <B>-pady</B> <I>pad</I>
              Sets the padding above and below the text.  <I>Pad</I> can be a list of
              one or two screen distances.  If <I>pad</I> has two elements, the  area
              above  the  text  is  padded  by the first distance and the area
              below by the second.  If <I>pad</I> is just one distance, both the  top
              and bottom areas are padded evenly.  The default is 4.

       <B>-rotate</B> <I>theta</I>
              Specifies  the number of degrees to rotate the text.  <I>Theta</I> is a

       <I>option</I>-<I>value</I> pairs may be used with the marker's <B>configure</B> command.

       The following options are specific to window markers:

       <B>-anchor</B> <I>anchor</I>
              <I>Anchor</I> tells how to position the widget relative  to  the  posi-
              tioning  point  for the widget. For example, if <I>anchor</I> is center
              then the widget is centered on the point; if <I>anchor</I>  is  n  then
              the  widget  will be displayed such that the top center point of
              the rectangular region occupied by the widget  will  be  at  the
              positioning point.  This option defaults to center.

       <B>-height</B> <I>pixels</I>
              Specifies  the height to assign to the marker's window.  If this
              option isn't specified, or if it is specified as  "",  then  the
              window  is given whatever height the widget requests internally.

       <B>-width</B> <I>pixels</I>
              Specifies the width to assign to the marker's window.   If  this
              option  isn't  specified,  or if it is specified as "", then the
              window is given whatever width the widget requests internally.

       <B>-window</B> <I>pathName</I>
              Specifies the widget to be managed by the graph.  <I>PathName</I>  must
              be a child of the <B>graph</B> widget.


</PRE>
<H2>GRAPH COMPONENT BINDINGS</H2><PRE>
       Specific  graph  components,  such  as  elements,  markers  and  legend
       entries, can have a command trigger when event  occurs  in  them,  much
       like  canvas  items in Tk's canvas widget.  Not all event sequences are
       valid.  The only binding events that may be specified are those related
       to  the  mouse and keyboard (such as <B>Enter</B>, <B>Leave</B>, <B>ButtonPress</B>, <B>Motion</B>,
       and <B>KeyPress</B>).

       Only one element or marker can be picked during an event.  This  means,
       that  if  the mouse is directly over both an element and a marker, only
       the uppermost component  is  selected.   This  isn't  true  for  legend
       entries.   Both  a legend entry and an element (or marker) binding com-
       mands will be invoked if both items are picked.

       It is possible for multiple bindings to match a particular event.  This
       could occur, for example, if one binding is associated with the element
       name and another is associated with one of the element's tags (see  the
       <B>-bindtags</B>  option).  When this occurs, all of the matching bindings are
       invoked.  A binding associated with the element name is invoked  first,
       followed  by  one binding for each of the element's bindtags.  If there
       are multiple matching bindings for a single tag,  then  only  the  most
       specific  binding  is  invoked.  A continue command in a binding script
       terminates that script, and a break command terminates that script  and
       skips  any  remaining  scripts for the event, just as for the bind com-
       mand.

       vectors are updated.

       From  Tcl,  create  the  vectors and configure the element to use them.
       vector X Y .g element configure line1 -xdata X -ydata  Y  To  set  data
       points  from  C,  you  pass  the  values as arrays of doubles using the
       <B>Blt_ResetVector</B> call.  The vector is reset with the new data and at the
       next  idle  point (when Tk re-enters its event loop), the graph will be
       redrawn automatically.  #include &lt;tcl.h&gt; #include &lt;blt.h&gt;

       register int i; Blt_Vector *xVec, *yVec; double x[50], y[50];

       /* Get the BLT vectors "X" and "Y"  (created  above  from  Tcl)  */  if
       ((Blt_GetVector(interp, "X", &amp;xVec) != TCL_OK) ||
           (Blt_GetVector(interp, "Y", &amp;yVec) != TCL_OK)) {
           return TCL_ERROR; }

       for (i = 0; i &lt; 50; i++) {
           x[i] = i * 0.02;
           y[i] = sin(x[i]); }

       /*  Put  the data into BLT vectors */ if ((Blt_ResetVector(xVec, x, 50,
       50, TCL_VOLATILE) != TCL_OK) ||
           (Blt_ResetVector(yVec, y, 50, 50, TCL_VOLATILE) != TCL_OK)) {
          return TCL_ERROR; } See the <B>vector</B> manual page for more details.


</PRE>
<H2>SPEED TIPS</H2><PRE>
       There may be cases where the graph needs to be  drawn  and  updated  as
       quickly  as possible.  If drawing speed becomes a big problem, here are
       a few tips to speed up displays.

       <B>o</B> Try to minimize the number of data points.  The more data points  the
         looked at, the more work the graph must do.

       <B>o</B> If your data is generated as floating point values, the time required
         to convert the data values to and from ASCII strings can be  signifi-
         cant,  especially when there any many data points.  You can avoid the
         redundant string-to-decimal conversions using the C API to  BLT  vec-
         tors.

       <B>o</B> Data  elements  without  symbols  are drawn faster than with symbols.
         Set the data element's <B>-symbol</B> option to none.  If you need  to  draw
         symbols, try using the simple symbols such as splus and scross.

       <B>o</B> Don't stipple or dash the element.  Solid lines are much faster.

       <B>o</B> If  you update data elements frequently, try turning off the widget's
         <B>-bufferelements</B> option.  When the graph is first displayed, it  draws
         data  elements  into an internal pixmap.  The pixmap acts as a cache,
         so that when the graph needs to be redrawn again, and the  data  ele-
         ments or coordinate axes haven't changed, the pixmap is simply copied
         to the screen.  This is especially useful when you are using  markers
         to  highlight  points  and regions on the graph.  But if the graph is



BLT                               BLT_VERSION                         graph(n)
</PRE>
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