NAME

       stripchart  -  2D strip chart for plotting x and y coordi­
       nate data.


SYNOPSIS

       stripchart pathName ?option value?...
_________________________________________________________________


DESCRIPTION

       The stripchart command creates a strip chart for  plotting
       two-dimensional  data  (x,y coordinates). It has many con­
       figurable components: coordinate axes,  elements,  legend,
       grid lines, cross hairs, etc.  They allow you to customize
       the look and feel of the strip chart.

       The stripchart is essentially the same as the  graph  wid­
       get.  It works almost exactly the very same way.

       The  use of a strip chart differs in that the X-axis typi­
       cally refers to time points.  Data  values  are  added  at
       intervals.   The  strip chart lets you automatically main­
       tain a view of the most  recent  time  points.   The  axis
       options  -shiftby  and  -autorange  control this.  You can
       specify different line styles for  data  points  (see  the
       -styles option).


INTRODUCTION

       The  stripchart  command creates a new window for plotting
       two-dimensional data (x,y coordinates).  Data  points  are
       plotted  in  a box displayed in the center of the new win­
       dow.  This is the plotting area.  The coordinate axes  are
       displayed  in  the  margins  around the plotting area.  By
       default, the legend is displayed in the right margin.  The
       title is displayed in top margin.

       A  strip  chart is composed of several components: coordi­
       nate axes, data elements, legend, grid, cross hairs, pens,
       postscript, and annotation markers.

       axis      The  stripchart  widget  can  display up to four
                 coordinate axes (two  X-coordinate  and  two  Y-
                 coordinate axes), but you can create and use 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 dis­
                 play the value of each major tick.

       crosshairs
                 Cross hairs are  used  to  finely  position  the
                 mouse  pointer  in  relation  to  the coordinate
                 axes. Two perpendicular lines are  drawn  across

                 location of the mouse pointer.

       element   An element represents a set of data points. Ele­
                 ments  can be plotted with a symbol at each data
                 point and  lines  connecting  the  points.   The
                 appearance  of  the element, such as its symbol,
                 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 widgets.

       pen       Pens  define  attributes  (both  symbol and line
                 style) for elements.  Data elements use pens  to
                 specify  how  they should be drawn.  A data ele­
                 ment may use many pens at once.  Here, the  par­
                 ticular  pen used for a data point is determined
                 from each element's weight vector (see the  ele­
                 ment's -weight and -style options).

       postscript
                 The  widget can generate encapsulated PostScript
                 output. This component has  several  options  to
                 configure how the PostScript is generated.


SYNTAX

              stripchart pathName ?option value?...

       The  stripchart  command creates a new window pathName and
       makes it into a stripchart widget.  At the time this  com­
       mand is invoked, there must not exist a window named path­
       Name,  but  pathName's  parent  must  exist.    Additional
       options may may be specified on the command line or in the
       option database to configure aspects of  the  strip  chart
       such  as its colors and font.  See the configure operation
       below for the exact details as to what  option  and  value
       pairs are valid.

       If  successful,  stripchart  returns  the path name of the
       widget.  It also creates a new Tcl  command  by  the  same
       name.   You can use this command to perform various opera­
       tions that query or modify the graph.   The  general  form


              pathName operation ?arg?...

       Both  operation  and  its  arguments  determine  the exact
       behavior of the command.  The operations available for the
       strip  chart  are  described  in the STRIPCHART OPERATIONS
       section.

       The command can also be used to access components  of  the
       strip chart.

              pathName component operation ?arg?...

       The  operation,  now  located after the name of the compo­
       nent, is the function to be performed on  that  component.
       Each  component has its own set of operations that manipu­
       late that component.  They  will  be  described  below  in
       their own sections.


EXAMPLE

       The stripchart command creates a new strip chart.

              # Create a new strip chart.  Plotting area is black.
              stripchart .s -plotbackground black

       A new Tcl command .s is also created.  This command can be
       used to query and modify the strip chart.  For example, to
       change  the title of the strip chart to "My Plot", you use
       the new command and the widget's configure operation.

              # Change the title.
              .s configure -title "My Plot"

       A strip chart has several components. To access a particu­
       lar  component  you use the component's name. For example,
       to add data elements, you use the new command and the ele­
       ment component.

              # Create a new element named "line1"
              .s 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  and  Y  coordinates are specified using
       lists of numbers.  Alternately, BLT vectors could be  used
       to hold the X-Y coordinates.

              # Create two vectors and add them to the strip chart.
              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 }


       The  advantage  of  using  vectors is that when you modify
       one, the graph is automatically redrawn to display the new
       values.

              # Change the X-Y coordinates of the first point.
              set xVec(0) 0.18
              set yVec(0) 25.18

       An  element named line1 is now created in .s.  By default,
       the element's label in the legend will be also line1.  You
       can  change  the  label, or specify no legend entry, again
       using the element's configure operation.

              # Don't display "line1" in the legend.
              .s element configure line1 -label ""

       You can configure more than just the element's label.   An
       element  has many attributes such as symbol type and size,
       dashed or solid lines, colors, line width, etc.

              .s element configure line1 -symbol square -color red \
                   -dashes { 2 4 2 } -linewidth 2 -pixels 2c

       Four coordinate axes are automatically created: x, x2,  y,
       and y2.  And by default, elements are mapped onto the axes
       x and y.  This can be changed with  the  -mapx  and  -mapy
       options.

              # Map "line1" on the alternate Y-axis "y2".
              .s element configure line1 -mapy y2

       Axes can be configured in many ways too.  For example, you
       change the scale of the Y-axis from linear  to  log  using
       the axis operation.

              # Y-axis is log scale.
              .s axis configure y -logscale yes

       Axis limits are reset by simply specifying new axis limits
       using the -min and -max configuration options.

              .s axis configure x -min 1.0 -max 1.5
              .s axis configure y -min 12.0 -max 55.15

       By default, the limits of the  axis  are  determined  from
       data values.  To reset back to the default limits, set the
       -min and -max options to the empty value.

              # Reset the axes to autoscale again.
              .s axis configure x -min {} -max {}
              .s axis configure y -min {} -max {}

       view  of  the most recent time points.  You can do this my
       setting the -autorange option.

              .s axis configure x -autorange 20.0

       If the time points are added in  X-coordinates  1.0  unit,
       only  the  last  twenty time points will be displayed.  As
       more data is added, the view will march along.

       Sometimes the rate of data is so high  that  changing  the
       axis  limits  with  each  additional  time  point  is pro­
       hibitive.  You can use the -shiftby option  to  define  an
       increment to shift the view when needed.

              .s axis configure x -shiftby 15.0

       When  the view is shifted, it will allow a range of 15 new
       time points to be added until the axis limits  are  recom­
       puted.

       By  default,  the legend is displayed in the right margin.
       You can change this  or  any  other  legend  configuration
       options using the legend component.

              # Configure the legend font, color, and relief
              .s legend configure -position left -relief raised \
                   -font fixed -fg blue

       To  prevent  the  legend from being displayed, turn on the
       -hide option.

              # Don't display the legend.
              .s legend configure -hide yes

       The stripchart widget has simple drawing procedures called
       markers.   They  can be used to highlight or annotate data
       in the strip chart. The types  of  markers  available  are
       bitmaps, images, polygons, lines, or windows.  Markers can
       be used, for example, to mark or brush points.  Here is  a
       text  marker  which  labels the data first point.  Markers
       are created using the marker operation.

              # Create a label for the first data point of "line1".
              .s 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 -anchor, -xoffset, and  -yoffset  options
       are  used  to  display the marker above and to the left of
       the data point, so that the actual data point  isn't  cov­
       ered  by  the marker.  By default, markers are drawn last,
       on top of data.  You  can  change  this  with  the  -under


              # Draw the label before elements are drawn.
              .s marker configure first_marker -under yes

       You can add cross hairs or grid lines using the crosshairs
       and grid operations.

              # Display both cross hairs and grid lines.
              .s crosshairs configure -hide no -color red
              .s grid configure -hide no -dashes { 2 2 }

       Finally, to get hardcopy  of  the  strip  chart,  use  the
       postscript operation.

              # Print the strip chart into file "file.ps"
              .s postscript output file.ps -maxpect yes -decorations no

       This  generates a file file.ps containing the encapsulated
       PostScript of the strip chart.  The option  -maxpect  says
       to  scale  the  plot to the size of the page.  Turning off
       the -decorations option indicates that no borders or color
       backgrounds  should  be  displayed (i.e. the background of
       the margins, legend, and plotting area will be white).


STRIPCHART OPERATIONS

       pathName axis operation ?arg?...
              See the AXIS COMPONENTS section.

       pathName bar elemName ?option value?...
              Creates a new barchart element elemName.   It's  an
              error  if  an element elemName already exists.  See
              the manual for  barchart  for  details  about  what
              option and value pairs are valid.

       pathName cget option
              Returns the current value of the stripchart config­
              uration option given by option.  Option may be  any
              option described below for the configure operation.

       pathName configure ?option value?...
              Queries or modifies the  configuration  options  of
              the strip chart.  If option isn't specified, a list
              describing all of the current options for  pathName
              is  returned.   If  option  is  specified,  but not
              value, then a list describing option  is  returned.
              If  one  or  more option and value pairs are speci­
              fied, then for each  pair,  the  stripchart  option
              option  is set to value.  The following options are
              valid for the stripchart.

              -background color
                     Sets the background color. This includes the
                     margins  and  legend,  but  not the plotting


              -borderwidth pixels
                     Sets the width of the 3-D border around  the
                     outside  edge  of  the  widget.  The -relief
                     option determines if the  border  is  to  be
                     drawn.  The default is 2.

              -bottommargin pixels
                     Specifies  the  size of the margin below the
                     X-coordinate axis.  If pixels is 0, the size
                     of  the  margin  is  selected automatically.
                     The default is 0.

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

              -cursor cursor
                     Specifies the widget's cursor.  The  default
                     cursor is crosshair.

              -font fontName
                     Specifies  the  title  font.  The default is
                     *-Helvetica-Bold-R-Normal-*-18-180-*.

              -halo pixels
                     Specifies a  maximum  distance  to  consider
                     when  searching  for  the closest data point
                     (see the element's closest operation below).
                     Data  points  further  than  pixels away are
                     ignored.  The default is 0.5i.

              -height pixels
                     Specifies the requested  height  of  widget.
                     The default is 4i.

              -invertxy boolean
                     Indicates  whether  the placement X-axis and
                     Y-axis should be inverted.   If  boolean  is
                     true,  the  X  and  Y axes are swapped.  The
                     default is 0.

              -justify justify
                     Specifies how the title should be justified.
                     This  matters  only  when the title contains
                     more than one line of text. Justify must  be

                     ter.

              -leftmargin pixels
                     Sets the size of the margin  from  the  left
                     edge of the window to the Y-coordinate axis.
                     If pixels is 0, the size is calculated auto­
                     matically.  The default is 0.

              -plotbackground color
                     Specifies  the background color of the plot­
                     ting area.  The default is white.

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

              -plotpadx pad
                     Sets  the  amount  of padding to be added to
                     the left and right  sides  of  the  plotting
                     area.   Pad  can  be  a  list  of one or two
                     screen distances.  If pad 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 pad is just one dis­
                     tance, both the left  and  right  sides  are
                     padded evenly.  The default is 8.

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

              -plotrelief relief
                     Specifies  the  3-D  effect for the plotting
                     area.  Relief indicates how the interior  of
                     the  plotting area should appear relative to
                     rest of the strip chart; for example, raised
                     means  the  plot  should  appear to protrude
                     from the strip chart, relative to  the  sur­
                     face  of  the  strip  chart.  The default is
                     sunken.

              -relief relief
                     Specifies the 3-D  effect  for  the  widget.
                     Relief  indicates how the strip chart should
                     appear relative to widget it is packed into;

                     should appear to protrude.  The  default  is
                     flat.

              -rightmargin pixels
                     Sets  the  size  of margin from the plotting
                     area to the right edge of  the  window.   By
                     default,  the  legend  is  displayed in this
                     margin.  If pixels is  than  1,  the  margin
                     size is selected automatically.

              -takefocus focus
                     Provides  information  used  when moving the
                     focus from window  to  window  via  keyboard
                     traversal  (e.g.,  Tab  and  Shift-Tab).  If
                     focus is 0,  this  means  that  this  window
                     should  be  skipped entirely during keyboard
                     traversal.  1 means  that  the  this  window
                     should  always  receive the input focus.  An
                     empty value means that the traversal scripts
                     make  the  decision  whether to focus on the
                     window.  The default is "".

              -tile image
                     Specifies  a  tiled  background.   If  image
                     isn't  "",  the  background  is  tiled using
                     image.   Otherwise,  the  normal  background
                     color is drawn (see the -background option).
                     Image must be an image created using the  Tk
                     image command.  The default is "".

              -title text
                     Sets  the  title  to text. If text is "", no
                     title will be displayed.

              -topmargin pixels
                     Specifies the size of the margin  above  the
                     x2 axis.  If pixels is 0, the margin size is
                     calculated automatically.

              -width pixels
                     Specifies the requested width of the widget.
                     The default is 5i.

       pathName crosshairs operation ?arg?
              See the CROSSHAIRS COMPONENT section.

       pathName element operation ?arg?...
              See the ELEMENT COMPONENTS section.

       pathName extents item
              Returns  the size of a particular item in the strip
              chart.  Item must be either  leftmargin,  rightmar­
              gin,   topmargin,   bottommargin,   plotwidth,   or


       pathName grid operation ?arg?...
              See the GRID COMPONENT section.

       pathName invtransform winX winY
              Performs an inverse coordinate transformation, map­
              ping  window coordinates back to graph coordinates,
              using the standard X-axis and  Y-axis.   Returns  a
              list of containing the graph coordinates.

       pathName legend operation ?arg?...
              See the LEGEND COMPONENT section.

       pathName line elemName ?option value?...
              The operation is the same as element.

       pathName marker operation ?arg?...
              See the MARKER COMPONENTS section.

       pathName metafile ?fileName?
              This  operation is for Window platforms only.  Cre­
              ates a Windows enhanced metafile of the stripchart.
              If  present,  fileName  is the file name of the new
              metafile.  Otherwise, the metafile is automatically
              added to the clipboard.

       pathName postscript operation ?arg?...
              See the POSTSCRIPT COMPONENT section.

       pathName snap photoName
              Takes  a snapshot of the strip chart and stores the
              contents in the photo image  photoName.   PhotoName
              is  the  name of a Tk photo image that must already
              exist.

       pathName transform x y
              Performs a coordinate transformation, mapping graph
              coordinates  to window coordinates, using the stan­
              dard X-axis and Y-axis.  Returns a list  containing
              the X-Y screen coordinates.

       pathName xaxis operation ?arg?...

       pathName x2axis operation ?arg?...

       pathName yaxis operation ?arg?...

       pathName y2axis operation ?arg?...
              See the AXIS COMPONENTS section.


STRIPCHART COMPONENTS

       A  strip  chart is composed of several components: coordi­
       nate axes,  data  elements,  legend,  grid,  cross  hairs,

       of configuration options and operations, the  strip  chart
       is  partitioned, where each component has its own configu­
       ration options and operations  that  specifically  control
       that aspect or part of the strip chart.

   AXIS COMPONENTS
       Four   coordinate  axes  are  automatically  created:  two
       X-coordinate axes (x and x2) and two Y-coordinate axes (y,
       and  y2).  By default, the axis x is located in the bottom
       margin, y in the left margin, x2 in the top margin, and y2
       in the right margin.

       An  axis consists of the axis line, title, major and minor
       ticks, and tick labels.  Major ticks are drawn at  uniform
       intervals  along  the axis.  Each tick is labeled with its
       coordinate value.  Minor ticks are drawn at uniform inter­
       vals within major ticks.

       The  range  of  the  axis  controls what region of data is
       plotted.  Data points outside the minimum and maximum lim­
       its  of the axis are not plotted.  By default, the minimum
       and maximum limits are determined from the data,  but  you
       can reset either limit.

       You  can  create  and use several axes. To create an axis,
       invoke the axis component and its create operation.

              # Create a new axis called "temperature"
              .s axis create temperature

       You map data elements to an axis using the element's -mapy
       and  -mapx configuration options. They specify the coordi­
       nate axes an element is mapped onto.

              # Now map the temperature data to this axis.
              .s element create "temp" -xdata $x -ydata $tempData \
                  -mapy temperature

       While you can have many axes, only four axes can  be  dis­
       played simultaneously.  They are drawn in each of the mar­
       gins surrounding the plotting area.  The axes x and y  are
       drawn  in  the bottom and left margins. The axes x2 and y2
       are drawn in top and right margins.   Only  x  and  y  are
       shown  by  default.  Note that the axes can have different
       scales.

       To display a different axis, you invoke one of the follow­
       ing components: xaxis, yaxis, x2axis, and y2axis.  The use
       operation designates the axis to be drawn  in  the  corre­
       sponding  margin:  xaxis in the bottom, yaxis in the left,
       x2axis in the top, and y2axis in the right.

              # Display the axis temperature in the left 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 as you wish.  You can control  how  ticks
       are drawn, by changing the major tick interval or the num­
       ber of minor  ticks.   You  can  define  non-uniform  tick
       intervals, such as for time-series plots.

       pathName axis cget axisName option
              Returns  the  current  value of the option given by
              option for axisName.   Option  may  be  any  option
              described below for the axis configure operation.

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

              -autorange range
                     Sets the range of values  for  the  axis  to
                     range.   The  axis  limits are automatically
                     reset   to  display  the  most  recent  data
                     points  in this range.  If range is 0.0, the
                     range is determined from the limits  of  the
                     data.   If  -min or -max are specified, they
                     override this option.  The default is 0.0.

              -color color
                     Sets the color of the axis and tick  labels.
                     The default is black.

              -command prefix
                     Specifies  a  Tcl command to be invoked when
                     formatting the axis tick labels. Prefix 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 format­
                     ted tick label.  If "" is returned, no label
                     will  appear  next to the tick.  You can get
                     the standard tick labels  again  by  setting


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

              -descending boolean
                     Indicates  whether the values along the axis
                     are monotonically increasing or  decreasing.
                     If  boolean is true, the axis values will be
                     decreasing.  The default is 0.

              -hide boolean
                     Indicates whether the axis is displayed.

              -justify justify
                     Specifies how the axis title should be  jus­
                     tified.   This  matters  only  when the axis
                     title contains more than one line  of  text.
                     Justify must be left, right, or center.  The
                     default is center.

              -limits formatStr
                     Specifies a printf-like description to  for­
                     mat  the  minimum  and maximum limits of the
                     axis.   The  limits  are  displayed  at  the
                     top/bottom  or left/right sides of the plot­
                     ting area.  FormatStr is a list  of  one  or
                     two format descriptions.  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 displayed.  The
                     default is "".

              -linewidth pixels
                     Sets the width of the axis and  tick  lines.
                     The default is 1 pixel.

              -logscale boolean
                     Indicates  whether  the scale of the axis is
                     logarithmic or linear.  If boolean is  true,
                     the  axis is logarithmic.  The default scale
                     is linear.

              -loose boolean
                     Indicates whether the  limits  of  the  axis
                     should  fit  the data points tightly, at the
                     outermost data points, or  loosely,  at  the
                     outer tick intervals.  This is relevant only

                     lated.   If  boolean is true, the axis range
                     is "loose".  The default is 0.

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

              -max value
                     Sets the maximum  limit  of  axisName.   Any
                     data  point  greater  than value is not dis­
                     played.  If value is "", the  maximum  limit
                     is  calculated using the largest data value.
                     The default is "".

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

              -minorticks minorList
                     Specifies where to display minor axis ticks.
                     You  can  use  this  option to display minor
                     ticks at non-uniform intervals. MinorList 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
                     -majortick option is also set.  If minorList
                     is  "",  minor  ticks  will be automatically
                     computed. The default is "".

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

              -shiftby value
                     Specifies how much  to  automatically  shift
                     the  range  of  the axis.  When the new data
                     exceeds the current axis maximum, the  maxi­
                     mum  is  increased  in  increments of value.
                     You can use this option to prevent the  axis
                     limits  from  being  recomputed  at each new
                     time point. If value is 0.0, then  no  auto­
                     matic  shifting is done. The default is 0.0.

                     Indicates  whether  axis  ticks  should   be
                     drawn.  If boolean is true, ticks are drawn.
                     If false, only the axis line is  drawn.  The
                     default is 1.

              -stepsize value
                     Specifies  the  interval  between major axis
                     ticks.  If  value  isn't  a  valid  interval
                     (must  be  less  than  the  axis range), the
                     request is ignored  and  the  step  size  is
                     automatically calculated.

              -subdivisions number
                     Indicates  how  many minor axis ticks are to
                     be drawn.  For example, if  number  is  two,
                     only  one minor tick is drawn.  If number is
                     one, no  minor  ticks  are  displayed.   The
                     default is 2.

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

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

              -title text
                     Sets the title of the axis. If text  is  "",
                     no axis title will be displayed.

              -titlecolor color
                     Sets  the  color  of  the  axis  title.  The
                     default is black.

              -titlefont fontName
                     Specifies  the  font  for  axis  title.  The
                     default      is      *-Helvetica-Bold-R-Nor­
                     mal-*-14-140-*.

              Axis configuration options may be also  be  set  by
              the  option  command.   The resource class is Axis.
              The resource names are the names of the axes  (such
              as x or x2).

                     option add *Stripchart.Axis.Color  blue
                     option add *Stripchart.x.LogScale  true
                     option add *Stripchart.x2.LogScale false

              Creates  a  new axis by the name axisName.  No axis
              by the same name  can  already  exist.  Option  and
              value  are described in above in the axis configure
              operation.

       pathName axis delete ?axisName?...
              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 elements.

       pathName axis invtransform axisName value
              Performs the inverse transformation,  changing  the
              screen coordinate value to a graph coordinate, map­
              ping the value mapped  to  axisName.   Returns  the
              graph coordinate.

       pathName axis limits axisName
              Returns  a  list  of the minimum and maximum limits
              for axisName.  The order of the list is min max.

       pathName axis names ?pattern?...
              Returns a list of axes matching zero or  more  pat­
              terns.   If  no pattern argument is give, the names
              of all axes are returned.

       pathName axis transform axisName value
              Transforms the coordinate value to a screen coordi­
              nate  by  mapping  the it to axisName.  Returns the
              transformed screen coordinate.

       Only  four  axes  can  be  displayed  simultaneously.   By
       default,  they  are  x,  y, x2, and y2.  You can swap in a
       different axis with use operation of the special axis com­
       ponents: xaxis, x2axis, yaxis, and y2axis.

              .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 xaxis, x2axis, yaxis, and y2axis components operate on
       an axis location rather than a specific axis like the more
       general axis component does.  The xaxis component  manages
       the  X-axis  located  in  the bottom margin (whatever axis
       that happens to be).  Likewise, yaxis uses the  Y-axis  in
       the  left  margin,  x2axis  the top X-axis, and y2axis the
       right Y-axis.

       They implicitly control the axis that is  currently  using

       yaxis uses y, x2axis uses x2, and y2axis uses  y2.   These
       components  can  be  more  convenient  to  use than always
       determining what axes are current being displayed  by  the
       graph.

       The following operations are available for axes. They mir­
       ror exactly the operations of  the  axis  component.   The
       axis argument must be xaxis, x2axis, yaxis, or y2axis.

       pathName axis cget option

       pathName axis configure ?option value?...

       pathName axis invtransform value

       pathName axis limits

       pathName axis transform value

       pathName axis use ?axisName?
              Designates  the axis axisName is to be displayed at
              this location.  AxisName can not be already in  use
              at another location.  This command returns the name
              of the axis currently using this location.

   CROSSHAIRS COMPONENT
       Cross hairs consist of two intersecting lines (one  verti­
       cal  and one horizontal) drawn completely across the plot­
       ting area.  They are used to position the mouse  in  rela­
       tion 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 without redrawing the entire strip chart.

       The following operations are available for cross hairs:

       pathName crosshairs cget option
              Returns the current value of the cross  hairs  con­
              figuration  option  given by option.  Option may be
              any option described below for the cross hairs con­
              figure operation.

       pathName crosshairs configure ?option value?...
              Queries  or  modifies  the configuration options of
              the cross hairs.  If option isn't specified, a list
              describing  all  the  current options for the cross
              hairs is returned.  If option is specified, but not
              value,  then  a list describing option is returned.
              If one or more option and value  pairs  are  speci­
              fied,  then  for  each pair, the cross hairs option
              option is set to value.  The following options  are
              available for cross hairs.

                     Sets  the  color  of  the  cross hairs.  The
                     default is black.

              -dashes dashList
                     Sets the dash  style  of  the  cross  hairs.
                     DashList  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
                     dashList  is  "",  the  cross  hairs will be
                     solid lines.

              -hide boolean
                     Indicates whether cross hairs are drawn.  If
                     boolean  is true, cross hairs are not drawn.
                     The default is yes.

              -linewidth pixels
                     Set the width of the cross hair lines.   The
                     default is 1.

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

              Cross hairs configuration options may  be  also  be
              set  by  the option command.  The resource name and
              class are crosshairs and Crosshairs respectively.

                     option add *Stripchart.Crosshairs.LineWidth 2
                     option add *Stripchart.Crosshairs.Color     red

       pathName crosshairs off
              Turns of the cross hairs.

       pathName crosshairs on
              Turns on the display of the cross hairs.

       pathName crosshairs toggle
              Toggles the  current  state  of  the  cross  hairs,
              alternately  mapping and unmapping the cross hairs.

   ELEMENT COMPONENTS
       A data element represents a set of data.   It  contains  x
       and  y  vectors  containing  the  coordinates  of the data
       points.  Elements can be displayed 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.

       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.

       pathName element activate elemName ?index?...
              Specifies the data points of element elemName to be
              drawn using active foreground and  background  col­
              ors.  ElemName is the name of the element and index
              is a number representing  the  index  of  the  data
              point.  If  no  indices  are  present then all data
              points become active.

       pathName element cget elemName option
              Returns the current value of the element configura­
              tion  option  given  by  option.  Option may be any
              option described below for  the  element  configure
              operation.

       pathName  element  closest  x  y varName ?option value?...
              ?elem­ Name?...
              Finds  the data point closest to the window coordi­
              nates x and y in the element elemName.  ElemName is
              the  name  of  an element, that must not be hidden.
              If no elements are specified, then all visible ele­
              ments are searched.  It returns via the array vari­
              able varName the name of the closest  element,  the
              index  of  its closest point, and the graph coordi­
              nates of the point. Returns 0,  if  no  data  point
              within  the threshold distance can be found, other­
              wise 1 is  returned.   The  following  option-value
              pairs are available.

              -halo pixels
                     Specifies   a   threshold   distance   where
                     selected data points are ignored.  Pixels 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 stripchart's
                     -halo option.

              -interpolate boolean
                     Indicates that  both  the  data  points  and
                     interpolated  points  along the line segment
                     formed should be considered.  If boolean  is
                     true,  the  closest  line  segment  will  be
                     selected instead of the  closest  point.  If
                     this   option   isn't   specified,   boolean
                     defaults to 0.

       pathName element configure elemName ?option value?...
              Queries or modifies the configuration  options  for
              elements.    If  option  isn't  specified,  a  list

              returned.   If  option is specified, but not value,
              then  a  list  describing  the  option  option   is
              returned.   If  one  or more option and value pairs
              are specified, then  for  each  pair,  the  element
              option  option  is  set  to  value.   The following
              options are valid for elements.

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

              -color color
                     Sets the color of the traces connecting  the
                     data points.

              -dashes dashList
                     Sets  the  dash style of element line. Dash­
                     List 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 dash­
                     List is "", the lines will be solid.

              -data coordList
                     Specifies the X-Y coordinates of  the  data.
                     CoordList  is  a list of numeric expressions
                     representing the  X-Y  coordinate  pairs  of
                     each data point.

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

              -hide boolean
                     Indicates  whether the element is displayed.
                     The default is no.

              -label text
                     Sets the element's label in the legend.   If
                     text  is  "", the element will have no entry
                     in the legend.  The  default  label  is  the
                     element's name.

              -linewidth pixels
                     Sets  the  width  of  the  connecting  lines
                     between data points.  If  pixels  is  0,  no
                     connecting  lines will be drawn between sym­
                     bols.  The default is 0.

                     Selects the  X-axis  to  map  the  element's
                     X-coordinates  onto.  XAxis must be the name
                     of an axis.  The default is x.

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

              -offdash color
                     Sets the color of the  stripes  when  traces
                     are  dashed  (see  the  -dashes option).  If
                     color is "", then the "off" pixels will rep­
                     resent gaps instead of stripes.  If color is
                     defcolor, then the color will be the same as
                     the -color option.  The default is defcolor.

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

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

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

              -scalesymbols boolean
                     If boolean is true, the size of the  symbols
                     drawn for elemName 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  -pix­
                     els  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 boolean is false, the  element's
                     symbols  are  drawn  at the designated size,
                     regardless of axis scales.  The  default  is
                     0.

              -smooth smooth
                     Specifies  how  connecting line segments are
                     drawn between data points.   Smooth  can  be

                     If smooth is linear, a single  line  segment
                     is  drawn, connecting both data points. When
                     smooth is step, two line segments are drawn.
                     The first is a horizontal line segment which
                     steps the next x-coordinate.  The second  is
                     a  vertical line, moving to the next y-coor­
                     dinate.  Both natural and quadratic generate
                     multiple  segments  between data points.  If
                     natural, the segments are generated using  a
                     cubic  spline.   If  quadratic,  a quadratic
                     spline is used.  The default is linear.

              -styles styleList
                     Specifies what pen to  use  based  upon  the
                     range of weights given.  StyleList is a list
                     of style specifications. Each style specifi­
                     cation,  in  turn, is a list consisting of a
                     pen name, and optionally a minimum and maxi­
                     mum  range.   Data  points whose weight (see
                     the -weight option) falls in this range, are
                     drawn  with this pen.  If no range is speci­
                     fied it defaults to the number of the pen in
                     the list.

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

              -weights wVec
                     Specifies the weights of the individual data
                     points.   This, in conjunction with the list
                     pen styles (see the -styles option) controls
                     how data points are drawn.  WVec is the name
                     of a BLT vector or a list of numeric expres­
                     sions representing the weights for each data
                     point.

              -xdata xVec
                     Specifies the  x-coordinates  of  the  data.
                     XVec  is  the name of a BLT vector or a list
                     of numeric expressions.

              -ydata yVec
                     Specifies the  y-coordinates  of  the  data.
                     YVec  is  the name of a BLT vector or a list
                     of numeric expressions.

              the option command.  The resource class is Element.
              The resource name is the name of the element.

                     option add *Stripchart.Element.symbol line
                     option add *Stripchart.e1.symbol line

       pathName element create elemName ?option value?...
              Creates a new element elemName.  It's an  error  is
              an  element elemName already exists.  If additional
              arguments are present, they specify  options  valid
              for element configure operation.

       pathName element deactivate elemName ?elemName?...
              Deactivates  all  the  elements  matching  pattern.
              Elements whose names  match  any  of  the  patterns
              given are redrawn using their normal colors.

       pathName element delete ?elemName?...
              Deletes all the named elements.  The graph is auto­
              matically redrawn.

       pathName element exists elemName
              Returns 1 if an element elemName  currently  exists
              and 0 otherwise.

       pathName element names ?pattern?...
              Returns  the elements matching one or more pattern.
              If no pattern is given, the names of  all  elements
              is returned.

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

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

   GRID COMPONENT
       Grid lines extend from the major and minor ticks  of  each
       axis  horizontally or vertically across the plotting area.
       The following operations are available for grid lines.

       pathName grid cget option
              Returns the current value of the grid line configu­
              ration  option  given by option.  Option may be any

              ation.

       pathName grid configure ?option value?...
              Queries  or  modifies the configuration options for
              grid lines.  If  option  isn't  specified,  a  list
              describing  all  the current grid options for path­
              Name is returned.  If option is specified, but  not
              value,  then  a list describing option is returned.
              If one or more option and value  pairs  are  speci­
              fied,  then  for  each  pair,  the grid line option
              option is set to value.  The following options  are
              valid for grid lines.

              -color color
                     Sets  the  color  of  the  grid  lines.  The
                     default is black.

              -dashes dashList
                     Sets the dash style of the grid lines. Dash­
                     List  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  dash­
                     List is "", the grid will be solid lines.

              -hide boolean
                     Indicates  whether the grid should be drawn.
                     If boolean  is  true,  grid  lines  are  not
                     shown. The default is yes.

              -linewidth pixels
                     Sets  the  width of grid lines.  The default
                     width is 1.

              -mapx xAxis
                     Specifies the X-axis to display grid  lines.
                     XAxis  must  be  the  name  of an axis.  The
                     default is x.

              -mapy yAxis
                     Specifies the Y-axis to display grid  lines.
                     YAxis  must  be  the  name  of  an axis. The
                     default is y.

              -minor boolean
                     Indicates whether the grid lines  should  be
                     drawn  for minor ticks.  If boolean is true,
                     the lines will appear at minor  tick  inter­
                     vals.  The default is 1.

              Grid  configuration  options may also be set by the
              option command.  The resource name  and  class  are
              grid and Grid respectively.

                     option add *Stripchart.Grid.Color     black

       pathName grid off
              Turns off the display the grid lines.

       pathName grid on
              Turns on the display the grid lines.

       pathName grid toggle
              Toggles the display of the grid.

   LEGEND COMPONENT
       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 positioned  anywhere
       within the plotting area.

       The following operations are valid for the legend.

       pathName legend activate pattern...
              Selects legend entries to be drawn using the active
              legend colors and relief.  All entries  whose  ele­
              ment  names  match  pattern   are  selected.  To be
              selected, the element name must match only one pat­
              tern.

       pathName legend cget option
              Returns the current value of a legend configuration
              option.  Option may be any option  described  below
              in the legend configure operation.

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

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

              -activeborderwidth pixels
                     Sets the width of the 3-D border around  the
                     outside  edge  of the active legend entries.


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

              -activerelief relief
                     Specifies  the 3-D effect desired for active
                     legend  entries.   Relief  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
                     legend, relative to the surface of the  leg­
                     end.  The default is flat.

              -anchor anchor
                     Tells how to position the legend relative to
                     the positioning point for the legend.   This
                     is  dependent  on the value of the -position
                     option.  The default is center.

                      left or right
                                  The  anchor  describes  how  to
                                  position the legend vertically.

                      top or bottom
                                  The  anchor  describes  how  to
                                  position  the  legend  horizon­
                                  tally.

                      @x,y        The  anchor  specifies  how  to
                                  position the legend relative to
                                  the  positioning   point.   For
                                  example,  if  anchor  is center
                                  then the legend is centered  on
                                  the  point; if anchor is n then
                                  the legend will be  drawn  such
                                  that  the  top  center point of
                                  the rectangular region occupied
                                  by  the  legend  will be at the
                                  positioning point.

                      plotarea    The  anchor  specifies  how  to
                                  position the legend relative to
                                  the plotting area. For example,
                                  if  anchor  is  center then the
                                  legend is centered in the plot­
                                  ting area; if anchor is ne then
                                  the legend will be  drawn  such
                                  that  occupies  the upper right
                                  corner of the plotting area.

                     Sets the background color of the legend.  If
                     color  is  "", the legend background with be
                     transparent.

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

              -font fontName
                     FontName  specifies a font to use when draw­
                     ing the labels of each element into the leg­
                     end.  The default is *-Helvetica-Bold-R-Nor­
                     mal-*-12-120-*.

              -foreground color
                     Sets the foreground color of the text  drawn
                     for  the  element's  label.   The default is
                     black.

              -hide boolean
                     Indicates whether the legend should be  dis­
                     played.  If boolean is true, the legend will
                     not be draw.  The default is no.

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

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

              -padx pad
                     Sets the padding to the left and right exte­
                     riors  of  the legend.  Pad can be a list of
                     one or two screen distances.  If pad has two
                     elements,  the  left  side  of the legend is

                     side  by  the  second.   If pad has just one
                     distance, both the left and right sides  are
                     padded evenly.  The default is 4.

              -pady pad
                     Sets the padding above and below the legend.
                     Pad can be a list of one or two screen  dis­
                     tances.   If  pad has two elements, the area
                     above the legend is padded by the first dis­
                     tance  and the area below by the second.  If
                     pad is just one distance, both the  top  and
                     bottom areas are padded evenly.  The default
                     is 0.

              -position pos
                     Specifies where the  legend  is  drawn.  The
                     -anchor option also affects where the legend
                     is positioned.  If pos is left,  left,  top,
                     or bottom, the legend is drawn in the speci­
                     fied margin.  If pos is plotarea,  then  the
                     legend  is drawn inside the plotting area at
                     a particular anchor.  If pos is in the  form
                     "@x,y", where x and y are the window coordi­
                     nates, the legend is drawn in  the  plotting
                     area  at  the  specified  coordinates.   The
                     default is right.

              -raised boolean
                     Indicates whether the  legend  is  above  or
                     below  the data elements.  This matters only
                     if the legend is in the plotting  area.   If
                     boolean is true, the legend will be drawn on
                     top of any elements that may overlap it. The
                     default is no.

              -relief relief
                     Specifies  the  3-D  effect  for  the border
                     around the legend.  Relief specifies how the
                     interior  of  the legend should appear rela­
                     tive to the strip chart; for example, raised
                     means  the  legend should appear to protrude
                     from the strip chart, relative to  the  sur­
                     face  of  the  strip  chart.  The default is
                     sunken.

              Legend configuration options may also be set by the
              option  command.   The  resource name and class are
              legend and Legend respectively.

                     option add *Stripchart.legend.Foreground blue
                     option add *Stripchart.Legend.Relief     raised

              Selects legend entries to be drawn using the normal
              legend  colors  and relief.  All entries whose ele­
              ment names  match  pattern  are  selected.   To  be
              selected, the element name must match only one pat­
              tern.

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

   PEN COMPONENTS
       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
       -weight and -style 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 sim­
       ply reconfiguring this pen.

              .s pen configure "activeLine" -color green

       You can create and use any number of  pens.  To  create  a
       pen, invoke the pen component and its create operation.

              .s pen create myPen

       You  map pens to a data element using either the element's
       -pen or -activepen options.

              .s 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 -styles option).

              .s 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 element's default attributes.

       The following operations are available for pen components.

              Returns  the  current  value of the option given by
              option for  penName.   Option  may  be  any  option
              described below for the pen configure operation.

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

              -color color
                     Sets the color of the traces connecting  the
                     data points.

              -dashes dashList
                     Sets  the  dash style of element line. Dash­
                     List 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 dash­
                     List is "", the lines will be solid.

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

              -linewidth pixels
                     Sets  the  width  of  the  connecting  lines
                     between  data  points.   If  pixels is 0, no
                     connecting lines will be drawn between  sym­
                     bols.  The default is 0.

              -offdash color
                     Sets  the  color  of the stripes when traces
                     are dashed (see  the  -dashes  option).   If
                     color is "", then the "off" pixels will rep­
                     resent gaps instead of stripes.  If color is
                     defcolor, then the color will be the same as
                     the -color option.  The default is defcolor.

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

                     Sets the width of the outline bordering each
                     symbol.  If pixels is 0, no outline will  be
                     drawn. The default is 1.

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

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

              -type elemType
                     Specifies the type of element the pen is  to
                     be  used  with.   This option should only be
                     employed when creating the pen.  This is for
                     those  that  wish  to mix different types of
                     elements (bars and lines) on the same graph.
                     The default type is "line".

              Pen configuration options may be also be set by the
              option command.  The resource class  is  Pen.   The
              resource names are the names of the pens.

                     option add *Stripchart.Pen.Color  blue
                     option add *Stripchart.activeLine.color  green

       pathName pen create penName ?option value?...
              Creates  a  new pen by the name penName.  No pen by
              the same name can already exist. Option  and  value
              are  described in above in the pen configure opera­
              tion.

       pathName pen delete ?penName?...
              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 elements.

       pathName pen names ?pattern?...
              Returns a list of pens matching zero or  more  pat­
              terns.   If  no pattern argument is give, the names
              of all pens are returned.

   POSTSCRIPT COMPONENT
       The  strip  chart  can  generate  encapsulated  PostScript

       specify to control how the plot  is  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.

       pathName postscript cget option
              Returns the current value of the postscript  option
              given   by   option.   Option  may  be  any  option
              described below for the postscript configure opera­
              tion.

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

              -center boolean
                     Indicates  whether  the  plot should be cen­
                     tered on the PostScript page.  If boolean is
                     false,  the plot will be placed in the upper
                     left corner of the page.  The default is  1.

              -colormap varName
                     VarName  must  be the name of a global array
                     variable that specifies a color mapping from
                     the  X  color name to PostScript.  Each ele­
                     ment of varName must consist  of  PostScript
                     code  to  set a particular color value (e.g.
                     ``1.0 1.0  0.0  setrgbcolor'').   When  out­
                     putting color information in PostScript, the
                     array variable varName is checked to see  if
                     an  element of the name of the color exists.
                     If so, it uses the value of the  element  as
                     the PostScript command to set the color.  If
                     this option hasn't  been  specified,  or  if
                     there  isn't an entry in varName for a given
                     color, then it uses the red, green, and blue
                     intensities from the X color.

              -colormode mode
                     Specifies  how  to output color information.
                     Mode must be either color  (for  full  color
                     output),  gray  (convert all colors to their
                     gray-scale  equivalents)  or  mono  (convert

                     colors  to  white).   The  default  mode  is
                     color.

              -fontmap varName
                     VarName  must  be the name of a global array
                     variable that specifies a font mapping  from
                     the X font name to PostScript.  Each element
                     of varName must consist of a Tcl  list  with
                     one  or two elements, which are the name and
                     point size of a PostScript font.  When  out­
                     putting PostScript commands for a particular
                     font, the array variable varName is  checked
                     to  see  an  element  of  the specified font
                     exists.  If there is such an  element,  then
                     the  font information contained in that ele­
                     ment 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 Adobe (such as Times, Helvetica, Courier,
                     etc.).   If  all of this fails then the font
                     defaults to Helvetica-Bold.

              -decorations boolean
                     Indicates if PostScript commands to generate
                     color  backgrounds and 3-D borders should be
                     output.  If boolean is false, the background
                     will  be  white  and  no 3-D borders will be
                     generated. The default is 1.

              -height pixels
                     Sets the height of the plot.  This lets  you
                     plot  the stripchart with a height different
                     from the one displayed on  the  screen.   If
                     pixels  is  0, the height is the same as the
                     displayed height.  The default is 0.

              -landscape boolean
                     If  boolean  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  (``landscape''
                     orientation).  Defaults to 0.

              -maxpect boolean
                     Indicates  to  scale the the plot so that it
                     fills the PostScript page.  The aspect ratio
                     of  the  strip chart is still retained.  The


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

              -pady pad
                     Sets the vertical padding for  the  top  and
                     bottom  page  borders. The borders are exte­
                     rior to the plot.  Pad can be a list of  one
                     or  two  screen  distances.   If pad has two
                     elements, the top border is  padded  by  the
                     first  distance and the bottom border by the
                     second.  If pad has just one distance,  both
                     the   top  and  bottom  borders  are  padded
                     evenly.  The default is 1i.

              -paperheight pixels
                     Sets the  height  of  the  postscript  page.
                     This can be used to select between different
                     page sizes (letter, A4, etc).   The  default
                     height is 11.0i.

              -paperwidth pixels
                     Sets the width of the postscript page.  This
                     can be used to select between different page
                     sizes  (letter, A4, etc).  The default width
                     is 8.5i.

              -width pixels
                     Sets the width of the plot.  This  lets  you
                     plot  the strip chart with a width different
                     from the one drawn on the screen.  If pixels
                     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 option command.  The resource name and class
              are postscript and Postscript respectively.

                     option add *Stripchart.postscript.Decorations false
                     option add *Stripchart.Postscript.Landscape   true

       pathName postscript output ?fileName? ?option value?...
              Outputs a file of encapsulated  PostScript.   If  a
              fileName   argument   isn't  present,  the  command

              are  present,  they  set configuration options con­
              trolling how the PostScript is  generated.   Option
              and   value   can   be  anything  accepted  by  the
              postscript configure operation above.

   MARKER COMPONENTS
       Markers are simple drawing procedures used to annotate  or
       highlight  areas of the strip chart.  Markers have various
       types: text strings,  bitmaps,  images,  connected  lines,
       windows,  or polygons.  They can be associated with a par­
       ticular 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
       -under option.

       Markers, in contrast to elements, don't affect the scaling
       of  the coordinate axes.  They can also have elastic coor­
       dinates (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.

       pathName marker after markerId ?afterId?
              Changes the order of the markers, drawing the first
              marker  after  the  second.   If  no second afterId
              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.

       pathName marker before markerId ?beforeId?
              Changes the order of the markers, drawing the first
              marker before the second.  If  no  second  beforeId
              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.

       pathName marker cget option
              Returns  the current value of the marker configura­
              tion option given by option.   Option  may  be  any
              option  described below in the configure operation.

       pathName marker configure markerId ?option value?...
              Queries or modifies the configuration  options  for
              markers.    If   option  isn't  specified,  a  list
              describing the  current  options  for  markerId  is
              returned.   If  option is specified, but not value,

              or  more option and value pairs are specified, then
              for each pair, the marker option option is  set  to
              value.

              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.

              -coords coordList
                     Specifies the  coordinates  of  the  marker.
                     CoordList  is  a  list of graph coordinates.
                     The number of coordinates required is depen­
                     dent  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
                     coordList is "", the marker will not be dis­
                     played.  The default is "".

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

              -hide boolean
                     Indicates whether the marker  is  drawn.  If
                     boolean  is  true,  the marker is not drawn.
                     The default is no.

              -mapx xAxis
                     Specifies the X-axis  to  map  the  marker's
                     X-coordinates  onto.  XAxis must the name of
                     an axis.  The default is x.

              -mapy yAxis
                     Specifies the Y-axis  to  map  the  marker's
                     Y-coordinates  onto.  YAxis must the name of
                     an axis.  The default is y.

              -name markerId
                     Changes the identifier for the marker.   The
                     identifier  markerId can not already be used
                     by another marker.   If  this  option  isn't
                     specified,  the  marker's  name  is uniquely
                     generated.

              -under boolean
                     Indicates  whether  the  marker   is   drawn

                     true, the marker is be drawn underneath  the
                     data  element symbols and lines.  Otherwise,
                     the marker is drawn on top of  the  element.
                     The default is 0.

              -xoffset pixels
                     Specifies  a  screen  distance to offset the
                     marker  horizontally.   Pixels  is  a  valid
                     screen  distance,  such  as  2 or 1.2i.  The
                     default is 0.

              -yoffset pixels
                     Specifies a screen distance  to  offset  the
                     markers   vertically.   Pixels  is  a  valid
                     screen distance, such as  2  or  1.2i.   The
                     default is 0.

              Marker configuration options may also be set by the
              option  command.   The  resource  class  is  either
              BitmapMarker,   ImageMarker,  LineMarker,  Polygon­
              Marker, TextMarker, or WindowMarker,  depending  on
              the  type of marker.  The resource name is the name
              of the marker.

                     option add *Stripchart.TextMarker.Foreground white
                     option add *Stripchart.BitmapMarker.Foreground white
                     option add *Stripchart.m1.Background     blue

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

       pathName marker delete ?name?...
              Removes  one of more markers.  The graph will auto­
              matically be redrawn without the marker..

       pathName marker exists markerId
              Returns 1 if the marker markerId exists and 0  oth­
              erwise.

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

              Returns  the  type of the marker given by markerId,
              such as line or text.  If markerId is not a valid a
              marker identifier, "" is returned.

   BITMAP MARKERS
       A bitmap marker displays a bitmap.  The size of the bitmap
       is controlled by the number of coordinates specified.   If
       two coordinates, they specify the position of the top-left
       corner of the bitmap.  The bitmap retains its normal width
       and  height.   If  four  coordinates, the first and second
       pairs of coordinates represent the corners of the  bitmap.
       The  bitmap  will  be stretched or reduced as necessary to
       fit into the bounding rectangle.

       Bitmap markers are created with the marker's create opera­
       tion in the form:

              pathName marker create bitmap ?option value?...

       There may be many option-value pairs, each sets a configu­
       ration options for the marker.   These  same  option-value
       pairs may be used with the marker's configure operation.

       The following options are specific to bitmap markers:

       -background color
              Sets  the background color of the bitmap.  If color
              is "", the background color  will  be  transparent.
              The default background color is white.

       -bitmap bitmap
              Specifies the bitmap to be displayed.  If bitmap is
              "", the marker will not be displayed.  The  default
              is "".

       -foreground color
              Sets  the  foreground  color  of  the  bitmap.  The
              default foreground color is black.

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

       -rotate theta
              Sets  the  rotation of the bitmap.  Theta is a real
              number  representing  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.

       A  image marker displays an image.  Image markers are cre­
       ated with the marker's create operation in the form:

              pathName marker create image ?option value?...

       There may be many option-value pairs, each sets a configu­
       ration  option  for  the  marker.  These same option-value
       pairs may be used with the marker's configure operation.

       The following options are specific to image markers:

       -anchor anchor
              Anchor tells how to position the image relative  to
              the  positioning  point for the image. For example,
              if anchor is center then the image is  centered  on
              the  point;   if anchor is n then the image will be
              drawn such that the top center point of the rectan­
              gular  region  occupied by the image will be at the
              positioning point.  This option defaults to center.

       -image image
              Specifies  the  image to be drawn.  If image is "",
              the marker will not be drawn.  The default is "".

   LINE MARKERS
       A line marker displays one or  more  connected  line  seg­
       ments.   Line  markers  are  created  with marker's create
       operation in the form:

              pathName marker create line ?option value?...

       There may be many option-value pairs, each sets a configu­
       ration  option  for  the  marker.  These same option-value
       pairs may be used with the marker's configure operation.

       The following options are specific to line markers:

       -background color
              Sets the background color of the line.  The  option
              is  affects  the  line color only when the -stipple
              option is set.  If this option isn't specified then
              it defaults to white.

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

       -foreground color
              Sets  the foreground color.  The default foreground
              color is black.

              Sets the width of the lines.  The default width  is
              0.

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

   POLYGON MARKERS
       A polygon marker displays a closed region described as two
       or more connected line segments.  It is assumed the  first
       and  last  points are connected.  Polygon markers are cre­
       ated using the marker create operation in the form:

              pathName marker create polygon ?option value?...

       There may be many option-value pairs, each sets a configu­
       ration  option  for  the  marker.  These same option-value
       pairs may be used with the  marker  configure  command  to
       change  the marker's configuration.  The following options
       are supported for polygon markers:

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

       -fill color
              Sets  the  fill  color of the polygon.  If color is
              "", then the interior of the polygon  is  transpar­
              ent.  The default is white.

       -linewidth pixels
              Sets  the  width  of the outline of the polygon. If
              pixels is zero, no outline is drawn. The default is
              0.

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

       -stipple bitmap
              Specifies that the polygon should be drawn  with  a
              stippled  pattern rather than a solid color. Bitmap
              specifies a bitmap to use as the  stipple  pattern.
              If  bitmap is "", then the polygon is filled with a

              default is "".

   TEXT MARKERS
       A  text  marker  displays a string of characters on one or
       more lines of text.  Embedded newlines cause line  breaks.
       They  may  be used to annotate regions of the strip chart.
       Text markers are created with the create operation in  the
       form:

              pathName marker create text ?option value?...

       There may be many option-value pairs, each sets a configu­
       ration  option  for   the   text   marker.    These   same
       option-value pairs may be used with the marker's configure
       operation.

       The following options are specific to text markers:

       -anchor anchor
              Anchor tells how to position the text  relative  to
              the positioning point for the text. For example, if
              anchor is center then the text is centered  on  the
              point;  if  anchor 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 posi­
              tioning point.  This default is center.

       -background color
              Sets the background color of the text  string.   If
              color  is  "",  the background will be transparent.
              The default is white.

       -font fontName
              Specifies the font of the  text.   The  default  is
              *-Helvetica-Bold-R-Normal-*-120-*.

       -foreground color
              Sets the foreground color of the text.  The default
              is black.

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

       -padx pad
              Sets the padding to the left and right exteriors of
              the text.  Pad can be a list of one or  two  screen
              distances.   If pad has two elements, the left side
              of the text is padded by the first distance and the
              right side by the second.  If pad has just one dis­
              tance, both the left and  right  sides  are  padded


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

       -rotate theta
              Specifies the number of degrees to rotate the text.
              Theta is a real number representing  the  angle  of
              rotation.   The  marker  is first rotated along its
              center and is then drawn according  to  its  anchor
              position. The default is 0.0.

       -text text
              Specifies  the  text  of the marker.  The exact way
              the text is displayed  may  be  affected  by  other
              options such as -anchor or -rotate.

   WINDOW MARKERS
       A  window  marker  displays  a widget at a given position.
       Window markers are created with the marker's create opera­
       tion in the form:

              pathName marker create window ?option value?...

       There may be many option-value pairs, each sets a configu­
       ration option for the  marker.   These  same  option-value
       pairs may be used with the marker's configure command.

       The following options are specific to window markers:

       -anchor anchor
              Anchor tells how to position the widget relative to
              the positioning point for the widget. For  example,
              if  anchor is center then the widget is centered on
              the point; if anchor 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.

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

       -width pixels
              Specifies  the  width  to  assign  to  the marker's

              is  specified as "", then the window is given what­
              ever width the widget requests internally.

       -window pathName
              Specifies the widget to be managed.  PathName  must
              be a child of the stripchart widget.


GRAPH COMPONENT BINDINGS

       Specific  stripchart 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 wid­
       get.  Not all event sequences are valid.  The only binding
       events  that  may  be  specified  are those related to the
       mouse and keyboard (such  as  Enter,  Leave,  ButtonPress,
       Motion, and KeyPress).

       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 commands
       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 -bindtags 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 bind­
       ings for a single tag, then only the most specific binding
       is invoked.  A continue command in a binding script termi­
       nates that script, and a  break  command  terminates  that
       script and skips any remaining scripts for the event, just
       as for the bind command.

       The -bindtagsoption for these components controls addition
       tag  names  which can be matched.  Implicitly elements and
       markers always have tags matching  their  names.   Setting
       the value of the -bindtags option doesn't change this.


C LANGUAGE API

       You  can  manipulate  data  elements  from the C language.
       There may be situations  where  it  is  too  expensive  to
       translate  the  data  values  from  ASCII strings.  Or you
       might want to read data in a special file format.

       Data can manipulated from the C language  using  BLT  vec­
       tors.  You specify the x and y data coordinates of an ele­
       ment as vectors and manipulate the  vector  from  C.   The
       strip  chart  will be redrawn automatically after the vec­
       tors are updated.

       use them.

              vector X Y
              .s element configure line1 -xdata X -ydata Y

       To  set  data points from C, you pass the values as arrays
       of doubles using the Blt_ResetVector call.  The vector  is
       reset  with  the new data and at the next idle point (when
       Tk re-enters its event loop),  the  strip  chart  will  be
       redrawn automatically.

              #include <tcl.h>
              #include <blt.h>

              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", 50, &xVec) != TCL_OK) ||
                  (Blt_GetVector(interp, "Y", 50, &yVec) != TCL_OK)) {
                  return TCL_ERROR;
              }

              for (i = 0; i < 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 vector manual page for more details.


SPEED TIPS

       There may be cases where the strip chart 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.

       · Try to minimize the number of  data  points.   The  more
         data points the looked at, the more work the strip chart
         must do.

       · If your data is generated as floating point values,  the
         time  required  to  convert  the data values to and from
         ASCII strings can be significant, especially when  there
         any  many  data  points.   You  can  avoid the redundant
         string-to-decimal conversions using the  C  API  to  BLT
         vectors.

         symbols.  Set the data element's -symbol option to none.
         If  you  need to draw symbols, try using the simple sym­
         bols such as splus and scross.

       · Don't stipple or dash the element.  Solid lines are much
         faster.

       · If  you update data elements frequently, try turning off
         the widget's -bufferelements  option.   When  the  strip
         chart is first displayed, it draws data elements into an
         internal pixmap.  The pixmap acts as a  cache,  so  that
         when  the strip chart needs to be redrawn again, and the
         data elements or coordinate axes  haven't  changed,  the
         pixmap  is  simply  copied to the screen.  This is espe­
         cially useful when you are using  markers  to  highlight
         points and regions on the strip chart.  But if the strip
         chart is updated frequently, changing either the element
         data  or  coordinate  axes, the buffering becomes redun­
         dant.


LIMITATIONS

       Auto-scale routines do not use requested min/max limits as
       boundaries when the axis is logarithmically scaled.

       The  PostScript  output  generated  for polygons with more
       than 1500 points may exceed the limits  of  some  printers
       (See PostScript Language Reference Manual, page 568).  The
       work-around is to break the polygon into separate  pieces.


FUTURE INCOMPATIBILITY

       The  -mapped  options  are  obsoleted and will be removed.
       You can achieve the same results using  the  -hide  option
       instead.

              # Works for now.
              .s legend configure -mapped no

              # Instead use this.
              .s legend configure -hide yes


KEYWORDS

       stripchart, graph, widget


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