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<A HREF="#toc">Table of Contents</A><P>
 
<H2><A NAME="sect0" HREF="#toc0">Name</A></H2>
graph -  2D graph for plotting
X-Y coordinate data. 
<H2><A NAME="sect1" HREF="#toc1">Synopsis</A></H2>
<B>graph<I> <I>pathName </I></I></B>?<I>option value</I>?... 
<H2><A NAME="sect2" HREF="#toc2">Description</A></H2>
The
<B>graph</B> command creates a graph for plotting two-dimensional data (X-Y coordinates).
It has many configurable components: coordinate axes, elements, legend,
grid lines, cross hairs, etc.  They allow you to customize the look and
feel of the graph. 
<H2><A NAME="sect3" HREF="#toc3">Introduction</A></H2>
The <B>graph</B> command creates a new window for
plotting two-dimensional data (X-Y coordinates).  Data points are plotted
in a rectangular area displayed in the center of the new window.  This is
the <I>plotting area</I>.  The coordinate axes are drawn in the margins around
the plotting area.  By default, the legend is displayed in the right margin.
 The title is displayed in top margin. <P>
The <B>graph</B> widget is composed of several
components: coordinate axes, data elements, legend, grid, cross hairs,
pens, postscript, and annotation markers. 
<DL>

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

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

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

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

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

<DT>marker </DT>
<DD>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. </DD>

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

<DT>postscript
</DT>
<DD>The widget can generate encapsulated PostScript output. This component has
several options to configure how the PostScript is generated. </DD>
</DL>

<H2><A NAME="sect4" HREF="#toc4">Syntax</A></H2>
<BR>
<P>
<CODE><B>graph <I>pathName </I></B>?<I>option value</I>?...<BR>
</CODE>The <B>graph</B> command creates a new window <I>pathName</I> and makes it into a <B>graph</B>
widget.  At the time this command is invoked, there must not exist a window
named <I>pathName</I>, but <I>pathName</I>'s parent must exist.  Additional options may
be specified on the command line or in the option database to configure
aspects of the graph such as its colors and font.  See the <B>configure</B> operation
below for the exact details about what <I>option</I> and <I>value</I> pairs are valid.
<P>
If successful, <B>graph</B> returns the path name of the widget.  It also creates
a new Tcl command by the same name.  You can use this command to invoke
various operations that query or modify the graph. The general form is:
<BR>
<P>
<CODE><I>pathName <I>operation</I></I> ?<I>arg</I>?...<BR>
</CODE>Both <I>operation</I> and its arguments determine the exact behavior of the command.
 The operations available for the graph are described in  the  <FONT SIZE=-1><B>GRAPH OPERATIONS</B></FONT>

 section. <P>
The command can also be used to access components of the graph.
<BR>
<P>
<CODE><I>pathName component operation</I> ?<I>arg</I>?...<BR>
</CODE>The operation, now located after the name of the component, is the function
to be performed on that component. Each component has its own set of operations
that manipulate that component.  They will be described below in their own
sections. 
<H2><A NAME="sect5" HREF="#toc5">Example</A></H2>
The <B>graph</B> command creates a new graph.   <BR>
<CODE># Create a new graph.  Plotting area is black.<BR>
graph .g -plotbackground black<BR>
</CODE>A new Tcl command .g is also created.  This command can be used to query
and modify the graph.  For example, to change the title of the graph to
"My Plot", you use the new command and the graph's <B>configure</B> operation. <BR>
<CODE># Change the title.<BR>
.g configure -title "My Plot"<BR>
</CODE>A graph has several components. To access a particular component you use
the component's name. For example, to add data elements, you use the new
command and the <B>element</B> component. <BR>
<CODE># Create a new element named "line1"<BR>
.g element create line1 \<BR>
<tt> </tt>&nbsp;<tt> </tt>&nbsp;-xdata { 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 } \<BR>
<tt> </tt>&nbsp;<tt> </tt>&nbsp;-ydata { 26.18 50.46 72.85 93.31 111.86 128.47 143.14 <BR>
<tt> </tt>&nbsp;<tt> </tt>&nbsp;<tt> </tt>&nbsp;<tt> </tt>&nbsp;155.85 166.60 175.38 }<BR>
</CODE>The element's X-Y coordinates are specified using lists of numbers.  Alternately,
BLT vectors could be used to hold the X-Y coordinates. <BR>
<CODE># Create two vectors and add them to the graph.<BR>
vector xVec yVec<BR>
xVec set { 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 }<BR>
yVec set { 26.18 50.46 72.85 93.31 111.86 128.47 143.14 155.85 <BR>
<tt> </tt>&nbsp;<tt> </tt>&nbsp;166.60 175.38 }<BR>
.g element create line1 -xdata xVec -ydata yVec<BR>
</CODE>The advantage of using vectors is that when you modify one, the graph is
automatically redrawn to reflect the new values. <BR>
<CODE># Change the y coordinate of the first point.<BR>
set yVector(0) 25.18<BR>
</CODE>An element named e1 is now created in .b.  It  is automatically added
to the display list of elements.  You can use this list to control in what
order elements are displayed. To query or reset the element display list,
you use the element's  <B>show</B> operation. <BR>
<CODE># Get the current display list <BR>
set elemList [.b element show]<BR>
# Remove the first element so it won't be displayed.<BR>
.b element show [lrange $elemList 0 end]<BR>
</CODE>The element will be displayed by as many bars as there are data points
(in this case there are ten).  The bars will be drawn centered at the x-coordinate
of the data point.  All the bars will have the same attributes (colors,
stipple, etc).  The width of each bar is by default one unit.  You can change
this with using the <B>-barwidth</B> option. <BR>
<CODE># Change the X-Y coordinates of the first point.<BR>
set xVec(0) 0.18<BR>
set yVec(0) 25.18<BR>
</CODE>An element named line1 is now created in .g.  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 <B>configure</B> operation. <BR>
<CODE># Don't display "line1" in the legend.<BR>
.g element configure line1 -label ""<BR>
</CODE>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. <BR>
<CODE>.g element configure line1 -symbol square -color red \<BR>
<tt> </tt>&nbsp;<tt> </tt>&nbsp;-dashes { 2 4 2 } -linewidth 2 -pixels 2c<BR>
</CODE>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 <B>-mapx</B> and <B>-mapy</B> options. <BR>
<CODE># Map "line1" on the alternate Y-axis "y2".<BR>
.g element configure line1 -mapy y2<BR>
</CODE>Axes can be configured in many ways too.  For example, you change the scale
of the Y-axis from linear to log using the <B>axis</B> component. <BR>
<CODE># Y-axis is log scale.<BR>
.g axis configure y -logscale yes<BR>
</CODE>One important way axes are used is to zoom in on a particular data region.
 Zooming is done by simply specifying new axis limits using the <B>-min</B> and
<B>-max</B> configuration options. <BR>
<CODE>.g axis configure x -min 1.0 -max 1.5<BR>
.g axis configure y -min 12.0 -max 55.15<BR>
</CODE>To zoom interactively, you link the <B>axis configure</B> operations with some
user interaction (such as pressing the mouse button), using the <B>bind</B> command.
 To convert between screen and graph coordinates, use the <B>invtransform</B>
operation. <BR>
<CODE># Click the button to set a new minimum <BR>
bind .g &lt;ButtonPress-1&gt; { <BR>
    %W axis configure x -min [%W axis invtransform x %x]<BR>
    %W axis configure x -min [%W axis invtransform x %y]<BR>
}<BR>
</CODE>By default, the limits of the axis are determined from data values. To reset
back to the default limits, set the <B>-min</B> and <B>-max</B> options to the empty value.
<BR>
<CODE># Reset the axes to autoscale again.<BR>
.g axis configure x -min {} -max {}<BR>
.g axis configure y -min {} -max {}<BR>
</CODE>By default, the legend is drawn in the right margin.  You can change this
or any legend configuration options using the <B>legend</B> component. <BR>
<CODE># Configure the legend font, color, and relief<BR>
.g legend configure -position left -relief raised \<BR>
<tt> </tt>&nbsp;<tt> </tt>&nbsp;-font fixed -fg blue<BR>
</CODE>To prevent the legend from being displayed, turn on the <B>-hide</B> option. <BR>
<CODE># Don't display the legend.<BR>
.g legend configure -hide yes<BR>
</CODE>The <B>graph</B> widget has simple drawing procedures called markers. They can
be used to highlight or annotate data in the graph. The types of markers
available are bitmaps, images, polygons, lines, or windows. Markers can
be used, for example, to mark or brush points.  In this example, is a text
marker that labels the data first point.  Markers are created using the
<B>marker</B> component. <BR>
<CODE># Create a label for the first data point of "line1".<BR>
.g marker create text -name first_marker -coords { 0.2 26.18 } \<BR>
<tt> </tt>&nbsp;<tt> </tt>&nbsp;-text "start" -anchor se -xoffset -10 -yoffset -10<BR>
</CODE>This creates a text marker named first_marker.  It will display the text
"start" near the coordinates of the first data point.  The <B>-anchor</B>, <B>-xoffset</B>,
and <B>-yoffset</B> options are used to display the marker above and to the left
of the data point, so that the data point isn't covered by the marker.  By
default, markers are drawn last, on top of data.  You can change this with
the <B>-under</B> option. <BR>
<CODE># Draw the label before elements are drawn.<BR>
.g marker configure first_marker -under yes<BR>
</CODE>You can add cross hairs or grid lines using the <B>crosshairs</B> and <B>grid</B> components.
<BR>
<CODE># Display both cross hairs and grid lines.<BR>
.g crosshairs configure -hide no -color red<BR>
.g grid configure -hide no -dashes { 2 2 }<BR>
# Set up a binding to reposition the crosshairs.<BR>
bind .g &lt;Motion&gt; {<BR>
    .g crosshairs configure -position @%x,%y<BR>
}<BR>
</CODE>The crosshairs are repositioned as the mouse pointer is moved in the graph.
 The pointer X-Y coordinates define the center of the crosshairs. <P>
Finally,
to get hardcopy of the graph, use the <B>postscript</B> component. <BR>
<CODE># Print the graph into file "file.ps"<BR>
.g postscript output file.ps -maxpect yes -decorations no<BR>
</CODE>This generates a file file.ps containing the encapsulated PostScript of
the graph.  The option <B>-maxpect</B> says to scale the plot to the size of the
page.  Turning off the <B>-decorations</B> option denotes that no borders or color
backgrounds should be drawn (i.e. the background of the margins, legend,
and plotting area will be white). 
<H2><A NAME="sect6" HREF="#toc6">Graph Operations</A></H2>

<DL>

<DT><I>pathName <B>axis <I>operation
</I></B></I>?<I>arg</I>?... </DT>
<DD>See the  <FONT SIZE=-1><B>AXIS COMPONENTS</B></FONT>
  section. </DD>

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

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

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

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

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

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

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

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

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

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

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

<DT><B>-height
<I>pixels</I></B> </DT>
<DD>Specifies the requested height of widget.  The default is 4i. </DD>

<DT><B>-invertxy
<I>boolean</I></B> </DT>
<DD>Indicates whether the placement X-axis and Y-axis should be inverted.
 If <I>boolean</I> is true, the X and Y axes are swapped.  The default is 0. </DD>

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

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

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

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

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

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

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

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

<DT><B>-rightmargin <I>pixels</I></B> </DT>
<DD>If non-zero, overrides the computed size of the margin
extending  from the plotting area to the right edge of the window. By default,
the legend is drawn in this margin.  If <I>pixels</I> is 0, the automatically
computed size is used.   The default is 0. </DD>

<DT><B>-takefocus</B> <I>focus</I>  </DT>
<DD>Provides information
used when moving the focus from window to window via keyboard traversal
(e.g., Tab and Shift-Tab).  If <I>focus</I> 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 "". </DD>

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

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

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

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

<DL>

<DT><I>pathName <B>crosshairs <I>operation </I></B></I>?<I>arg</I>? </DT>
<DD>See
the  <FONT SIZE=-1><B>CROSSHAIRS COMPONENT</B></FONT>
  section. </DD>

<DT><I>pathName <B>element <I>operation </I></B></I>?<I>arg</I>?... </DT>
<DD>See
the  <FONT SIZE=-1><B>ELEMENT COMPONENTS</B></FONT>
  section. </DD>

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

<DT><I>pathName <B>grid
<I>operation </I></B></I>?<I>arg</I>?... </DT>
<DD>See the  <FONT SIZE=-1><B>GRID COMPONENT</B></FONT>
  section. </DD>

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

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

<DT><I>pathName <B>legend <I>operation </I></B></I>?<I>arg</I>?... </DT>
<DD>See the
 <FONT SIZE=-1><B>LEGEND COMPONENT</B></FONT>
  section. </DD>

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

<DT><I>pathName <B>marker <I>operation </I></B></I>?<I>arg</I>?... </DT>
<DD>See the  <FONT SIZE=-1><B>MARKER COMPONENTS</B></FONT>

 section. </DD>

<DT><I>pathName <B>postscript <I>operation </I></B></I>?<I>arg</I>?... </DT>
<DD>See the  <FONT SIZE=-1><B>POSTSCRIPT COMPONENT</B></FONT>

 section. </DD>

<DT><I>pathName <B>snap </B></I>?<I>switches</I>? <I>outputName</I> </DT>
<DD>Takes a snapshot of the graph,
saving the output in <I>outputName</I>. The following switches are available. <blockquote></DD>

<DT><B>-format</B>
<I>format</I> </DT>
<DD>Specifies how the snapshot is output. <I>Format</I> may be one of  the following
listed below.  The default is photo.  <blockquote></DD>

<DT>photo </DT>
<DD>Saves a Tk photo image. <I>OutputName</I>
represents the name of a  Tk photo image that must already have been created.
  </DD>

<DT>wmf </DT>
<DD>Saves an Aldus Placeable Metafile.  <I>OutputName</I> represents the filename
where the metafile is written.  If <I>outputName</I> is CLIPBOARD, then output
is written directly to the Windows clipboard.  This format is available
only under Microsoft Windows. </DD>

<DT>emf </DT>
<DD>Saves an Enhanced Metafile. <I>OutputName</I>
represents the filename where the metafile is written.  If <I>outputName</I> is
CLIPBOARD, then output is written directly to the Windows clipboard. 
This format is available only under Microsoft Windows. </DD>
</DL>
</blockquote>

<DL>

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

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

<DL>

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

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

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

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

<DT><I>pathName <B>y2axis
<I>operation</I></B></I> ?<I>arg</I>?...  </DT>
<DD>See the  <FONT SIZE=-1><B>AXIS COMPONENTS</B></FONT>
  section. </DD>
</DL>

<H2><A NAME="sect7" HREF="#toc7">Graph Components</A></H2>
A graph
is composed of several components: coordinate axes, data elements, legend,
grid, cross hairs, postscript, and annotation markers. Instead of one big
set of configuration options and operations, the graph is partitioned,
where each component has its own configuration options and operations that
specifically control that aspect or part of the graph.  
<H3><A NAME="sect8" HREF="#toc8">Axis Components</A></H3>
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. <P>
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 intervals within major ticks.  
<P>
The range of the axis controls what region of data is plotted. Data points
outside the minimum and maximum limits of the axis are not plotted.  By
default, the minimum and maximum limits are determined from the data, but
you can reset either limit. <P>
You can have several axes. To create an axis,
invoke the axis component and its create operation. <BR>
<CODE># Create a new axis called "tempAxis"<BR>
.g axis create tempAxis<BR>
</CODE>You map data elements to an axis using the element's -mapy and -mapx configuration
options. They specify the coordinate axes an element is mapped onto. <BR>
<CODE># Now map the tempAxis data to this axis.<BR>
.g element create "e1" -xdata $x -ydata $y -mapy tempAxis<BR>
</CODE>Any number of axes can be displayed simultaneously. They are drawn in the
margins surrounding the plotting area.  The default axes x and y are
drawn in the bottom and left margins. The axes x2 and y2 are drawn in
top and right margins.  By default, only x and y are shown. Note that
the axes can have different scales. <P>
To display a different axis or more
than one axis, you invoke one of the following components: <B>xaxis</B>, <B>yaxis</B>,
<B>x2axis</B>, and <B>y2axis</B>.  Each component has a <B>use</B> operation that designates
the axis (or axes) to be drawn in that corresponding margin: <B>xaxis</B> in the
bottom, <B>yaxis</B> in the left, <B>x2axis</B> in the top, and <B>y2axis</B> in the right. <BR>
<CODE># Display the axis tempAxis in the left margin.<BR>
.g yaxis use tempAxis<BR>
</CODE>The <B>use</B> operation takes a list of axis names as its last argument.  This
is the list of axes to be drawn in this margin. <P>
You can configure axes in
many ways. The axis scale can be linear or logarithmic.  The values along
the axis can either monotonically increase or decrease.  If you need custom
tick labels, you can specify a Tcl procedure to format the label any way
you wish.  You can control how ticks are drawn, by changing the major tick
interval or the number of minor ticks.  You can define non-uniform tick intervals,
such as for time-series plots. <P>

<DL>

<DT><I>pathName <B>axis bind <I>tagName</I></B></I> ?<I>sequence</I>?  ?<I>command</I>?
 </DT>
<DD>Associates <I>command</I> with <I>tagName</I> such that whenever the event sequence
given by <I>sequence</I> occurs for an axis with this tag, <I>command</I> will be invoked.
 The syntax is similar to the  <B>bind</B> command except that it operates on
graph axes, rather  than widgets. See the <B>bind</B> manual entry for complete
details on <I>sequence</I> and the substitutions performed on  <I>command</I> before
invoking it.   <P>
If all arguments are specified then a new binding is created,
replacing  any existing binding for the same <I>sequence</I> and <I>tagName</I>. If the
first character of <I>command</I> is + then <I>command</I>  augments an existing binding
rather than replacing it.  If no <I>command</I> argument is provided then the command
currently associated with <I>tagName</I> and <I>sequence</I> (it's an error occurs  if
there's no such binding) is returned.  If both <I>command</I> and  <I>sequence</I> are
missing then a list of all the event sequences for  which bindings have
been defined for <I>tagName</I>.  </DD>

<DT><I>pathName <B>axis <B>cget <I>axisName <I>option</I></I></B></B></I> </DT>
<DD>Returns the
current value of the option given by <I>option</I> for <I>axisName</I>.  <I>Option</I> may be
any option described below for the axis <B>configure</B> operation. </DD>

<DT><I>pathName <B>axis
<B>configure <I>axisName </I></B></B></I>?<I>axisName</I>?... ?<I>option value</I>?... </DT>
<DD>Queries or modifies the configuration
options of <I>axisName</I>. Several axes can be changed.  If <I>option</I> isn't specified,
a list describing all the current options for <I>axisName</I> is returned.  If
<I>option</I> is specified, but not <I>value</I>, then a list describing <I>option</I> is returned.
 If one or more <I>option</I> and <I>value</I> pairs are specified, then for each pair,
the axis option <I>option</I> is set to <I>value</I>.  The following options are valid
for axes. <blockquote></DD>

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

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

<DT><B>-command <I>prefix</I></B> </DT>
<DD>Specifies a Tcl command to be invoked when formatting
the axis tick labels. <I>Prefix</I> is a string containing the name of a Tcl proc
and any extra arguments for the procedure.  This command is invoked for
each major tick on the axis.  Two additional arguments are passed to the
procedure: the pathname of the widget and the current the numeric value
of the tick.  The procedure returns the formatted tick label.  If "" is
returned, no label will appear next to the tick.  You can get the standard
tick labels again by setting <I>prefix</I> to "".  The default is "". <P>
Please
note that this procedure is invoked while the graph is redrawn. You may
query configuration options.  But do not them, because this can have unexpected
results. </DD>

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

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

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

<DT><B>-limits <I>formatStr</I></B>
</DT>
<DD>Specifies a printf-like description to format the minimum and maximum limits
of the axis.  The limits are displayed at the top/bottom or left/right sides
of the plotting area.  <I>FormatStr</I> is a list of one or two format 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
"". </DD>

<DT><B>-linewidth <I>pixels</I></B> </DT>
<DD>Sets the width of the axis and tick lines.  The default
is 1 pixel. </DD>

<DT><B>-logscale <I>boolean</I></B> </DT>
<DD>Indicates whether the scale of the axis is
logarithmic or linear.  If <I>boolean</I> is true, the axis is logarithmic.  The
default scale is linear. </DD>

<DT><B>-loose <I>boolean</I></B> </DT>
<DD>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. If the axis limit is set with the
-min or -max option, the axes are displayed tightly. If <I>boolean</I> is true, the
axis range is "loose". The default is 0. </DD>

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

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

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

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

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

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

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

<DT><B>-scrollmin <I>value</I></B>  </DT>
<DD>Sets
the minimum limit of axis scroll region.  If <I>value</I> is "", the minimum
limit is calculated using the smallest data value.  The default is "".
</DD>

<DT><B>-showticks <I>boolean</I></B> </DT>
<DD>Indicates whether axis ticks should be drawn. If <I>boolean</I>
is true, ticks are drawn.  If false, only the axis line is drawn. The default
is 1. </DD>

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

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

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

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

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

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

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

<DT><B>-titlefont <I>fontName</I></B>
 </DT>
<DD>Specifies the font for axis title. The default is *-Helvetica-Bold-R-Normal-*-14-140-*.
</DD>
</DL>
<P>
Axis configuration options may be also be set by the <B>option</B> command.  The
resource class is Axis.  The resource names are the names of the axes
(such as x or x2). <BR>
<CODE>option add *Graph.Axis.Color  blue<BR>
option add *Graph.x.LogScale  true<BR>
option add *Graph.x2.LogScale false<BR>
</blockquote>

<DL>

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

<DT><I>pathName <B>axis <B>delete
</B></B></I>?<I>axisName</I>?... </DT>
<DD>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. </DD>

<DT><I>pathName
<B>axis invtransform <I>axisName value</I></B></I> </DT>
<DD>Performs the inverse transformation, changing
the screen coordinate <I>value</I> to a graph coordinate, mapping the value mapped
to <I>axisName</I>.  Returns the graph coordinate. </DD>

<DT><I>pathName <B>axis limits <I>axisName</I></B></I>
</DT>
<DD>Returns a list of the minimum and maximum limits for <I>axisName</I>.  The order
of the list is min max. </DD>

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

<DT><I>pathName <B>axis transform <I>axisName value</I></B></I> </DT>
<DD>Transforms
the coordinate <I>value</I> to a screen coordinate by mapping the it to <I>axisName</I>.
 Returns the transformed screen coordinate. </DD>

<DT><I>pathName <B>axis view <I>axisName</I></B></I>
</DT>
<DD>Change the viewable area of this axis. Use as an argument to a scrollbar's
"<I>-command</I>". </DD>
</DL>
<P>
The default axes are x, y, x2, and y2. But you can display
more than four axes simultaneously.  You can also swap in a different axis
with <B>use</B> operation of the special axis components: <B>xaxis</B>, <B>x2axis</B>, <B>yaxis</B>,
and <B>y2axis</B>. <BR>
<CODE>.g create axis temp<BR>
.g create axis time<BR>
...<BR>
.g xaxis use temp<BR>
.g yaxis use time<BR>
</CODE>Only the axes specified for use are displayed on the screen. <P>
The <B>xaxis</B>,
<B>x2axis</B>, <B>yaxis</B>, and <B>y2axis</B> components operate on an axis location rather
than a specific axis like the more general <B>axis</B> component does.  They implicitly
control the axis that is currently using to that location.  By default,
<B>xaxis</B> uses the x axis, <B>yaxis</B> uses y, <B>x2axis</B> uses x2, and <B>y2axis</B> uses
y2.  When more than one axis is displayed in a margin, it represents the
first axis displayed. <P>
The following operations are available for axes. They
mirror exactly the operations of the <B>axis</B> component.  The <I>axis</I> argument
must be <B>xaxis</B>, <B>x2axis</B>, <B>yaxis</B>, or <B>y2axis</B>.  This feature is deprecated since
more than one axis can now be used a margin.  You should only use the <B>xaxis</B>,
<B>x2axis</B>, <B>yaxis</B>, and <B>y2axis</B> components with the <B>use</B> operation. For all other
operations, use the general <B>axis</B> component instead. 
<DL>

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

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

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

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

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

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

<H3><A NAME="sect9" HREF="#toc9">Crosshairs Component</A></H3>
Cross
hairs consist of two intersecting lines (one vertical and one horizontal)
drawn completely across the plotting area.  They are used to position the
mouse in relation to the coordinate axes.  Cross hairs differ from line
markers in that they are implemented using XOR drawing primitives. This
means that they can be quickly drawn and erased without redrawing the entire
graph.  Note that crosshair are enabled by calling <B>Blt_Crosshairs</B> and turned
off by calling <B>Blt_ResetCrosshairs</B>. Similarly call <B>Blt_ZoomStack</B> for zooming.
<P>
The following operations are available for cross hairs: 
<DL>

<DT><I>pathName <B>crosshairs
cget <I>option</I></B></I> </DT>
<DD>Returns the current value of the cross hairs configuration
option given by <I>option</I>.  <I>Option</I> may be any option described below for the
cross hairs <B>configure</B> operation. </DD>

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

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

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

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

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

<DT><B>-position <I>pos</I></B>  </DT>
<DD>Specifies the screen position where the cross hairs
intersect. <I>Pos</I> must be in the form "<I>@x,y</I>", where <I>x</I> and <I>y</I> are the window
coordinates of the intersection. </DD>
</DL>
<P>
Cross hairs configuration options may be
also be set by the <B>option</B> command.  The resource name and class are crosshairs
and Crosshairs respectively. <BR>
<CODE>option add *Graph.Crosshairs.LineWidth 2<BR>
option add *Graph.Crosshairs.Color     red<BR>
</blockquote>

<DL>

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

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

<DT><I>pathName <B>crosshairs toggle</B></I> 
</DT>
<DD>Toggles the current state of the cross hairs, alternately mapping and unmapping
the cross hairs. </DD>
</DL>

<H3><A NAME="sect10" HREF="#toc10">Element Components</A></H3>
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. <P>
When new data elements are created,
they are automatically added to a list of displayed elements.   The display
list controls what elements are drawn and in what order.   <P>
The following
operations are available for elements. 
<DL>

<DT><I>pathName <B>element activate <I>elemName
</I></B></I>?<I>index</I>?... </DT>
<DD>Specifies the data points of element <I>elemName</I> to be drawn using
active foreground and background colors.  <I>ElemName</I> is the name of the element
and <I>index</I> is a number representing the index of the data point. If no indices
are present then all data points become active. </DD>

<DT><I>pathName <B>element bind <I>tagName</I></B></I>
?<I>sequence</I>?  ?<I>command</I>?  </DT>
<DD>Associates <I>command</I> with <I>tagName</I> such that whenever
the event sequence given by <I>sequence</I> occurs for an element with this tag,
<I>command</I> will be invoked.  The syntax is similar to the  <B>bind</B> command except
that it operates on graph elements, rather  than widgets. See the <B>bind</B> manual
entry for complete details on <I>sequence</I> and the substitutions performed
on  <I>command</I> before invoking it.   <P>
If all arguments are specified then a
new binding is created, replacing  any existing binding for the same <I>sequence</I>
and <I>tagName</I>. If the first character of <I>command</I> is + then <I>command</I>  augments
an existing binding rather than replacing it.  If no <I>command</I> argument is
provided then the command currently associated with <I>tagName</I> and <I>sequence</I>
(it's an error occurs  if there's no such binding) is returned.  If both <I>command</I>
and  <I>sequence</I> are missing then a list of all the event sequences for  which
bindings have been defined for <I>tagName</I>.  </DD>

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

<DT><I>pathName <B>element closest <I>x y</I></B></I> <I>varName</I> ?<I>option value</I>?...
?<I>elemName</I>?... </DT>
<DD><P>
 Searches for the data point closest to the window coordinates
<I>x</I> and <I>y</I>.  By default, all elements are searched.  Hidden elements (see the
<B>-hide</B> option is false) are ignored.  You can limit the search by specifying
only the elements you want to be considered.  <I>ElemName</I> must be the name
of an element that is not be hidden. <I>VarName</I> is the name of a Tcl array
variable and will contain the search results: the name of the closest element,
the index of the closest data point, and the graph coordinates of the point.
Returns 0, if no data point within the threshold distance can be found,
otherwise 1 is returned.  The following <I>option</I>-<I>value</I> pairs are available.
<blockquote></DD>

<DT><B>-along <I>direction</I></B> </DT>
<DD>Search for the closest element using the following criteria:
<blockquote></DD>

<DT>x </DT>
<DD>Find closest element vertically from the given X-coordinate.  </DD>

<DT>y </DT>
<DD>Find
the closest element horizontally from the given Y-coordinate.  </DD>

<DT>both </DT>
<DD>Find
the closest element for the given point (using both the X and Y coordinates).
  </DD>
</DL>
</blockquote>

<DL>

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

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

<DT>no  </DT>
<DD>Search only for the closest data point. </DD>

<DT>yes </DT>
<DD>Search
includes projections that lie along the line segments connecting the data
points.   </DD>
</DL>
</blockquote>
</blockquote>

<DL>

<DT><I>pathName <B>element configure <I>elemName </I></B></I>?<I>elemName</I>... ?<I>option value</I>?... </DT>
<DD>Queries
or modifies the configuration options for elements.  Several elements can
be modified at the same time. If <I>option</I> isn't specified, a list describing
all the current options for <I>elemName</I> is returned.  If <I>option</I> is specified,
but not <I>value</I>, then a list describing the option <I>option</I> is returned.  If
one or more <I>option</I> and <I>value</I> pairs are specified, then for each pair, the
element option <I>option</I> is set to <I>value</I>.  The following options are valid
for elements. <blockquote></DD>

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

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

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

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

<DT><B>-data <I>coordList</I></B> </DT>
<DD>Specifies
the X-Y coordinates of the data.  <I>CoordList</I> is a list of numeric expressions
representing the X-Y coordinate pairs of each data point. </DD>

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

<DT><B>-hide <I>boolean</I></B> </DT>
<DD>Indicates
whether the element is displayed.   The default is no. </DD>

<DT><B>-label <I>text</I></B> </DT>
<DD>Sets
the element's label in the legend.  If <I>text</I> is "", the element will have
no entry in the legend. The default label is the element's name.  </DD>

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

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

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

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

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

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

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

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

<DT><B>-scalesymbols
<I>boolean</I></B>  </DT>
<DD>If <I>boolean</I> is true, the size of the symbols drawn for <I>elemName</I>
will change with scale of the X-axis and Y-axis. At the time this option is
set, the current ranges of the axes are saved as the normalized scales
(i.e scale factor is 1.0) and the element is drawn at its designated size
(see the <B>-pixels</B> option).  As the scale of the axes change, the symbol will
be scaled according to the smaller of the X-axis and Y-axis scales.  If <I>boolean</I>
is false, the element's symbols are drawn at the designated size, regardless
of axis scales.  The default is 0. </DD>

<DT><B>-smooth <I>smooth</I></B>  </DT>
<DD>Specifies how connecting
line segments are drawn between data points. <I>Smooth</I> can be either linear,
step, natural, or quadratic.  If <I>smooth</I> is linear, a single line
segment is drawn, connecting both data points. When <I>smooth</I> is step, two
line segments are drawn. The first is a horizontal line segment that steps
the next X-coordinate.  The second is a vertical line, moving to the next
Y-coordinate.  Both <I>natural</I> and <I>quadratic</I> generate multiple segments between
data points.  If <I>natural</I>, the segments are generated using a cubic spline.
 If <I>quadratic</I>, a quadratic spline is used.  The default is <I>linear</I>. </DD>

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

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

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

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

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

<DT><B>-ydata <I>yVec</I></B>  </DT>
<DD>Specifies the Y-coordinates of the data.  <I>YVec</I> is the name of
a BLT vector or a list of numeric expressions. </DD>
</DL>
<P>
Element configuration options
may also be set by the <B>option</B> command.  The resource class is Element.
The resource name is the name of the element. <BR>
<CODE>option add *Graph.Element.symbol line<BR>
option add *Graph.e1.symbol line<BR>
</blockquote>

<DL>

<DT></CODE><I>pathName <B>element create <I>elemName</I></B></I> ?<I>option value</I>?... </DT>
<DD>Creates a new element <I>elemName</I>.
 It's an error is an element <I>elemName</I> already exists.  If additional arguments
are present, they specify options valid for  the element <B>configure</B> operation.
</DD>

<DT><I>pathName <B>element deactivate <I>elemName</I></B></I> ?<I>elemName</I>?... </DT>
<DD>Deactivates all the elements
matching <I>pattern</I>. Elements whose names match any of the patterns given are
redrawn using their normal colors. </DD>

<DT><I>pathName <B>element delete</B></I> ?<I>elemName</I>?... </DT>
<DD>Deletes
all the named elements.  The graph is automatically redrawn. </DD>

<DT><I>pathName <B>element
exists <I>elemName</I></B></I> </DT>
<DD>Returns 1 if an element <I>elemName</I> currently exists and
0 otherwise. </DD>

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

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

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

<H3><A NAME="sect11" HREF="#toc11"></CODE>Grid Component</A></H3>
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. 
<DL>

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

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

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

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

<DT><B>-hide <I>boolean</I></B> </DT>
<DD>Indicates whether the grid should be drawn. If <I>boolean</I> is true,
grid lines are not shown. The default is yes. </DD>

<DT><B>-linewidth <I>pixels</I></B> </DT>
<DD>Sets the
width of grid lines.  The default width is 1. </DD>

<DT><B>-mapx <I>xAxis</I></B> </DT>
<DD>Specifies the
X-axis to display grid lines.  <I>XAxis</I> must be the name of an axis or ""
for no grid lines.   The default is "". </DD>

<DT><B>-mapy <I>yAxis</I></B> </DT>
<DD>Specifies the Y-axis
to display grid lines.  <I>YAxis</I> must be the name of an axis or "" for no
grid lines.  The default is y. </DD>

<DT><B>-minor <I>boolean</I></B> </DT>
<DD>Indicates whether the grid
lines should be drawn for minor ticks.  If <I>boolean</I> is true, the lines will
appear at minor tick intervals.  The default is 1. </DD>
</DL>
<P>
Grid configuration options
may also be set by the  <B>option</B> command.  The resource name and class are
grid and  Grid respectively.  <BR>
<CODE>option add *Graph.grid.LineWidth 2<BR>
option add *Graph.Grid.Color     black<BR>

<DL>

<DT></CODE><B>-raised <I>boolean</I></B> </DT>
<DD>Grid is to be raised or drawn over elements. </DD>
</DL>
</blockquote>

<DL>

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

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

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

<H3><A NAME="sect12" HREF="#toc12">Legend Component</A></H3>
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. <P>
The following operations
are valid for the legend. 
<DL>

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

<DT><I>pathName <B>legend bind <I>tagName</I></B></I> ?<I>sequence</I>?
 ?<I>command</I>?  </DT>
<DD>Associates <I>command</I> with <I>tagName</I> such that whenever the event
sequence given by <I>sequence</I> occurs for a legend entry with this tag, <I>command</I>
will be invoked.  Implicitly the element names in the entry are tags.  The
syntax is similar to the  <B>bind</B> command except that it operates on legend
entries, rather  than widgets. See the <B>bind</B> manual entry for complete details
on <I>sequence</I> and the substitutions performed on  <I>command</I> before invoking
it.   <P>
If all arguments are specified then a new binding is created, replacing
 any existing binding for the same <I>sequence</I> and <I>tagName</I>. If the first character
of <I>command</I> is + then <I>command</I>  augments an existing binding rather than
replacing it.  If no <I>command</I> argument is provided then the command currently
associated with <I>tagName</I> and <I>sequence</I> (it's an error occurs  if there's no
such binding) is returned.  If both <I>command</I> and  <I>sequence</I> are missing then
a list of all the event sequences for  which bindings have been defined
for <I>tagName</I>.  </DD>

<DT><I>pathName <B>legend cget <I>option</I></B></I> </DT>
<DD>Returns the current value of a
legend configuration option. <I>Option</I> may be any option described below in
the legend <B>configure</B> operation. </DD>

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

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

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

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

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

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

<DT>left or right </DT>
<DD>The anchor describes how to position
the legend vertically.   </DD>

<DT>top or bottom </DT>
<DD>The anchor describes how to position
the legend horizontally.   </DD>

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

<DT>plotarea </DT>
<DD>The
anchor specifies how to position the legend relative to the plotting area.
For example, if <I>anchor</I> is center then the legend is centered in the plotting
area; if <I>anchor</I> is ne then the legend will be drawn such that occupies
the upper right corner of the plotting area. </DD>
</DL>
</blockquote>

<DL>

<DT><B>-background <I>color</I></B> </DT>
<DD>Sets the background
color of the legend. If <I>color</I> is "", the legend background with be transparent.
</DD>

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

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

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

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

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

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

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

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

<DT><B>-pady <I>pad</I></B> </DT>
<DD>Sets the padding above and
below the legend.  <I>Pad</I> can be a list of one or two screen distances.  If
<I>pad</I> has two elements, the area above the legend is padded by the first
distance and the area below by the second.  If <I>pad</I> is just one distance,
both the top and bottom areas are padded evenly.  The default is 0. </DD>

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

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

<DT><B>-relief <I>relief</I></B> </DT>
<DD>Specifies the 3-D
effect for the border around the legend. <I>Relief</I> specifies how the interior
of the legend should appear relative to the graph; for example, raised
means the legend should appear to protrude from the graph, relative to
the surface of the graph.  The default is sunken. </DD>
</DL>
<P>
Legend configuration
options may also be set by the <B>option</B> command.  The resource name and class
are legend and Legend respectively. <BR>
<CODE>option add *Graph.legend.Foreground blue<BR>
option add *Graph.Legend.Relief     raised<BR>
</blockquote>

<DL>

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

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

<H3><A NAME="sect13" HREF="#toc13">Pen Components</A></H3>
Pens define
attributes (both symbol and line style) for elements. Pens mirror the configuration
options of data elements that pertain to how symbols and lines are drawn.
 Data elements use pens to determine how they are drawn.  A data element
may use several pens at once.  In this case, the pen used for a particular
data point is determined from each element's weight vector (see the element's
<B>-weight</B> and <B>-style</B> options). <P>
One pen, called activeLine, is automatically
created. It's used as the default active pen for elements. So you can change
the active attributes for all elements by simply reconfiguring this pen.
<BR>
<CODE>.g pen configure "activeLine" -color green<BR>
</CODE>You can create and use several pens. To create a pen, invoke the pen component
and its create operation. <BR>
<CODE>.g pen create myPen<BR>
</CODE>You map pens to a data element using either the element's  <B>-pen</B> or <B>-activepen</B>
options. <BR>
<CODE>.g element create "line1" -xdata $x -ydata $tempData \<BR>
    -pen myPen<BR>
</CODE>An element can use several pens at once. This is done by specifying the
name of the pen in the element's style list (see the <B>-styles</B> option). <BR>
<CODE>.g element configure "line1" -styles { myPen 2.0 3.0 }<BR>
</CODE>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. <P>
The following operations are available for pen components.
<P>

<DL>

<DT><I>pathName <B>pen <B>cget <I>penName <I>option</I></I></B></B></I> </DT>
<DD>Returns the current value of the option
given by <I>option</I> for <I>penName</I>.  <I>Option</I> may be any option described below for
the pen <B>configure</B> operation. </DD>

<DT><I>pathName <B>pen <B>configure <I>penName </I></B></B></I>?<I>penName</I>... ?<I>option
value</I>?... </DT>
<DD>Queries or modifies the configuration options of <I>penName</I>. Several
pens can be modified at once.  If <I>option</I> isn't specified, a list describing
the current options for <I>penName</I> is returned.  If <I>option</I> is specified, but
not <I>value</I>, then a list describing <I>option</I> is returned.  If one or more <I>option</I>
and <I>value</I> pairs are specified, then for each pair, the pen option <I>option</I>
is set to <I>value</I>.  The following options are valid for pens. <blockquote></DD>

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

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

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

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

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

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

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

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

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

<DT><B>-type <I>elemType</I></B>  </DT>
<DD>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". </DD>
</DL>
<P>
Pen configuration options may be also be set by the <B>option</B> command.
 The resource class is Pen.  The resource names are the names of the pens.
<BR>
<CODE>option add *Graph.Pen.Color  blue<BR>
option add *Graph.activeLine.color  green<BR>
</blockquote>

<DL>

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

<DT><I>pathName <B>pen <B>delete
</B></B></I>?<I>penName</I>?... </DT>
<DD>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. </DD>

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

<H3><A NAME="sect14" HREF="#toc14">PostScript
Component</A></H3>
The graph can generate encapsulated PostScript output.  There are
several configuration options you can specify to control how the plot will
be generated.  You can change the page dimensions and borders.  The plot
itself can be scaled, centered, or rotated to landscape.  The PostScript
output can be written directly to a file or returned through the interpreter.
<P>
The following postscript operations are available. 
<DL>

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

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

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

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

<DT><B>-colormode <I>mode</I></B> </DT>
<DD>Specifies how to output color information.
 <I>Mode</I> must be either color (for full color output), gray (convert all
colors to their gray-scale equivalents) or mono (convert foreground colors
to black and background colors to white).  The default mode is color. 
</DD>

<DT><B>-fontmap <I>varName</I></B> </DT>
<DD><I>VarName</I> must be the name of a global array variable that
specifies a font mapping from the X font name to PostScript.  Each element
of <I>varName</I> must consist of a Tcl list with one or two elements; the name
and point size of a PostScript font. When outputting PostScript commands
for a particular font, the array variable <I>varName</I> is checked to see if
an element by the  specified font exists.  If there is such an element,
then the font information contained in that element is used in the PostScript
output.  (If the point size is omitted from the list, the point size of
the X font is used).  Otherwise the X font is examined in an attempt to
guess what PostScript font to use.  This works only for fonts whose foundry
property is <I>Adobe</I> (such as Times, Helvetica, Courier, etc.).  If all of this
fails then the font defaults to Helvetica-Bold. </DD>

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

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

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

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

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

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

<DT><B>-paperheight <I>pixels</I></B> </DT>
<DD>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. </DD>

<DT><B>-paperwidth <I>pixels</I></B> </DT>
<DD>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. </DD>

<DT><B>-width <I>pixels</I></B> </DT>
<DD>Sets the width of the
plot.  This lets you generate a plot of a width different from that of the
widget.  If <I>pixels</I> is 0, the width is the same as the widget's width.  The
default is 0. </DD>
</DL>
<P>
Postscript configuration options may be also be set by the
<B>option</B> command.  The resource name and class are postscript and Postscript
respectively. <BR>
<CODE>option add *Graph.postscript.Decorations false<BR>
option add *Graph.Postscript.Landscape   true<BR>
</blockquote>

<DL>

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

<H3><A NAME="sect15" HREF="#toc15">Marker
Components</A></H3>
Markers are simple drawing procedures used to annotate or highlight
areas of the graph.  Markers have various types: text strings, bitmaps,
images, connected lines, windows, or polygons.  They can be associated with
a particular element, so that when the element is hidden or un-hidden, so
is the marker.  By default, markers are the last items drawn, so that data
elements will appear in behind them.  You can change this by configuring
the <B>-under</B> option. <P>
Markers, in contrast to elements, don't affect the scaling
of the coordinate axes.  They can also have <I>elastic</I> coordinates (specified
by -Inf and Inf respectively) that translate into the minimum or maximum
limit of the axis.  For example, you can place a marker so it always remains
in the lower left corner of the plotting area, by using the coordinates
-Inf,-Inf. <P>
The following operations are available for markers. 
<DL>

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

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

<DT><I>pathName
<B>marker bind <I>tagName</I></B></I> ?<I>sequence</I>?  ?<I>command</I>?  </DT>
<DD>Associates <I>command</I> with <I>tagName</I>
such that whenever the event sequence given by <I>sequence</I> occurs for a marker
with this tag, <I>command</I> will be invoked.  The syntax is similar to the  <B>bind</B>
command except that it operates on graph markers, rather  than widgets.
See the <B>bind</B> manual entry for complete details on <I>sequence</I> and the substitutions
performed on  <I>command</I> before invoking it.   <P>
If all arguments are specified
then a new binding is created, replacing  any existing binding for the
same <I>sequence</I> and <I>tagName</I>. If the first character of <I>command</I> is + then
<I>command</I>  augments an existing binding rather than replacing it.  If no <I>command</I>
argument is provided then the command currently associated with <I>tagName</I>
and <I>sequence</I> (it's an error occurs  if there's no such binding) is returned.
 If both <I>command</I> and  <I>sequence</I> are missing then a list of all the event
sequences for  which bindings have been defined for <I>tagName</I>.  </DD>

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

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

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

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

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

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

<DT><B>-mapx <I>xAxis</I></B>  </DT>
<DD>Specifies the X-axis to map the marker's X-coordinates onto. <I>XAxis</I>
must the name of an axis.  The default is x. </DD>

<DT><B>-mapy <I>yAxis</I></B> </DT>
<DD>Specifies the Y-axis
to map the marker's Y-coordinates onto. <I>YAxis</I> must the name of an axis.  The
default is y. </DD>

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

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

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

<DT><B>-yoffset <I>pixels</I></B> </DT>
<DD>Specifies a screen distance to offset the
markers vertically. <I>Pixels</I> is a valid screen distance, such as 2 or 1.2i.
The default is 0. </DD>
</DL>
<P>
Marker configuration options may also be set by the
<B>option</B> command. The resource class is either BitmapMarker,  ImageMarker,
 LineMarker, PolygonMarker, TextMarker, or WindowMarker, depending
on the type of marker.  The resource name is the name of the marker. <BR>
<CODE>option add *Graph.TextMarker.Foreground white<BR>
option add *Graph.BitmapMarker.Foreground white<BR>
option add *Graph.m1.Background     blue<BR>
</blockquote>

<DL>

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

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

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

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

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

<H3><A NAME="sect16" HREF="#toc16">Bitmap Markers</A></H3>
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. <P>
Bitmap markers are created with the
marker's <B>create</B> operation in the form: <BR>
<P>
<CODE><I>pathName <B>marker create bitmap </B></I>?<I>option value</I>?...<BR>
</CODE>There may be many <I>option</I>-<I>value</I> pairs, each  sets a configuration options
for the marker.  These same <I>option</I>-<I>value</I> pairs may be used with the marker's
<B>configure</B> operation. <P>
The following options are specific to bitmap markers:

<DL>

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

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

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

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

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

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

<DT><B>-rotate
<I>theta</I></B> </DT>
<DD>Sets the rotation of the bitmap.  <I>Theta</I> 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. </DD>
</DL>

<H3><A NAME="sect17" HREF="#toc17">Image
Markers</A></H3>
A image marker displays an image.  Image markers are created with
the marker's <B>create</B> operation in the form: <BR>
<P>
<CODE><I>pathName <B>marker create image </B></I>?<I>option value</I>?...<BR>
</CODE>There may be many <I>option</I>-<I>value</I> pairs, each sets a configuration option for
the marker.  These same <I>option</I>-<I>value</I> pairs may be used with the marker's <B>configure</B>
operation. <P>
The following options are specific to image markers: 
<DL>

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

<DT><B>-image <I>image</I></B>
</DT>
<DD>Specifies the image to be drawn. If <I>image</I> is "", the marker will not be
drawn.  The default is "". </DD>
</DL>

<H3><A NAME="sect18" HREF="#toc18">Line Markers</A></H3>
A line marker displays one or more
connected line segments. Line markers are created with marker's <B>create</B> operation
in the form: <BR>
<P>
<CODE><I>pathName <B>marker create line </B></I>?<I>option value</I>?...<BR>
</CODE>There may be many <I>option</I>-<I>value</I> pairs, each sets a configuration option for
the marker.  These same <I>option</I>-<I>value</I> pairs may be used with the marker's <B>configure</B>
operation. <P>
The following options are specific to line markers: 
<DL>

<DT><B>-dashes <I>dashList</I></B>
</DT>
<DD>Sets the dash style of the line. <I>DashList</I> 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 <I>dashList</I> is "", the marker
line will be solid. </DD>

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

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

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

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

<H3><A NAME="sect19" HREF="#toc19">Polygon Markers</A></H3>
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 created using the marker <B>create</B> operation in the form: <BR>
<P>
<CODE><I>pathName <B>marker create polygon </B></I>?<I>option value</I>?...<BR>
</CODE>There may be many <I>option</I>-<I>value</I> pairs, each sets a configuration option for
the marker.  These same <I>option</I>-<I>value</I> pairs may be used with the <B>marker configure</B>
command to change the marker's configuration. The following options are supported
for polygon markers: 
<DL>

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

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

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

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

<DT><B>-stipple <I>bitmap</I></B> </DT>
<DD>Specifies that the polygon should be
drawn with a stippled pattern rather than a solid color. <I>Bitmap</I> specifies
a bitmap to use as the stipple pattern.  If <I>bitmap</I> is "", then the polygon
is filled with a solid color (if the <B>-fill</B> option is set).  The default is
"". </DD>
</DL>

<H3><A NAME="sect20" HREF="#toc20">Text Markers</A></H3>
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 graph.  Text markers are created with the <B>create</B>
operation in the form: <BR>
<P>
<CODE><I>pathName <B>marker create text </B></I>?<I>option value</I>?...<BR>
</CODE>There may be many <I>option</I>-<I>value</I> pairs,  each sets a configuration option
for the text marker.   These same <I>option</I>-<I>value</I> pairs may be used with the
 marker's <B>configure</B> operation.   <P>
The following options are specific to text
markers: 
<DL>

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

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

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

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

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

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

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

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

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

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

<DT><B>-text <I>text</I></B> </DT>
<DD>Specifies the text of the marker.
 The exact way the text is displayed may be affected by other options such
as <B>-anchor</B> or <B>-rotate</B>. </DD>
</DL>

<H3><A NAME="sect21" HREF="#toc21">Window Markers</A></H3>
A window marker displays a widget at
a given position. Window markers are created with the marker's <B>create</B> operation
in the form: <BR>
<P>
<CODE><I>pathName <B>marker create window </B></I>?<I>option value</I>?...<BR>
</CODE>There may be many <I>option</I>-<I>value</I> pairs, each sets a configuration option for
the marker.  These same <I>option</I>-<I>value</I> pairs may be used with the marker's <B>configure</B>
command. <P>
The following options are specific to window markers: 
<DL>

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

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

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

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

<H2><A NAME="sect22" HREF="#toc22">Graph Component
Bindings</A></H2>
Specific graph components, such as elements, markers and legend
entries, can have a command trigger when event occurs in them, much like
canvas items in Tk's canvas widget.  Not all event sequences are valid.  The
only binding events that may be specified are those related to the mouse
and keyboard (such as <B>Enter</B>, <B>Leave</B>, <B>ButtonPress</B>, <B>Motion</B>, and <B>KeyPress</B>).
<P>
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. <P>
It is possible for multiple bindings to match a particular
event. This could occur, for example, if one binding is associated with
the element name and another is associated with one of the element's tags
(see the <B>-bindtags</B> option).  When this occurs, all of the  matching bindings
are invoked.  A binding associated with the element name is invoked first,
followed by one binding for each of the element's  bindtags.  If there are
multiple matching bindings for a single tag,  then only the most specific
binding is invoked.  A continue command  in a binding script terminates
that script, and a break command  terminates that script and skips any
remaining scripts for the event,  just as for the bind command. <P>
The <B>-bindtags</B>
option 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 <B>-bindtags</B> option doesn't change this. 
<H2><A NAME="sect23" HREF="#toc23">C Language
API</A></H2>
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. <P>
Data can manipulated
from the C language using BLT vectors. You specify the X-Y data coordinates
of an element as vectors and manipulate the vector from C.  The graph will
be redrawn automatically after the vectors are updated. <P>
From Tcl, create
the vectors and configure the element to use them. <BR>
<CODE>vector X Y<BR>
.g element configure line1 -xdata X -ydata Y<BR>
</CODE>To set data points from C, you pass the values as arrays of doubles using
the <B>Blt_ResetVector</B> call.  The vector is reset with the new data and at
the next idle point (when Tk re-enters its event loop), the graph will be
redrawn automatically. <BR>
<CODE>#include &lt;tcl.h&gt;<BR>
#include &lt;blt.h&gt;<BR>
<P>
register int i;<BR>
Blt_Vector *xVec, *yVec;<BR>
double x[50], y[50];<BR>
<P>
/* Get the BLT vectors "X" and "Y" (created above from Tcl) */<BR>
if ((Blt_GetVector(interp, "X", &amp;xVec) != TCL_OK) ||<BR>
    (Blt_GetVector(interp, "Y", &amp;yVec) != TCL_OK)) {<BR>
    return TCL_ERROR;<BR>
}<BR>
<P>
for (i = 0; i &lt; 50; i++) {<BR>
    x[i] = i * 0.02;<BR>
    y[i] = sin(x[i]);<BR>
}<tt> </tt>&nbsp;<tt> </tt>&nbsp;<BR>
<P>
/* Put the data into BLT vectors */<BR>
if ((Blt_ResetVector(xVec, x, 50, 50, TCL_VOLATILE) != TCL_OK) ||<BR>
    (Blt_ResetVector(yVec, y, 50, 50, TCL_VOLATILE) != TCL_OK)) {<BR>
   return TCL_ERROR;<BR>
}<BR>
</CODE>See the <B>vector</B> manual page for more details. 
<H2><A NAME="sect24" HREF="#toc24">Speed Tips</A></H2>
There may be cases
where the graph needs to be drawn and updated as quickly as possible.  If
drawing speed becomes a big problem, here are a few tips to speed up displays.

<UL>
<LI>Try to minimize the number of data points.  The more data points the looked
at, the more work the graph must do. </LI><LI>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. </LI><LI>Data elements without symbols are drawn faster than with
symbols. Set the data element's <B>-symbol</B> option to none.  If you need to draw
symbols, try using the simple symbols such as splus and scross. </LI><LI>Don't
stipple or dash the element.  Solid lines are much faster. </LI><LI>If you update
data elements frequently, try turning off the widget's <B>-bufferelements</B> option.
 When the graph is first displayed, it draws data elements into an internal
pixmap.  The pixmap acts as a cache, so that when the graph needs to be
redrawn again, and the data elements or coordinate axes haven't changed,
the pixmap is simply copied to the screen.  This is especially useful when
you are using markers to highlight points and regions on the graph.  But
if the graph is updated frequently, changing either the element data or
coordinate axes, the buffering becomes redundant. </LI>
</UL>

<H2><A NAME="sect25" HREF="#toc25">Limitations</A></H2>
Auto-scale routines
do not use requested min/max limits as boundaries when the axis is logarithmically
scaled. <P>
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. 
<H2><A NAME="sect26" HREF="#toc26">Keywords</A></H2>
graph, widget <P>

<HR><P>
<A NAME="toc"><B>Table of Contents</B></A><P>
<UL>
<LI><A NAME="toc0" HREF="#sect0">Name</A></LI>
<LI><A NAME="toc1" HREF="#sect1">Synopsis</A></LI>
<LI><A NAME="toc2" HREF="#sect2">Description</A></LI>
<LI><A NAME="toc3" HREF="#sect3">Introduction</A></LI>
<LI><A NAME="toc4" HREF="#sect4">Syntax</A></LI>
<LI><A NAME="toc5" HREF="#sect5">Example</A></LI>
<LI><A NAME="toc6" HREF="#sect6">Graph Operations</A></LI>
<LI><A NAME="toc7" HREF="#sect7">Graph Components</A></LI>
<UL>
<LI><A NAME="toc8" HREF="#sect8">Axis Components</A></LI>
<LI><A NAME="toc9" HREF="#sect9">Crosshairs Component</A></LI>
<LI><A NAME="toc10" HREF="#sect10">Element Components</A></LI>
<LI><A NAME="toc11" HREF="#sect11">Grid Component</A></LI>
<LI><A NAME="toc12" HREF="#sect12">Legend Component</A></LI>
<LI><A NAME="toc13" HREF="#sect13">Pen Components</A></LI>
<LI><A NAME="toc14" HREF="#sect14">PostScript Component</A></LI>
<LI><A NAME="toc15" HREF="#sect15">Marker Components</A></LI>
<LI><A NAME="toc16" HREF="#sect16">Bitmap Markers</A></LI>
<LI><A NAME="toc17" HREF="#sect17">Image Markers</A></LI>
<LI><A NAME="toc18" HREF="#sect18">Line Markers</A></LI>
<LI><A NAME="toc19" HREF="#sect19">Polygon Markers</A></LI>
<LI><A NAME="toc20" HREF="#sect20">Text Markers</A></LI>
<LI><A NAME="toc21" HREF="#sect21">Window Markers</A></LI>
</UL>
<LI><A NAME="toc22" HREF="#sect22">Graph Component Bindings</A></LI>
<LI><A NAME="toc23" HREF="#sect23">C Language API</A></LI>
<LI><A NAME="toc24" HREF="#sect24">Speed Tips</A></LI>
<LI><A NAME="toc25" HREF="#sect25">Limitations</A></LI>
<LI><A NAME="toc26" HREF="#sect26">Keywords</A></LI>
</UL>
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