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<A HREF="#toc">Table of Contents</A><P>
 
<H2><A NAME="sect0" HREF="#toc0">Name</A></H2>
barchart -  Bar chart for plotting X-Y coordinate
data. 
<H2><A NAME="sect1" HREF="#toc1">Synopsis</A></H2>
<B>barchart<I> <I>pathName </I></I></B>?<I>option value</I>?... 
<H2><A NAME="sect2" HREF="#toc2">Description</A></H2>
The <B>barchart</B> command
creates a bar chart for plotting two-dimensional data (X-Y coordinates). A
bar chart is a graphic means of comparing numbers by displaying bars of
lengths proportional to the y-coordinates of the points they represented.
 The bar chart 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>barchart</B> command creates a new window
for plotting two-dimensional data (X-Y coordinates), using bars of various
lengths to represent the data points.  The bars are drawn 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 surrounding the plotting
area.  By default, the legend is drawn in the right margin.  The title is
displayed in top margin. <P>
A <B>barchart</B> widget has several configurable components:
coordinate axes, data elements, legend, grid, cross hairs, pens, postscript,
and annotation markers.  Each component can be queried or modified. 
<DL>

<DT><I>axis</I>
 </DT>
<DD><P>
 Up to four coordinate axes (two X-coordinate and two Y-coordinate axes)
can be displayed, but you can create and use any number of axes. Axes control
what region of data is displayed and how the data is scaled. Each axis consists
of the axis line, title, major and minor ticks, and tick labels. Tick labels
display the value at each major tick. </DD>

<DT><I>crosshairs</I>  </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><I>element</I>  </DT>
<DD>An element
represents a set of data to be plotted.  It contains an x and y vector of
values representing the data points.  Each data point is displayed as a
bar where the length of the bar is proportional to the ordinate (Y-coordinate)
of the data point. The appearance of the bar, such as its color, stipple,
or relief is configurable. <P>
A special case exists when two or more data points
have the same abscissa (X-coordinate).  By default, the bars are overlayed,
one on top of the other.  The bars are drawn in the order of the element
display list.  But you can also configure the bars to be displayed in two
other ways.  They may be displayed as a stack, where each bar (with the
same abscissa) is stacked on the previous.  Or they can be drawn side-by-side
as thin bars.  The width of each bar is a function of the number of data
points with the same abscissa. </DD>

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

<DT><I>legend</I>  </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><I>marker</I> </DT>
<DD>Markers are used annotate or highlight
areas of the graph. For example, you could use 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><I>pen</I>  </DT>
<DD>Pens
define attributes 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><I>postscript</I> </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>barchart <I>pathName </I></B>?<I>option value</I>?...<BR>
</CODE><P>The <B>barchart</B> command creates a new window <I>pathName</I> and makes it into a
<B>barchart</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>barchart</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><P>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>BARCHART
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><P>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>barchart</B> command creates a new bar chart.   <BR>
<CODE># Create a new bar chart.  Plotting area is black.<BR>
barchart .b -plotbackground black<BR>
</CODE><P>A new Tcl command <I>.b</I> is created.  This command can be used to query and modify
the bar chart.  For example, to change the title of the graph to "My Plot",
you use the new command and the <B>configure</B> operation. <BR>
<CODE># Change the title.<BR>
.b configure -title "My Plot"<BR>
</CODE><P>To add data elements, you use the command and the <B>element</B> component. <BR>
<CODE># Create a new element named "e1"<BR>
.b element create e1 \<BR>
<tt>&#32;</tt>&nbsp;<tt>&#32;</tt>&nbsp;-xdata { 1 2 3 4 5 6 7 8 9 10 } \<BR>
<tt>&#32;</tt>&nbsp;<tt>&#32;</tt>&nbsp;-ydata { 26.18 50.46 72.85 93.31 111.86 128.47 143.14 <BR>
<tt>&#32;</tt>&nbsp;<tt>&#32;</tt>&nbsp;<tt>&#32;</tt>&nbsp;<tt>&#32;</tt>&nbsp;155.85 166.60 175.38 }<BR>
</CODE><P>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 barchart.<BR>
vector xVector yVector<BR>
xVector set { 1 2 3 4 5 6 7 8 9 10 }<BR>
yVector set { 26.18 50.46 72.85 93.31 111.86 128.47 143.14 155.85 <BR>
<tt>&#32;</tt>&nbsp;<tt>&#32;</tt>&nbsp;166.60 175.38 }<BR>
n.b element create e1 -xdata xVector -ydata yVector<BR>
</CODE><P>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><P>An element named <I>e1</I> is now created in <I>.b</I>.  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><P>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 scale of the x-coordinate data <BR>
xVector set { 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 }<BR>
# Make sure we change the bar width too.<BR>
.b configure -barwidth 0.2<BR>
</CODE><P>The height of each bar is proportional to the ordinate (Y-coordinate) of
the data point. <P>
If two or more data points have the same abscissa (X-coordinate
value), the bars representing those data points may be drawn in  various
ways. The default is to overlay the bars, one on top of the other. The ordering
is determined from the of element display list.  If the stacked mode is
selected (using the <B>-barmode</B> configuration option), the bars are stacked,
each bar above the previous. <BR>
<CODE># Display the elements as stacked.<BR>
.b configure -barmode stacked<BR>
</CODE><P>If the aligned mode is selected, the bars having the same x-coordinates
are displayed side by side.  The width of each bar is a fraction of its
normal width, based upon the number of bars with the same x-coordinate. <BR>
<CODE># Display the elements side-by-side.<BR>
.b configure -barmode aligned<BR>
</CODE><P>By default, the element's label in the legend will be also <I>e1</I>.  You can change
the label, or specify no legend entry, again using the element's <B>configure</B>
operation. <BR>
<CODE># Don't display "e1" in the legend.<BR>
.b element configure e1 -label ""<BR>
</CODE><P>You can configure more than just the element's label.  An element has many
attributes such as stipple, foreground and background colors, relief, etc.
<BR>
<CODE>.b element configure e1 -fg red -bg pink \<BR>
<tt>&#32;</tt>&nbsp;<tt>&#32;</tt>&nbsp;-stipple gray50<BR>
</CODE><P>Four coordinate axes are automatically created: <I>x</I>, <I>x2</I>, <I>y</I>, and <I>y2</I>.  And by
default, elements are mapped onto the axes <I>x</I> and <I>y</I>.  This can be changed
with the <B>-mapx</B> and <B>-mapy</B> options. <BR>
<CODE># Map "e1" on the alternate y axis "y2".<BR>
.b element configure e1 -mapy y2<BR>
</CODE><P>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>
.b axis configure y -logscale yes<BR>
</CODE><P>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>.b axis configure x -min 1.0 -max 1.5<BR>
.b axis configure y -min 12.0 -max 55.15<BR>
</CODE><P>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 .b &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><P>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>
.b axis configure x -min {} -max {}<BR>
.b axis configure y -min {} -max {}<BR>
</CODE><P>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>
.b legend configure -position left -relief raised \<BR>
<tt>&#32;</tt>&nbsp;<tt>&#32;</tt>&nbsp;-font fixed -fg blue<BR>
</CODE><P>To prevent the legend from being displayed, turn on the <B>-hide</B> option. <BR>
<CODE># Don't display the legend.<BR>
.b legend configure -hide yes<BR>
</CODE><P>The <B>barchart</B> 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, polygons, lines, or windows.  Markers can be used, for example,
to mark or brush points.  For example there may be a line marker which indicates
some low-water value.  Markers are created using the <B>marker</B> operation. <BR>
<CODE># Create a line represent the low water mark at 10.0<BR>
.b marker create line -name "low_water" \<BR>
<tt>&#32;</tt>&nbsp;<tt>&#32;</tt>&nbsp;-coords { -Inf 10.0 Inf 10.0 } \<BR>
<tt>&#32;</tt>&nbsp;<tt>&#32;</tt>&nbsp;-dashes { 2 4 2 } -fg red -bg blue <BR>
</CODE><P>This creates a line marker named <I>low_water</I>.  It will display a horizontal
line stretching across the plotting area at the y-coordinate 10.0.  The coordinates
"-Inf" and "Inf" indicate the relative minimum and maximum of the axis (in
this case the x-axis).  By default, markers are drawn last, on top of the
bars.  You can change this with the <B>-under</B> option. <BR>
<CODE># Draw the marker before elements are drawn.<BR>
.b marker configure low_water -under yes<BR>
</CODE><P>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>
.b crosshairs configure -hide no -color red<BR>
.b grid configure -hide no -dashes { 2 2 }<BR>
</CODE><P>Finally, to get hardcopy of the graph, use the <B>postscript</B> component. <BR>
<CODE># Print the bar chart into file "file.ps"<BR>
.b postscript output file.ps -maxpect yes -decorations no<BR>
</CODE><P>This generates a file <I>file.ps</I> 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">Syntax</A></H2>
<BR>
<P>
<CODE><B>barchart <I>pathName </I></B>?<I>option value</I>?...<BR>
</CODE><P>The <B>barchart</B> command creates a new window <I>pathName</I> and makes it into a
barchart 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 may be specified on the command line or in the option database to configure
aspects of the bar chart such as its colors and font.  See the <B>configure</B>
operation below for the exact details as to what <I>option</I> and <I>value</I> pairs
are valid. <P>
If successful, <B>barchart</B> returns <I>pathName</I>. It also creates a new
Tcl command <I>pathName</I>.  This command may be used to invoke various operations
to query or modify the bar chart.  It has the general form: <BR>
<P>
<CODE><I>pathName <I>operation</I></I> ?<I>arg</I>?...<BR>
</CODE><P>Both <I>operation</I> and its arguments determine the exact behavior of the command.
 The operations available for the bar chart are described in the following
section. 
<H2><A NAME="sect7" HREF="#toc7">Barchart Operations</A></H2>

<DL>

<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>-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>-barmode <I>mode</I></B>  </DT>
<DD>Indicates how related bar elements
will be drawn.  Related elements have data points with the same abscissas
(X-coordinates). <I>Mode</I> indicates how those segments should be drawn. <I>Mode</I> can
be <I>infront</I>, <I>aligned</I>, <I>overlap</I>, or <I>stacked</I>. The default mode is <I>infront</I>. <blockquote></DD>

<DT><I>infront</I>
</DT>
<DD>Each successive segment is drawn in front of the previous.  </DD>

<DT><I>stacked</I> </DT>
<DD>Each
successive segment is stacked vertically on top of the previous.   </DD>

<DT><I>aligned</I>
</DT>
<DD>Segments is displayed aligned from right-to-left.   </DD>

<DT><I>overlap</I> </DT>
<DD>Like <I>aligned</I> but
segments slightly overlap each other.   </DD>
</DL>
</blockquote>

<DL>

<DT><B>-barwidth <I>value</I></B>  </DT>
<DD>Specifies the width
of the bars.  This value can be overridden by the individual elements using
their <B>-barwidth</B> configuration option. <I>Value</I> is the width in terms of graph
coordinates.  The default width is <I>1.0</I>. </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 <I>2</I>. </DD>

<DT><B>-bottommargin
<I>pixels</I></B> </DT>
<DD>Specifies the size of the margin below the X-coordinate axis.  If
<I>pixels</I> is <I>0</I>, the size of the margin is selected automatically. The default
is <I>0</I>. </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 <I>1</I>. </DD>

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

<DT><B>-font <I>fontName</I></B>  </DT>
<DD>Specifies the font of the graph title. The default
is <I>*-Helvetica-Bold-R-Normal-*-18-180-*</I>. </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 <I>0.5i</I>. </DD>

<DT><B>-height <I>pixels</I></B> </DT>
<DD>Specifies the requested height of widget.
 The default is <I>4i</I>. </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 <I>0</I>. </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 <I>left</I>, <I>right</I>, or <I>center</I>.  The default is <I>center</I>. </DD>

<DT><B>-leftmargin
<I>pixels</I></B> </DT>
<DD>Sets the size of the margin from the left edge of the window to
 the Y-coordinate axis.  If <I>pixels</I> is <I>0</I>, the size is calculated automatically.
 The default is <I>0</I>. </DD>

<DT><B>-plotbackground <I>color</I></B> </DT>
<DD>Specifies the background color of
the plotting area.  The default is <I>white</I>. </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 <I>2</I>. </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 <I>8</I>. </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 <I>8</I>. </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,
<I>raised</I> means the plot should appear to protrude from the graph, relative
to the surface of the graph.  The default is <I>sunken</I>. </DD>

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

<DT><B>-rightmargin <I>pixels</I></B>
</DT>
<DD>Sets the size of margin 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 than
1, the margin size is selected automatically. </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 <I>0</I>, this means that this window
should be skipped entirely during keyboard traversal.  <I>1</I> 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 <I>""</I>. </DD>

<DT><B>-tile <I>image</I></B>  </DT>
<DD>Specifies a tiled background for the widget.
 If <I>image</I> isn't <I>""</I>, 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 <I>""</I>. </DD>

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

<DT><B>-topmargin
<I>pixels</I></B> </DT>
<DD>Specifies the size of the margin above the x2 axis.  If <I>pixels</I> is
<I>0</I>, the margin size is calculated automatically. </DD>

<DT><B>-width <I>pixels</I></B> </DT>
<DD>Specifies the
requested width of the widget.  The default is <I>5i</I>. </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 <I>leftmargin</I>,
<I>rightmargin</I>, <I>topmargin</I>, <I>bottommargin</I>, <I>plotwidth</I>, or <I>plotheight</I>. </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 <I>1</I> is the designated screen coordinate (<I>x</I> and <I>y</I>) is inside the
plotting area and <I>0</I> 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</I> <B>metafile</B> ?<I>fileName</I>? </DT>
<DD><I>This operation is for Window platforms
only</I>.   Creates a Windows enhanced metafile of the barchart. If present,
<I>fileName</I> is the file name of the new metafile. Otherwise, the metafile is
automatically added to the clipboard. </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 <I>photoName</I></B></I> </DT>
<DD>Takes a
snapshot of the graph and stores the contents in the photo image <I>photoName</I>.
 <I>PhotoName</I> is the name of a Tk photo image that must already exist. </DD>

<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="sect8" HREF="#toc8">Barchart 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="sect9" HREF="#toc9">Axis Components</A></H3>
Four
coordinate axes are automatically created: two X-coordinate axes (<I>x</I> and
<I>x2</I>) and two Y-coordinate axes (<I>y</I>, and <I>y2</I>).  By default, the axis <I>x</I> is located
in the bottom margin, <I>y</I> in the left margin, <I>x2</I> in the top margin, and <I>y2</I>
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 create and use several axes. To create an axis, invoke the
axis component and its create operation. <BR>
<CODE># Create a new axis called "temperature"<BR>
.b axis create temperature<BR>
</CODE><P>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 temperature data to this axis.<BR>
.b element create "temp" -xdata $x -ydata $tempData \<BR>
    -mapy temperature<BR>
</CODE><P>While you can have many axes, only four axes can be displayed simultaneously.
 They are drawn in each of the margins surrounding the plotting area.  The
axes <I>x</I> and <I>y</I> are drawn in the bottom and left margins. The axes <I>x2</I> and <I>y2</I>
are drawn in top and right margins.  Only <I>x</I> and <I>y</I> are shown by default. Note
that the axes can have different scales. <P>
To display a different axis, you
invoke one of the following components: <B>xaxis</B>, <B>yaxis</B>, <B>x2axis</B>, and <B>y2axis</B>.
The <B>use</B> operation designates the axis to be drawn in the 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 temperature in the left margin.<BR>
.b yaxis use temperature<BR>
<P>
</CODE><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 <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>-autorange <I>range</I></B>  </DT>
<DD>Sets the range of values for
the axis to <I>range</I>.  The axis limits are automatically reset to display the
most recent data points in this range.   If <I>range</I> is 0.0, the range is determined
from the limits of the data.  If <B>-min</B> or <B>-max</B> are specified, they override
this option.  The default is <I>0.0</I>. </DD>

<DT><B>-color <I>color</I></B> </DT>
<DD>Sets the color of the axis and
tick labels. The default is <I>black</I>. </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 <I>""</I> is returned, no label will appear next to the tick.  You can
get the standard tick labels again by setting <I>prefix</I> to <I>""</I>.  The default
is <I>""</I>. <P>
Please note that this procedure is invoked while the bar chart is
redrawn. You may query the widget's configuration options.  But do not reset
options, 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
<I>0</I>. </DD>

<DT><B>-hide <I>boolean</I></B> </DT>
<DD>Indicates whether the axis is displayed.  </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 <I>left</I>,
<I>right</I>, or <I>center</I>.  The default is <I>center</I>. </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 <I>""</I> is given as either description, then  the
that limit will not be displayed.  The default is <I>""</I>. </DD>

<DT><B>-linewidth <I>pixels</I></B> </DT>
<DD>Sets
the width of the axis and tick lines.  The default is <I>1</I> 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. This
is relevant only when the axis limit is automatically calculated. If <I>boolean</I>
is true, the axis range is "loose". The default is <I>0</I>. </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 <I>""</I>,  major ticks will be automatically computed. The default is <I>""</I>. </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 <I>""</I>,  the maximum limit is calculated
using the largest data value. The default is <I>""</I>. </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 <I>""</I>, the minimum limit is calculated using the smallest data value.
The default is <I>""</I>. </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 <I>""</I>, minor ticks will be automatically
computed. The default is <I>""</I>. </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 <I>0.0</I> degrees. </DD>

<DT><B>-shiftby
<I>value</I></B> </DT>
<DD>Specifies how much to automatically shift the range of the axis. When
the new data exceeds the current axis maximum, the maximum is increased
in increments of <I>value</I>.  You can use this option to prevent the axis limits
from being recomputed at each new time point. If <I>value</I> is 0.0, then no automatic
shifting is down. The default is <I>0.0</I>. </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 <I>1</I>. </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 <I>2</I>. </DD>

<DT><B>-tickfont <I>fontName</I></B>  </DT>
<DD>Specifies the font for axis tick labels. The default
is <I>*-Courier-Bold-R-Normal-*-100-*</I>. </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 <I>0.1i</I>. </DD>

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

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

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

<DL>

<DT></CODE><P><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 <I>min max</I>. </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>
</DL>
<P>
Only four axes can be displayed
simultaneously.  By default, they are <I>x</I>, <I>y</I>, <I>x2</I>, and <I>y2</I>.  You can 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><P>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.  The <B>xaxis</B>
component manages the X-axis located in the bottom margin (whatever axis
that happens to be).  Likewise, <B>yaxis</B> uses the Y-axis in the left margin,
<B>x2axis</B> the top X-axis, and <B>y2axis</B> the right Y-axis. <P>
They implicitly control
the axis that is currently using to that location.  By default, <B>xaxis</B> uses
the <I>x</I> axis, <B>yaxis</B> uses <I>y</I>, <B>x2axis</B> uses <I>x2</I>, and <B>y2axis</B> uses <I>y2</I>.  These components
can be more convenient to use than always determining what axes are current
being displayed by the graph. <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>. 
<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="sect10" HREF="#toc10">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
widget. <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 <I>black</I>. </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 <I>""</I>, 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
<I>yes</I>. </DD>

<DT><B>-linewidth <I>pixels</I></B> </DT>
<DD>Set the width of the cross hair lines.  The default
is <I>1</I>. </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 <I>crosshairs</I>
and <I>Crosshairs</I> respectively. <BR>
<CODE>option add *Barchart.Crosshairs.LineWidth 2<BR>
option add *Barchart.Crosshairs.Color     red<BR>
</blockquote>

<DL>

<DT></CODE><P><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>

<H2><A NAME="sect11" HREF="#toc11">Elements</A></H2>
A data element represents a set of data.  It contains
x and y vectors which are the coordinates of the data points.  Elements
are displayed as bars where the length of the bar is proportional to the
ordinate of the data point.  Elements also control the appearance of the
data, such as the color, stipple, relief, 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 <I>+</I> 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>option value</I>?... ?<I>elemName</I>?...
</DT>
<DD>Finds the data point representing the bar closest to the window coordinates
<I>x</I> and <I>y</I> in the element <I>elemName</I>. <I>ElemName</I> is the name of an element, which
must be displayed.  If no elements are specified, then all displayed elements
are searched.  It returns a list containing the name of the closest element,
the index of its closest point, and the graph coordinates of the point.
If no data point within the threshold distance can be found, <I>""</I> is returned.
 The following <I>option</I>-<I>value</I> pairs are available. <blockquote></DD>

<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 <I>2</I> or <I>1.2i</I>. If this option isn't specified, then it
defaults to the value of the <B>barchart</B>'s <B>-halo</B> option. </DD>
</DL>
</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 <I>""</I>, no active
elements will be drawn.  The default is  <I>activeLine</I>. </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 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 <I>all</I>. </DD>

<DT><B>-background <I>color</I></B> </DT>
<DD>Sets the the color
of the border around each bar.  The default is <I>white</I>. </DD>

<DT><B>-barwidth <I>value</I></B>  </DT>
<DD>Specifies
the width the bars drawn for the element.  <I>Value</I> is the width in X-coordinates.
 If this option isn't specified, the width of each bar is the value of the
widget's <B>-barwidth</B> option. </DD>

<DT><B>-baseline <I>value</I></B>  </DT>
<DD>Specifies the baseline of the bar
segments.  This affects how bars are  drawn since bars are drawn from their
respective y-coordinate the  baseline. By default the baseline is <I>0.0</I>.   </DD>

<DT><B>-borderwidth
<I>pixels</I></B> </DT>
<DD>Sets the border width of the 3-D border drawn around the outside
of each bar.  The <B>-relief</B> option determines if such a border is drawn.  <I>Pixels</I>
must be a valid screen distance like <I>2</I> or <I>0.25i</I>. The default is <I>2</I>. </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>-foreground
<I>color</I></B>  </DT>
<DD>Sets the color of the interior of the bars.   </DD>

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

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

<DT><B>-relief
<I>string</I></B> </DT>
<DD>Specifies the 3-D effect desired for bars.  <I>Relief</I> indicates how the
interior of the bar should appear relative to the surface of the chart;
for example, <I>raised</I> means the bar should appear to protrude from the surface
of the plotting area.  The default is <I>raised</I>. </DD>

<DT><B>-stipple <I>bitmap</I></B> </DT>
<DD>Specifies a
stipple pattern with which to draw the bars.  If <I>bitmap</I> is <I>""</I>, then the
bar is drawn in a solid fashion. </DD>

<DT><B>-xdata <I>xVector</I></B>  </DT>
<DD>Specifies the x-coordinate
vector of the data. <I>XVector</I> is the name of a BLT vector or a list of numeric
expressions.   </DD>

<DT><B>-ydata <I>yVector</I></B>  </DT>
<DD>Specifies the y-coordinate vector of the data.
<I>YVector</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 names  in the option database  are prefixed by <I>elem</I>. <BR>
<CODE>option add *Barchart.Element.background blue<BR>
</blockquote>

<DL>

<DT></CODE><P><I>pathName <B>element create <I>elemName</I></B></I> ?<I>option value</I>?... </DT>
<DD>Creates a new element <I>elemName</I>.
 Element names must be unique, so an element <I>elemName</I> may not already exist.
 If additional arguments are present, they specify any of the element options
valid for element <B>configure</B> operation. </DD>

<DT><I>pathName <B>element deactivate <I>pattern</I></B></I>...
</DT>
<DD>Deactivates all the elements matching <I>pattern</I> for the graph.   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>pattern</I>?... </DT>
<DD>Deletes all the elements matching
<I>pattern</I> for the graph.   Elements whose names match any of the patterns
given are deleted.  The graph will be redrawn without the deleted elements.
  </DD>

<DT><I>pathName <B>element exists <I>elemName</I></B></I> </DT>
<DD>Returns <I>1</I> if an element <I>elemName</I> currently
exists and <I>0</I> 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 <I>"bar"</I>, otherwise it returns <I>"line"</I>. </DD>
</DL>

<H3><A NAME="sect12" HREF="#toc12"></CODE><P>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 <I>black</I>. </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 <I>""</I>, 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 <I>yes</I>. </DD>

<DT><B>-linewidth <I>pixels</I></B> </DT>
<DD>Sets the width
of grid lines.  The default width is <I>1</I>. </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 <I>""</I> for no grid
lines.   The default is <I>""</I>. </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 <I>""</I> for no grid lines.  The default
is <I>y</I>. </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 <I>1</I>. </DD>
</DL>
<P>
Grid configuration options may also be set by the  <B>option</B>
command.  The resource name and class are <I>grid</I> and  <I>Grid</I> respectively.  <BR>
<CODE>option add *Barchart.grid.LineWidth 2<BR>
option add *Barchart.Grid.Color     black<BR>
</blockquote>

<DL>

<DT></CODE><P><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="sect13" HREF="#toc13">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 <I>+</I> 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 <I>2</I>. </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, <I>raised</I> means the entry should appear to protrude from the
legend, relative to the surface of the legend.  The default is <I>flat</I>. </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 <I>center</I>. <blockquote></DD>

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

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

<DT><I>@x,y</I> </DT>
<DD>The anchor specifies how to position the
legend relative to the positioning point. For example, if <I>anchor</I> is <I>center</I>
then the legend is centered on the point; if <I>anchor</I> is <I>n</I> 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><I>plotarea</I> </DT>
<DD>The anchor
specifies how to position the legend relative to the plotting area. For
example, if <I>anchor</I> is <I>center</I> then the legend is centered in the plotting
area; if <I>anchor</I> is <I>ne</I> 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 <I>""</I>, 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 for legend entries.  Each tag in the list matching the current
 event sequence will have its Tcl command executed. The default value  is
<I>all</I>. </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 <I>2</I> 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 <I>*-Helvetica-Bold-R-Normal-*-12-120-*</I>. </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 <I>black</I>. </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 <I>no</I>. </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 <I>2</I>. </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 <I>2</I>. </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 <I>4</I>. </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 <I>0</I>. </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 <I>left</I>, <I>left</I>,
<I>top</I>, or <I>bottom</I>, the legend is drawn in the specified margin.  If <I>pos</I> is
<I>plotarea</I>, 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 <I>right</I>. </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 <I>no</I>. </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 bar chart; for example, <I>raised</I> means
the legend should appear to protrude from the bar chart, relative to the
surface of the bar chart.  The default is <I>sunken</I>. </DD>
</DL>
<P>
Legend configuration options
may also be set by the <B>option</B> command.  The resource name and class are
<I>legend</I> and <I>Legend</I> respectively. <BR>
<CODE>option add *Barchart.legend.Foreground blue<BR>
option add *Barchart.Legend.Relief     raised<BR>
</blockquote>

<DL>

<DT></CODE><P><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, <I>""</I> is returned. </DD>
</DL>

<H3><A NAME="sect14" HREF="#toc14">Pen Components</A></H3>
Pens define
attributes 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 <I>activeBar</I>, 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 "activeBar" -fg green -bg green4<BR>
</CODE><P>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><P>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 "e1" -xdata $x -ydata $tempData \<BR>
    -pen myPen<BR>
</CODE><P>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 "e1" -styles { myPen 2.0 3.0 }<BR>
</CODE><P>This says that any data point with a weight between 2.0 and 3.0 is to be
drawn using the pen <I>myPen</I>.  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>-background <I>color</I></B>
</DT>
<DD>Sets the the color of the border around each bar.  The default is <I>white</I>.
</DD>

<DT><B>-borderwidth <I>pixels</I></B> </DT>
<DD>Sets the border width of the 3-D border drawn around
the outside of each bar.  The <B>-relief</B> option determines if such a border
is drawn.  <I>Pixels</I> must be a valid screen distance like <I>2</I> or <I>0.25i</I>. The default
is <I>2</I>. </DD>

<DT><B>-foreground <I>color</I></B>  </DT>
<DD>Sets the color of the interior of the bars.   </DD>

<DT><B>-relief
<I>string</I></B> </DT>
<DD>Specifies the 3-D effect desired for bars.  <I>Relief</I> indicates how the
interior of the bar should appear relative to the surface of the chart;
for example, <I>raised</I> means the bar should appear to protrude from the bar
chart, relative to the surface of the plotting area.  The default is <I>raised</I>.
</DD>

<DT><B>-stipple <I>bitmap</I></B> </DT>
<DD>Specifies a stipple pattern with which to draw the bars.
 If <I>bitmap</I> is <I>""</I>, then the bar is drawn in a solid fashion. </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 "bar". </DD>
</DL>
<P>
Pen configuration options may be also be set by the
<B>option</B> command.  The resource class is <I>Pen</I>.  The resource names are the names
of the pens. <BR>
<CODE>option add *Barchart.Pen.Foreground<tt>&#32;</tt>&nbsp;<tt>&#32;</tt>&nbsp;   blue<BR>
option add *Barchart.activeBar.foreground  green<BR>
</blockquote>

<DL>

<DT></CODE><P><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="sect15" HREF="#toc15">PostScript
Component</A></H3>
The barchart 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 <I>1</I>. </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. ``<I>1.0
1.0 0.0 setrgbcolor</I>'').  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 <I>color</I> (for full color output), <I>gray</I> (convert all colors
to their gray-scale equivalents) or <I>mono</I> (convert foreground colors to black
and background colors to white).  The default mode is <I>color</I>.  </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
<I>Helvetica-Bold</I>. </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 graph will background will be white and no 3-D borders will
be generated. The default is <I>1</I>. </DD>

<DT><B>-height <I>pixels</I></B> </DT>
<DD>Sets the height of the plot.
 This lets you print the bar chart 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 <I>0</I>. </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 <I>0</I>. </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 barchart is still retained.  The default is <I>0</I>. </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 <I>1i</I>. </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 <I>1i</I>. </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 <I>11.0i</I>. </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 <I>8.5i</I>. </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 <I>0</I>. </DD>
</DL>
<P>
Postscript configuration options
may be also be set by the <B>option</B> command.  The resource name and class are
<I>postscript</I> and <I>Postscript</I> respectively. <BR>
<CODE>option add *Barchart.postscript.Decorations false<BR>
option add *Barchart.Postscript.Landscape   true<BR>
</blockquote>

<DL>

<DT></CODE><P><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="sect16" HREF="#toc16">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 <I>-Inf</I> and <I>Inf</I> 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
<I>-Inf</I>,<I>-Inf</I>. <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 <I>+</I> 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 <I>all</I>. </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 <I>""</I>, the marker will not be displayed. The default is <I>""</I>. </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 <I>""</I>, the marker is always drawn.  The default is <I>""</I>. </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 <I>no</I>. </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 <I>x</I>. </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 <I>y</I>. </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 elements.  Otherwise, the marker is drawn on top of the element.
 The default is <I>0</I>. </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 <I>2</I> or
<I>1.2i</I>. The default is <I>0</I>. </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 <I>2</I> or
<I>1.2i</I>. The default is <I>0</I>. </DD>
</DL>
<P>
Marker configuration options may also be set by the
<B>option</B> command. The resource class is either <I>BitmapMarker</I>,  <I>ImageMarker</I>,
 <I>LineMarker</I>, <I>PolygonMarker</I>, <I>TextMarker</I>, or <I>WindowMarker</I>, depending on the
type of marker.  The resource name is the name of the marker. <BR>
<CODE>option add *Barchart.TextMarker.Foreground white<BR>
option add *Barchart.BitmapMarker.Foreground white<BR>
option add *Barchart.m1.Background     blue<BR>
</blockquote>

<DL>

<DT></CODE><P><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 <I>text</I>, <I>line</I>, <I>bitmap</I>, <I>image</I>, <I>polygon</I>, or <I>window</I>. 
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 <I>1</I> if the
marker <I>markerId</I> exists and <I>0</I> 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 <I>line</I> or <I>text</I>.  If <I>markerId</I> is not a valid a marker identifier, <I>""</I>
is returned. </DD>
</DL>

<H3><A NAME="sect17" HREF="#toc17">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><P>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 <I>""</I>, the marker will not be displayed.  The
default is <I>""</I>. </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 <I>""</I>. </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 <I>""</I>, all pixels of the bitmap
will be drawn.  The default is <I>""</I>. </DD>

<DT><B>-outline <I>color</I></B> </DT>
<DD>Sets the foreground color
of the bitmap. The default value is <I>black</I>. </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 <I>0.0</I>. </DD>
</DL>

<H3><A NAME="sect18" HREF="#toc18">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><P>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 <I>center</I> then the image is centered
on the point;  if <I>anchor</I> is <I>n</I> 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 <I>center</I>. </DD>

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

<H3><A NAME="sect19" HREF="#toc19">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><P>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 <I>""</I>, 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>-fdashesR option). If <I>color</I></B> is the empty
string, no background color is drawn (the line will be dashed, not striped).
 The default background color is <I>""</I>. </DD>

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

<DT><B>-outline <I>color</I></B> </DT>
<DD>Sets the foreground color
of the line. The default value is <I>black</I>. </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 <I>""</I>, then the line
is drawn in a solid fashion. The default is <I>""</I>. </DD>
</DL>

<H3><A NAME="sect20" HREF="#toc20">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><P>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 <I>""</I>, 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 <I>""</I>, then
the interior of the polygon is transparent. The default is <I>white</I>. </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 <I>0</I>. </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
<I>black</I>. </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 <I>""</I>, then the polygon is filled
with a solid color (if the <B>-fill</B> option is set).  The default is <I>""</I>. </DD>
</DL>

<H3><A NAME="sect21" HREF="#toc21">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><P>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 <I>center</I> then
the text is centered on the point; if <I>anchor</I> is <I>n</I> 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 <I>center</I>. </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 <I>*-Helvetica-Bold-R-Normal-*-120-*</I>. </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 <I>""</I>. </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 <I>left</I>, <I>right</I>, or <I>center</I>.  The default is <I>center</I>. </DD>

<DT><B>-outline <I>color</I></B>
</DT>
<DD>Sets the color of the text. The default value is <I>black</I>. </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 <I>4</I>. </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 <I>4</I>. </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 <I>0.0</I>. </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="sect22" HREF="#toc22">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><P>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 <I>center</I> then the widget is centered
on the point; if <I>anchor</I> is <I>n</I> 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 <I>center</I>. </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 <I>""</I>, 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 <I>""</I>, 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 barchart.  <I>PathName</I> must be a child of the <B>barchart</B> widget. </DD>
</DL>

<H2><A NAME="sect23" HREF="#toc23">Graph
Component Bindings</A></H2>
Specific barchart 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="sect24" HREF="#toc24">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 barchart 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><P>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", 50, &amp;xVec) != TCL_OK) ||<BR>
    (Blt_GetVector(interp, "Y", 50, &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>&#32;</tt>&nbsp;<tt>&#32;</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><P>See the <B>vector</B> manual page for more details. 
<H2><A NAME="sect25" HREF="#toc25">Speed Tips</A></H2>
There may be cases
where the bar chart needs to be drawn and updated as quickly as possible.
 If drawing speed becomes a big problem, here are a few tips to speed up
displays. 
<UL>
&#183;<LI>Try to minimize the number of data points.  The more data points
 looked at, the more work the bar chart must do.   </LI>&#183;<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>&#183;<LI>Don't stipple or dash the element.  Solid
bars are much faster. </LI>&#183;<LI>If you update data elements frequently, try turning
off the widget's <B>-bufferelements</B> option.  When the bar chart is first displayed,
it draws data elements into an internal pixmap.  The pixmap acts as a cache,
so that when the bar chart needs to be redrawn again, and the data elements
or coordinate axes haven't changed, the pixmap is simply copied to the screen.
 This is especially useful when you are using markers to highlight points
and regions on the bar chart.  But if the bar chart is updated frequently,
changing either the element data or coordinate axes, the buffering becomes
redundant. </LI>
</UL>

<H2><A NAME="sect26" HREF="#toc26">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="sect27" HREF="#toc27">Keywords</A></H2>
bar
chart, 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">Syntax</A></LI>
<LI><A NAME="toc7" HREF="#sect7">Barchart Operations</A></LI>
<LI><A NAME="toc8" HREF="#sect8">Barchart Components</A></LI>
<UL>
<LI><A NAME="toc9" HREF="#sect9">Axis Components</A></LI>
<LI><A NAME="toc10" HREF="#sect10">Crosshairs Component</A></LI>
</UL>
<LI><A NAME="toc11" HREF="#sect11">Elements</A></LI>
<UL>
<LI><A NAME="toc12" HREF="#sect12">Grid Component</A></LI>
<LI><A NAME="toc13" HREF="#sect13">Legend Component</A></LI>
<LI><A NAME="toc14" HREF="#sect14">Pen Components</A></LI>
<LI><A NAME="toc15" HREF="#sect15">PostScript Component</A></LI>
<LI><A NAME="toc16" HREF="#sect16">Marker Components</A></LI>
<LI><A NAME="toc17" HREF="#sect17">Bitmap Markers</A></LI>
<LI><A NAME="toc18" HREF="#sect18">Image Markers</A></LI>
<LI><A NAME="toc19" HREF="#sect19">Line Markers</A></LI>
<LI><A NAME="toc20" HREF="#sect20">Polygon Markers</A></LI>
<LI><A NAME="toc21" HREF="#sect21">Text Markers</A></LI>
<LI><A NAME="toc22" HREF="#sect22">Window Markers</A></LI>
</UL>
<LI><A NAME="toc23" HREF="#sect23">Graph Component Bindings</A></LI>
<LI><A NAME="toc24" HREF="#sect24">C Language API</A></LI>
<LI><A NAME="toc25" HREF="#sect25">Speed Tips</A></LI>
<LI><A NAME="toc26" HREF="#sect26">Limitations</A></LI>
<LI><A NAME="toc27" HREF="#sect27">Keywords</A></LI>
</UL>
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