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<A HREF="#toc">Table of Contents</A><P>
<H2><A NAME="sect0" HREF="#toc0">Name</A></H2>
graph - 2D graph for plotting X-Y coordinate data.
<H2><A NAME="sect1" HREF="#toc1">Synopsis</A></H2>
<B>graph<I> <I>pathName </I></I></B>?<I>option value</I>?...
<H2><A NAME="sect2" HREF="#toc2">Description</A></H2>
The <B>graph</B> command creates
a graph for plotting two-dimensional data (X-Y coordinates). It has many configurable
components: coordinate axes, elements, legend, grid lines, cross hairs,
etc. They allow you to customize the look and feel of the graph.
<H2><A NAME="sect3" HREF="#toc3">Introduction</A></H2>
The
<B>graph</B> command creates a new window for plotting two-dimensional data (X-Y
coordinates). Data points are plotted in a rectangular area displayed in
the center of the new window. This is the <I>plotting area</I>. The coordinate
axes are drawn in the margins around the plotting area. By default, the
legend is displayed in the right margin. The title is displayed in top
margin. <P>
The <B>graph</B> widget is composed of several components: coordinate axes,
data elements, legend, grid, cross hairs, pens, postscript, and annotation
markers.
<DL>
<DT><I>axis</I> </DT>
<DD>The graph has four standard axes (<I>x</I>, <I>x2</I>, <I>y</I>, and <I>y2</I>), but
you can create and display any number of axes. Axes control what region
of data is displayed and how the data is scaled. Each axis consists of the
axis line, title, major and minor ticks, and tick labels. Tick labels display
the value at each major tick. </DD>
<DT><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 points. Elements can be plotted with a symbol at each data
point and lines connecting the points. The appearance of the element, such
as its symbol, line width, and color is configurable. </DD>
<DT><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 polygon marker to fill an area under a curve, or a text marker to
label a particular data point. Markers come in various forms: text strings,
bitmaps, connected line segments, images, polygons, or embedded widgets.
</DD>
<DT><I>pen</I> </DT>
<DD>Pens define attributes (both symbol and line style) for elements.
Data elements use pens to specify how they should be drawn. A data element
may use many pens at once. Here, the particular pen used for a data point
is determined from each element's weight vector (see the element's <B>-weight</B>
and <B>-style</B> options). </DD>
<DT><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>graph <I>pathName </I></B>?<I>option value</I>?...<BR>
</CODE><P>The <B>graph</B> command creates a new window <I>pathName</I> and makes it into a <B>graph</B>
widget. At the time this command is invoked, there must not exist a window
named <I>pathName</I>, but <I>pathName</I>'s parent must exist. Additional options may
be specified on the command line or in the option database to configure
aspects of the graph such as its colors and font. See the <B>configure</B> operation
below for the exact details about what <I>option</I> and <I>value</I> pairs are valid.
<P>
If successful, <B>graph</B> returns the path name of the widget. It also creates
a new Tcl command by the same name. You can use this command to invoke
various operations that query or modify the graph. The general form is:
<BR>
<P>
<CODE><I>pathName <I>operation</I></I> ?<I>arg</I>?...<BR>
</CODE><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>GRAPH OPERATIONS</B></FONT>
section. <P>
The command can also be used to access components of the graph.
<BR>
<P>
<CODE><I>pathName component operation</I> ?<I>arg</I>?...<BR>
</CODE><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>graph</B> command creates a new graph. <BR>
<CODE># Create a new graph. Plotting area is black.<BR>
graph .g -plotbackground black<BR>
</CODE><P>A new Tcl command <I>.g</I> is also created. This command can be used to query
and modify the graph. For example, to change the title of the graph to
"My Plot", you use the new command and the graph's <B>configure</B> operation. <BR>
<CODE># Change the title.<BR>
.g configure -title "My Plot"<BR>
</CODE><P>A graph has several components. To access a particular component you use
the component's name. For example, to add data elements, you use the new
command and the <B>element</B> component. <BR>
<CODE># Create a new element named "line1"<BR>
.g element create line1 \<BR>
<tt> </tt> <tt> </tt> -xdata { 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 } \<BR>
<tt> </tt> <tt> </tt> -ydata { 26.18 50.46 72.85 93.31 111.86 128.47 143.14 <BR>
<tt> </tt> <tt> </tt> <tt> </tt> <tt> </tt> 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 graph.<BR>
vector xVec yVec<BR>
xVec set { 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 }<BR>
yVec set { 26.18 50.46 72.85 93.31 111.86 128.47 143.14 155.85 <BR>
<tt> </tt> <tt> </tt> 166.60 175.38 }<BR>
.g element create line1 -xdata xVec -ydata yVec<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 X-Y coordinates of the first point.<BR>
set xVec(0) 0.18<BR>
set yVec(0) 25.18<BR>
</CODE><P>An element named <I>line1</I> is now created in <I>.g</I>. By default, the element's label
in the legend will be also <I>line1</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 "line1" in the legend.<BR>
.g element configure line1 -label ""<BR>
</CODE><P>You can configure more than just the element's label. An element has many
attributes such as symbol type and size, dashed or solid lines, colors,
line width, etc. <BR>
<CODE>.g element configure line1 -symbol square -color red \<BR>
<tt> </tt> <tt> </tt> -dashes { 2 4 2 } -linewidth 2 -pixels 2c<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 "line1" on the alternate Y-axis "y2".<BR>
.g element configure line1 -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>
.g 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>.g axis configure x -min 1.0 -max 1.5<BR>
.g 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 .g <ButtonPress-1> { <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>
.g axis configure x -min {} -max {}<BR>
.g 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>
.g legend configure -position left -relief raised \<BR>
<tt> </tt> <tt> </tt> -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>
.g legend configure -hide yes<BR>
</CODE><P>The <B>graph</B> widget has simple drawing procedures called markers. They can
be used to highlight or annotate data in the graph. The types of markers
available are bitmaps, images, polygons, lines, or windows. Markers can
be used, for example, to mark or brush points. In this example, is a text
marker that labels the data first point. Markers are created using the
<B>marker</B> component. <BR>
<CODE># Create a label for the first data point of "line1".<BR>
.g marker create text -name first_marker -coords { 0.2 26.18 } \<BR>
<tt> </tt> <tt> </tt> -text "start" -anchor se -xoffset -10 -yoffset -10<BR>
</CODE><P>This creates a text marker named <I>first_marker</I>. It will display the text
"start" near the coordinates of the first data point. The <B>-anchor</B>, <B>-xoffset</B>,
and <B>-yoffset</B> options are used to display the marker above and to the left
of the data point, so that the data point isn't covered by the marker. By
default, markers are drawn last, on top of data. You can change this with
the <B>-under</B> option. <BR>
<CODE># Draw the label before elements are drawn.<BR>
.g marker configure first_marker -under yes<BR>
</CODE><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>
.g crosshairs configure -hide no -color red<BR>
.g grid configure -hide no -dashes { 2 2 }<BR>
# Set up a binding to reposition the crosshairs.<BR>
bind .g <Motion> {<BR>
.g crosshairs configure -position @%x,%y<BR>
}<BR>
</CODE><P>The crosshairs are repositioned as the mouse pointer is moved in the graph.
The pointer X-Y coordinates define the center of the crosshairs. <P>
Finally,
to get hardcopy of the graph, use the <B>postscript</B> component. <BR>
<CODE># Print the graph into file "file.ps"<BR>
.g postscript output file.ps -maxpect yes -decorations no<BR>
</CODE><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">Graph Operations</A></H2>
<DL>
<DT><I>pathName <B>axis <I>operation
</I></B></I>?<I>arg</I>?... </DT>
<DD>See the <FONT SIZE=-1><B>AXIS COMPONENTS</B></FONT>
section. </DD>
<DT><I>pathName <B>bar <I>elemName </I></B></I>?<I>option value</I>?...
</DT>
<DD>Creates a new barchart element <I>elemName</I>. It's an error if an element <I>elemName</I>
already exists. See the manual for <B>barchart</B> for details about what <I>option</I>
and <I>value</I> pairs are valid. </DD>
<DT><I>pathName <B>cget</B></I> <I>option</I> </DT>
<DD>Returns the current value
of the configuration option given by <I>option</I>. <I>Option</I> may be any option described
below for the <B>configure</B> operation. </DD>
<DT><I>pathName <B>configure </B></I>?<I>option value</I>?... </DT>
<DD>Queries
or modifies the configuration options of the graph. If <I>option</I> isn't specified,
a list describing the current options for <I>pathName</I> is returned. If <I>option</I>
is specified, but not <I>value</I>, then a list describing <I>option</I> is returned.
If one or more <I>option</I> and <I>value</I> pairs are specified, then for each pair,
the option <I>option</I> is set to <I>value</I>. The following options are valid. <blockquote></DD>
<DT><B>-background
<I>color</I></B> </DT>
<DD>Sets the background color. This includes the margins and legend, but
not the plotting area. </DD>
<DT><B>-borderwidth <I>pixels</I></B> </DT>
<DD>Sets the width of the 3-D border
around the outside edge of the widget. The <B>-relief</B> option determines if
the border is to be drawn. The default is <I>2</I>. </DD>
<DT><B>-bottommargin <I>pixels</I></B> </DT>
<DD>If non-zero,
overrides the computed size of the margin extending below the X-coordinate
axis. If <I>pixels</I> is <I>0</I>, the automatically computed size is used. 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>If non-zero, overrides the computed size of the margin extending
from the left edge of the window to the Y-coordinate axis. If <I>pixels</I> is
<I>0</I>, the automatically computed size is used. 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 graph
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>If non-zero, overrides
the computed size of the margin extending from the plotting area to the
right edge of the window. By default, the legend is drawn in this margin.
If <I>pixels</I> is <I>0</I>, the automatically computed size is used. The default
is <I>0</I>. </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>If non-zero, overrides
the computed size of the margin above the x2 axis. If <I>pixels</I> is <I>0</I>, the
automatically computed size is used. The default is <I>0</I>. </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 graph. 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="sect7" HREF="#toc7">Graph Components</A></H2>
A graph is composed
of several components: coordinate axes, data elements, legend, grid, cross
hairs, postscript, and annotation markers. Instead of one big set of configuration
options and operations, the graph is partitioned, where each component
has its own configuration options and operations that specifically control
that aspect or part of the graph.
<H3><A NAME="sect8" HREF="#toc8">Axis Components</A></H3>
Four coordinate axes are
automatically created: two X-coordinate axes (<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 have several
axes. To create an axis, invoke the axis component and its create operation.
<BR>
<CODE># Create a new axis called "tempAxis"<BR>
.g axis create tempAxis<BR>
</CODE><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 tempAxis data to this axis.<BR>
.g element create "e1" -xdata $x -ydata $y -mapy tempAxis<BR>
</CODE><P>Any number of axes can be displayed simultaneously. They are drawn in the
margins surrounding the plotting area. The default 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. By default, only <I>x</I> and <I>y</I> are shown. Note that the axes can
have different scales. <P>
To display a different axis or more than one axis,
you invoke one of the following components: <B>xaxis</B>, <B>yaxis</B>, <B>x2axis</B>, and <B>y2axis</B>.
Each component has a <B>use</B> operation that designates the axis (or axes)
to be drawn in that corresponding margin: <B>xaxis</B> in the bottom, <B>yaxis</B> in
the left, <B>x2axis</B> in the top, and <B>y2axis</B> in the right. <BR>
<CODE># Display the axis tempAxis in the left margin.<BR>
.g yaxis use tempAxis<BR>
</CODE><P>The <B>use</B> operation takes a list of axis names as its last argument. This
is the list of axes to be drawn in this margin. <P>
You can configure axes in
many ways. The axis scale can be linear or logarithmic. The values along
the axis can either monotonically increase or decrease. If you need custom
tick labels, you can specify a Tcl procedure to format the label any way
you wish. You can control how ticks are drawn, by changing the major tick
interval or the number of minor ticks. You can define non-uniform tick intervals,
such as for time-series plots. <P>
<DL>
<DT><I>pathName <B>axis bind <I>tagName</I></B></I> ?<I>sequence</I>? ?<I>command</I>?
</DT>
<DD>Associates <I>command</I> with <I>tagName</I> such that whenever the event sequence
given by <I>sequence</I> occurs for an axis with this tag, <I>command</I> will be invoked.
The syntax is similar to the <B>bind</B> command except that it operates on
graph axes, rather than widgets. See the <B>bind</B> manual entry for complete
details on <I>sequence</I> and the substitutions performed on <I>command</I> before
invoking it. <P>
If all arguments are specified then a new binding is created,
replacing any existing binding for the same <I>sequence</I> and <I>tagName</I>. If the
first character of <I>command</I> is <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>axis <B>cget <I>axisName <I>option</I></I></B></B></I> </DT>
<DD>Returns the
current value of the option given by <I>option</I> for <I>axisName</I>. <I>Option</I> may be
any option described below for the axis <B>configure</B> operation. </DD>
<DT><I>pathName <B>axis
<B>configure <I>axisName </I></B></B></I>?<I>axisName</I>?... ?<I>option value</I>?... </DT>
<DD>Queries or modifies the configuration
options of <I>axisName</I>. Several axes can be changed. If <I>option</I> isn't specified,
a list describing all the current options for <I>axisName</I> is returned. If
<I>option</I> is specified, but not <I>value</I>, then a list describing <I>option</I> is returned.
If one or more <I>option</I> and <I>value</I> pairs are specified, then for each pair,
the axis option <I>option</I> is set to <I>value</I>. The following options are valid
for axes. <blockquote></DD>
<DT><B>-bindtags <I>tagList</I></B> </DT>
<DD>Specifies the binding tags for the axis. <I>TagList</I>
is a list of binding tag names. The tags and their order will determine
how events for axes are handled. Each tag in the list matching the current
event sequence will have its Tcl command executed. Implicitly the name
of the element is always the first tag in the list. The default value is
<I>all</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 graph is redrawn. You may query configuration
options. But do not them, because this can have unexpected results. </DD>
<DT><B>-descending
<I>boolean</I></B> </DT>
<DD>Indicates whether the values along the axis are monotonically
increasing or decreasing. If <I>boolean</I> is true, the axis values will be decreasing.
The default is <I>0</I>. </DD>
<DT><B>-hide <I>string</I></B> </DT>
<DD>Indicates if the axis and all the elements
mapped to it will be displayed. The valid values for <I>string</I> are shown
below. The default value is <I>0</I>. <blockquote></DD>
<DT><I>false</I> </DT>
<DD>The axis and its data elements are
displayed. </DD>
<DT><I>true</I> </DT>
<DD>The axis is hidden, but the data elements mapped to it are
displayed. </DD>
<DT><I>all</I> </DT>
<DD>The axis and its data elements are hidden. </DD>
</DL>
</blockquote>
<DL>
<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. If
the axis limit is set with the -min or -max option, the axes are displayed
tightly. If <I>boolean</I> is true, the axis range is "loose". The default is <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>-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 *Graph.Axis.Color blue<BR>
option add *Graph.x.LogScale true<BR>
option add *Graph.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>
The default axes are <I>x</I>, <I>y</I>, <I>x2</I>,
and <I>y2</I>. But you can display more than four axes simultaneously. You can
also swap in a different axis with <B>use</B> operation of the special axis components:
<B>xaxis</B>, <B>x2axis</B>, <B>yaxis</B>, and <B>y2axis</B>. <BR>
<CODE>.g create axis temp<BR>
.g create axis time<BR>
...<BR>
.g xaxis use temp<BR>
.g yaxis use time<BR>
</CODE><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. 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>.
When more than one axis is displayed in a margin, it represents the first
axis displayed. <P>
The following operations are available for axes. They mirror
exactly the operations of the <B>axis</B> component. The <I>axis</I> argument must be
<B>xaxis</B>, <B>x2axis</B>, <B>yaxis</B>, or <B>y2axis</B>. This feature is deprecated since more
than one axis can now be used a margin. You should only use the <B>xaxis</B>,
<B>x2axis</B>, <B>yaxis</B>, and <B>y2axis</B> components with the <B>use</B> operation. For all other
operations, use the general <B>axis</B> component instead.
<DL>
<DT><I>pathName <I>axis <B>cget <I>option</I></B></I></I>
</DT>
<DD></DD>
<DT><I>pathName <I>axis <B>configure </B></I></I>?<I>option value</I>?... </DT>
<DD></DD>
<DT><I>pathName <I>axis<B> invtransform <I>value</I></B></I></I>
</DT>
<DD></DD>
<DT><I>pathName <I>axis <B>limits</B></I></I> </DT>
<DD></DD>
<DT><I>pathName <I>axis<B> transform <I>value</I></B></I></I> </DT>
<DD></DD>
<DT><I>pathName <I>axis<B> use </B></I></I>?<I>axisName</I>?
</DT>
<DD>Designates the axis <I>axisName</I> is to be displayed at this location. <I>AxisName</I>
can not be already in use at another location. This command returns the
name of the axis currently using this location. </DD>
</DL>
<H3><A NAME="sect9" HREF="#toc9">Crosshairs Component</A></H3>
Cross
hairs consist of two intersecting lines (one vertical and one horizontal)
drawn completely across the plotting area. They are used to position the
mouse in relation to the coordinate axes. Cross hairs differ from line
markers in that they are implemented using XOR drawing primitives. This
means that they can be quickly drawn and erased without redrawing the entire
graph. <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 *Graph.Crosshairs.LineWidth 2<BR>
option add *Graph.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>
<H3><A NAME="sect10" HREF="#toc10">Element Components</A></H3>
A data element represents a set of data.
It contains x and y vectors containing the coordinates of the data points.
Elements can be displayed with a symbol at each data point and lines connecting
the points. Elements also control the appearance of the data, such as the
symbol type, line width, color etc. <P>
When new data elements are created,
they are automatically added to a list of displayed elements. The display
list controls what elements are drawn and in what order. <P>
The following
operations are available for elements.
<DL>
<DT><I>pathName <B>element activate <I>elemName
</I></B></I>?<I>index</I>?... </DT>
<DD>Specifies the data points of element <I>elemName</I> to be drawn using
active foreground and background colors. <I>ElemName</I> is the name of the element
and <I>index</I> is a number representing the index of the data point. If no indices
are present then all data points become active. </DD>
<DT><I>pathName <B>element bind <I>tagName</I></B></I>
?<I>sequence</I>? ?<I>command</I>? </DT>
<DD>Associates <I>command</I> with <I>tagName</I> such that whenever
the event sequence given by <I>sequence</I> occurs for an element with this tag,
<I>command</I> will be invoked. The syntax is similar to the <B>bind</B> command except
that it operates on graph elements, rather than widgets. See the <B>bind</B> manual
entry for complete details on <I>sequence</I> and the substitutions performed
on <I>command</I> before invoking it. <P>
If all arguments are specified then a
new binding is created, replacing any existing binding for the same <I>sequence</I>
and <I>tagName</I>. If the first character of <I>command</I> is <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>varName</I> ?<I>option value</I>?...
?<I>elemName</I>?... </DT>
<DD>Finds the data point 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, that must
not be hidden. If no elements are specified, then all visible elements
are searched. It returns via the array variable <I>varName</I> the name of the
closest element, the index of its closest point, and the graph coordinates
of the point. Returns <I>0</I>, if no data point within the threshold distance
can be found, otherwise <I>1</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
graph's <B>-halo</B> option. </DD>
<DT><B>-interpolate <I>string</I></B> </DT>
<DD>Indicates whether to consider projections
that lie along the line segments connecting data points when searching
for the closest point. The default value is <I>0</I>. The values for <I>string</I> are
described below. <blockquote></DD>
<DT><I>no</I> </DT>
<DD>Search only for the closest data point. </DD>
<DT><I>yes</I> </DT>
<DD>Search includes
projections that lie along the line segments connecting the data points.
</DD>
<DT><I>x</I> </DT>
<DD>Search includes vertical projections from the given X-coordinate. </DD>
<DT><I>y</I>
</DT>
<DD>Search includes horizontal projections from the given Y-coordinate. </DD>
</DL>
</blockquote>
</blockquote>
<DL>
<DT><I>pathName
<B>element configure <I>elemName </I></B></I>?<I>elemName</I>... ?<I>option value</I>?... </DT>
<DD>Queries or modifies
the configuration options for elements. Several elements can be modified
at the same time. If <I>option</I> isn't specified, a list describing all the current
options for <I>elemName</I> is returned. If <I>option</I> is specified, but not <I>value</I>,
then a list describing the option <I>option</I> is returned. If one or more <I>option</I>
and <I>value</I> pairs are specified, then for each pair, the element option <I>option</I>
is set to <I>value</I>. The following options are valid for elements. <blockquote></DD>
<DT><B>-activepen
<I>penName</I></B> </DT>
<DD>Specifies pen to use to draw active element. If <I>penName</I> is <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 are handled
for elements. Each tag in the list matching the current event sequence
will have its Tcl command executed. Implicitly the name of the element
is always the first tag in the list. The default value is <I>all</I>. </DD>
<DT><B>-color <I>color</I></B>
</DT>
<DD>Sets the color of the traces connecting the data points. </DD>
<DT><B>-dashes <I>dashList</I></B>
</DT>
<DD>Sets the dash style of element line. <I>DashList</I> is a list of up to 11 numbers
that alternately represent the lengths of the dashes and gaps on the element
line. Each number must be between 1 and 255. If <I>dashList</I> is <I>""</I>, the lines
will be solid. </DD>
<DT><B>-data <I>coordList</I></B> </DT>
<DD>Specifies the X-Y coordinates of the data.
<I>CoordList</I> is a list of numeric expressions representing the X-Y coordinate
pairs of each data point. </DD>
<DT><B>-fill <I>color</I></B> </DT>
<DD>Sets the interior color of symbols.
If <I>color</I> is <I>""</I>, then the interior of the symbol is transparent. If <I>color</I>
is <I>defcolor</I>, then the color will be the same as the <B>-color</B> option. The default
is <I>defcolor</I>. </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>-linewidth <I>pixels</I></B> </DT>
<DD>Sets the width of the connecting lines
between data points. If <I>pixels</I> is <I>0</I>, no connecting lines will be drawn
between symbols. The default is <I>0</I>. </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>-offdash <I>color</I></B> </DT>
<DD>Sets the
color of the stripes when traces are dashed (see the <B>-dashes</B> option). If
<I>color</I> is <I>""</I>, then the "off" pixels will represent gaps instead of stripes.
If <I>color</I> is <I>defcolor</I>, then the color will be the same as the <B>-color</B> option.
The default is <I>defcolor</I>. </DD>
<DT><B>-outline <I>color</I></B> </DT>
<DD>Sets the color or the outline around
each symbol. If <I>color</I> is <I>""</I>, then no outline is drawn. If <I>color</I> is <I>defcolor</I>,
then the color will be the same as the <B>-color</B> option. The default is <I>defcolor</I>.
</DD>
<DT><B>-outlinewidth <I>pixels</I></B> </DT>
<DD>Sets the width of the outline bordering each symbol.
If <I>pixels</I> is <I>0</I>, no outline will be drawn. The default is <I>1</I>. </DD>
<DT><B>-pixels <I>pixels</I></B>
</DT>
<DD>Sets the size of symbols. If <I>pixels</I> is <I>0</I>, no symbols will be drawn. The
default is <I>0.125i</I>. </DD>
<DT><B>-scalesymbols <I>boolean</I></B> </DT>
<DD>If <I>boolean</I> is true, the size of
the symbols drawn for <I>elemName</I> will change with scale of the X-axis and
Y-axis. At the time this option is set, the current ranges of the axes are
saved as the normalized scales (i.e scale factor is 1.0) and the element
is drawn at its designated size (see the <B>-pixels</B> option). As the scale of
the axes change, the symbol will be scaled according to the smaller of
the X-axis and Y-axis scales. If <I>boolean</I> is false, the element's symbols are
drawn at the designated size, regardless of axis scales. The default is
<I>0</I>. </DD>
<DT><B>-smooth <I>smooth</I></B> </DT>
<DD>Specifies how connecting line segments are drawn between
data points. <I>Smooth</I> can be either <I>linear</I>, <I>step</I>, <I>natural</I>, or <I>quadratic</I>. If
<I>smooth</I> is <I>linear</I>, a single line segment is drawn, connecting both data
points. When <I>smooth</I> is <I>step</I>, two line segments are drawn. The first is a
horizontal line segment that steps the next X-coordinate. The second is
a vertical line, moving to the next Y-coordinate. Both <I>natural</I> and <I>quadratic</I>
generate multiple segments between data points. If <I>natural</I>, the segments
are generated using a cubic spline. If <I>quadratic</I>, a quadratic spline is
used. The default is <I>linear</I>. </DD>
<DT><B>-styles <I>styleList</I></B> </DT>
<DD>Specifies what pen to use
based on the range of weights given. <I>StyleList</I> is a list of style specifications.
Each style specification, in turn, is a list consisting of a pen name,
and optionally a minimum and maximum range. Data points whose weight (see
the <B>-weight</B> option) falls in this range, are drawn with this pen. If no
range is specified it defaults to the index of the pen in the list. Note
that this affects only symbol attributes. Line attributes, such as line
width, dashes, etc. are ignored. </DD>
<DT><B>-symbol <I>symbol</I></B> </DT>
<DD>Specifies the symbol for
data points. <I>Symbol</I> can be either <I>square</I>, <I>circle</I>, <I>diamond</I>, <I>plus</I>, <I>cross</I>,
<I>splus</I>, <I>scross</I>, <I>triangle</I>, <I>""</I> (where no symbol is drawn), or a bitmap. Bitmaps
are specified as "<I>source</I> ?<I>mask</I>?", where <I>source</I> is the name of the bitmap,
and <I>mask</I> is the bitmap's optional mask. The default is <I>circle</I>. </DD>
<DT><B>-trace <I>direction</I></B>
</DT>
<DD>Indicates whether connecting lines between data points (whose X-coordinate
values are either increasing or decreasing) are drawn. <I>Direction</I> must
be <I>increasing</I>, <I>decreasing</I>, or <I>both</I>. For example, if <I>direction</I> is <I>increasing</I>,
connecting lines will be drawn only between those data points where X-coordinate
values are monotonically increasing. If <I>direction</I> is <I>both</I>, connecting lines
will be draw between all data points. The default is <I>both</I>. </DD>
<DT><B>-weights <I>wVec</I></B>
</DT>
<DD>Specifies the weights of the individual data points. This, with the list
pen styles (see the <B>-styles</B> option), controls how data points are drawn.
<I>WVec</I> is the name of a BLT vector or a list of numeric expressions representing
the weights for each data point. </DD>
<DT><B>-xdata <I>xVec</I></B> </DT>
<DD>Specifies the X-coordinates
of the data. <I>XVec</I> is the name of a BLT vector or a list of numeric expressions.
</DD>
<DT><B>-ydata <I>yVec</I></B> </DT>
<DD>Specifies the Y-coordinates of the data. <I>YVec</I> is the name of
a BLT vector or a list of numeric expressions. </DD>
</DL>
<P>
Element configuration options
may also be set by the <B>option</B> command. The resource class is <I>Element</I>. The
resource name is the name of the element. <BR>
<CODE>option add *Graph.Element.symbol line<BR>
option add *Graph.e1.symbol line<BR>
</blockquote>
<DL>
<DT></CODE><P><I>pathName <B>element create <I>elemName</I></B></I> ?<I>option value</I>?... </DT>
<DD>Creates a new element <I>elemName</I>.
It's an error is an element <I>elemName</I> already exists. If additional arguments
are present, they specify options valid for the element <B>configure</B> operation.
</DD>
<DT><I>pathName <B>element deactivate <I>elemName</I></B></I> ?<I>elemName</I>?... </DT>
<DD>Deactivates all the elements
matching <I>pattern</I>. Elements whose names match any of the patterns given are
redrawn using their normal colors. </DD>
<DT><I>pathName <B>element delete</B></I> ?<I>elemName</I>?... </DT>
<DD>Deletes
all the named elements. The graph is automatically redrawn. </DD>
<DT><I>pathName <B>element
exists <I>elemName</I></B></I> </DT>
<DD>Returns <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="sect11" HREF="#toc11"></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 *Graph.grid.LineWidth 2<BR>
option add *Graph.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="sect12" HREF="#toc12">Legend Component</A></H3>
The legend displays a list of the data elements.
Each entry consists of the element's symbol and label. The legend can appear
in any margin (the default location is in the right margin). It can also
be positioned anywhere within the plotting area. <P>
The following operations
are valid for the legend.
<DL>
<DT><I>pathName <B>legend activate <I>pattern</I></B></I>... </DT>
<DD>Selects legend
entries to be drawn using the active legend colors and relief. All entries
whose element names match <I>pattern</I> are selected. To be selected, the element
name must match only one <I>pattern</I>. </DD>
<DT><I>pathName <B>legend bind <I>tagName</I></B></I> ?<I>sequence</I>?
?<I>command</I>? </DT>
<DD>Associates <I>command</I> with <I>tagName</I> such that whenever the event
sequence given by <I>sequence</I> occurs for a legend entry with this tag, <I>command</I>
will be invoked. Implicitly the element names in the entry are tags. The
syntax is similar to the <B>bind</B> command except that it operates on legend
entries, rather than widgets. See the <B>bind</B> manual entry for complete details
on <I>sequence</I> and the substitutions performed on <I>command</I> before invoking
it. <P>
If all arguments are specified then a new binding is created, replacing
any existing binding for the same <I>sequence</I> and <I>tagName</I>. If the first character
of <I>command</I> is <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 are handled for legend entries. Each tag in the list matching
the current event sequence will have its Tcl command executed. The default
value is <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 graph; for example, <I>raised</I> means the
legend should appear to protrude from the graph, relative to the surface
of the graph. 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 *Graph.legend.Foreground blue<BR>
option add *Graph.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="sect13" HREF="#toc13">Pen Components</A></H3>
Pens define
attributes (both symbol and line style) for elements. Pens mirror the configuration
options of data elements that pertain to how symbols and lines are drawn.
Data elements use pens to determine how they are drawn. A data element
may use several pens at once. In this case, the pen used for a particular
data point is determined from each element's weight vector (see the element's
<B>-weight</B> and <B>-style</B> options). <P>
One pen, called <I>activeLine</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 "activeLine" -color green<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 "line1" -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 "line1" -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>-color <I>color</I></B>
</DT>
<DD>Sets the color of the traces connecting the data points. </DD>
<DT><B>-dashes <I>dashList</I></B>
</DT>
<DD>Sets the dash style of element line. <I>DashList</I> is a list of up to 11 numbers
that alternately represent the lengths of the dashes and gaps on the element
line. Each number must be between 1 and 255. If <I>dashList</I> is <I>""</I>, the lines
will be solid. </DD>
<DT><B>-fill <I>color</I></B> </DT>
<DD>Sets the interior color of symbols. If <I>color</I>
is <I>""</I>, then the interior of the symbol is transparent. If <I>color</I> is <I>defcolor</I>,
then the color will be the same as the <B>-color</B> option. The default is <I>defcolor</I>.
</DD>
<DT><B>-linewidth <I>pixels</I></B> </DT>
<DD>Sets the width of the connecting lines between data points.
If <I>pixels</I> is <I>0</I>, no connecting lines will be drawn between symbols. The
default is <I>0</I>. </DD>
<DT><B>-offdash <I>color</I></B> </DT>
<DD>Sets the color of the stripes when traces are
dashed (see the <B>-dashes</B> option). If <I>color</I> is <I>""</I>, then the "off" pixels will
represent gaps instead of stripes. If <I>color</I> is <I>defcolor</I>, then the color
will be the same as the <B>-color</B> option. The default is <I>defcolor</I>. </DD>
<DT><B>-outline <I>color</I></B>
</DT>
<DD>Sets the color or the outline around each symbol. If <I>color</I> is <I>""</I>, then
no outline is drawn. If <I>color</I> is <I>defcolor</I>, then the color will be the same
as the <B>-color</B> option. The default is <I>defcolor</I>. </DD>
<DT><B>-outlinewidth <I>pixels</I></B> </DT>
<DD>Sets
the width of the outline bordering each symbol. If <I>pixels</I> is <I>0</I>, no outline
will be drawn. The default is <I>1</I>. </DD>
<DT><B>-pixels <I>pixels</I></B> </DT>
<DD>Sets the size of symbols.
If <I>pixels</I> is <I>0</I>, no symbols will be drawn. The default is <I>0.125i</I>. </DD>
<DT><B>-symbol <I>symbol</I></B>
</DT>
<DD>Specifies the symbol for data points. <I>Symbol</I> can be either <I>square</I>, <I>circle</I>,
<I>diamond</I>, <I>plus</I>, <I>cross</I>, <I>splus</I>, <I>scross</I>, <I>triangle</I>, <I>""</I> (where no symbol is drawn),
or a bitmap. Bitmaps are specified as "<I>source</I> ?<I>mask</I>?", where <I>source</I> is
the name of the bitmap, and <I>mask</I> is the bitmap's optional mask. The default
is <I>circle</I>. </DD>
<DT><B>-type <I>elemType</I></B> </DT>
<DD>Specifies the type of element the pen is to be
used with. This option should only be employed when creating the pen. This
is for those that wish to mix different types of elements (bars and lines)
on the same graph. The default type is "line". </DD>
</DL>
<P>
Pen configuration options
may be also be set by the <B>option</B> command. The resource class is <I>Pen</I>. The
resource names are the names of the pens. <BR>
<CODE>option add *Graph.Pen.Color blue<BR>
option add *Graph.activeLine.color green<BR>
</blockquote>
<DL>
<DT></CODE><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="sect14" HREF="#toc14">PostScript
Component</A></H3>
The graph can generate encapsulated PostScript output. There are
several configuration options you can specify to control how the plot will
be generated. You can change the page dimensions and borders. The plot
itself can be scaled, centered, or rotated to landscape. The PostScript
output can be written directly to a file or returned through the interpreter.
<P>
The following postscript operations are available.
<DL>
<DT><I>pathName <B>postscript cget
<I>option</I></B></I> </DT>
<DD>Returns the current value of the postscript option given by <I>option</I>.
<I>Option</I> may be any option described below for the postscript <B>configure</B>
operation. </DD>
<DT><I>pathName <B>postscript configure </B></I>?<I>option value</I>?... </DT>
<DD>Queries or modifies
the configuration options for PostScript generation. If <I>option</I> isn't specified,
a list describing the current postscript options for <I>pathName</I> is returned.
If <I>option</I> is specified, but not <I>value</I>, then a list describing <I>option</I> is
returned. If one or more <I>option</I> and <I>value</I> pairs are specified, then for
each pair, the postscript option <I>option</I> is set to <I>value</I>. The following
postscript options are available. <blockquote></DD>
<DT><B>-center <I>boolean</I></B> </DT>
<DD>Indicates whether the plot
should be centered on the PostScript page. If <I>boolean</I> is false, the plot
will be placed in the upper left corner of the page. The default is <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 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 graph with a height different from the one drawn on the screen.
If <I>pixels</I> is 0, the height is the same as the widget's height. The default
is <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 graph 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 *Graph.postscript.Decorations false<BR>
option add *Graph.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="sect15" HREF="#toc15">Marker
Components</A></H3>
Markers are simple drawing procedures used to annotate or highlight
areas of the graph. Markers have various types: text strings, bitmaps,
images, connected lines, windows, or polygons. They can be associated with
a particular element, so that when the element is hidden or un-hidden, so
is the marker. By default, markers are the last items drawn, so that data
elements will appear in behind them. You can change this by configuring
the <B>-under</B> option. <P>
Markers, in contrast to elements, don't affect the scaling
of the coordinate axes. They can also have <I>elastic</I> coordinates (specified
by <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 element symbols and lines. 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 *Graph.TextMarker.Foreground white<BR>
option add *Graph.BitmapMarker.Foreground white<BR>
option add *Graph.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="sect16" HREF="#toc16">Bitmap Markers</A></H3>
A bitmap marker displays a bitmap. The size of
the bitmap is controlled by the number of coordinates specified. If two
coordinates, they specify the position of the top-left corner of the bitmap.
The bitmap retains its normal width and height. If four coordinates, the
first and second pairs of coordinates represent the corners of the bitmap.
The bitmap will be stretched or reduced as necessary to fit into the bounding
rectangle. <P>
Bitmap markers are created with the marker's <B>create</B> operation
in the form: <BR>
<P>
<CODE><I>pathName <B>marker create bitmap </B></I>?<I>option value</I>?...<BR>
</CODE><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="sect17" HREF="#toc17">Image Markers</A></H3>
A image marker
displays an image. Image markers are created with the marker's <B>create</B> operation
in the form: <BR>
<P>
<CODE><I>pathName <B>marker create image </B></I>?<I>option value</I>?...<BR>
</CODE><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="sect18" HREF="#toc18">Line Markers</A></H3>
A line marker displays one or more connected
line segments. Line markers are created with marker's <B>create</B> operation in
the form: <BR>
<P>
<CODE><I>pathName <B>marker create line </B></I>?<I>option value</I>?...<BR>
</CODE><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>-fdashes</B> option). If <I>color</I> is the empty
string, no background color is drawn (the line will be dashed, not striped).
The default background color is <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="sect19" HREF="#toc19">Polygon Markers</A></H3>
A polygon
marker displays a closed region described as two or more connected line
segments. It is assumed the first and last points are connected. Polygon
markers are created using the marker <B>create</B> operation in the form: <BR>
<P>
<CODE><I>pathName <B>marker create polygon </B></I>?<I>option value</I>?...<BR>
</CODE><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="sect20" HREF="#toc20">Text
Markers</A></H3>
A text marker displays a string of characters on one or more lines
of text. Embedded newlines cause line breaks. They may be used to annotate
regions of the graph. Text markers are created with the <B>create</B> operation
in the form: <BR>
<P>
<CODE><I>pathName <B>marker create text </B></I>?<I>option value</I>?...<BR>
</CODE><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="sect21" HREF="#toc21">Window Markers</A></H3>
A window
marker displays a widget at a given position. Window markers are created
with the marker's <B>create</B> operation in the form: <BR>
<P>
<CODE><I>pathName <B>marker create window </B></I>?<I>option value</I>?...<BR>
</CODE><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 graph. <I>PathName</I> must be a child of the <B>graph</B> widget. </DD>
</DL>
<H2><A NAME="sect22" HREF="#toc22">Graph Component
Bindings</A></H2>
Specific graph components, such as elements, markers and legend
entries, can have a command trigger when event occurs in them, much like
canvas items in Tk's canvas widget. Not all event sequences are valid. The
only binding events that may be specified are those related to the mouse
and keyboard (such as <B>Enter</B>, <B>Leave</B>, <B>ButtonPress</B>, <B>Motion</B>, and <B>KeyPress</B>).
<P>
Only one element or marker can be picked during an event. This means, that
if the mouse is directly over both an element and a marker, only the uppermost
component is selected. This isn't true for legend entries. Both a legend
entry and an element (or marker) binding commands will be invoked if both
items are picked. <P>
It is possible for multiple bindings to match a particular
event. This could occur, for example, if one binding is associated with
the element name and another is associated with one of the element's tags
(see the <B>-bindtags</B> option). When this occurs, all of the matching bindings
are invoked. A binding associated with the element name is invoked first,
followed by one binding for each of the element's bindtags. If there are
multiple matching bindings for a single tag, then only the most specific
binding is invoked. A continue command in a binding script terminates
that script, and a break command terminates that script and skips any
remaining scripts for the event, just as for the bind command. <P>
The <B>-bindtags</B>
option for these components controls addition tag names which can be matched.
Implicitly elements and markers always have tags matching their names.
Setting the value of the <B>-bindtags</B> option doesn't change this.
<H2><A NAME="sect23" HREF="#toc23">C Language
API</A></H2>
You can manipulate data elements from the C language. There may be situations
where it is too expensive to translate the data values from ASCII strings.
Or you might want to read data in a special file format. <P>
Data can manipulated
from the C language using BLT vectors. You specify the X-Y data coordinates
of an element as vectors and manipulate the vector from C. The graph will
be redrawn automatically after the vectors are updated. <P>
From Tcl, create
the vectors and configure the element to use them. <BR>
<CODE>vector X Y<BR>
.g element configure line1 -xdata X -ydata Y<BR>
</CODE><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 <tcl.h><BR>
#include <blt.h><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", &xVec) != TCL_OK) ||<BR>
(Blt_GetVector(interp, "Y", &yVec) != TCL_OK)) {<BR>
return TCL_ERROR;<BR>
}<BR>
<P>
for (i = 0; i < 50; i++) {<BR>
x[i] = i * 0.02;<BR>
y[i] = sin(x[i]);<BR>
}<tt> </tt> <tt> </tt> <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="sect24" HREF="#toc24">Speed Tips</A></H2>
There may be cases
where the graph needs to be drawn and updated as quickly as possible. If
drawing speed becomes a big problem, here are a few tips to speed up displays.
<UL>
·<LI>Try to minimize the number of data points. The more data points the looked
at, the more work the graph must do. </LI>·<LI>If your data is generated as floating
point values, the time required to convert the data values to and from
ASCII strings can be significant, especially when there any many data points.
You can avoid the redundant string-to-decimal conversions using the C API
to BLT vectors. </LI>·<LI>Data elements without symbols are drawn faster than with
symbols. Set the data element's <B>-symbol</B> option to <I>none</I>. If you need to draw
symbols, try using the simple symbols such as <I>splus</I> and <I>scross</I>. </LI>·<LI>Don't stipple
or dash the element. Solid lines are much faster. </LI>·<LI>If you update data elements
frequently, try turning off the widget's <B>-bufferelements</B> option. When the
graph is first displayed, it draws data elements into an internal pixmap.
The pixmap acts as a cache, so that when the graph needs to be redrawn
again, and the data elements or coordinate axes haven't changed, the pixmap
is simply copied to the screen. This is especially useful when you are
using markers to highlight points and regions on the graph. But if the
graph is updated frequently, changing either the element data or coordinate
axes, the buffering becomes redundant. </LI>
</UL>
<H2><A NAME="sect25" HREF="#toc25">Limitations</A></H2>
Auto-scale routines do
not use requested min/max limits as boundaries when the axis is logarithmically
scaled. <P>
The PostScript output generated for polygons with more than 1500
points may exceed the limits of some printers (See PostScript Language
Reference Manual, page 568). The work-around is to break the polygon into
separate pieces.
<H2><A NAME="sect26" HREF="#toc26">Keywords</A></H2>
graph, widget <P>
<HR><P>
<A NAME="toc"><B>Table of Contents</B></A><P>
<UL>
<LI><A NAME="toc0" HREF="#sect0">Name</A></LI>
<LI><A NAME="toc1" HREF="#sect1">Synopsis</A></LI>
<LI><A NAME="toc2" HREF="#sect2">Description</A></LI>
<LI><A NAME="toc3" HREF="#sect3">Introduction</A></LI>
<LI><A NAME="toc4" HREF="#sect4">Syntax</A></LI>
<LI><A NAME="toc5" HREF="#sect5">Example</A></LI>
<LI><A NAME="toc6" HREF="#sect6">Graph Operations</A></LI>
<LI><A NAME="toc7" HREF="#sect7">Graph Components</A></LI>
<UL>
<LI><A NAME="toc8" HREF="#sect8">Axis Components</A></LI>
<LI><A NAME="toc9" HREF="#sect9">Crosshairs Component</A></LI>
<LI><A NAME="toc10" HREF="#sect10">Element Components</A></LI>
<LI><A NAME="toc11" HREF="#sect11">Grid Component</A></LI>
<LI><A NAME="toc12" HREF="#sect12">Legend Component</A></LI>
<LI><A NAME="toc13" HREF="#sect13">Pen Components</A></LI>
<LI><A NAME="toc14" HREF="#sect14">PostScript Component</A></LI>
<LI><A NAME="toc15" HREF="#sect15">Marker Components</A></LI>
<LI><A NAME="toc16" HREF="#sect16">Bitmap Markers</A></LI>
<LI><A NAME="toc17" HREF="#sect17">Image Markers</A></LI>
<LI><A NAME="toc18" HREF="#sect18">Line Markers</A></LI>
<LI><A NAME="toc19" HREF="#sect19">Polygon Markers</A></LI>
<LI><A NAME="toc20" HREF="#sect20">Text Markers</A></LI>
<LI><A NAME="toc21" HREF="#sect21">Window Markers</A></LI>
</UL>
<LI><A NAME="toc22" HREF="#sect22">Graph Component Bindings</A></LI>
<LI><A NAME="toc23" HREF="#sect23">C Language API</A></LI>
<LI><A NAME="toc24" HREF="#sect24">Speed Tips</A></LI>
<LI><A NAME="toc25" HREF="#sect25">Limitations</A></LI>
<LI><A NAME="toc26" HREF="#sect26">Keywords</A></LI>
</UL>
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