#set TITLE = "proc breakaxis"
#include top

.SH DESCRIPTION
\fBproc breakaxis\fR may be used to render a "break" symbol
when preparing plots that have a broken axis in order to accomodate
an extreme value.  (Introduced in version 1.3).
.LP
In terms of plotting mechanics, breaking an axis means that one
region of the plotting area uses one scale space, while the other
region uses a different scale space.  A "break" symbol is used to
illustrate where these two regions meet.
Ploticus cannot render broken axis plots
automatically; generally they are "by hand" efforts.
.LP
The general approach is to use a "trick": 
set up one space, plot the values with
a truncate option so that the extreme values do not go out of range,
then set up a second space immediately adjacent to the first one,
plot the values again so that only extremeties show, then 
use \fBproc breakaxis\fR to render a break symbol along the
axis and again within the plot.
The two plotting areas must be proportional in scaling.
.LP
Broken axis plotting works with proc bars, proc rangebar, and proc scatterplot.
It currently does not work with lineplots or rangesweep, 
because these are unable to confine to the plotting area.

.SH EXAMPLE
Gallery examples where this is used is
.ig >>
<a href="../gallery/brokenaxis.htm">
.>>
 brokenaxis
.ig >>
</a>
.>>
 and 
.ig >>
<a href="../gallery//spence1_rt.htm">
.>>
spence_rt
.ig >>
</a>
.>>



.SH MANDATORY ATTRIBUTES
The \fCbreakpoint\fR attribute must be specified.

.SH ATTRIBUTES
.LP
\fBaxis\fR \fCx\fR | \fCy\fR
.IP
The axis that is to be broken.  Default is \fCy\fR.

.LP
\fBbreakpoint\fR
.ig >>
<a href="attributetypes.html#plotvalue">
.>>
\fI plotvalue \fR
.ig >>
</a>
.>>
.IP
Where the break is to be rendered, in \fCaxis\fR space.
This attribute \fBmust\fR be specified.
.IP
Example: 
\fCaxis: y
breakpoint: 25\fR
.fi
would break the Y axis at Y = 25.

.LP
\fBlocation\fR \fCaxis\fR | 
.ig >>
<a href="attributetypes.html#plotvalue">
.>>
\fI plotvalue \fR
.ig >>
</a>
.>>
.IP
The location where the break symbol is to be rendered.
\fCaxis\fR causes the symbol to be placed on the left
or bottom axis.  Otherwise, \fIplotvalue\fR is used.
Default is \fCaxis\fR.
.IP
Example: 
\fCaxis: y
breakpoint: 25
location: axis\fR
.fi
would render a break symbol 
on the Y axis at Y = 25.
.IP
Example: 
\fCaxis: y
breakpoint: 25
location: 30\fR
.fi
would render a break symbol at X = 30, Y = 25, presumably
to break a bar, etc.  

.LP
\fBstyle\fR \fCslant\fR | \fCstraight\fR
.IP
The style of the break symbol. Default is \fCslant\fR.

.LP
\fBlinelength\fR \fIn\fR
.IP
The length of the break symbol lines.
\fIn\fR is in absolute units.  Default is 0.2 inches.

.LP
\fBfillcolor\fR
.ig >>
<a href="color.html">
.>>
\fI color \fR
.ig >>
</a>
.>>
.IP
The color used for the rubout area.  Default is the current background
color.  If you used a different color for the plotting area, that color
should be specified here.

.LP
\fBgapsize\fR \fIn\fR
.IP
The distance (in absolute units) between the two lines of the break symbol.

.LP
\fBlinedetails\fR 
.ig >>
<a href="linedetails.html">
.>>
\fI linedetails \fR
.ig >>
</a>
.>>
.IP
Controls the color, line width, etc. of the break symbol lines.

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