Geografic-Information-System/display/d.graph/d.graph.html

<h2>DESCRIPTION</h2>

<em>d.graph</em>
draws graphics that are described either from standard input (default), 
or within a file (if an <b>input</b> file name is identified on the 
command line). If graphics commands are entered from standard input, 
a <em>CTRL-d</em> is used to signal the end of input to <em>d.graph</em>.
Coordinates are given either as a percentage of frame height and width
(default) or in geographic coordinates (with the <b>-m</b> flag).
<p>
The program can be run interactively or non-interactively. 
The user can run the program completely non-interactively 
by specifying the name of a graphics file containing the 
<em>d.graph</em> graphics commands. If run non-interactively the
<em>d.graph</em> command is saved to the display's dedraw history.

The user can also elect to run the program partially interactively, 
by specifying any/all of the parameters <em>except</em> 
the graphics file <b>input=</b><em>name</em> parameter on the command line. 
In this case, <em>d.graph</em> will expect the user to input <em>d.graph</em> 
graphics commands from standard input (i.e., the keyboard) and 
will (silently) prompt the user for these graphics commands. 

<p>Alternately, the user can simply type <b>d.graph</b> on the command line, 
and be prompted for the values of all parameters<!-- (the user can still 
input graphics commands from either an input file or standard input 
using this form)-->. In this case, the user is presented with the standard 
GRASS GUI interface.

<p>The default coordinate system used is 0-100 percent of the active frame 
in x and similarly 0-100 in y,
regardless of the graphics monitor display frame size and aspect. 
The (0,0) location is the lower left corner of the active graphics 
monitor display frame. All values may be floating point.
If the <b>-m</b> flag is given, geographic coordinates will be used instead.


<h2>COMMANDS</h2>

<p>The graphics language is simple, and uses the following commands: 
<br>
<dl>
<dd>[
<a href="#comment">#</a>&nbsp;|
<a href="#move">move</a>&nbsp;|
<a href="#draw">draw</a>&nbsp;|
<a href="#polygon">polygon</a>&nbsp;|
<a href="#polyline">polyline</a>&nbsp;|
<a href="#color">color</a>&nbsp;|
<a href="#text">text</a>&nbsp;|
<a href="#size">size</a>&nbsp;|
<a href="#symbol">symbol</a>&nbsp;|
<a href="#rotation">rotation</a>&nbsp;|
<a href="#icon">icon</a>&nbsp;|
<a href="#width">width</a>
]</dd>
</dl>


<dl>
<dt><a name="comment"></a><b>#</b> <em>comment</em></dt>
<dd>A line of comment which is ignored in the processing.</dd>

<dt><a name="move"></a><b>move</b> <em>xpos ypos</em></dt>
<dd>The current location is updated to <em>xpos ypos</em>. 

Unless the <b>-m</b> flag is used,
values are stated as a percent of the active display frame's 
horizontal (<em>xpos</em>) and vertical (<em>ypos</em>) size, 
and may be floating point values. Values are between 0-100. 
<b>Note.</b> A space must separate <em>xpos</em> and <em>ypos</em>.</dd>

<dt><a name="draw"></a><b>draw</b> <em>xpos ypos</em></dt>
<dd>A line is drawn in the current color from the current location to the new 
location <em>xpos ypos</em>, which then becomes the current location. 
Unless the <b>-m</b> flag is used,
values are stated as a percent of the active display frame's 
horizontal (<em>xpos</em>) and vertical (<em>ypos</em>) size, 
and may be floating point values. Values are between 0-100. 
<b>Note.</b> A space must separate <em>xpos</em> and <em>ypos</em>.</dd>

<dt><a name="polygon"></a><b>polygon</b> 
<br>&nbsp;&nbsp;<em> xpos ypos</em> 
<br>&nbsp;&nbsp;<em> xpos ypos</em> 
<br>&nbsp;&nbsp;...</dt>

<dd>The coordinates appearing beneath the word <em>polygon</em>, 
one pair per line, 
circumscribe a polygon that is to be filled with the current color.</dd>

<dt><a name="polyline"></a><b>polyline</b> 
<br>&nbsp;&nbsp;<em> xpos ypos</em> 
<br>&nbsp;&nbsp;<em> xpos ypos</em> 
<br>&nbsp;&nbsp;...</dt>

<dd>The coordinates appearing beneath the word <em>polyline</em>, 
one pair per line, 
circumscribe a polygon that is not to be filled with color.</dd>

<dt><a name="color"></a><b>color</b> <em>color</em></dt>

<dd>Sets the current color to that stated; subsequent graphics will be drawn 
in the stated color, until the current color is set to a different color. 
Options are <em>red</em>, 
<em>orange</em>,
<em>yellow</em>,
<em>green</em>,
<em>blue</em>,
<em>indigo</em>,
<em>violet</em>,
<em>brown</em>,
<em>magenta</em>,
<em>gray</em>,
<em>white</em>,
<em>black</em>,
an R:G:B triplet (separated by colons),
or the word "none" (draws in the default background color).</dd>

<dt><a name="text"></a><b>text</b> <em>line-of-text</em></dt>
<dd>The stated text is drawn at the current location using the current color, 
and the new current location is then positioned at the end of the text string.</dd>

<dt><a name="size"></a><b>size</b> <em>xper yper</em></dt>
<dd>Subsequent text will be drawn such that the text is 
<em>xper</em> percent of the graphics monitor display frame wide and 
<em>yper</em> percent of the frame high. By default, the text size is set to
5 percent of the active frame's width and 5 percent of the frame's height.
If only one value is given, then that value will be used for both x and y 
scaling.
<br>
<b>Note.</b> A space must separate <em>xper</em> and <em>yper</em>.</dd>

<dt><a name="symbol"></a><b>symbol</b> <em>type size xper yper [line_color [fill_color]]</em></dt>
<dd>A symbol is drawn at the given size on the display monitor. The
<em>xper</em> and <em>yper</em> options define the center of the icon and
are given as a percentage of the display frame (<tt>0,0</tt> is lower left).
The symbol can be any of those stored in <tt>$GISBASE/etc/symbol/</tt>
(e.g. <i>basic/circle</i>) or stored in the user's mapset directory in the
form <tt>$MAPSET/symbol/</tt><em>type/name</em>.
The colors may be either a standard color name, an R:G:B triplet,
or "none". If using an R:G:B triplet, each color value can range from 0-255.
If not specified the default <em>line_color</em> is black and the default 
<em>fill_color</em> is grey.</dd>

<dt><a name="rotation"></a><b>rotation</b> <em>angle</em></dt>
<dd>Subsequent text and symbols will be drawn such that they are rotated 
<em>angle</em> degrees counter-clockwise from east.</dd>

<dt><a name="icon"></a><b>icon</b> <em>type size x y</em></dt>
<dd>Draws an icon of types <em>o</em>, <em>x</em>, or <em>+</em> 
with specified <em>size</em> (in %) at location <em>x,y</em>. 
Note: type <em>o</em> designates a square.</dd>

<dt><a name="width"></a><b>width</b> <em>value</em></dt>
<dd>Subsequent lines (including non-FreeType text) will be drawn with
the given pixel thickness.
<br>The default value is 0.</dd>

</dl>

<h2>EXAMPLES</h2>

For an example use of <em>d.graph</em>, examine the contents of the  
command file <em><a href="grass_logo.txt">grass_logo.txt</a></em>
located in the <em>d.graph</em> source code directory. It will draw the
CERL GRASS logo using the <em>d.graph</em> graphing commands stored in the file. 
Note that the coordinates in the <em><a href="grass_logo.txt">grass_logo.txt</a></em> file were 
taken directly off an image drawn by hand on graph paper. 
<!-- formerly names "grass.logo.sh" in GRASS 5 code. -->
<p>A dynamic example can be found in the <em>d.polar</em> shell script.


<h3>Draw a "star" symbol at a given map coordinate</h3>

<div class="code"><pre>
echo "symbol basic/star 20 2264417 5413182 black red" | d.graph -m
</pre></div>


<h3>Split the screen into quadrants:</h3>

<div class="code"><pre>
d.frame -s full_screen

d.graph &lt;&lt; EOF
  color 80:80:120
  polygon
   0 49.75
   0 50.25
   100 50.25
   100 49.75
  polygon
   49.85 0
   50.15 0
   50.15 100
   49.85 100
EOF
</pre></div>


<h2>NOTES</h2>

<em>d.graph</em> remembers the last screen location (<em>xpos ypos</em>) to which 
the user moved, even after the user erases the display frame. 
If the user runs <em>d.graph</em> repeatedly, and wishes to start anew with 
the default (xpos ypos) screen location, the user should <em>clear</em> the 
display frame between runs of <em>d.graph</em>.

<h2>LIMITATIONS</h2>

There are no automated ways of generating graphic images. It is anticipated 
that GRASS user sites will write programs to convert output from a resident 
graphics editor into GRASS <em>d.graph</em> format.
(e.g. EPS -> <em>d.graph</em>, perhaps with the help of a
<a href="http://www.pstoedit.net/">pstoedit</a> plugin)

<h2>SEE ALSO</h2>

<em>
<a href="d.font.html">d.font</a>,
<a href="d.labels.html">d.labels</a>,
<!-- <a href="d.mapgraph.html">d.mapgraph</a>, superseded by -m -->
<a href="d.polar.html">d.polar</a>,
<a href="d.text.html">d.text</a>,
<a href="d.where.html">d.where</a>
</em>

<h2>AUTHOR</h2>

James Westervelt, U.S. Army Construction Engineering Research Laboratory

<p>
<i>Last changed: $Date$</i>