d.graph - Program for generating and displaying simple graphics to the graphics display monitor.

d.graph

d.graph help

d.graph [input=string] [color=string]

Parameters:

d.graph draws graphics that are described either from standard input (default), or within a file (if an input file name is identified on the command line). If graphics commands are entered from standard input, a CTRL-d is used to signal the end of input to d.graph.

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

Alternately, the user can simply type d.graph 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 parser interface.

The coordinate system used is 0-100 in x and 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.

The graphics language is simple, and uses the following commands:

"#

A line of comment which is ignored in the processing.

"move

The current location is updated to xpos ypos. Values are stated as a percent of the active display frame's horizontal (xpos) and vertical (ypos) size, and may be floating point values. Values are between 0-100. Note. A space must separate xpos and ypos.

"draw

A line is drawn in the current color from the current location to the new location xpos ypos, which then becomes the current location. Values are stated as a percent of the active display frame's horizontal (xpos) and vertical (ypos) size, and may be floating point values. Values are between 0-100. Note. A space must separate xpos and ypos.

"color

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 red, orange, yellow, green, blue, indigo, violet, brown, magenta, gray, white, and black.

"size

Subsequent text will be drawn such that the text is xper percent of the graphics monitor display frame wide and yper percent of the frame high. By default, the text size is set to 1 percent of the active frame's width and 1 percent of the frame's height if unspecified by the user (this may be too small to be seen by the user).

Note. A space must separate xper and yper.

"text

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.

"icon

xpos ypos

xpos ypos

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

For an example use of d.graph, examine the contents of the macro command $GISBASE/bin/grass.logo.sh located in the GRASS command bin (which draws a GRASS logo by inputting d.graph graphics commands that are stored in a shell file). Note that the coordinates in the grass.logo.sh macro were taken directly off an image drawn by hand on graph paper.

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

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 d.graph format.

d.font

d.mapgraph

d.text

grass.logo.sh

parser

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

Last changed: $Date: 2003/04/11 14:41:45 $

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