BGRAPH(1)

NAME
bgraph - do a set of batch graphs to a metafile

SYNOPSIS
bgraph [ -type .. ][ +variable value .. ][ file .. ]

DESCRIPTION
Bgraph reads each graph file in sequence and converts it to a plot suitable for use by a metafile driver program. If no files are given, the standard input is read.

The graph type can be defined with a -type option. Types are simply include files which set default values for certain variables. The actual include file name is the type concatanated with ".plt". Typical types are "scatter", "line", and "curve". A scatter graph shows only points. A line graph shows only lines connecting points. A curve graph shows both points and connecting lines.

Variables can be set explicitly with +variable value options. The following standard graph variables are supported:

fthick
    The frame thickness, valued from 0 to 4. A value of 0 turns the frame off.

grid
    The grid: 1 is on, 0 is off.

include
    The include file name. Graph input is taken from the file. If the file is not found in the current directory, it is searched for in a set of standard locations.

legend
    The legend title.

othick
    The origin axis thickness, valued from 0 to 4. A value of 0 turns the origin off.

period
    The period for a polar plot. For a plot in degrees, use 360. For radians, use 6.283. A value of 0 (the default) indicates a Cartesian plot.

subtitle
    The graph subtitle.

symfile
    The point symbol metafile.

tstyle
    The frame tick mark style. The default value is 1, which is outward tick marks. A value of 2 is inward ticks, 3 is cross ticks. A value of 0 disables frame tick marks.

title
    The graph title.

xlabel
    The x axis label.

xmap
    The x axis mapping function. An x axis mapping xmap(x)=log(x) produces a log x axis.

xmax
    The x axis maximum.

xmin
    The x axis minimum.

xstep
    The x axis step.

ylabel
    The y axis label.

ymap
    The y axis mapping function. An y axis mapping ymap(y)=log(y) produces a log y axis.

ymax
    The y axis maximum.

ymin
    The y axis minimum.

ystep
    The y axis step.

In addition to the standard graph variables, each curve has a set of variables. The variables for curve 'A' all begin with the letter 'A'; the variables for curve 'B' all begin with the letter 'B', and so on. Up to 8 curves are supported on a single graph, 'A' through 'H'. The variables for curve 'A' are:

A   The function for curve 'A'. If Adata is undefined, xmin, xmax and Anpoints are used to determine which x values to plot. If Adata is defined and A is a function of a single variable (ie. A(x)), data values are interpreted as x values to be plotted. If Adata is defined and A is a function of two variables (ie. A(x,y)), data values are interpreted as (x,y) pairs and A becomes a mapping function for the data.

Acolor
    The color for curve A. The values 1-4 map to black, red, green, and blue respectively. A value of 0 turns curve A off.

Adata
    The point data for curve 'A'. If Adata is set to the name of a file, data is read and interpreted from that file. If Adata is set to a command (beginning with an exclamation, '!'), the output of the command is read as data. Otherwise, data is read from the current file. Data values are separated by white space and/or commas. A semicolon or end of file indicates the end of data.

Alabel
    The label for curve 'A'. The curve label is printed in the legend when a curve is defined.

Alintype
    The line type for curve 'A', valued from 0 to 4. A value of 0 turns line drawing off. A value of 1 is solid, 2 is dashed, 3 is dotted, and 4 is dot-dashed.

Anpoints
    The number of symbol points for curve 'A'. If Adata is defined, all points will be connected with the selected curve line, but only Anpoints points will be indicated with a symbol. This prevents messy graphs when large number of points are defined. If A is defined and Adata is not, Anpoints is used along with xmin and xmax to determine which x values to plot.

Asymsize
    The symbol radius for curve 'A'. The default size is 100. A value of 0 turns symbols off.

Asymtype
    This is the name of a segment in symfile which defines the graphics symbol for curve 'A'.

Athick
    The line thickness for curve 'A', valued from 0 to 4. A thickness of 0 turns line drawing off.

GRAPH FILE FORMAT
A graph file contains definitions for graph and curve variables. These definitions fall one per line in the following formats:
	vreal        = expression       # real variable
	vfunction(x) = expression(x)    # function
	vstring      = "string"         # string variable
	vdata        = filename         # data file
	vdata        = "!command"       # data generator
	variable     = continued \
	        line                    # newline escaped
	vdata        =                  # data
		v1 v2 v3 v4 ... ;
Comments are preceded by a '#', and continue to the end of the line. Except for comments, the newline can be escaped with a backslash. Note that in the special case where data is contained in the graph file, a definition will continue over more than one line. Data values can be separated by commas or white space, and reading continues until a semicolon is reached. No comments are allowed in the data section of a file.

An expression is an algebraic formula containing numbers, variables, functions, and the standard operators {+,-,*,/,^,(,)} (see icalc(1)). Besides the variables described in the last section, definitions of intermediate real variables and functions are allowed for convenience. They may be used in expressions of graph and curve variables.

EXAMPLE
A file to graph the sine function is:
	title = "Sine Function from 0 to Pi"
	PI = 3.141592653589793
	A(x) = sin(x)
	xmin = 0
	xmax = PI
	Anpoints = 100
Or, to graph selected points:
	title = "Sine Function at 0, .2, .6, and .8"
	A(x) = sin(x)
	Adata =
		0 , .2
		.6 , .8
	;
The commands to plot these files might be:
	bgraph -line sine1.plt | psmeta | lpr
	bgraph -curve +ymin -1 +ymax 1 sine2.plt | x11meta

FILES
/usr/local/lib/meta/*.mta /usr/local/lib/meta/*.plt *.plt

AUTHOR
Greg Ward

BUGS
There is no mechanism provided for undefining a variable. An axis mapping function which is not invertible (monotonically increasing or decreasing) confuses the program terribly.

SEE ALSO
dgraph(1), gcomp(1), icalc(1), igraph(1), metafile(5), x11meta(1)