Provided by: radiance_4R1+20120125-1.1_amd64 
NAME
metafile - graphics command interface, similar to plot(5)
DESCRIPTION
The metafile graphics format was designed with the primary goal of serving as a temporary
file for routines which output to dot-matrix and other line-at-a-time devices. As a
result, all of the "primitives" are completely self-contained to facilitate sorting.
A primitive is a command which can itself be plotted. Into this catagory fall line
segments, rectangle and triangle fills, matrix and vector strings. Every primitive has a
zeroeth argument which contains bundled attribute information, and an extent. The extent
gives the x and y minimum and maximum values which enclose the primitive. The extent is
used in sorting, and typically also in describing the primitive. For example, a line
segment will be described completely by its enclosing rectangle and attributes including
specification of which diagonal the segment falls on. Other primitives will have
additional arguments, such as vector string, which must specify the string to be output
within its extent.
"Global" commands separate the primitives and allow functions which affect all commands.
These are commands such as end of page, pause, open and close segment, set, unset and
reset, and a special global, end of file. The end of file command is included to
facilitate finding the end of file on systems which do not keep track exactly. Global
commands sometimes have arguments. The open command, for instance, specifies the name of
the segment. Global commands never have extents.
The metafile commands are as follows:
F end of file: no arguments.
When end of file is reached, all processing stops.
E end of page: no arguments.
This causes the device to advance to the next screen or page. If the output device is
a terminal, it will beep and wait for the user to hit return before clearing the
screen.
P pause: arguments specify the message to be printed.
This causes output to be flushed and the controlling terminal to be opened. The user
is then prompted with the specified string followed by the message "- (hit return to
continue)". If no string is specified, the bell is sounded without a message. After
the user hits return, output continues. This command is useful when the user is
required for some part of the output, such as changing paper or pens.
D draw global: no arguments.
This global forces flushing of output and updating of device.
I include file: arg0 TRUE if standard file.
The include global causes the contents of the named file to be substituted in the
include command's location. If arg0 is 1 (TRUE), a standard location is searched if
the file is not found in the working directory. If arg0 is 0 (FALSE), the file must be
in the working directory. Include files can be nested to the number of allowed open
files.
S set: arg0 specifies what to set (from meta.h):
SALL: place context mark on current settings.
SPAT0: set pattern 0 to the specified value.
SPAT1: set pattern 1 to the specified value.
SPAT2: set pattern 2 to the specified value.
SPAT3: set pattern 3 to the specified value.
The set command is used to globally affect certain attributes. The zeroeth argument
specifies the variable to set, and the arguments following specify the value. Pattern
values can have two forms. The first form begins with the letter 'P', immediately
followed by an integer between 0 and 11. This selects one from the following patterns:
solid, thick \\\, thin \\\, mixed \\\, thick ///, thin ///, mixed ///, crisscross, web.
The default pattern settings are: 0=P0, 1=P1, 2=P2, 3=P3. The second form gives the
explicit values for a pattern. The set all command makes a context mark with the
current settings. All settings which follow can be undone with the unset all command.
U unset: arg0 specifies what to unset (from meta.h):
SALL: return to previous context.
SPAT0: set pattern 0 to the previous value.
SPAT1: set pattern 1 to the previous value.
SPAT2: set pattern 2 to the previous value.
SPAT3: set pattern 3 to the previous value.
The unset command returns a variable to its previous value. The unset all command
returns the settings to the values they had in the previous context. If no context has
been marked by set all, variables are returned to their default values.
R reset: arg0 specifies what to reset (from meta.h):
SALL: reset all variables.
SPAT0: set pattern 0 to the default value.
SPAT1: set pattern 1 to the default value.
SPAT2: set pattern 2 to the default value.
SPAT3: set pattern 3 to the default value.
The reset command returns a variable to its default setting. The reset all command
returns all variables to their initial state.
O open segment: arguments specify segment name.
The commands following up to a C (close segment) are not to be output, but are to be
stored in the named segment. Segment names can contain any ascii character (except
newline) in any sequence of reasonable length. Segment definitions are local to the
enclosing segment. Side effects should be avoided in segments by balancing calls to
set and unset. A segment cannot reference itself.
C close segment: no arguments.
The current segment is closed, which completes its usable definition.
l line segment: fields of arg0 are:
100: orientation: positive slope, negative slope.
060: type: solid, dashed, dotted, dotted-dashed.
014: width: 0, 12, 24, 48, 96 units.
003: color: black, red, green, blue.
r rectangle fill: fields of arg0 are:
100: toggle: OR fill, XOR fill.
014: pattern: choice of 4 (see set).
003: color: black, red, green, blue.
Fills the given extent with the specified pattern. Toggle (XOR) fill allows the
reversal of previous fills to an area.
t triangle fill: fields of arg0 are:
100: toggle: OR fill, XOR fill.
060: orientation: right (& down), up, left, down.
014: pattern: choice of 4 (see set).
003: color: black, red, green, blue.
Fills the given half-rectangle with the specified pattern. A triangle is oriented to
the right if the the area between the positive-sloped diagonal and the lower right
corner of the extent is filled. Rotating this triangle ccw successively yields up,
left and down triangles. Toggle (XOR) fill allows the reversal of previous fills to an
area.
p polygon fill: fields of arg0 are:
100: border: no border, line border.
060: orientation: right (& down), up, left, down.
014: pattern: choice of 4 (see set).
003: color: black, red, green, blue.
The argument string gives a blank separated list of the polygon vertices in the form:
"x0 y0 x1 y1 x2 y2 ... ". The coordinates must be integers ranging between 0 and
16383. The bounding box and orientation will be used to fit the original polygon into
a scaled and rotated position. The last vertex will be connected to the first, and the
polygon will be filled in with the specified pattern. If a border is requested, one
will be drawn of solid black zero width lines. All polygon fills will toggle,
therefore other polygon and toggled triangle and rectangle fills will affect the final
appearance of the image. For example, a polygon drawn inside another polygon of the
same pattern will make a hole.
m matrix string: fields of arg0 are:
100: strike: single, double.
060: density: 10 cpi, 12 cpi, 17 cpi, 20 cpi.
014: size: normal, double width, double height, double both.
003: color: black, red, green, blue.
The upper left corner of the extent is used to place the beginning of the string
specified after the command. More sophisticated drivers will use the extent for
clipping, but the size of the characters will not be altered.
v vector string: fields of arg0 are:
060: orientation: right, up, left, down.
014: thickness: 0, 12, 24, 48, 96 units.
003: color: black, red, green, blue.
The string specified following the command will be made to fit within the given extent.
s print segment: fields of arg0 are:
060: orientation: right, up, left, down.
014: thickness: 0, 12, 24, 48, 96 units.
003: color: black, red, green, blue.
The segment whose name is specified in the arguments will be oriented according to arg0
and made to fit in the given extent. The thickness and color of the lines in the
segment will be changed also according to arg0. In the case of area fill, it is the
pattern rather than the width which will change. The segment must have been previously
defined using the open segment global. Note that matrix strings will not transfer well
since they cannot be oriented or scaled.
The metafile has two basic formats. The first format is meant to be user readable, and
has the form:
c arg0 xmin ymin xmax ymax `args
Where c is the single letter command, arg0 is the octal value for arg0, xmin ymin xmax
ymax are the extent (ranging from 0 to 16283), and the optional args following the
backquote are additional arguments, terminated by a newline. If the command is a global,
the extent is not present. If the global has no arg0, 0200 is appropriate. Any global
which has a following string must have a value for arg0 (< 0200). Comments are permitted
on lines beginning with a pound sign ('#').
The second format is roughly equivalent, but packs the extrema into two bytes each. It
takes between one quarter and one third as much space, and much less processing to use
this type of file, hence it is the default format for all of the programs. Conversion
between formats is accomplished with cv(1).
FILES
The standard location for metafiles used by the programs is /usr/lib/meta/, but can be
changed by setting the environment variable MDIR. This is useful for systems where the
owner does not have access to the /usr/lib/ directory. It also allows the user to create
his own metafiles for vector characters and other symbols.
BUGS
The command for line segment ('l') is awkward at best.
AUTHOR
Greg Ward
SEE ALSO
cv(1), meta(3), pexpand(1), primout(3), psort(1)