Fig Format 3.2
This is a description of the Fig Format 3.2,
which is a copy of xfig.3.2.x/Doc/FORMAT3.2
in the xfig 3.2.x source distribution.
/*
* FIG : Facility for Interactive Generation of figures
* Copyright (c) 1985 by Supoj Sutanthavibul
* Parts Copyright (c) 1989-2002 by Brian V. Smith
* Parts Copyright (c) 1991 by Paul King
* Parts Copyright (c) 1995 by C. Blanc and C. Schlick
*
* Any party obtaining a copy of these files is granted, free of charge, a
* full and unrestricted irrevocable, world-wide, paid up, royalty-free,
* nonexclusive right and license to deal in this software and
* documentation files (the "Software"), including without limitation the
* rights to use, copy, modify, merge, publish and/or distribute copies of
* the Software, and to permit persons who receive copies from any such
* party to do so, with the only requirement being that this copyright
* notice remain intact.
*/
The new components in protocol 3.2 are the paper size, magnification,
single/multiple page indicator and transparent color for GIF export in the
header.
The other modification between version 3.1 and version 3.2 of the
protocol is the mathematical model used for splines. The new version
uses X-splines which allows the user to mix interpolation and approximation
points in a same curve. More precisely, it means that an X-spline curve
is neither an interpolated spline nor an approximated one, it is BOTH
(the behaviour of each point is controlled by one single parameter
called "shape factor"). For additional information about X-splines, see:
"X-Splines: A Spline Model Designed for the End User"
by C. Blanc and C. Schlick, Proceedings of SIGGRAPH'95
Caveat: Because spline models of previous versions (quadratic B-splines
and Bezier with hidden points) are no longer supported, curves that are
present in version 3.1 and older files are automatically converted to
X-splines. This translation is only an approximation process. It means
that the converted curves are not exactly the same as the original ones.
Though the translation usually provides almost identical curves, some
hand-fitting may be needed in some pathological cases.
-------------------------------------------------------------------------------
Description of the Fig Format Follows
-------------------------------------------------------------------------------
(1) The very first line is a comment line containing the name and version:
#FIG 3.2
The character # at the first column of a line indicates that the line
is a comment line which will be preserved when the Fig file is read in.
The user may edit them with the popup editor.
The comment line(s) must immediately precede the object to which they
are associated. In the case of the "whole figure comments" mentioned
below, they immediately precede the (resolution,coord_system) line.
(2) The first non-comment line consists of the following:
string orientation ("Landscape" or "Portrait")
string justification ("Center" or "Flush Left")
string units ("Metric" or "Inches")
string papersize ("Letter", "Legal", "Ledger", "Tabloid",
"A", "B", "C", "D", "E",
"A4", "A3", "A2", "A1", "A0" and "B5")
float magnification (export and print magnification, %)
string multiple-page ("Single" or "Multiple" pages)
int transparent color (color number for transparent color for GIF
export. -3=background, -2=None, -1=Default,
0-31 for standard colors or 32- for user colors)
# optional comment (An optional set of comments may be here,
which are associated with the whole figure)
int resolution coord_system (Fig units/inch and coordinate system:
1: origin at lower left corner (NOT USED)
2: upper left)
Fig_resolution is the resolution of the figure in the file.
Xfig will always write the file with a resolution of 1200ppi so it
will scale the figure upon reading it in if its resolution is different
from 1200ppi. Pixels are assumed to be square.
Note about metric units: To preserve a regular grid on the canvas the
centimeter is defined to be 450 Fig units and not 472.4 (1200/2.54).
For drawings done in metric units, fig2dev magnifies the output when
exporting or printing to compensate for the difference (472.4/450).
Also, if you make a drawing in one unit scale and switch to the other
units in xfig, the drawing will be rescaled on the screen by xfig to
remain consistent.
Xfig will read the orientation string and change the canvas to match
either the Landscape or Portrait mode of the figure file.
The units specification is self-explanatory.
The coordinate_system variable is ignored - the origin is ALWAYS the
upper-left corner.
** Coordinates are given in "fig_resolution" units.
** Line thicknesses are given in 1/80 inch (0.3175mm) or 1 screen pixel.
When exporting to EPS, PostScript or any bitmap format (e.g. GIF), the
line thickness is reduced to 1/160 inch (0.159mm) to "lighten" the look.
** dash-lengths/dot-gaps are given in 80-ths of an inch.
(3) The rest of the file contains various objects. An object can be one
of six classes (or types).
0) Color pseudo-object.
1) Ellipse which is a generalization of circle.
2) Polyline which includes polygon and box.
3) Spline which includes
closed/open approximated/interpolated/x-spline spline.
4) Text.
5) Arc.
6) Compound object which is composed of one or more objects.
In the following elaboration on object formats, every value of fig
output are separated by blank characters or new line ('\n'). The
value of the unused parameters will be -1.
Some fields are described as "enumeration type" or "bit vector"; the
values which these fields can take are defined in the header file object.h.
The pen_style field is unused.
These values may be defined in some future version of Fig.
The two color fields (pen and fill; pen only, for texts) are
defined as follows:
-1 = Default
0 = Black
1 = Blue
2 = Green
3 = Cyan
4 = Red
5 = Magenta
6 = Yellow
7 = White
8-11 = four shades of blue (dark to lighter)
12-14 = three shades of green (dark to lighter)
15-17 = three shades of cyan (dark to lighter)
18-20 = three shades of red (dark to lighter)
21-23 = three shades of magenta (dark to lighter)
24-26 = three shades of brown (dark to lighter)
27-30 = four shades of pink (dark to lighter)
31 = Gold
values from 32 to 543 (512 total) are user colors and
are defined in color pseudo-objects (type 0)
Your X server may limit the number of colors to something less
than this, especially on a 8-bit PseudoColor visual, where
the number of usable colors will be 256 minus the number of colors
xfig preallocates for itself and the 32 standard colors (about 48).
For WHITE color, the area fill field is defined as follows:
-1 = not filled
0 = black
... values from 1 to 19 are shades of grey, from darker to lighter
20 = white
21-40 not used
41-56 see patterns for colors, below
For BLACK or DEFAULT color, the area fill field is defined as follows:
-1 = not filled
0 = white
... values from 1 to 19 are shades of grey, from lighter to darker
20 = black
21-40 not used
41-56 see patterns for colors, below
For all other colors, the area fill field is defined as follows:
-1 = not filled
0 = black
... values from 1 to 19 are "shades" of the color, from darker to lighter.
A shade is defined as the color mixed with black
20 = full saturation of the color
... values from 21 to 39 are "tints" of the color from the color to white.
A tint is defined as the color mixed with white
40 = white
41 = 30 degree left diagonal pattern
42 = 30 degree right diagonal pattern
43 = 30 degree crosshatch
44 = 45 degree left diagonal pattern
45 = 45 degree right diagonal pattern
46 = 45 degree crosshatch
47 = horizontal bricks
48 = vertical bricks
49 = horizontal lines
50 = vertical lines
51 = crosshatch
52 = horizontal "shingles" skewed to the right
53 = horizontal "shingles" skewed to the left
54 = vertical "shingles" skewed one way
55 = vertical "shingles"skewed the other way
56 = fish scales
57 = small fish scales
58 = circles
59 = hexagons
60 = octagons
61 = horizontal "tire treads"
62 = vertical "tire treads"
The depth field is defined as follows:
0 ... 999 where larger value means object is deeper than (under)
objects with smaller depth
The line_style field is defined as follows:
-1 = Default
0 = Solid
1 = Dashed
2 = Dotted
3 = Dash-dotted
4 = Dash-double-dotted
5 = Dash-triple-dotted
The style_val field is defined as the length, in 1/80 inches, of the on/off
dashes for dashed lines, and the distance between the dots, in 1/80 inches,
for dotted lines.
The join_style field is defined FOR LINES only as follows:
0 = Miter (the default in xfig 2.1 and earlier)
1 = Round
2 = Bevel
The cap_style field is defined FOR LINES, OPEN SPLINES and ARCS only as follows:
0 = Butt (the default in xfig 2.1 and earlier)
1 = Round
2 = Projecting
The arrow_type field is defined for LINES, ARCS and OPEN SPLINES
only as follows:
0 = Stick-type (the default in xfig 2.1 and earlier)
\
\
_______________\
/
/
/
1 = Closed triangle:
|\
| \
________| \
| /
| /
|/
2 = Closed with "indented" butt:
|\
\ \
\ \
__________\ \
/ /
/ /
/ /
|/
3 = Closed with "pointed" butt:
/\
/ \
/ \
________/ \
\ /
\ /
\ /
\/
The arrow_style field is defined for LINES, ARCS and OPEN SPLINES
only as follows:
0 = Hollow (actually filled with white)
1 = Filled with pen_color
(3.0) OBJECT DEFINITIONS:
================================================
(3.1) Color Pseudo-objects (user-defined colors)
================================================
This is used to define arbitrary colors beyond the 32 standard colors.
The color objects must be defined before any other Fig objects.
First line:
type name (brief description)
---- ---- -------------------
int object_code (always 0)
int color_number (color number, from 32-543 (512 total))
hex string rgb values (hexadecimal string describing red,
green and blue values (e.g. #330099) )
============================================================================
(3.2) ARC
=========
First line:
type name (brief description)
---- ---- -------------------
int object_code (always 5)
int sub_type (1: open ended arc
2: pie-wedge (closed) )
int line_style (enumeration type, solid, dash, dotted, etc.)
int line_thickness (1/80 inch)
int pen_color (enumeration type, pen color)
int fill_color (enumeration type, fill color)
int depth (enumeration type)
int pen_style (pen style, not used)
int area_fill (enumeration type, -1 = no fill)
float style_val (1/80 inch, specification for dash/dotted lines)
int cap_style (enumeration type)
int direction (0: clockwise, 1: counterclockwise)
int forward_arrow (0: no forward arrow, 1: on)
int backward_arrow (0: no backward arrow, 1: on)
float center_x, center_y (center of the arc)
int x1, y1 (Fig units, the 1st point the user entered)
int x2, y2 (Fig units, the 2nd point)
int x3, y3 (Fig units, the last point)
Forward arrow line (Optional; absent if forward_arrow is 0):
type name (brief description)
---- ---- -------------------
int arrow_type (enumeration type)
int arrow_style (enumeration type)
float arrow_thickness (1/80 inch)
float arrow_width (Fig units)
float arrow_height (Fig units)
Backward arrow line (Optional; absent if backward_arrow is 0):
type name (brief description)
---- ---- -------------------
int arrow_type (enumeration type)
int arrow_style (enumeration type)
float arrow_thickness (1/80 inch)
float arrow_width (Fig units)
float arrow_height (Fig units)
============================================================================
(3.3) COMPOUND
==============
A line with object code 6 signifies the start of a compound.
There are four more numbers on this line which indicate the
upper left corner and the lower right corner of the bounding
box of this compound. A line with object code -6 signifies
the end of the compound. Compound may be nested.
First line:
type name (brief description)
---- ---- -------------------
int object_code (always 6)
int upperleft_corner_x (Fig units)
int upperleft_corner_y (Fig units)
int lowerright_corner_x (Fig units)
int lowerright_corner_y (Fig units)
Subsequent lines:
objects
.
.
Last line:
-6
============================================================================
(3.4) ELLIPSE
=============
First line:
type name (brief description)
---- ---- -------------------
int object_code (always 1)
int sub_type (1: ellipse defined by radii
2: ellipse defined by diameters
3: circle defined by radius
4: circle defined by diameter)
int line_style (enumeration type, solid, dash, dotted, etc.)
int thickness (1/80 inch)
int pen_color (enumeration type, pen color)
int fill_color (enumeration type, fill color)
int depth (enumeration type)
int pen_style (pen style, not used)
int area_fill (enumeration type, -1 = no fill)
float style_val (1/80 inch, specification for dash/dotted lines)
int direction (always 1)
float angle (radians, the angle of the x-axis)
int center_x, center_y (Fig units)
int radius_x, radius_y (Fig units)
int start_x, start_y (Fig units; the 1st point entered)
int end_x, end_y (Fig units; the last point entered)
============================================================================
(3.5) POLYLINE
==============
First line:
type name (brief description)
---- ---- -------------------
int object_code (always 2)
int sub_type (1: polyline
2: box
3: polygon
4: arc-box)
5: imported-picture bounding-box)
int line_style (enumeration type, solid, dash, dotted, etc.)
int thickness (1/80 inch)
int pen_color (enumeration type, pen color)
int fill_color (enumeration type, fill color)
int depth (enumeration type)
int pen_style (pen style, not used)
int area_fill (enumeration type, -1 = no fill)
float style_val (1/80 inch, specification for dash/dotted lines)
int join_style (enumeration type)
int cap_style (enumeration type, only used for POLYLINE)
int radius (1/80 inch, radius of arc-boxes)
int forward_arrow (0: off, 1: on)
int backward_arrow (0: off, 1: on)
int npoints (number of points in line)
Forward arrow line: same as ARC object
Backward arrow line: same as ARC object
For picture (type 5) the following line follows:
type name (brief description)
---- ---- -------------------
boolean flipped orientation = normal (0) or flipped (1)
char file[] name of picture file to import
Points line(s). The x,y coordinates follow, any number to a line, with
as many lines as are necessary:
type name (brief description)
---- ---- -------------------
int x1, y1 (Fig units)
int x2, y2 (Fig units)
.
.
int xnpoints ynpoints (this will be the same as the 1st
point for polygon and box)
============================================================================
(3.6) SPLINE
============
First line:
type name (brief description)
---- ---- -------------------
int object_code (always 3)
int sub_type (0: open approximated spline
1: closed approximated spline
2: open interpolated spline
3: closed interpolated spline
4: open x-spline
5: closed x-spline)
int line_style (enumeration type, solid, dash, dotted, etc.)
int thickness (1/80 inch)
int pen_color (enumeration type, pen color)
int fill_color (enumeration type, fill color)
int depth (enumeration type)
int pen_style (pen style, not used)
int area_fill (enumeration type, -1 = no fill)
float style_val (1/80 inch, specification for dash/dotted lines)
int cap_style (enumeration type, only used for open splines)
int forward_arrow (0: off, 1: on)
int backward_arrow (0: off, 1: on)
int npoints (number of control points in spline)
Forward arrow line: same as ARC object
Backward arrow line: same as ARC object
Points line: same as POLYLINE object
Control points line :
There is one shape factor for each point. For positive values of this
factor, the spline is approximated at this point, for negative values the
spline is interpolated at this point. The spline is always smooth in the
neighbourhood of a control point, except when the value of the factor is 0
for which there is a first-order discontinuity (i.e., an angular point).
Recommended values for this factor are 1.0 for an approximated spline, 0.0
for an angular point and -0.5 for interpolated splines.
The shape factor used here corresponds to the parameter s_k defined in
section 4.1 of Blanc & Schlick (1995) for values greater than 0, for values
smaller than 0 it corresponds to the negative of the parameter q defined in
section 5.1 of Blanc & Schlick (1995).
============================================================================
(3.7) TEXT
==========
type name (brief description)
---- ---- -------------------
int object (always 4)
int sub_type (0: Left justified
1: Center justified
2: Right justified)
int color (enumeration type)
int depth (enumeration type)
int pen_style (enumeration , not used)
int font (enumeration type)
float font_size (font size in points)
float angle (radians, the angle of the text)
int font_flags (bit vector)
float height (Fig units)
float length (Fig units)
int x, y (Fig units, coordinate of the origin
of the string. If sub_type = 0, it is
the lower left corner of the string.
If sub_type = 1, it is the lower
center. Otherwise it is the lower
right corner of the string.)
char string[] (ASCII characters; starts after a blank
character following the last number and
ends before the sequence '\001'. This
sequence is not part of the string.
Characters above octal 177 are
represented by \xxx where xxx is the
octal value. This permits fig files to
be edited with 7-bit editors and sent
by e-mail without data loss.
Note that the string may contain '\n'.)
The font_flags field is defined as follows:
Bit Description
0 Rigid text (text doesn't scale when scaling compound objects)
1 Special text (for LaTeX)
2 PostScript font (otherwise LaTeX font is used)
3 Hidden text
The font field is defined as follows:
For font_flags bit 2 = 0 (LaTeX fonts):
0 Default font
1 Roman
2 Bold
3 Italic
4 Sans Serif
5 Typewriter
For font_flags bit 2 = 1 (PostScript fonts):
-1 Default font
0 Times Roman
1 Times Italic
2 Times Bold
3 Times Bold Italic
4 AvantGarde Book
5 AvantGarde Book Oblique
6 AvantGarde Demi
7 AvantGarde Demi Oblique
8 Bookman Light
9 Bookman Light Italic
10 Bookman Demi
11 Bookman Demi Italic
12 Courier
13 Courier Oblique
14 Courier Bold
15 Courier Bold Oblique
16 Helvetica
17 Helvetica Oblique
18 Helvetica Bold
19 Helvetica Bold Oblique
20 Helvetica Narrow
21 Helvetica Narrow Oblique
22 Helvetica Narrow Bold
23 Helvetica Narrow Bold Oblique
24 New Century Schoolbook Roman
25 New Century Schoolbook Italic
26 New Century Schoolbook Bold
27 New Century Schoolbook Bold Italic
28 Palatino Roman
29 Palatino Italic
30 Palatino Bold
31 Palatino Bold Italic
32 Symbol
33 Zapf Chancery Medium Italic
34 Zapf Dingbats
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