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.

    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)
	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)
	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)
	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)
	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)
	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)
	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		(See the end of this section)
	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)
	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. The value of this factor
    must be between -1 (which means that the spline is interpolated at
    this point) and 1 (which means that the spline is approximated 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. angular point).


    (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

