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XFIG Users Manual

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


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