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Usenet 1994 January
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volume8
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xfig2.8
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part10
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FORMAT1.4X
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1990-07-03
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The following is the format of fig output (fig 1.4X).
(0) The only difference between 1.4 and 1.4X is that the interpretation
of the "pen" value in ARC_BOX is now the radius of the corners of the box.
Also, the ARC_BOX is sub-type 4 of POLYLINE.
(1) The very first line is a comment line containing the name and version:
#FIG 1.4X
The character # at the first column of a line indicates that the line
is a comment line which will be ignored.
(2) The first non-comment line consists of two numbers :
int fig_resolution (pixels/inch)
int coordinate_system (1 : origin is at the lower left corner
2 : Upper left)
Fig_resolution is the resolution fig is using for the current file.
It may not be the same as screen resolution (which can be higher or
lower). I assume that a pixel is square, therefore this number
represents drawing resolution in both direction. I've experimented
with fig automatically changing this number according to the resolution
of the monitor it is running on (The screen resolution, width and height
in pixels, not pixel/inch, can be done by doing a ioctl on the /dev/fb).
I've found that for monitors with higher resolution but same size
(19" diagonal), I preferred using the pixels for other things than
having fig occupying most of the screen. Thus I opted for a fixed
pixel-per-inch number which make fig window smaller on higher resolution
monitor (than the standard sun monitor). This however may change in
the future version.
(3) The rest of the file contains various objects. An object can be one
of six classes (or types).
i) Ellipse which is a generalization of circle.
ii) Polyline which includes polygon and box.
iii) Spline which includes closed/open control/interpolated spline.
iv) Text.
v) Arc.
vi) 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 not-used parameters will be -1.
A number of values are described as unused or not applicable to some
object even though they are defined for those objects. These value
will (hopefully) be used in the future version of fig. The intention
of their uses are the following.
Value Usage
----- -----
area_fill The stipple pattern (which will be align) for
filling object internals. For example, an filled
arc will look like a piece of pie.
** pen This will be a structure defining the shape of
pen used in drawing objects. It also includes
the the stipple pattern for line filling.
The default pen is a circular pen with black
filling.
** In 1.4X, pen is the radius (pixels) of the rounded-corner boxes.
thickness Every pen has the thickness of one.
Thickness scales the size of a pen.
depth This value adds a half dimension to fig.
It is useful when we have overlapping filled
objects and we want one to obliterate another.
An object can have only one depth (including
compound object). An object that is in less
depth can obscure the one with greater depth
if they overlap.
style Only polyline (including polygon and box) can
be rendered with dashed line. However the
objects created when the dash-line mode was on
will be recorded as such. Currently the filter
f2ps (1) is able to render the desired line style
effect on hard copy. Three line styles are defined.
0 : SOLID_LINE
1 : DASH_LINE
2 : DOTTED_LINE
style_val For dash style, it is the length of a dash.
For dotted line it indicates the approximated
gap of consecutive dots.
(3.1) ELLIPSE
First line :
type name (brief description)
---- ---- -------------------
int object_code (always 1)
int sub_type (1 : ellipse defined by radiuses
2 : ellipse defined by diameters
3 : circle defined by radius
4 : circle defined by diameter)
int style (See the end of this section)
int thickness (pixels, not used)
int color (not used)
int depth (not used)
int pen (not used)
int area_fill (not used)
float style_val (pixels, not used)
int direction (always 1)
float angle (radian, the angle of the x-axis)
int center_x, center_y (pixels)
int radius_x, radius_y (pixels)
int start_x, start_y (pixels; the 1st point entered)
int end_x, end_y (pixels; the last point entered)
(3.2) POLYLINE
First line :
type name (brief description)
---- ---- -------------------
int object_code (always 2)
int sub_type (1 : polyline, 2 : box,
3 : polygon, 4 : rounded-corner box)
int style (See the end of this section)
int thickness (pixels, not used)
int color (not used)
int depth (not used)
int pen **** (pixels, radius of rounded-corner boxes)
int area_fill (not used)
float style_val (pixels)
int forward_arrow (0: off, 1: on)
int backward_arrow (0: off, 1: on)
Forward arrow line : same as ARC object
Backward arrow line : same as ARC object
Points line :
type name (brief description)
---- ---- -------------------
int x1, y1 (pixels)
int x2, y2 (pixels)
.
.
int xn, yn (this will be the same as the 1st
point for polygon and box)
int x, y (always 9999, 9999; marks the end of
point for polygon and box)
(3.3) SPLINE
First line :
type name (brief description)
---- ---- -------------------
int object_code (always 3)
int sub_type (0 : open spline
1 : closed spline
2 : open interpolated spline
3 : closed interpolated spline)
int style (See the end of this section)
int thickness (pixels, not used)
int color (not used)
int depth (not used)
int pen (not used)
int area_fill (not used)
float style_val (pixels, not used)
int forward_arrow (0: off, 1: on)
int backward_arrow (0: off, 1: on)
Forward arrow line : same as ARC object
Backward arrow line : same as ARC object
Points line : same as POLYLINE object
Control points line (absent if sub_type is 1 or 2) :
Control points of interpolated spline. There are two control
points for each knots. A section i, of the spline is drawn
using Bezier cubic with the following four points:
(x ,y ), (rx ,ry ), (lx , ly ), (x , y ).
i i i i i+1 i+1 i+1 i+1
For closed interpolated spline the last pair of control points,
(lxn,lyn) and (rxn,ryn) (which can be ignored), are the same as
(lx1,ly1) and (rx1,ry1) respectively.
type name (brief description)
---- ---- -------------------
float lx1, ly1 (pixels)
float rx1, ry1 (pixels)
float lx2, ly2 (pixels)
float rx2, ry2 (pixels)
.
.
float lxn, lyn (pixels)
float rxn, ryn (pixels)
(3.4) TEXT
type name (brief description)
---- ---- -------------------
int object (always 4)
int sub_type (0 : Left justified
1 : Center justified
2 : Right justified)
int font (font number 0-...)
int font_size (point size)
int pen (not used)
int color (not used)
int depth (not used)
int angle (radian, not used, the angle of the
the base line of the string)
int font_style (not used)
int height (pixels)
int length (pixels)
int x, y (pixels, 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 character '\1'. This
character is not part of the string.
Note that the string may contain '\n'.)
(3.5) ARC
First line :
type name (brief description)
---- ---- -------------------
int object_code (always 5)
int sub_type (always 1)
int style (See the end of this section)
int line_thickness (pixels, not used)
int color (not used)
int depth (not used)
int pen (not used)
int area_fill (not used)
float style_val (pixels, not used)
int direction (0 : clockwise, 1 : counterclockwise)
int forward_arrow (0: no forward arrow, 1: on)
int backward_arrow (0: no forward arrow, 1: on)
float center_x, center_y (center of the arc)
int x1, y1 (pixels, the 1st point the user entered)
int x2, y2 (pixels, the 2nd point)
int x3, y3 (pixels, the last point)
Forward arrow line (Optional; absent if forward_arrow is 0) :
type name (brief description)
---- ---- -------------------
int arrow_type (not used)
int arrow_style (not used)
float arrow_thickness (not used)
float arrow_width (pixels)
float arrow_height (pixels)
Backward arrow line (Optional; absent if backward_arrow is 0) :
type name (brief description)
---- ---- -------------------
int arrow_type (not used)
int arrow_style (not used)
float arrow_thickness (not used)
float arrow_width (pixels)
float arrow_height (pixels)
(3.6) 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 right corner and the lower left 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 upperright_corner_x (pixels)
int upperright_corner_y (pixels)
int lowerleft_corner_x (pixels)
int lowerleft_corner_y (pixels)
Subsequent lines :
objects
.
.
Last line :
-6