1 Locations, angles, etc.
3 Key type is a `loc', which is a named location (absolute, 2D) and
4 direction (at the location). Angles are generally positive
5 anticlockwise; bearings are angles measured from East. The origin is
11 -<identifier> reverse the sense (ie, 180 degrees off)
13 <identifier> simply the named location
14 -<identifier> reverse the sense (ie, 180 degrees off)
15 O![-]<identifier> the location from the specified object
16 in whatever coordinate system that object
18 ^O![-]<identifier> the same, but the object is flipped
19 N-S first (see `part' and `objflip')
20 Quantity (length/angle)
22 Angle units: d (degrees,default) r (radians)
23 Length units: mm (default) cm m
24 Identifiers (of locs and objects) start with lc letter, then
25 alphanums and underscores
30 Defines loc P given coordinates (distances) and absolute bearing
33 Defines loc T: start at loc F, go forward L, translate right R,
34 turn left A (defaults are all 0).
37 K is layer kind (letters and `_', may be empty), L is a layer depth
38 (digits). Controls drawing style, by selecting appropriate parts of
39 the track and locs to draw, according to element selection rules.
41 K L result (description) result (element letters)
43 empty current default track RLMNasco
44 `s' current nothing (`silent') -
45 `l' current centrelines only CLMNarso
46 other current everything ARSCLMNO
48 extend F T len L [R] length L
49 extend F T upto U [R] s.t. perpendicular at T passes through U
50 extend F T ang A R subtending directionally A
51 extend F T uptoang A R s.t. direction at T is A
52 extend F T parallel U R s.t. direction at T is same as at U
53 Draws an arc or line from loc F, defining the other end as loc T.
54 If length R specified, draws an arc of radius R; R +ve curves to the
55 right; R -ve to the left.
58 Joins one existing loc, F, to another, T. F's direction points to
59 the new track; T's away - ie the added track leaves F in F's
60 direction and arrives at T in T's direction. R is the minimum curve
61 radius allowed. S selects from the available solutions, and may be
63 long prefer longer length solution
64 short prefer shorter length solution
65 right|left prefer mostly bending to the left resp. right
66 beginright|beginleft prefer first bend to the right
67 endright|endleft prefer final bend to the right
68 [!]twoarcs prefer [not] two circular arcs of equal radius
69 [!]arcline prefer [not] one line and an arc of max radius
70 [!]arcsline prefer [not] line between two arcs of min radius
71 if this doesn't resolve, will pick the shortest.
76 Defines the object or part O. Inside the definition, the commands
77 do not draw when the object is being defined. The object has its
78 own coordinate space and its own location namespace. `defpart'
79 defines a `part', which is like an object except that:
80 * showlibrary lists only parts, not objects
81 * the -e and -E command line options distinguish parts and objects
83 part N [^]O [F [A]] [FR AR ...]
85 Places an instance of object or part O. The loc defined inside O as
86 F (`formal parameter', F must be just <identifier>) is placed at
87 existing loc A (`actual parameter').
89 Both objects (defined with defobj) and parts (defined with defpart)
90 may be placed with either command ! Whether it's a part or an obj
91 depends on the definition, not on the use - the use is just
92 different syntaxes for the same kind of operation, and where the
93 features offered by both `part' and `obj[flip]' overlap the
94 behaviour is identical.
96 If `part N ^O' or `objflip' is used, rather than `part N O' or
97 `obj', then the object is placed with object-space y coordinates
98 negated (ie, it is mirrored so that the object's North exchanges
101 For `part', each FR (`formal result') and AR (`actual result')
102 specifies that the loc FR inside O is exported into the global
103 namespace as a new loc AR. Either FR or AR may start with `-'.
104 Also, each loc L inside O is exported into the global namespace as a
105 new loc N_L (unless N_L already exists). If A is not specified then
108 For `obj[flip]' if prefix P (syntax is that of an identifier) is
109 specified, each other loc L inside O is exported into the global
110 namespace as a new loc PL (unless PL already exists). P may be `='
111 to indicate an empty prefix (default is not to export locs).
115 -D turn on debug (level 1) } currently only debug levels are
116 -Dnnn set debug level to nnn } 0 (none) and 1 (some), default=0
118 -lL output for layer L (digits, or `*' for any) (default: *)
120 -e<layersel>[ARSCcLlMNOm]...
121 Turn on and off drawing of elements in groups.
122 These are abbreviations for various -E... options.
126 S rails and sleepers only aRSc
127 C centrelines only arsC
128 c swept area and ticks only Arsc
130 L label top-level locs (turns on bars for them too) LM
131 l do not label any locs l
132 bars at locs (thick lines perp to track dir'n)
133 M bars for top-level locs only Mno
134 N bars for top-level locs and those in obj's MNo
135 O bars for everything, including those inside parts MNO
136 m no bars (turns off labelling too) mnol
138 -E<layersel>[ARSCLMNOarsclmno]...
139 enable (capitals) or disable (lowercase) drawing of
141 A draw track swept area, with ticks
143 S draw track sleepers
144 C draw track centrelines
146 M mark locs with a bar
147 N mark locs with a bar in objs
148 O mark locs with a bar in parts
150 -q quiet: do not print info to stderr
151 (default: prints bounding box, at the moment)
153 <layersel> (for -e and -E) works as follows:
155 When file says `layer KL', default drawing element set is set
156 depending on K and L (see description of `layer' command), using last
157 specified -l layer. Then all -e/-E options are scanned, in order,
158 and each one that matches modifies the drawing element set.
160 <layersel> is GN[D][C][V]. It matches `layer KL' iff the glob
161 pattern G (which may be empty) matches the whole of K, and layer
162 restriction N[D]C matches L. C is several identical `=', `+' or `-';
163 D+ matches L iff L>=D; D++ iff L>D; D+++ iff L>D+1 and so on; D-
164 matches L iff L<=D; D-- iff L<D; etc.; D= matches L iff L==D; D== iff
165 D-1<=L<=D+1; D=== iff D-2<=L<=D+2; etc. If D is omitted the current
166 layer (from the most recent -l option) is used. N may be empty or
167 `~'; the latter simply inverts the sense of the match. If C is
168 omitted then `=' is assumed.
170 If V is present then C must be exactly one character and it is as if
171 V (must be an integer) copies of C were specified.
174 Special comments in PostScript:
177 a command C with args A is read for execution in scope S
179 point L in scope S has coords X Y and angle A
180 %L bbox width W (L..R)
181 %L bbox height H (B..T)
182 bounding box, giving width W, height H, left L, right R,
183 bottom B and top T. Includes full swept area of track,
184 but only at locs (so curves which bend outside bounding
185 box don't get counted)
186 %L bbox no locs, no bbox
187 there were no locs, so there is no bounding box
188 usu because input file was just obj defns and showlibrary
191 O! when defining object or part O
192 N:T scope T but inside part (introduced with `part') N } when
193 O::T scope T but inside obj (introduced with `obj[flip]') O } placing