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).
36 segment [K*] [S0 D0 ...] Sn
37 Specifies that arcs and lines in layer kind K are part of subsegment
40 If additional Di and Si are provided then each Si apart from the
41 last is followed by a distance Di saying how much track it applies
42 to; the first D0 of track is part of subsegment S0, the next D1 of
43 track is part of the next subsegment S1, and so on, with the last
44 subsegment Sn (without a distance restriction) being used for track
45 beyond that. Each segment command resets the distance counter, and
46 it is not an error for there to be unused subsegment specs in a
47 segment command. For these distances, only track whose subsegment
48 encoding is actually drawn counts.
50 If a part or object is used, then the arcs and lines inside it are
51 processed for subsegments as if they appeared directly.
53 A subsegment is a specification of:
54 * The named electrically separate track segment of which
55 this track forms part.
56 * If this track is part of one possible configuration of a
57 junction or point, the moveable feature name and configuration
58 number. Any one junction or point is one moveable feature and
59 must be associated with and form part of one track segment.
60 Moveable segments must be entirely contained within objects or
61 parts (ie, one moveable segment cannot span multiple parts).
62 Configuration numbers should start at 0 and be allocated densely.
64 Subsegment specs Si are
67 N is the segment name (alphanumeric, may be empty)
68 M is the moveable feature name (alphabetic, nonempty)
69 P is the moveable feature position (numeric, nonempty, 0-indexed)
70 If N is empty and MP is omitted then / must be present.
71 Underscore (`_') counts as a letter.
73 If a segment command occurs in a part or object, N is appended to
74 the N in force at the start of the part or object, and in this
75 case the segment will be set back to the last one from the list
76 in force when the object was entered, as if the object had merely
77 drawn an infinite amount of track.
79 At the start of processing at the toplevel, the empty-named fixed
80 subsegment is in use. The empty-named top-level segment indicates
81 that the subsegment is unspecified, unknown or absent. All segments
82 defined by objects at whose invocation the empty-named top-level
83 segment is in force, are also assigned to the empty segment.
87 Maps specified (sub)segments or moveable feature(s) S to
88 consequently defined (sub)segments or moveable features D. This is
89 primarily intended so that parts' internal segment and feature names
90 can be remapped to correspond to the layout naming scheme.
94 N N' remaps an entire segment including all features
95 N/M M' remaps a particular moveable feature; N is the
96 unmapped name (if applicable)
98 The effect is that (sub)segments or features used in segment
99 commands are translated when the segment command is read; the
100 specified names (S) are those which the segment command would
103 Where segmap is used outside a part or object, the mappings apply to
104 the segment names which would result at the toplevel. When segmap
105 is used inside a part or object, the mappings apply to the segment
106 names defined within the part (perhaps by its subparts). Ie, the
107 mapping operates on the segment names visible at the level at which
108 segmap is used (and thus several segmaps at different levels may
109 operate on a signal segment name, in sequence).
111 Mappings in later segmap commands replace earlier mappings at the
114 The remapping may coalesce otherwise-distinct segments.
117 K is layer kind (letters and `_', may be empty), L is a layer depth
118 (digits, or `=' meaning current layer, or `*' meaning output layer;
119 default for L is `='; default KL at start of file is `layer 5').
120 Controls drawing style, by selecting appropriate parts of the track
121 and locs to draw, according to element selection rules. Default
123 K result (description) result (element letters)
124 empty default track RLMNasco
125 `s' nothing (`silent') -
126 `l' centrelines only CLMNarso
127 other everything ARSCLMNO
129 extend F T len L [R] length L
130 extend F T upto U [R] s.t. perpendicular at T passes through U
131 extend F T ang A R subtending directionally A
132 extend F T uptoang A R s.t. direction at T is A
133 extend F T parallel U R s.t. direction at T is same as at U
134 Draws an arc or line from loc F, defining the other end as loc T.
135 If length R specified, draws an arc of radius R; R +ve curves to the
136 right; R -ve to the left.
139 Joins one existing loc, F, to another, T. F's direction points to
140 the new track; T's away - ie the added track leaves F in F's
141 direction and arrives at T in T's direction. R is the minimum curve
142 radius allowed. S selects from the available solutions, and may be
144 long prefer longer length solution
145 short prefer shorter length solution
146 right|left prefer mostly bending to the left resp. right
147 beginright|beginleft prefer first bend to the right
148 endright|endleft prefer final bend to the right
149 [!]twoarcs prefer [not] two circular arcs of equal radius
150 [!]arcline prefer [not] one line and an arc of max radius
151 [!]arcsline prefer [not] line between two arcs of min radius
152 [!]loop prefer [not] loop (arcsline, arc of same sense)
153 [!]cross prefer [not] cross (arcsline 2 senses, or twoarcs)
154 if this doesn't resolve, will pick the shortest.
159 Defines the object or part O. Inside the definition, the commands
160 do not draw when the object is being defined. The object has its
161 own coordinate space and its own location namespace. `defpart'
162 defines a `part', which is like an object except that:
163 * showlibrary lists only parts, not objects
164 * the -e and -E command line options distinguish parts and objects
166 part N [^]O [F [A]] [FR AR ...]
168 Places an instance of object or part O. The loc defined inside O as
169 F (`formal parameter', F must be just <identifier>) is placed at
170 existing loc A (`actual parameter').
172 Both objects (defined with defobj) and parts (defined with defpart)
173 may be placed with either command ! Whether it's a part or an obj
174 depends on the definition, not on the use - the use is just
175 different syntaxes for the same kind of operation, and where the
176 features offered by both `part' and `obj[flip]' overlap the
177 behaviour is identical.
179 If `part N ^O' or `objflip' is used, rather than `part N O' or
180 `obj', then the object is placed with object-space y coordinates
181 negated (ie, it is mirrored so that the object's North exchanges
184 For `part', each FR (`formal result') and AR (`actual result')
185 specifies that the loc FR inside O is exported into the global
186 namespace as a new loc AR. Either FR or AR may start with `-'.
187 Also, each loc L inside O is exported into the global namespace as a
188 new loc N_L (unless N_L already exists). If A is not specified then
191 For `obj[flip]' if prefix P (syntax is that of an identifier) is
192 specified, each other loc L inside O is exported into the global
193 namespace as a new loc PL (unless PL already exists). P may be `='
194 to indicate an empty prefix (default is not to export locs).
198 -D turn on debug (level 1) } currently only debug levels are
199 -Dnnn set debug level to nnn } 0 (none) and 1 (some), default=0
201 -lL output for layer L (digits, or `*' for any) (default: *)
203 -S<scale> set scale divider to <scale> (default is 7.0, ie
204 output is 1/7 actual size)
206 -P<xp>x<yp> output physical page (<xp>,<yp>). xp and yp are
207 integers specifying the number of pages to shift by
208 in each direction. xp is multiplied by 270mm; yp
209 is multiplied by 190mm.
211 -e<layersel>[ARSCcLlMNOm]...
212 Turn on and off drawing of elements in groups.
213 These are abbreviations for various -E... options.
217 S rails and sleepers only aRScg
218 C centrelines only arsCg
219 c swept area and ticks only Arscg
220 r no lines drawn at all arcs
222 L label top-level locs (turns on bars for them too) LMg
223 l do not label any locs l
224 bars at locs (thick lines perp to track dir'n)
225 M bars for top-level locs only Mnog
226 N bars for top-level locs and those in obj's MNog
227 O bars for everything, including those inside parts MNOg
228 m no bars (turns off labelling too) mnol
230 G draw only subsegment encoding Garcslmno
232 -E<layersel>[ARSCLMNOarsclmno]...
233 enable (capitals) or disable (lowercase) drawing of
235 A draw track swept area, with ticks
237 S draw track sleepers
238 C draw track centrelines
240 M mark locs with a bar
241 N mark locs with a bar in objs
242 O mark locs with a bar in parts
243 G draw subsegment encoding
245 -GL output segment colour map request list
246 use with -eG or -EG to write out the list of subsegment
247 specs which will need colours, one per line (and not
248 necessarily only once each)
250 -q quiet: do not print info to stderr
251 (default: prints bounding box, at the moment)
253 <layersel> (for -e and -E) works as follows:
255 When file says `layer KL', default drawing element set is set
256 depending on K and L (see description of `layer' command), using last
257 specified -l layer. Then all -e/-E options are scanned, in order,
258 and each one that matches modifies the drawing element set.
260 <layersel> is GN[D][C][V]. It matches `layer KL' iff the glob
261 pattern G (which may be empty) matches the whole of K, and layer
262 restriction N[D]C matches L. C is several identical `=', `+' or `-';
263 D+ matches L iff L>=D; D++ iff L>D; D+++ iff L>D+1 and so on; D-
264 matches L iff L<=D; D-- iff L<D; etc.; D= matches L iff L==D; D== iff
265 D-1<=L<=D+1; D=== iff D-2<=L<=D+2; etc. If D is omitted the current
266 layer (from the most recent -l option) is used (or `5' if current
267 layer is `*'). N may be empty or `~'; the latter simply inverts the
268 sense of the match. If C is omitted then `=' is assumed. If the
269 final output layer is `*' then we pretend, for the moment, that L was
270 D. N[D][C][V] may be N[=]* to match, or not match, all layers.
272 If V is present then C must be exactly one character and it is as if
273 V (must be an integer) copies of C were specified.
276 Special comments in PostScript:
279 a command C with args A is read for execution in scope S
281 point L in scope S has coords X Y and angle A
282 %L bbox width W (L..R)
283 %L bbox height H (B..T)
284 bounding box, giving width W, height H, left L, right R,
285 bottom B and top T. Includes full swept area of track,
286 but only at locs (so curves which bend outside bounding
287 box don't get counted)
288 %L bbox no locs, no bbox
289 there were no locs, so there is no bounding box
290 usu because input file was just obj defns and showlibrary
293 O! when defining object or part O
294 N:T scope T but inside part (introduced with `part') N } when
295 O::T scope T but inside obj (introduced with `obj[flip]') O } placing