1if not modules then modules = { } end modules ['trac-jus'] = {
2 version = 1.001,
3 comment = "companion to trac-jus.mkiv",
4 author = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
5 copyright = "PRAGMA ADE / ConTeXt Development Team",
6 license = "see context related readme files"
7}
8
9local checkers = typesetters.checkers or { }
10typesetters.checkers = checkers
11
12
13
14local a_alignstate <const> = attributes.private("alignstate")
15local a_justification <const> = attributes.private("justification")
16
17local nuts = nodes.nuts
18
19local getfield = nuts.getfield
20local getlist = nuts.getlist
21local getattr = nuts.getattr
22local setattr = nuts.setattr
23local setlist = nuts.setlist
24local setlink = nuts.setlink
25local getwidth = nuts.getwidth
26local findtail = nuts.tail
27
28local nexthlist = nuts.traversers.hlist
29
30local getdimensions = nuts.dimensions
31local copylist = nuts.copylist
32
33local tracedrule = nodes.tracers.pool.nuts.rule
34
35local nodepool = nuts.pool
36
37local new_hlist = nodepool.hlist
38local new_kern = nodepool.kern
39
40local hlist_code <const> = nodes.nodecodes.hlist
41
42local texsetattribute = tex.setattribute
43
44local unsetvalue <const> = attributes.unsetvalue
45
46local enableaction = nodes.tasks.enableaction
47
48local min_threshold = 0
49local max_threshold = 0
50
51local function set(n)
52 enableaction("mvlbuilders", "typesetters.checkers.handler")
53 enableaction("vboxbuilders","typesetters.checkers.handler")
54 texsetattribute(a_justification,n or 1)
55 function typesetters.checkers.set(n)
56 texsetattribute(a_justification,n or 1)
57 end
58end
59
60local function reset()
61 texsetattribute(a_justification,unsetvalue)
62end
63
64checkers.set = set
65checkers.reset = reset
66
67interfaces.implement {
68 name = "showjustification",
69 actions = set
70}
71
72trackers.register("visualizers.justification", function(v)
73 if v then
74 set(1)
75 else
76 reset()
77 end
78end)
79
80function checkers.handler(head)
81 for current in nexthlist, head do
82 if getattr(current,a_justification) == 1 then
83 setattr(current,a_justification,0)
84 local width = getwidth(current)
85 if width > 0 then
86 local list = getlist(current)
87 if list then
88 local naturalwidth, naturalheight, naturaldepth = getdimensions(list)
89 local delta = naturalwidth - width
90 if naturalwidth == 0 or delta == 0 then
91
92 elseif delta >= max_threshold then
93 local rule = new_hlist(tracedrule(delta,naturalheight,naturaldepth,getfield(list,"glueset") == 1 and "trace:dr" or "trace:db"))
94 setlink(findtail(list),rule)
95 setlist(current,list)
96 elseif delta <= min_threshold then
97 local alignstate = getattr(list,a_alignstate)
98 if alignstate == 1 then
99 local rule = new_hlist(tracedrule(-delta,naturalheight,naturaldepth,"trace:dc"))
100 setlink(rule,list)
101 setlist(current,rule)
102 elseif alignstate == 2 then
103 local lrule = new_hlist(tracedrule(-delta/2,naturalheight,naturaldepth,"trace:dy"))
104 local rrule = copylist(lrule)
105 setlink(lrule,list)
106 setlink(findtail(list),new_kern(delta/2),rrule)
107 setlist(current,lrule)
108 elseif alignstate == 3 then
109 local rule = new_hlist(tracedrule(-delta,naturalheight,naturaldepth,"trace:dm"))
110 setlink(findtail(list),new_kern(delta),rule)
111 setlist(current,list)
112 else
113 local rule = new_hlist(tracedrule(-delta,naturalheight,naturaldepth,"trace:dg"))
114 setlink(findtail(list),new_kern(delta),rule)
115 setlist(current,list)
116 end
117 end
118 end
119 end
120 end
121 end
122 return head
123end
124 |
