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-rw-r--r--Master/texmf-dist/tex/context/base/mkxl/typo-pag.lmt206
1 files changed, 206 insertions, 0 deletions
diff --git a/Master/texmf-dist/tex/context/base/mkxl/typo-pag.lmt b/Master/texmf-dist/tex/context/base/mkxl/typo-pag.lmt
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index 00000000000..9f8a3a1f418
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+++ b/Master/texmf-dist/tex/context/base/mkxl/typo-pag.lmt
@@ -0,0 +1,206 @@
+if not modules then modules = { } end modules ['typo-pag'] = {
+ version = 1.001,
+ comment = "companion to typo-pag.mkiv",
+ author = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
+ copyright = "PRAGMA ADE / ConTeXt Development Team",
+ license = "see context related readme files"
+}
+
+
+builders = builders or { }
+local builders = builders
+
+builders.paragraphs = builders.paragraphs or { }
+local parbuilders = builders.paragraphs
+
+local nodes = nodes
+local nodecodes = nodes.nodecodes
+
+local hlist_code = nodecodes.hlist
+local vlist_code = nodecodes.vlist
+local glue_code = nodecodes.glue
+local kern_code = nodecodes.kern
+local penalty_code = nodecodes.penalty
+
+local unsetvalue = attributes.unsetvalue
+local a_keeptogether = attributes.private("keeptogether")
+
+local nuts = nodes.nuts
+
+local getnext = nuts.getnext
+local getprev = nuts.getprev
+local getid = nuts.getid
+local getattr = nuts.getattr
+local takeattr = nuts.takeattr
+local setattr = nuts.setattr
+local getwhd = nuts.getwhd
+local getkern = nuts.getkern
+local setpenalty = nuts.setpenalty
+local getwidth = nuts.getwidth
+local getdepth = nuts.getdepth
+
+local insert_node_after = nuts.insert_after
+local new_penalty = nuts.pool.penalty
+
+local trace_keeptogether = false
+local report_keeptogether = logs.reporter("parbuilders","keeptogether")
+
+local enableaction = nodes.tasks.enableaction
+
+local cache = { }
+local last = 0
+local enabled = false
+
+trackers.register("parbuilders.keeptogether", function(v) trace_keeptogether = v end)
+
+-- todo: also support lines = 3 etc (e.g. dropped caps) but how to set that
+-- when no hlists are there ?
+
+function parbuilders.registertogether(line,specification) -- might change
+ if not specification then
+ return
+ end
+ if not enabled then
+ enableaction("finalizers","builders.paragraphs.keeptogether")
+ end
+ local a = getattr(line,a_keeptogether)
+ local c = a and cache[a]
+ if c then
+ local height = specification.height
+ local depth = specification.depth
+ local slack = specification.slack
+ if height and height > c.height then
+ c.height = height
+ end
+ if depth and depth > c.depth then
+ c.depth = depth
+ end
+ if slack and slack > c.slack then
+ c.slack = slack
+ end
+ else
+ last = last + 1
+ cache[last] = specification
+ if not specification.height then
+ specification.height = 0
+ end
+ if not specification.depth then
+ specification.depth = 0
+ end
+ if not specification.slack then
+ specification.slack = 0
+ end
+ setattr(line,a_keeptogether,last)
+ end
+ if trace_keeptogether then
+ local a = a or last
+ local c = cache[a]
+ local noflines = specification.lineheight
+ local height = c.height
+ local depth = c.depth
+ local slack = c.slack
+ if not noflines or noflines == 0 then
+ noflines = "unknown"
+ else
+ noflines = math.round((height + depth - slack) / noflines)
+ end
+ report_keeptogether("registered, index %s, height %p, depth %p, slack %p, noflines %a",a,height,depth,slack,noflines)
+ end
+end
+
+local function keeptogether(start,a,specification)
+ local current = getnext(start)
+ local previous = start
+ local total = getdepth(previous)
+ local slack = specification.slack
+ local threshold = specification.depth - slack
+ if trace_keeptogether then
+ report_keeptogether("%s, index %s, total %p, threshold %p, slack %p","list",a,total,threshold,slack)
+ end
+ while current do
+ local id = getid(current)
+ if id == vlist_code or id == hlist_code then
+ local wd, ht, dp = getwhd(current)
+ total = total + ht + dp
+ if trace_keeptogether then
+ report_keeptogether("%s, index %s, total %p, threshold %p","list",a,total,threshold)
+ end
+ if total <= threshold then
+ if getid(previous) == penalty_code then
+ setpenalty(previous,10000)
+ else
+ insert_node_after(head,previous,new_penalty(10000))
+ end
+ else
+ break
+ end
+ elseif id == glue_code then
+ -- hm, breakpoint, maybe turn this into kern
+ total = total + getwidth(current)
+ if trace_keeptogether then
+ report_keeptogether("%s, index %s, total %p, threshold %p","glue",a,total,threshold)
+ end
+ if total <= threshold then
+ if getid(previous) == penalty_code then
+ setpenalty(previous,10000)
+ else
+ insert_node_after(head,previous,new_penalty(10000))
+ end
+ else
+ break
+ end
+ elseif id == kern_code then
+ total = total + getkern(current)
+ if trace_keeptogether then
+ report_keeptogether("%s, index %s, total %s, threshold %s","kern",a,total,threshold)
+ end
+ if total <= threshold then
+ if getid(previous) == penalty_code then
+ setpenalty(previous,10000)
+ else
+ insert_node_after(head,previous,new_penalty(10000))
+ end
+ else
+ break
+ end
+ elseif id == penalty_code then
+ if total <= threshold then
+ if getid(previous) == penalty_code then
+ setpenalty(previous,10000)
+ end
+ setpenalty(current,10000)
+ else
+ break
+ end
+ end
+ previous = current
+ current = getnext(current)
+ end
+end
+
+-- also look at first non glue/kern node e.g for a dropped caps
+
+-- todo: find_attribute and unset_attributes instead of takeattr
+
+function parbuilders.keeptogether(head)
+ local done = false -- can go
+ local current = head
+ while current do
+ if getid(current) == hlist_code then
+ local a = takeattr(current,a_keeptogether)
+ if a and a > 0 then
+ local specification = cache[a]
+ if specification then
+ keeptogether(current,a,specification)
+ -- this is tricky ... we need a better resetter, maybe some
+ -- injected latelua or a gc method on a property (interesting
+ -- experiment)
+ cache[a] = nil
+ done = true
+ end
+ end
+ end
+ current = getnext(current)
+ end
+ return head, done
+end