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if not modules then modules = { } end modules ['typo-fln'] = {
version = 1.001,
comment = "companion to typo-fln.mkiv",
author = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
copyright = "PRAGMA ADE / ConTeXt Development Team",
license = "see context related readme files"
}
-- When I ran into the following experimental code again, I figured that it dated
-- from the early days of mkiv, so I updates it a bit to fit into todays context.
-- In the process I might have messed up things. For instance we had a diffent
-- wrapper then using head and tail.
-- todo: only letters (no punctuation)
-- todo: nuts
local trace_firstlines = false trackers.register("typesetters.firstlines", function(v) trace_firstlines = v end)
local report_firstlines = logs.reporter("nodes","firstlines")
typesetters.firstlines = typesetters.firstlines or { }
local firstlines = typesetters.firstlines
local nodes = nodes
local tasks = nodes.tasks
local nodecodes = nodes.nodecodes
local glyph = nodecodes.glyph
local rule = nodecodes.rule
local disc = nodecodes.disc
local kern = nodecodes.kern
local traverse_id = nodes.traverse_id
local free_node_list = nodes.flush_list
local free_node = nodes.flush_node
local copy_node_list = nodes.copy_list
local insert_node_after = nodes.insert_after
local insert_node_before = nodes.insert_before
local hpack_node_list = nodes.hpack
local hpack_filter = nodes.processors.hpack_filter
local newpenalty = nodes.pool.penalty
local newkern = nodes.pool.kern
local tracerrule = nodes.tracers.pool.nodes.rule
local actions = { }
firstlines.actions = actions
local a_firstline = attributes.private('firstline')
local a_color = attributes.private('color')
local a_transparency = attributes.private('transparency')
local a_colorspace = attributes.private('colormodel')
local texsetattribute = tex.setattribute
local unsetvalue = attributes.unsetvalue
local variables = interfaces.variables
local v_default = variables.default
local v_line = variables.line
local v_word = variables.word
----- is_letter = characters.is_letter
----- categories = characters.categories
local settings = nil
function firstlines.set(specification)
settings = specification or { }
tasks.enableaction("processors","typesetters.firstlines.handler")
if trace_firstlines then
report_firstlines("enabling firstlines")
end
texsetattribute(a_firstline,1)
end
commands.setfirstline = firstlines.set
actions[v_line] = function(head,setting)
-- local attribute = fonts.specifiers.contextnumber(setting.feature) -- was experimental
local dynamic = setting.dynamic
local font = setting.font
local noflines = setting.n or 1
local ma = setting.ma or 0
local ca = setting.ca
local ta = setting.ta
local hangafter = tex.hangafter
local hangindent = tex.hangindent
local parindent = tex.parindent
local nofchars = 0
local n = 0
local temp = copy_node_list(head)
local linebreaks = { }
for g in traverse_id(glyph,temp) do
if dynamic > 0 then
g[0] = dynamic
end
g.font = font
end
local start = temp
local list = temp
local prev = temp
for i=1,noflines do
local hsize = tex.hsize - tex.leftskip.width - tex.rightskip.width
if i == 1 then
hsize = hsize - parindent
end
if i <= - hangafter then
hsize = hsize - hangindent
end
while start do
local id = start.id
if id == glyph then
n = n + 1
elseif id == disc then
-- this could be an option
elseif id == kern then -- todo: fontkern
-- this could be an option
elseif n > 0 then
local pack = hpack_node_list(copy_node_list(list,start))
if pack.width > hsize then
free_node_list(pack)
list = prev
break
else
linebreaks[i] = n
prev = start
free_node_list(pack)
nofchars = n
end
end
start = start.next
end
if not linebreaks[i] then
linebreaks[i] = n
end
end
local start = head
local n = 0
for i=1,noflines do
local linebreak = linebreaks[i]
while start and n < nofchars do
local id = start.id
if id == glyph then -- or id == disc then
if dynamic > 0 then
start[0] = dynamic
end
start.font = font
if ca and ca > 0 then
start[a_colorspace] = ma == 0 and 1 or ma
start[a_color] = ca
end
if ta and ta > 0 then
start[a_transparency] = ta
end
n = n + 1
end
if linebreak == n then
if trace_firstlines then
head, start = insert_node_after(head,start,newpenalty(10000)) -- nobreak
head, start = insert_node_after(head,start,newkern(-65536))
head, start = insert_node_after(head,start,tracerrule(65536,4*65536,2*65536,"darkblue"))
end
head, start = insert_node_after(head,start,newpenalty(-10000)) -- break
break
end
start = start.next
end
end
free_node_list(temp)
return head, true
end
actions[v_word] = function(head,setting)
-- local attribute = fonts.specifiers.contextnumber(setting.feature) -- was experimental
local dynamic = setting.dynamic
local font = setting.font
local words = 0
local nofwords = setting.n or 1
local start = head
local ok = false
local ma = setting.ma or 0
local ca = setting.ca
local ta = setting.ta
while start do
local id = start.id
-- todo: delete disc nodes
if id == glyph then
if not ok then
words = words + 1
ok = true
end
if ca and ca > 0 then
start[a_colorspace] = ma == 0 and 1 or ma
start[a_color] = ca
end
if ta and ta > 0 then
start[a_transparency] = ta
end
if dynamic > 0 then
start[0] = dynamic
end
start.font = font
elseif id == disc then
-- continue
elseif id == kern then -- todo: fontkern
-- continue
else
ok = false
if words == nofwords then
break
end
end
start = start.next
end
return head, true
end
actions[v_default] = actions[v_line]
local function process(namespace,attribute,head)
local start = head
local attr = nil
while start do
attr = start[attribute]
if attr then
break
elseif start.id == glyph then
break
else
start = start.next
end
end
if attr then
-- here as we can process nested boxes first so we need to keep state
tasks.disableaction("processors","typesetters.firstlines.handler")
-- texsetattribute(attribute,unsetvalue)
local alternative = settings.alternative or v_default
local action = actions[alternative] or actions[v_default]
if action then
if trace_firstlines then
report_firstlines("processing firstlines, alternative %a",alternative)
end
return action(head,settings)
end
end
return head, false
end
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