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if not modules then modules = { } end modules ['math-spa'] = {
version = 1.001,
comment = "companion to math-ini.mkiv",
author = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
copyright = "PRAGMA ADE / ConTeXt Development Team",
license = "see context related readme files"
}
-- for the moment (when testing) we use a penalty 1
local setmetatableindex = table.setmetatableindex
local boundary_code = nodes.nodecodes.boundary
local hlist_code = nodes.nodecodes.hlist
local glue_code = nodes.nodecodes.glue
local line_code = nodes.listcodes.line
local ghost_code = nodes.listcodes.ghost
local nuts = nodes.nuts
local tonut = nodes.tonut
local tonode = nodes.tonode
local getid = nuts.getid
local getsubtype = nuts.getsubtype
local getnext = nuts.getnext
local getwidth = nuts.getwidth
local getdata = nuts.getdata
local getdepth = nuts.getdepth
local getlist = nuts.getlist
local setglue = nuts.setglue
local getdimensions = nuts.dimensions
local getnormalizedline = node.direct.getnormalizedline
local getbox = nuts.getbox
local setoffsets = nuts.setoffsets
local nextglue = nuts.traversers.glue
local nextlist = nuts.traversers.list
local nextboundary = nuts.traversers.boundary
local texgetdimen = tex.getdimen
local texsetdimen = tex.setdimen
local texsetcount = tex.setcount
local boundary = tex.boundaries.system("mathalign")
local stages = { }
local initial = { }
stages[1] = function(specification,stage)
local box = getbox(specification.box)
local head = getlist(box)
local align = specification.alignstate
local distance = specification.distance
for s in nextboundary, head do
if getdata(s) == boundary then
-- todo: skip over ghost, maybe penalty, maybe glues all in one loop
local n = getnext(s)
while n and getid(n) == hlist_code and getsubtype(n) == ghost_code do
n = getnext(n)
end
-- while n and getid(n) == glue_code do
if n and getid(n) == glue_code then
n = getnext(n)
end
distance = distance + getdimensions(head,n)
break
end
end
texsetdimen("global","d_strc_math_indent",distance)
if align == 2 then
for n in nextglue, head do
setglue(n,getwidth(n),0,0,0,0)
end
end
end
stages[2] = function(specification,stage)
local head = getlist(getbox(specification.box))
local align = specification.alignstate
local max = false
local cnt = 0
local width = 0
local depth = 0
for n, id, subtype, list in nextlist, head do
if subtype == line_code then
local t = getnormalizedline(n)
local m = t.rightskip + t.parfillrightskip
if not max then
max = m
elseif m < max then
max = m
end
cnt = cnt + 1
width = m
depth = getdepth(n)
end
end
if stage == 2 and (align == 2 or align == 3) then
for n, id, subtype, list in nextlist, head do
if subtype == line_code then
if align == 1 then -- flushleft
elseif align == 2 then -- middle
setoffsets(n,max/2,0)
elseif align == 3 then -- flushright
setoffsets(n,max,0)
end
end
end
end
texsetcount("global","c_strc_math_n_of_lines",cnt)
texsetdimen("global","d_strc_math_max_width",max)
texsetdimen("global","d_strc_math_last_width",width)
texsetdimen("global","d_strc_math_last_depth",depth)
end
stages[3] = stages[2]
stages[4] = function(specification,stage)
nuts.openup(specification,getlist(getbox(specification.box)))
end
interfaces.implement {
name = "handlemathhang",
arguments = {
{
{ "stage", "integer" },
-- { "method" },
{ "alignstate", "integer" },
{ "box", "integer" },
{ "distance", "dimension" },
{ "inbetween", "dimension" },
{ "height", "dimension" },
{ "depth", "dimension" },
}
},
actions = function(specification)
local stage = specification.stage
if stage == 1 then
initial = specification
else
setmetatableindex(specification,initial)
end
if stage > 0 and stage <= #stages then
stages[stage](specification,stage)
end
end
}
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