9409557472

Committed 07 Jun 2024 12:09AM UTC coverage: 69.448% (-4.5%) from 73.988%

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alerque

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fix(build): Distribute vendored compat-5.3.c source file

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86.11

/packages/insertions/init.lua

local base = require("packages.base")

local package = pl.class(base)
package._name = "insertions"

--[[
 Insertions handling is the most complicated and bug-prone part of
 SILE, and thus deserves to be well documented. If you plan to work
 on this, it would help you a lot to read chapter 29 of "TeX By Topic"
 by Victor Eijkhout.

 Note: While most SILE packages are completely self-contained, this one
 requires some support from the SILE core. We'll get to it later, but
 when the page builder comes across some of the magic boxes that are
 defined as part of insertions handling, it triggers a routine here
 which can alter the page builder's operation. So it is not really an
 optional package.

--

The typical insertion is a footnote but we provide a generic mechanism for
handling any kind of insertion. An insertion is material which is added from
the main flow of the document into a specific area on the page, and where
moving such material alters the shape of the page.

Because this is a generic mechanism, each insertion is part of a "class"
(just like in TeX.); you may have several different classes putting insertions
in different places on the page. These classes also define how the page shape
is altered by the insertion. So, a class using the footnotes package may specify
that insertions get added into the `footnotes' frame and the space used up by
those insertions also reduces the 'content' frame. If you have two columns but
one footnote frame, then an insertion will steal space equal to half the
insertion's height from each column's frame. This is specified as:

  insertInto = "footnotes",
  stealFrom = { leftColumn = 0.5, rightColumn = 0.5 }

Insertion classes also need to define the maximum height they can stretch to,
the skip or box placed before the first insertion on a page, and the skip placed
between insertions.

--]]

local initInsertionClass = function (_, classname, options)
   SU.required(options, "insertInto", "initializing insertions")
   SU.required(options, "stealFrom", "initializing insertions")
   SU.required(options, "maxHeight", "initializing insertions")
   if not options.topSkip and not options.topBox then
      SU.required(options, "topSkip", "initializing insertions")
   end

   -- Turn stealFrom into a hash, if it isn't one.
   if SU.type(options.stealFrom) ~= "table" then
      options.stealFrom = { options.stealFrom }
   end
   if options.stealFrom[1] then
      local rl = {}
      for i = 1, #options.stealFrom do
         rl[options.stealFrom[i]] = 1
      end
      options.stealFrom = rl
   end

   if SU.type(options.insertInto) ~= "table" then
      options.insertInto = { frame = options.insertInto, ratio = 1 }
   end

   options.maxHeight = SILE.types.length(options.maxHeight)

   SILE.scratch.insertions.classes[classname] = options
end

--[[

Each insertion class stores a page's worth of content in a box.
In some ways it's a fairly standard vbox, but it also knows its own
typesetter and frame.

--]]

local insertionsThisPage = {}
SILE.types.node.insertionlist = pl.class(SILE.types.node.vbox)

SILE.types.node.insertionlist.type = "insertionlist"
SILE.types.node.insertionlist.frame = nil

function SILE.types.node.insertionlist:_init (spec)
   SILE.types.node.vbox._init(self, spec)
   self.typesetter = SILE.typesetters.base()
end

function SILE.types.node.insertionlist:__tostring ()
   return "PI<" .. self.nodes .. ">"
end

function SILE.types.node.insertionlist:outputYourself ()
   self.typesetter:initFrame(SILE.getFrame(self.frame))
   for _, node in ipairs(self.nodes) do
      node:outputYourself(self.typesetter, node)
   end
end

local thisPageInsertionBoxForClass = function (class)
   if not insertionsThisPage[class] then
      insertionsThisPage[class] = SILE.types.node.insertionlist({
         frame = SILE.scratch.insertions.classes[class].insertInto.frame,
      })
   end
   return insertionsThisPage[class]
end

--[[

An insertion vbox, on the other hand, is a place where insertion material
is held until we are sure it is going to end up on the current page. (We
might be consuming material that will eventually end up on a future page.)
So we stick the material into an insertion vbox, and when the pagebuilder
sees this, magic will happen.

--]]
SILE.types.node.insertion = pl.class(SILE.types.node.vbox)

SILE.types.node.insertion.discardable = true
SILE.types.node.insertion.type = "insertion"
SILE.types.node.insertion.seen = false

function SILE.types.node.insertion:__tostring ()
   return "I<" .. self.nodes[1] .. "...>"
end

function SILE.types.node.insertion.outputYourself (_) end

-- And some utility methods to make the insertion processing code
-- easier to read.
function SILE.types.node.insertion:dropDiscardables ()
   while #self.nodes > 1 and self.nodes[#self.nodes].discardable do
      self.nodes[#self.nodes] = nil
   end
end

function SILE.types.node.insertion:split (materialToSplit, maxsize)
   local firstpage = SILE.pagebuilder:findBestBreak({
      vboxlist = materialToSplit,
      target = maxsize,
      restart = false,
      force = true,
   })
   if firstpage then
      self.nodes = {}
      self:append(materialToSplit)
      self.contentHeight = self.height
      self.contentDepth = self.depth
      self.depth = SILE.types.length(0)
      self.height = SILE.types.length(0)
      return SILE.pagebuilder:collateVboxes(firstpage)
   end
end

--[[

Set up a value to track how much smaller/larger to make a frame.
We have to track this on the frame, because different insertion
classes might affect the same frame; so we can't track it per class.
We also have to ensure it's initialized every time because we might
be shrinking a frame further down the page that the typesetter hasn't
entered yet.

--]]

local initShrinkage = function (frame)
   if not frame.state or not frame.state.totals then
      frame:init()
   end
   if not frame.state.totals.shrinkage then
      frame.state.totals.shrinkage = SILE.types.measurement(0)
   end
end

local nextInterInsertionSkip = function (class)
   local options = SILE.scratch.insertions.classes[class]
   local stuffSoFar = thisPageInsertionBoxForClass(class)
   if #stuffSoFar.nodes == 0 then
      if options["topBox"] then
         return options["topBox"]:absolute()
      elseif options["topSkip"] then
         return SILE.types.node.vglue(options["topSkip"]:tonumber())
      end
   else
      local skipSize = options["interInsertionSkip"]:tonumber()
      skipSize = skipSize - stuffSoFar.nodes[#stuffSoFar.nodes].depth:tonumber()
      return SILE.types.node.vglue(skipSize)
   end
end

local debugInsertion = function (ins, insbox, topBox, target, targetFrame, totalHeight)
   local insertionsHeight = ins.contentHeight:absolute()
      + topBox.height:absolute()
      + topBox.depth:absolute()
      + ins.contentDepth:absolute()
   SU.debug("insertions", "## Incoming insertion")
   SU.debug("insertions", "Top box height", topBox.height)
   SU.debug("insertions", "Insertion", ins, ins.height, ins.depth)
   SU.debug("insertions", "Total incoming height", insertionsHeight)
   SU.debug("insertions", "Insertions already in this class", insbox.height, insbox.depth)
   SU.debug("insertions", "Page target", target)
   SU.debug("insertions", "Page frame", targetFrame)
   SU.debug("insertions", totalHeight, "worth of content on page so far")
end

-- This just puts the insertion vbox into the typesetter's queues.
local insert = function (_, classname, vbox)
   local insertion = SILE.scratch.insertions.classes[classname]
   if not insertion then
      SU.error("Uninitialized insertion class " .. classname)
   end
   SILE.typesetter:pushMigratingMaterial({
      SILE.types.node.penalty(SILE.settings:get("insertion.penalty")),
   })
   SILE.typesetter:pushMigratingMaterial({
      SILE.types.node.insertion({
         class = classname,
         nodes = vbox.nodes,
         -- actual height and depth must remain zero for page glue calculations
         contentHeight = vbox.height,
         contentDepth = vbox.depth,
         frame = insertion.insertInto.frame,
         parent = SILE.typesetter.frame,
      }),
   })
end

function package:_init ()
   base._init(self)
   if not SILE.scratch.insertions then
      SILE.scratch.insertions = { classes = {} }
   end
   if not SILE.insertions then
      SILE.insertions = {}
   end

   --[[ Mark a frame for reduction. --]]

   SILE.insertions.setShrinkage = function (classname, amount)
      local reduceList = SILE.scratch.insertions.classes[classname].stealFrom
      for fName, ratio in pairs(reduceList) do
         local frame = SILE.getFrame(fName)
         if frame then
            initShrinkage(frame)
            SU.debug("insertions", "Shrinking", fName, "by", amount * ratio)
            frame.state.totals.shrinkage = frame.state.totals.shrinkage + amount * ratio
         end
      end
   end

   --[[ Actually shrink the frame. --]]

   SILE.insertions.commitShrinkage = function (_, classname)
      local opts = SILE.scratch.insertions.classes[classname]
      local reduceList = opts["stealFrom"]
      local stealPosition = opts["steal-position"] or "bottom"
      for fName, _ in pairs(reduceList) do
         local frame = SILE.getFrame(fName)
         if frame then
            initShrinkage(frame)
            local newHeight = frame:height() - frame.state.totals.shrinkage
            if stealPosition == "bottom" then
               frame:relax("bottom")
            else
               frame:relax("top")
            end
            SU.debug("insertions", "Constraining height of", fName, "by", frame.state.totals.shrinkage, "to", newHeight)
            frame:constrain("height", newHeight)
            frame.state.totals.shrinkage = SILE.types.measurement(0)
         end
      end
   end

   SILE.insertions.increaseInsertionFrame = function (insertionvbox, classname)
      local amount = insertionvbox.height + insertionvbox.depth
      local opts = SILE.scratch.insertions.classes[classname]
      SU.debug("insertions", "Increasing insertion frame by", amount)
      local stealPosition = opts["steal-position"] or "bottom"
      local insertionFrame = SILE.getFrame(opts["insertInto"].frame)
      local oldHeight = insertionFrame:height()
      amount = amount * opts["insertInto"].ratio
      insertionFrame:constrain("height", oldHeight + amount)
      if stealPosition == "bottom" then
         insertionFrame:relax("top")
      end
      SU.debug("insertions", "New height is now", insertionFrame:height())
   end

   --[[
  So, this is the magic routine called by the page builder to determine what
  do to when an insertion is seen in the vertical list. The key design issue
  about this routine is that it needs to be very careful about state; it may
  end up processing the same list different times. (if the current list of
  vertical items is not tall enough to cause a page break yet) So it should
  not commit itself to anything yet. Another interesting complication is that
  when the page builder restarts, for optimization purposes it is at liberty
  to restart its calculations half-way through the list. So you can't
  completely forget the insertions that you've seen either.

  However, one mitigating factor is: if an insertion fits on the current page,
  it will end up on the current page. So if you've seen an insertion and it
  fits, you can commit to it at this point. If at some later date we have
  page builders which reflow multiple pages, then this may not be true.

  The main job is this routine is to make a decision about whether the
  upcoming insertion can fit on the page; if it needs to be split; or if it
  should not appear on this page at all (and hence force the line which
  caused the insertion off the page as well).
  --]]
   SILE.insertions.processInsertion = function (vboxlist, i, totalHeight, target)
      local ins = vboxlist[i]
      if ins.seen then
         return target
      end
      local targetFrame = SILE.getFrame(ins.frame)
      local options = SILE.scratch.insertions.classes[ins.class]

      ins:dropDiscardables()

      -- We look into the page's insertion box and choose the appropriate skip,
      -- so we know how high the whole insertion is.
      local topBox = nextInterInsertionSkip(ins.class)
      local insertionsHeight = SILE.types.length()
      insertionsHeight:___add(ins.contentHeight)
      insertionsHeight:___add(topBox.height)
      insertionsHeight:___add(topBox.depth)
      insertionsHeight:___add(ins.contentDepth)

      local insbox = thisPageInsertionBoxForClass(ins.class)
      initShrinkage(targetFrame)
      initShrinkage(SILE.typesetter.frame)

      if SU.debugging("insertions") then
         debugInsertion(ins, insbox, topBox, target, targetFrame, totalHeight)
      end

      local effectOnThisFrame = options.stealFrom[SILE.typesetter.frame.id]
      if effectOnThisFrame then
         effectOnThisFrame = insertionsHeight * effectOnThisFrame
      else
         effectOnThisFrame = SILE.types.measurement(0)
      end

      local newTarget = target - effectOnThisFrame

      -- We only fit if:
      -- the effect of the insertion on this frame doesn't take us over the page target
      -- and this doesn't take the target frame over the max height.

      if totalHeight + effectOnThisFrame <= target and insbox.height + insertionsHeight <= options.maxHeight then
         SU.debug("insertions", "fits")
         SILE.insertions.setShrinkage(ins.class, insertionsHeight)
         insbox:append(topBox)
         insbox:append(ins)
         ins.seen = true
         return newTarget
      end

      -- OK, we didn't fit. So now we have to split the insertion to fit the height
      -- we have within the insertion frame.
      SU.debug("insertions", "splitting")
      local maxsize = SU.min(target - totalHeight, options.maxHeight)

      -- If we're going to fit this insertion on the page, we will use the
      -- whole of topbox, so let's subtract the height of that now.
      -- The remaining height will be the amount of inserted material that we
      -- intend to put on this page.
      maxsize = maxsize - topBox.height
      local materialToSplit = {}
      pl.tablex.insertvalues(materialToSplit, ins:unbox())
      local deferredInsertions = ins:split(materialToSplit, maxsize)

      if deferredInsertions then
         SU.debug("insertions", "Split. Remaining insertion is", ins)
         SILE.insertions.setShrinkage(
            ins.class,
            topBox.height:absolute() + deferredInsertions.height:absolute() + deferredInsertions.depth:absolute()
         )
         insbox:append(topBox)
         -- deferredInsertions.contentHeight = deferredInsertions.height
         -- deferredInsertions.contentDepth = deferredInsertions.depth
         insbox:append(deferredInsertions)
         deferredInsertions.seen = true

         --[[ The insertion we're dealing with is currently vboxlist[i], and it
      now contains all the material that *didn't* make it onto the current
      page. We've dealt with the material that did fit on the page. We want
      the page builder to a) break the page immediately here - it's full by
      definition, or else we would not have needed to split (XXX This is not
      true, because we might not be stealing from the current frame.) and
      then b) retry the remaining material. By inserting a penalty into the
      vboxlist, when we return from here the pagebuilder will first consider
      the penalty (and break the page) and then consider the rest of the
      insertion. --]]

         table.insert(vboxlist, i, SILE.types.node.penalty(-20000))
         return target -- Who cares? The penalty is going to cause a split.
      end

      --[[ We couldn't even split the insertion.

    Assume that previously we have seen these nodes on the vboxlist:

      i-2 \vbox{Hello world. I am a footnote mark: 1}
      i-1 \vglue
      i   \insertionbox{1. Footnote}

    This insertion couldn't fit on the page at all. Therefore we need to
    take both the footnote *and* the previous vbox (from which the
    insertion has been migrated) onto a new page. The way we achieve this
    is by finding the most recent vbox and then continually inserting page
    break penalties, pushing the insertion and vbox further down the list
    until they are the next things to be considered. The end result of the
    vboxlist will be:

      i-2 \penalty
      i-1 \penalty
      i   \penalty <- considered now when we return to pagebuilder
      i+1 \vbox{Hello world. I am a footnote mark: 1}
      i+2 \vglue
      i+3 \insertionbox{1. Footnote}

    The page will be broken right now, and the old vbox will no longer
    be part of the material to be output on the page. The new page will
    start with the vbox and the insertion.

    --]]
      local lastbox = i
      while not vboxlist[lastbox].is_vbox do
         lastbox = lastbox - 1
      end
      while not (vboxlist[i].is_penalty and vboxlist[i].penalty == -20000) do
         table.insert(vboxlist, lastbox, SILE.types.node.penalty(-20000))
      end
      return target
   end

   self.class:registerPostinit(function (_)
      local typesetter = SILE.typesetter

      if not typesetter.noinsertion_getTargetLength then
         typesetter.noinsertion_getTargetLength = typesetter.getTargetLength
         typesetter.getTargetLength = function (self_)
            initShrinkage(self_.frame)
            return typesetter.noinsertion_getTargetLength(self_) - self_.frame.state.totals.shrinkage
         end
      end

      typesetter:registerFrameBreakHook(function (_, nodelist)
         pl.tablex.foreach(insertionsThisPage, SILE.insertions.commitShrinkage)
         return nodelist
      end)

      typesetter:registerPageEndHook(function (_)
         pl.tablex.foreach(insertionsThisPage, SILE.insertions.increaseInsertionFrame)
         for insertionclass, insertionlist in pairs(insertionsThisPage) do
            insertionlist:outputYourself()
            insertionsThisPage[insertionclass] = nil
         end
         if SU.debugging("insertions") then
            for _, frame in pairs(SILE.frames) do
               SILE.outputter:debugFrame(frame)
            end
         end
      end)
   end)

   self:export("initInsertionClass", initInsertionClass)
   self:export("thisPageInsertionBoxForClass", thisPageInsertionBoxForClass)
   self:export("insert", insert)
end

function package.declareSettings (_)
   SILE.settings:declare({
      parameter = "insertion.penalty",
      type = "integer",
      default = -3000,
      help = "Penalty to be applied before insertion",
   })
end

package.documentation = [[
\begin{document}
The \autodoc:package{footnotes} package works by taking auxiliary material (the footnote content), shrinking the current frame and inserting it into the footnote frame.
This is powered by the \autodoc:package{insertions} package; it doesn’t provide any user-visible SILE commands, but provides Lua functionality to other packages.
TeX wizards may be interested to realise that insertions are implemented by an external add-on package, rather than being part of the SILE core.
\end{document}
]]

return package

1	local base = require("packages.base")	15✔
2
3	local package = pl.class(base)	15✔
4	package._name = "insertions"	15✔
5
6	--[[
7	Insertions handling is the most complicated and bug-prone part of
8	SILE, and thus deserves to be well documented. If you plan to work
9	on this, it would help you a lot to read chapter 29 of "TeX By Topic"
10	by Victor Eijkhout.
11
12	Note: While most SILE packages are completely self-contained, this one
13	requires some support from the SILE core. We'll get to it later, but
14	when the page builder comes across some of the magic boxes that are
15	defined as part of insertions handling, it triggers a routine here
16	which can alter the page builder's operation. So it is not really an
17	optional package.
18
19	--
20
21	The typical insertion is a footnote but we provide a generic mechanism for
22	handling any kind of insertion. An insertion is material which is added from
23	the main flow of the document into a specific area on the page, and where
24	moving such material alters the shape of the page.
25
26	Because this is a generic mechanism, each insertion is part of a "class"
27	(just like in TeX.); you may have several different classes putting insertions
28	in different places on the page. These classes also define how the page shape
29	is altered by the insertion. So, a class using the footnotes package may specify
30	that insertions get added into the `footnotes' frame and the space used up by
31	those insertions also reduces the 'content' frame. If you have two columns but
32	one footnote frame, then an insertion will steal space equal to half the
33	insertion's height from each column's frame. This is specified as:
34
35	insertInto = "footnotes",
36	stealFrom = { leftColumn = 0.5, rightColumn = 0.5 }
37
38	Insertion classes also need to define the maximum height they can stretch to,
39	the skip or box placed before the first insertion on a page, and the skip placed
40	between insertions.
41
42	--]]
43
44	local initInsertionClass = function (_, classname, options)
45	SU.required(options, "insertInto", "initializing insertions")	16✔
46	SU.required(options, "stealFrom", "initializing insertions")	16✔
47	SU.required(options, "maxHeight", "initializing insertions")	16✔
48	if not options.topSkip and not options.topBox then	16✔
49	SU.required(options, "topSkip", "initializing insertions")	×
50	end
51
52	-- Turn stealFrom into a hash, if it isn't one.
53	if SU.type(options.stealFrom) ~= "table" then	32✔
54	options.stealFrom = { options.stealFrom }	×
55	end
56	if options.stealFrom[1] then	16✔
57	local rl = {}	15✔
58	for i = 1, #options.stealFrom do	30✔
59	rl[options.stealFrom[i]] = 1	15✔
60	end
61	options.stealFrom = rl	15✔
62	end
63
64	if SU.type(options.insertInto) ~= "table" then	32✔
65	options.insertInto = { frame = options.insertInto, ratio = 1 }	15✔
66	end
67
68	options.maxHeight = SILE.types.length(options.maxHeight)	32✔
69
70	SILE.scratch.insertions.classes[classname] = options	16✔
71	end
72
73	--[[
74
75	Each insertion class stores a page's worth of content in a box.
76	In some ways it's a fairly standard vbox, but it also knows its own
77	typesetter and frame.
78
79	--]]
80
81	local insertionsThisPage = {}	15✔
82	SILE.types.node.insertionlist = pl.class(SILE.types.node.vbox)	30✔
83
84	SILE.types.node.insertionlist.type = "insertionlist"	15✔
85	SILE.types.node.insertionlist.frame = nil	15✔
86
87	function SILE.types.node.insertionlist:_init (spec)	30✔
88	SILE.types.node.vbox._init(self, spec)	7✔
89	self.typesetter = SILE.typesetters.base()	14✔
90	end
91
92	function SILE.types.node.insertionlist:__tostring ()	30✔
93	return "PI<" .. self.nodes .. ">"	×
94	end
95
96	function SILE.types.node.insertionlist:outputYourself ()	30✔
97	self.typesetter:initFrame(SILE.getFrame(self.frame))	14✔
98	for _, node in ipairs(self.nodes) do	160✔
99	node:outputYourself(self.typesetter, node)	153✔
100	end
101	end
102
103	local thisPageInsertionBoxForClass = function (class)
104	if not insertionsThisPage[class] then	28✔
105	insertionsThisPage[class] = SILE.types.node.insertionlist({	14✔
106	frame = SILE.scratch.insertions.classes[class].insertInto.frame,	7✔
107	})	7✔
108	end
109	return insertionsThisPage[class]	28✔
110	end
111
112	--[[
113
114	An insertion vbox, on the other hand, is a place where insertion material
115	is held until we are sure it is going to end up on the current page. (We
116	might be consuming material that will eventually end up on a future page.)
117	So we stick the material into an insertion vbox, and when the pagebuilder
118	sees this, magic will happen.
119
120	--]]
121	SILE.types.node.insertion = pl.class(SILE.types.node.vbox)	30✔
122
123	SILE.types.node.insertion.discardable = true	15✔
124	SILE.types.node.insertion.type = "insertion"	15✔
125	SILE.types.node.insertion.seen = false	15✔
126
127	function SILE.types.node.insertion:__tostring ()	30✔
128	return "I<" .. self.nodes[1] .. "...>"	×
129	end
130
131	function SILE.types.node.insertion.outputYourself (_) end	25✔
132
133	-- And some utility methods to make the insertion processing code
134	-- easier to read.
135	function SILE.types.node.insertion:dropDiscardables ()	30✔
136	while #self.nodes > 1 and self.nodes[#self.nodes].discardable do	14✔
137	self.nodes[#self.nodes] = nil	×
138	end
139	end
140
141	function SILE.types.node.insertion:split (materialToSplit, maxsize)	30✔
142	local firstpage = SILE.pagebuilder:findBestBreak({	4✔
143	vboxlist = materialToSplit,	2✔
144	target = maxsize,	2✔
145	restart = false,
146	force = true,
147	})
148	if firstpage then	2✔
149	self.nodes = {}	2✔
150	self:append(materialToSplit)	2✔
151	self.contentHeight = self.height	2✔
152	self.contentDepth = self.depth	2✔
153	self.depth = SILE.types.length(0)	4✔
154	self.height = SILE.types.length(0)	4✔
155	return SILE.pagebuilder:collateVboxes(firstpage)	2✔
156	end
157	end
158
159	--[[
160
161	Set up a value to track how much smaller/larger to make a frame.
162	We have to track this on the frame, because different insertion
163	classes might affect the same frame; so we can't track it per class.
164	We also have to ensure it's initialized every time because we might
165	be shrinking a frame further down the page that the typesetter hasn't
166	entered yet.
167
168	--]]
169
170	local initShrinkage = function (frame)
171	if not frame.state or not frame.state.totals then	284✔
172	frame:init()	1✔
173	end
174	if not frame.state.totals.shrinkage then	284✔
175	frame.state.totals.shrinkage = SILE.types.measurement(0)	90✔
176	end
177	end
178
179	local nextInterInsertionSkip = function (class)
180	local options = SILE.scratch.insertions.classes[class]	14✔
181	local stuffSoFar = thisPageInsertionBoxForClass(class)	14✔
182	if #stuffSoFar.nodes == 0 then	14✔
183	if options["topBox"] then	7✔
184	return options["topBox"]:absolute()	7✔
185	elseif options["topSkip"] then	×
186	return SILE.types.node.vglue(options["topSkip"]:tonumber())	×
187	end
188	else
189	local skipSize = options["interInsertionSkip"]:tonumber()	7✔
190	skipSize = skipSize - stuffSoFar.nodes[#stuffSoFar.nodes].depth:tonumber()	14✔
191	return SILE.types.node.vglue(skipSize)	7✔
192	end
193	end
194
195	local debugInsertion = function (ins, insbox, topBox, target, targetFrame, totalHeight)
196	local insertionsHeight = ins.contentHeight:absolute()	×
197	+ topBox.height:absolute()	×
198	+ topBox.depth:absolute()	×
199	+ ins.contentDepth:absolute()	×
200	SU.debug("insertions", "## Incoming insertion")	×
201	SU.debug("insertions", "Top box height", topBox.height)	×
202	SU.debug("insertions", "Insertion", ins, ins.height, ins.depth)	×
203	SU.debug("insertions", "Total incoming height", insertionsHeight)	×
204	SU.debug("insertions", "Insertions already in this class", insbox.height, insbox.depth)	×
205	SU.debug("insertions", "Page target", target)	×
206	SU.debug("insertions", "Page frame", targetFrame)	×
207	SU.debug("insertions", totalHeight, "worth of content on page so far")	×
208	end
209
210	-- This just puts the insertion vbox into the typesetter's queues.
211	local insert = function (_, classname, vbox)
212	local insertion = SILE.scratch.insertions.classes[classname]	12✔
213	if not insertion then	12✔
214	SU.error("Uninitialized insertion class " .. classname)	×
215	end
216	SILE.typesetter:pushMigratingMaterial({	24✔
217	SILE.types.node.penalty(SILE.settings:get("insertion.penalty")),	36✔
218	})
219	SILE.typesetter:pushMigratingMaterial({	24✔
220	SILE.types.node.insertion({	24✔
221	class = classname,	12✔
222	nodes = vbox.nodes,	12✔
223	-- actual height and depth must remain zero for page glue calculations
224	contentHeight = vbox.height,	12✔
225	contentDepth = vbox.depth,	12✔
226	frame = insertion.insertInto.frame,	12✔
227	parent = SILE.typesetter.frame,	12✔
228	}),	12✔
229	})
230	end
231
232	function package:_init ()	15✔
233	base._init(self)	16✔
234	if not SILE.scratch.insertions then	16✔
235	SILE.scratch.insertions = { classes = {} }	15✔
236	end
237	if not SILE.insertions then	16✔
238	SILE.insertions = {}	15✔
239	end
240
241	--[[ Mark a frame for reduction. --]]
242
243	SILE.insertions.setShrinkage = function (classname, amount)	16✔
244	local reduceList = SILE.scratch.insertions.classes[classname].stealFrom	14✔
245	for fName, ratio in pairs(reduceList) do	26✔
246	local frame = SILE.getFrame(fName)	12✔
247	if frame then	12✔
248	initShrinkage(frame)	12✔
249	SU.debug("insertions", "Shrinking", fName, "by", amount * ratio)	24✔
250	frame.state.totals.shrinkage = frame.state.totals.shrinkage + amount * ratio	36✔
251	end
252	end
253	end
254
255	--[[ Actually shrink the frame. --]]
256
257	SILE.insertions.commitShrinkage = function (_, classname)	16✔
258	local opts = SILE.scratch.insertions.classes[classname]	8✔
259	local reduceList = opts["stealFrom"]	8✔
260	local stealPosition = opts["steal-position"] or "bottom"	8✔
261	for fName, _ in pairs(reduceList) do	14✔
262	local frame = SILE.getFrame(fName)	6✔
263	if frame then	6✔
264	initShrinkage(frame)	6✔
265	local newHeight = frame:height() - frame.state.totals.shrinkage	12✔
266	if stealPosition == "bottom" then	6✔
267	frame:relax("bottom")	12✔
268	else
269	frame:relax("top")	×
270	end
271	SU.debug("insertions", "Constraining height of", fName, "by", frame.state.totals.shrinkage, "to", newHeight)	6✔
272	frame:constrain("height", newHeight)	6✔
273	frame.state.totals.shrinkage = SILE.types.measurement(0)	12✔
274	end
275	end
276	end
277
278	SILE.insertions.increaseInsertionFrame = function (insertionvbox, classname)	16✔
279	local amount = insertionvbox.height + insertionvbox.depth	7✔
280	local opts = SILE.scratch.insertions.classes[classname]	7✔
281	SU.debug("insertions", "Increasing insertion frame by", amount)	7✔
282	local stealPosition = opts["steal-position"] or "bottom"	7✔
283	local insertionFrame = SILE.getFrame(opts["insertInto"].frame)	7✔
284	local oldHeight = insertionFrame:height()	7✔
285	amount = amount * opts["insertInto"].ratio	7✔
286	insertionFrame:constrain("height", oldHeight + amount)	14✔
287	if stealPosition == "bottom" then	7✔
288	insertionFrame:relax("top")	7✔
289	end
290	SU.debug("insertions", "New height is now", insertionFrame:height())	14✔
291	end
292
293	--[[
294	So, this is the magic routine called by the page builder to determine what
295	do to when an insertion is seen in the vertical list. The key design issue
296	about this routine is that it needs to be very careful about state; it may
297	end up processing the same list different times. (if the current list of
298	vertical items is not tall enough to cause a page break yet) So it should
299	not commit itself to anything yet. Another interesting complication is that
300	when the page builder restarts, for optimization purposes it is at liberty
301	to restart its calculations half-way through the list. So you can't
302	completely forget the insertions that you've seen either.
303
304	However, one mitigating factor is: if an insertion fits on the current page,
305	it will end up on the current page. So if you've seen an insertion and it
306	fits, you can commit to it at this point. If at some later date we have
307	page builders which reflow multiple pages, then this may not be true.
308
309	The main job is this routine is to make a decision about whether the
310	upcoming insertion can fit on the page; if it needs to be split; or if it
311	should not appear on this page at all (and hence force the line which
312	caused the insertion off the page as well).
313	--]]
314	SILE.insertions.processInsertion = function (vboxlist, i, totalHeight, target)	16✔
315	local ins = vboxlist[i]	61✔
316	if ins.seen then	61✔
317	return target	47✔
318	end
319	local targetFrame = SILE.getFrame(ins.frame)	14✔
320	local options = SILE.scratch.insertions.classes[ins.class]	14✔
321
322	ins:dropDiscardables()	14✔
323
324	-- We look into the page's insertion box and choose the appropriate skip,
325	-- so we know how high the whole insertion is.
326	local topBox = nextInterInsertionSkip(ins.class)	14✔
327	local insertionsHeight = SILE.types.length()	14✔
328	insertionsHeight:___add(ins.contentHeight)	14✔
329	insertionsHeight:___add(topBox.height)	14✔
330	insertionsHeight:___add(topBox.depth)	14✔
331	insertionsHeight:___add(ins.contentDepth)	14✔
332
333	local insbox = thisPageInsertionBoxForClass(ins.class)	14✔
334	initShrinkage(targetFrame)	14✔
335	initShrinkage(SILE.typesetter.frame)	14✔
336
337	if SU.debugging("insertions") then	28✔
338	debugInsertion(ins, insbox, topBox, target, targetFrame, totalHeight)	×
339	end
340
341	local effectOnThisFrame = options.stealFrom[SILE.typesetter.frame.id]	14✔
342	if effectOnThisFrame then	14✔
343	effectOnThisFrame = insertionsHeight * effectOnThisFrame	24✔
344	else
345	effectOnThisFrame = SILE.types.measurement(0)	4✔
346	end
347
348	local newTarget = target - effectOnThisFrame	14✔
349
350	-- We only fit if:
351	-- the effect of the insertion on this frame doesn't take us over the page target
352	-- and this doesn't take the target frame over the max height.
353
354	if totalHeight + effectOnThisFrame <= target and insbox.height + insertionsHeight <= options.maxHeight then	52✔
355	SU.debug("insertions", "fits")	12✔
356	SILE.insertions.setShrinkage(ins.class, insertionsHeight)	12✔
357	insbox:append(topBox)	12✔
358	insbox:append(ins)	12✔
359	ins.seen = true	12✔
360	return newTarget	12✔
361	end
362
363	-- OK, we didn't fit. So now we have to split the insertion to fit the height
364	-- we have within the insertion frame.
365	SU.debug("insertions", "splitting")	2✔
366	local maxsize = SU.min(target - totalHeight, options.maxHeight)	4✔
367
368	-- If we're going to fit this insertion on the page, we will use the
369	-- whole of topbox, so let's subtract the height of that now.
370	-- The remaining height will be the amount of inserted material that we
371	-- intend to put on this page.
372	maxsize = maxsize - topBox.height	2✔
373	local materialToSplit = {}	2✔
374	pl.tablex.insertvalues(materialToSplit, ins:unbox())	4✔
375	local deferredInsertions = ins:split(materialToSplit, maxsize)	2✔
376
377	if deferredInsertions then	2✔
378	SU.debug("insertions", "Split. Remaining insertion is", ins)	2✔
379	SILE.insertions.setShrinkage(	4✔
380	ins.class,	2✔
381	topBox.height:absolute() + deferredInsertions.height:absolute() + deferredInsertions.depth:absolute()	10✔
382	)
383	insbox:append(topBox)	2✔
384	-- deferredInsertions.contentHeight = deferredInsertions.height
385	-- deferredInsertions.contentDepth = deferredInsertions.depth
386	insbox:append(deferredInsertions)	2✔
387	deferredInsertions.seen = true	2✔
388
389	--[[ The insertion we're dealing with is currently vboxlist[i], and it
390	now contains all the material that didn't make it onto the current
391	page. We've dealt with the material that did fit on the page. We want
392	the page builder to a) break the page immediately here - it's full by
393	definition, or else we would not have needed to split (XXX This is not
394	true, because we might not be stealing from the current frame.) and
395	then b) retry the remaining material. By inserting a penalty into the
396	vboxlist, when we return from here the pagebuilder will first consider
397	the penalty (and break the page) and then consider the rest of the
398	insertion. --]]
399
400	table.insert(vboxlist, i, SILE.types.node.penalty(-20000))	4✔
401	return target -- Who cares? The penalty is going to cause a split.	2✔
402	end
403
404	--[[ We couldn't even split the insertion.
405
406	Assume that previously we have seen these nodes on the vboxlist:
407
408	i-2 \vbox{Hello world. I am a footnote mark: 1}
409	i-1 \vglue
410	i \insertionbox{1. Footnote}
411
412	This insertion couldn't fit on the page at all. Therefore we need to
413	take both the footnote and the previous vbox (from which the
414	insertion has been migrated) onto a new page. The way we achieve this
415	is by finding the most recent vbox and then continually inserting page
416	break penalties, pushing the insertion and vbox further down the list
417	until they are the next things to be considered. The end result of the
418	vboxlist will be:
419
420	i-2 \penalty
421	i-1 \penalty
422	i \penalty <- considered now when we return to pagebuilder
423	i+1 \vbox{Hello world. I am a footnote mark: 1}
424	i+2 \vglue
425	i+3 \insertionbox{1. Footnote}
426
427	The page will be broken right now, and the old vbox will no longer
428	be part of the material to be output on the page. The new page will
429	start with the vbox and the insertion.
430
431	--]]
432	local lastbox = i	×
433	while not vboxlist[lastbox].is_vbox do	×
434	lastbox = lastbox - 1	×
435	end
436	while not (vboxlist[i].is_penalty and vboxlist[i].penalty == -20000) do	×
437	table.insert(vboxlist, lastbox, SILE.types.node.penalty(-20000))	×
438	end
439	return target	×
440	end
441
442	self.class:registerPostinit(function (_)	32✔
443	local typesetter = SILE.typesetter	16✔
444
445	if not typesetter.noinsertion_getTargetLength then	16✔
446	typesetter.noinsertion_getTargetLength = typesetter.getTargetLength	15✔
447	typesetter.getTargetLength = function (self_)
448	initShrinkage(self_.frame)	238✔
449	return typesetter.noinsertion_getTargetLength(self_) - self_.frame.state.totals.shrinkage	714✔
450	end
451	end
452
453	typesetter:registerFrameBreakHook(function (_, nodelist)	32✔
454	pl.tablex.foreach(insertionsThisPage, SILE.insertions.commitShrinkage)	33✔
455	return nodelist	33✔
456	end)
457
458	typesetter:registerPageEndHook(function (_)	32✔
459	pl.tablex.foreach(insertionsThisPage, SILE.insertions.increaseInsertionFrame)	34✔
460	for insertionclass, insertionlist in pairs(insertionsThisPage) do	41✔
461	insertionlist:outputYourself()	7✔
462	insertionsThisPage[insertionclass] = nil	7✔
463	end
464	if SU.debugging("insertions") then	68✔
465	for _, frame in pairs(SILE.frames) do	×
466	SILE.outputter:debugFrame(frame)	×
467	end
468	end
469	end)
470	end)
471
472	self:export("initInsertionClass", initInsertionClass)	16✔
473	self:export("thisPageInsertionBoxForClass", thisPageInsertionBoxForClass)	16✔
474	self:export("insert", insert)	16✔
475	end
476
477	function package.declareSettings (_)	15✔
478	SILE.settings:declare({	15✔
479	parameter = "insertion.penalty",
480	type = "integer",
481	default = -3000,
482	help = "Penalty to be applied before insertion",
483	})
484	end
485
486	package.documentation = [[
487	\begin{document}
488	The \autodoc:package{footnotes} package works by taking auxiliary material (the footnote content), shrinking the current frame and inserting it into the footnote frame.
489	This is powered by the \autodoc:package{insertions} package; it doesn’t provide any user-visible SILE commands, but provides Lua functionality to other packages.
490	TeX wizards may be interested to realise that insertions are implemented by an external add-on package, rather than being part of the SILE core.
491	\end{document}
492	]]	15✔
493
494	return package	15✔

sile-typesetter / sile / 9409557472

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