summaryrefslogtreecommitdiff
path: root/macros/luatex/generic/lua-visual-debug/lua-visual-debug.lua
blob: 4fb7465a81e63b3994ec653195887b1a6e271a7b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
-- Copyright 2012-2021 Patrick Gundlach, patrick@gundla.ch
-- Public repository: https://github.com/pgundlach/lvdebug (issues/pull requests,...)
-- Version: 0.8

-- Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the
-- "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge,
-- publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do
-- so, subject to the following conditions:
--
-- The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
--
-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-- MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
-- FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
-- WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.



module(...,package.seeall)

-- There are 65782 scaled points in a PDF point
-- Therefore we need to divide all TeX lengths by
-- this amount to get the PDF points.
local number_sp_in_a_pdf_point = 65782


-- The idea is the following: at page shipout, all elements on a page are fixed.
-- TeX creates an intermediate data structure before putting that into the PDF
-- We can "intercept" that data structure and add pdf_literal (whatist) nodes,
-- that makes glues, kerns and other items visible by drawing a rule, rectangle or
-- other visual aids.
-- This has no influence on typeset material, because these pdf_literal instructions
-- are only visible to the PDF file (PDF renderer) and have no size themselves.

-- We recursively loop through the contents of boxes and look at the (linear) list of
-- items in that box. We start at the "shipout box".

-- The "algorithm" goes like this:
--
-- head = pointer_to_beginning_of_box_material
-- while head is not nil
--   if this_item_is_a_box
--     recurse_into_contents
--     draw a rectangle around the contents
--   elseif this_item_is_a_glue
--     draw a rule that has the length of that glue
--   elseif this_item_is_a_kern
--     draw a rectangle with width of that kern
--   ...
--   end
--   move pointer to the next item in the list
--   -- the pointer is "nil" if there is no next item
-- end

local HLIST = node.id("hlist")
local VLIST = node.id("vlist")
local RULE = node.id("rule")
local DIR  = node.id("dir")
local DISC = node.id("disc")
local GLUE = node.id("glue")
local KERN = node.id("kern")
local PENALTY = node.id("penalty")

function math.round(num, idp)
  if idp and idp>0 then
    local mult = 10^idp
    return math.floor(num * mult + 0.5) / mult
  end
  return math.floor(num + 0.5)
end

local curdir = {}, pardir

function show_page_elements(parent)
  local head = parent.list
  while head do
    local has_dir = false
    if head.dir == "TLT" then table.insert(curdir,"ltr") has_dir=true elseif head.dir == "TRT" then table.insert(curdir,"rtl") has_dir=true end
    if head.id == HLIST or head.id == VLIST then

      local rule_width = 0.1
      local wd = math.round(head.width                  / number_sp_in_a_pdf_point - rule_width     ,2)
      local ht = math.round((head.height + head.depth)  / number_sp_in_a_pdf_point - rule_width     ,2)
      local dp = math.round(head.depth                  / number_sp_in_a_pdf_point - rule_width / 2 ,2)

      -- recurse into the contents of the box
      show_page_elements(head)
      local rectangle = node.new("whatsit","pdf_literal")
      if curdir[#curdir] == "rtl" then wd = wd * -1 end
      if head.id == HLIST then -- hbox
        rectangle.data = string.format("q 0.5 G %g w %g %g %g %g re s Q", rule_width, -rule_width / 2, -dp, wd, ht)
      else
        rectangle.data = string.format("q 0.1 G %g w %g %g %g %g re s Q", rule_width, -rule_width / 2, 0, wd, -ht)
      end
      head.list = node.insert_before(head.list,head.list,rectangle)


    elseif head.id == RULE then
      local show_rule = node.new("whatsit","pdf_literal")
      if head.width == -1073741824 or head.height == -1073741824 or head.depth == -1073741824 then
        -- ignore for now -- these rules are stretchable
      else
        local dp = math.round( head.depth / number_sp_in_a_pdf_point  ,2)
        local ht = math.round( head.height / number_sp_in_a_pdf_point ,2)
        show_rule.data =  string.format("q 1 0 0 RG 1 0 0 rg 0.4 w 0 %g m 0 %g l S Q",-dp,ht)
      end
      parent.list = node.insert_before(parent.list,head,show_rule)


    elseif head.id == DISC then
      local hyphen_marker = node.new("whatsit","pdf_literal")
      hyphen_marker.data = "q 0 0 1 RG 0.3 w 0 -1 m 0 0 l S Q"
      parent.list = node.insert_before(parent.list,head,hyphen_marker)

    elseif head.id == DIR then
      local mode = string.sub(head.dir,1,1)
      local texdir = string.sub(head.dir,2,4)
      local ldir
      if texdir == "TLT" then ldir = "ltr" else ldir = "rtl" end
      if mode == "+" then
          table.insert(curdir,ldir)
      elseif mode == "-" then
          local x = table.remove(curdir)
          if x ~= ldir then
              warning("paragraph direction incorrect, found %s, expected %s",ldir,x)
          end
      end

  elseif head.id == GLUE then
      local head_spec = head.spec
      if not head_spec then
        head_spec = head
      end
      local wd = head_spec.width
      local color = "0.5 G"
      if parent.glue_sign == 1 and parent.glue_order == head_spec.stretch_order then
        wd = wd + parent.glue_set * head_spec.stretch
        color = "0 0 1 RG"
      elseif parent.glue_sign == 2 and parent.glue_order == head_spec.shrink_order then
        wd = wd - parent.glue_set * head_spec.shrink
        color = "1 0 1 RG"
      end
      local pdfstring = node.new("whatsit","pdf_literal")
      local wd_bp = math.round(wd / number_sp_in_a_pdf_point,2)
      if curdir[#curdir] == "rtl" then wd_bp = wd_bp * -1 end

      if parent.id == HLIST then
        pdfstring.data = string.format("q %s [0.2] 0 d  0.5 w 0 0  m %g 0 l s Q",color,wd_bp)
      else -- vlist
        pdfstring.data = string.format("q 0.1 G 0.1 w -0.5 0 m 0.5 0 l -0.5 %g m 0.5 %g l s [0.2] 0 d  0.5 w 0.25 0  m 0.25 %g l s Q",-wd_bp,-wd_bp,-wd_bp)
      end
      parent.list = node.insert_before(parent.list,head,pdfstring)

    elseif head.id == KERN then
      local rectangle = node.new("whatsit","pdf_literal")
      local color = "1 1 0 rg"
      if head.kern < 0 then color = "1 0 0 rg" end
      local k = math.round(head.kern / number_sp_in_a_pdf_point,2)
      if parent.id == HLIST then
        rectangle.data = string.format("q %s 0 w 0 0  %g 1 re B Q",color, k )
      else
        rectangle.data = string.format("q %s 0 w 0 0  1 %g re B Q",color, -k )
      end
      parent.list = node.insert_before(parent.list,head,rectangle)


    elseif head.id == PENALTY then
      local color = "1 g"
      local rectangle = node.new("whatsit","pdf_literal")
      if head.penalty < 10000 then
        color = string.format("%d g", 1 - math.floor(head.penalty / 10000))
      end
      rectangle.data = string.format("q %s 0 w 0 0 1 1 re B Q",color)
      parent.list = node.insert_before(parent.list,head,rectangle)
    end
    if has_dir then
      table.remove(curdir)
    end
    head = head.next
  end
  return true
end