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
|