-- Copyright 2012-2023 Patrick Gundlach, patrick@gundla.ch Public repository: -- https://github.com/pgundlach/lvdebug (issues/pull requests,...) Version: see -- Makefile -- 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. -- 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") local 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 = {} local show_page_elements 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 print(string.format("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 return { show_page_elements = show_page_elements }