Can I have the \overfullrule rule colored in pdfLaTeX?

I know that I can use \overfullrule=5pt to get overfull lines marked with a black marker. I am using pdfLaTeX. Is there a way I can get this marker or something similar in magenta instead?

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The macro \overfullrule=5pt only determines the width of the "slug," i.e., of the marker that's placed to the right of the text in overfull lines. I couldn't find a detailed-enough explanation in either "TeX by Topic" or in "TeX for the inpatient" to determine how and were TeX creates the slug. I hope somebody else can help you out. –  Mico Sep 13 '11 at 9:43
The slug is inserted down in TeX's bowels, if \overfullrule is positive and an \hbox is overfull. Usually this happens during paragraphing, but not necessarily. I believe there's no way to set the color. –  egreg Sep 13 '11 at 9:51

Aditya gave a very nice, portable solution (Patrick's is very nice, too, but less portable).

I've made a little package called overcolored out of it, which can currently be found on github:

\documentclass[pagesize=pdftex,paper=10cm:10cm]{scrbook}

\usepackage{lipsum}
\usepackage[color=blue,
width=3pt,
height=0.5\baselineskip]{overcolored}

\begin{document}

\lipsum[1-3]

\end{document}


Edit: I've seen quite a few shortcomings in complex environments using Aditya's code, while Patrick's code has no side effects that I could see. For this reason, the package now supports both implementations. When compiled with LuaTeX, it will use Patrick's code, otherwise, Aditya's code is used.

I still have to adapt the options to work with Patrick's code. Supporting the width parameter was quite straightforward, the height is a bit more tricky, and supporting color names with PDF annotations seems much more tricky still...

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I tried this package on the book but keep getting the following error on figures: ! Incompatible list can't be unboxed. <to be read again> } l.788 \end{figure} I will try to come up with a minimal example and file as an issue on Github. –  jonalv Sep 16 '11 at 13:53
@jonalv: using PDFTeX I guess? You didn't try the LuaTeX implementation? –  ℝaphink Sep 16 '11 at 13:54
Okey further studies has made me see "quite a few shortcomings in complex environments" as well. I suppose that one can't have everything... –  jonalv Sep 16 '11 at 14:29
yea, actually I am gonna start looking for a LuaTex for dummies or something real-soon-now™ :) –  jonalv Sep 16 '11 at 14:31
@jonalv: On the other hand, the LuaTeX implementation works great for me. All it requires is to use another rendering engine with the same package. –  ℝaphink Sep 16 '11 at 14:31

I am not sure if this is possible with old fashioned TeX/pdfTeX, but it is with LuaTeX (of course, it is!)

\documentclass{article}
\usepackage{luatexbase,luacode}
\overfullrule 5pt
\begin{luacode}

-- go through the hlists (the rows)

-- if there's a rule after the rightskip, this is the overfull box
-- node id 10 == glue, glue subtype 9 is rightskip, node id 2 is a rule

-- this must be an overfull box
local w1, w2
w1 = node.new("whatsit","pdf_literal")
w1.data = "q 1 0 1 rg"
w1.mode = 1
w2 = node.new("whatsit","pdf_literal")
w2.data = " Q"
w2.mode = 1

w1.next = head.next -- the rule
head.next = w1      -- color start
w1.next.next = w2   -- color end

end
end
return true
end

\end{luacode}

\begin{document}
\hsize 1.7in A verylongword verylongword verylongword
\end{document}


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Very nice. Yet a reason in the pile for switching to LuaTeX. I am afraid the pile is not big enough to warrant converting a 500 pages book project though. After all this is just a draft mode feature. I really would need it in pdfTeX for this project... –  jonalv Sep 13 '11 at 11:40
@jonalv: LuaTeX is based on PDFTeX and largely compatible with pretty much everything PDFTeX. The question might be what is keeping you from switching, still? Have you tried processing your 500 pages book through lualatex, just to check? –  ℝaphink Sep 15 '11 at 9:49
@Patrick: this solution does color overfull boxes, but it also ruins the next lines. It seems to generate a negative increasing indentation for every line. –  ℝaphink Sep 15 '11 at 9:56
@Raphink: I have edited my solution (mode=1 for w1 and w2). This will change the positioning of the PDF instructions (pdf_literal). I still don't have a good feeling when other modes then 0 are necessary. –  topskip Sep 15 '11 at 10:27
That works @Patrick, thanks. Going to make an overcolored package (unless someone finds a nicer name) :-) –  ℝaphink Sep 15 '11 at 12:18

Copied from a TeX pearl by Paweł Jackowski. In his words, never underestimate TeX's bells and whistles.

\def\ooops{\hbox to\wd0{\setbox0=\hbox to\wd0{\unhbox0}%

\interlinepenalty=-50000 % force the break between each two lines
\maxdeadcycles=50        % allow upto 50 \outputs with no \shipout
\newtoks\orioutput \orioutput=\output % wrap the original \output routine
\output
{\ifnum\outputpenalty>-20000 \the\orioutput
\else \ifnum\outputpenalty<-\maxdimen \the\orioutput
\else
\unvbox255        % flush the entire list back
\setbox0=\lastbox % strip the very last box
\nointerlineskip  % avoid doubled interline glue
\ooops            % make the test and return the box back.
\penalty\outputpenalty % weak lie that nothing happened...
\fi\fi}

\documentclass{article}
\usepackage[textwidth=1.5in,a6paper]{geometry}

\begin{document}
\pagestyle{empty}

This completely useless example shows a not-so-useless trick, which might be
used for quite advanced applications, such as line-numbering, some kind of
paragraph decoration, page optimization and probably many others. Things become
much more complicated if math displays, \verb|\marks|, \verb|\inserts| or
\verb|\vadjusts| come into play, but they don-F¢t spoil all of the game.
\end{document}


which gives

The definition of ooops can be changed to give a colored rule instead of the text. For example (thanks to Jake)

\def\ooops{\hbox to\wd0{\setbox0=\hbox to\wd0{\unhbox0}%

and loading xcolor.
Replacing Oooops! with \color{magenta}{\rule{0.5em}{3ex}} and loading the xcolor package is one way to get colored rules. –  Jake Sep 15 '11 at 12:28
@Aditya: Nice, but you need \usepackage{xcolor}. Also, the rules break the interline. –  ℝaphink Sep 15 '11 at 13:04
@Raphink: Perhaps wrapping the rules around \smash will help. –  Aditya Sep 15 '11 at 13:08
You can restore the original output routine before the index: \let\output=\orioutput –  Aditya Sep 15 '11 at 16:30