Text Formatting

gkl · Post by **gkl** » Wed Sep 28, 2011 4:44 pm

Dear All,

I am trying to change the definition of \leftmark so that if you are on a page that has text from Chapter 1 and the start of Chapter 2 it will print Chapter 1 and Chapter 2 rather than just Chapter 2.

I looked at article.cls and fancyhdr.sty but found only uses of it, no definitions.

Could somebody shed some light on that?

Regards,
George

$LaTeX Beginner's Guide$ $LaTeX Cookbook$ $LaTeX TikZ graphics$ $TikZによるLaTeXグラフィックス$

Post by **localghost** » Wed Sep 28, 2011 5:17 pm

You have to look at the LaTeX2e kernel (file »latex.ltx«). You can find out on the command line where it is located in your TeX installation tree.

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kpsewhich latex.ltx

Thorsten

gkl · Post by **gkl** » Wed Sep 28, 2011 6:57 pm

OK, I found this line:

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\def\leftmark{\expandafter\@leftmark\botmark\@empty\@empty}

which I think is what assigns a value to the variable leftmark.

Does anyone know where is the code that actually works out what the value of \@leftmark is?

Finally, could you please suggest any books containing information about macro programming in LaTeX (that would presumably explain the \expandafter and all the other concepts).

Regards,
George

Post by **localghost** » Wed Sep 28, 2011 7:15 pm

gkl wrote:[…] Finally, could you please suggest any books containing information about macro programming in LaTeX (that would presumably explain the \expandafter and all the other concepts). […]

Post by **Stefan Kottwitz** » Wed Sep 28, 2011 7:29 pm

Further recommendations:

Stefan

EmilioLazo · Post by **EmilioLazo** » Thu Sep 29, 2011 7:56 pm

This article [1] about \expandafter is really interesting.

Maybe you know that, but I'll explain some tips about what I understand about these marks:

When you issue a \chapter, the macro \chaptermark is invoked with the name of the chapter as its argument; the same applies to \section with \sectionmark.
The definition of \chaptermark and \sectionmark depends on the page style and on the 'oneside' or 'twoside' option to make TeX handle these marks "correctly".
\chaptermark issues \markboth to set the "right" mark (not exactly "right" but the mark corresponding to chapter information) and blanks the "left" (section) mark to prevent last section of previous chapter still being displayed after a new chapter is issued.
\markboth sets \leftmark and \rightmark; and \markright sets \rightmark. These \{left,right}mark variables are the text rendered at headers, so if you renew \leftmark are you redefining the current page headers not the command that produces it. What you need to redefine may be \markboth and \markright. (You may test wherever in the document text putting \rightmark to see what happens).

But why are you needing this? \chapter generally makes a new page, so I can't figure out how you can have two chapters in the same page without redefining also \chapter command or without using some other class. Instead you can have two sections on the same page.

My recommendation is that you may start with fancyhdr and try to redefine \markboth to not clear the previous \rightmark if \markboth is invoked twice at the same page.

Regards

[1] http://www.tug.org/TUGboat/tb09-1/tb20bechtolsheim.pdf
[2] http://www.ntg.nl/maps/16/29.pdf

gkl · Post by **gkl** » Fri Sep 30, 2011 6:55 pm

Dear All,

Many thanks for the prompt replies. Emilio you are right, I am looking for the case where you have two sections running in the same page. My idea was to look into the leftmark variable, see if it is empty and if not append the value of the section's name. I haven't tried it yet, hopefully over the weekend.

I will look at your suggestion as well and report back.

Regards,
George

EmilioLazo · Post by **EmilioLazo** » Fri Sep 30, 2011 7:23 pm

Hello!

As far as I can remember, \leftmark can't be void/blank unless a new chapter is defined and no sections are defined yet.

Always \leftmark has a value when a section is defined; but when a new chapter is defined, \leftmark has no text and \rightmark takes the chapter name (this behaviour changes with 'twoside'), i.e. when \section occurs at page 3 of your document, this page will display the section name as its header because \leftmark is defined, and this variable stays defined until a new section is invoked, so page 4, 5 and 6 will have the same section header because no new section is issued and \leftmark remains with its value.

I guess you need to redefine \markboth to baptize some new counter or variable to hold the page number (this will hold the page number of the last \section), and you may compare it with the page number when next \markboth is called, that is to say when new section is issued...

Regards.

LaTeX.org

Text Formatting ⇒ Where is \leftmark defined?

Where is \leftmark defined?

Where is \leftmark defined?

Where is \leftmark defined?

Where is \leftmark defined?

Where is \leftmark defined?

Where is \leftmark defined?

Re: Where is \leftmark defined?

Re: Where is \leftmark defined?