[Tex/LaTex] Beamer: what is purpose of .vrb files

beamer

Recently i work on presentation prepared with Beamer. every time when i made some error in document typing X in editor (WinEdt,) open me file .vrb with frame, where i made error.

That is fine, but not much useful to me. correction done there are not transferred to my document. so i wondering, what is purpose of this file? only to more easy find this frame in document?

edit:

i research again when .vrb file is open. its not caused with some error but when i use "back search" facility of pdf previewer (Sumatra in my case) and click on the shoved slide. if it contain verbatim text, than this open .vrb file and nod return to .tex file, where is code for this frame. otherwise this doesn't happen.

anyway, i'm still curious about how this file displayed in editor can be useful for someone. let me noted, that in .verbis only part of frame code.

Best Answer

The content of the body text of fragile frames gets a special treatment. Instead of processing it multiple times, like normal beamer frames, it is written to a special file, the .vrb (I assume this is short for verbatim?) and read directly from there. This allows you to have code in the frame, which would normally not work with beamer.

Synctex will always link to the file from where the problematic code was read in. For example if there is an error within a package, it will link to the .sty file. This also means that if there is an error within the fragile frame it will link to the .vrb file.

In theory you could use some sed replacement to replace the name of the vrb file with the original tex file in the syntex file (similar what to what ltx2any does to deal with build folders), but this would need some magic to get the line numbers right.

Related Solutions

[Tex/LaTex] latexmk -pvc option breaks when compiling beamer class

The problem is not specific for latexmk, but related to Skim, the way pdflatex works and how file notifications are implemented in OSX (and its Mach kernel under the hood).

The problem is that pdflatex does not change the PDF file in an atomic manner, but during the compilation process more or less continuously updates bits and bytes inside it.
The file system notices the writes to the file and sends an update notification to the monitoring Skim process. It uses some heuristics to not send an update event for every single changed byte (which would be very inefficient). The common approach here is to delay the update notification until no new changes have shown up for some time (usually a couple of milliseconds).
If this heuristic interacts badly with the write pattern of pdflatex, Skim gets notified before the PDF is ready and tries to read a not-yet complete PDF file. However, Skim is not well prepared for this, which result in all sorts of problems: from strange error messages over crashes to a lost of the notification handle. The last is the behaviour you observe.
The problem should not per se be bound to specific document classes, such as beamer. However, I also observed it especially in conjunction with beamer. My assumption is that when compiling beamer documents, pdflatex has usually to generate a whole extra bunch of files (all that .toc, .vrb, .nav, .snm files) and in between also spends relatively much computing time. As a result, updates to the PDF file during compilation are less frequent, which increases the probability of a bad interaction with the file system's heuristic to send change notifiations.

My personal solution to the problem is to add another level of indirection: Whenever the command to build the final PDF (I use pdflatex directly or rubber) has terminated successfully, I copy the resulting document.pdf to a document-view.pdf, which is the file I have open in Skim. The copying happens more or less instantaneous, the update mechanism works fine.

I personally use a Makefile for this task in combination with a small Ruby script that observes the source files to invoke make whenever a source file has changed. To integrate such behavior into latexmk one probably has to hack a bit around with the tool settings in latexmkrc (e.g., setting $pdf_previewer='cp %S %S-view.pdf'). However, my experience with latexmk is limited and I have not tested this.

[Tex/LaTex] Thumbnails of other frames in beamer

You can test with the macro \IfFileExist{filename}{then-do-this}{else-do-this} whether a file filename exists or not and respond accordingly. If the file filename exists, the then-do-this branch is executed, otherwise the else-do-this branch. Replace then-do-this and else-do-this with your own code.

In your new given MWE I would delete thr part to copy the pdf file and change the part to build the thumbnail slide to (supposing you have 4 thumbnails to include):

\IfFileExists{\jobname-copy.pdf}{%
\begin{frame}
  \foreach \i in {1,...,4} {
    \fbox{\includegraphics[width=0.2\linewidth, page=\i] {\jobname-copy.pdf}}
  }
\end{frame}
}{\typeout{No Thumbnails included}}

Now you only need to do (you can put this into a batch file):

pdflatex myslides.tex
pdflatex myslides.tex
cp myslides.pdf myslides-copy.pdf
pdflatex myslides.tex

The thumbnail were only included if the file myslides-copy.pdf exists. If not file myslides.tex compiles without included thumbnails.

Update 2:

The reason for the error message you got

Error: PDF file is damaged - attempting to reconstruct xref table...

is simple: you want to copy the file myslides.pdf you have already opened to compile it. That's not possible. So you have to first compile the presentation to get the frames and to close this file myslides.pdf. Then copy the file myslides.pdf to myslides-copy.pdf to include the thumbnails from myslides-copy.pdf into a new compiled file myslides.pdf.

Best Answer

Related Solutions

[Tex/LaTex] latexmk -pvc option breaks when compiling beamer class

[Tex/LaTex] Thumbnails of other frames in beamer

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