[lucida] problem with norm delimiters

[Bruno Voisin]

Le 24 Oct 2013 à 09:36, Antonis Tsolomitis <antonis.tsolomitis at gmail.com> a écrit :

> I have a problem with the characters \| when they are used with commands like \bigl \bigr or \left \right.
> Acrobat shows them erratically and prints them erratically. gv/xpdf shows them OK.
> I prepare a book and most probably the publisher will not use ghostscript or xpdf :-) .
> I attach a small pdf that shows the problem (my acrobat is 9.5.4 01/09/2013 on linux).
> Below I have the code and a screenshot in case your acroread shows it correctly.

Same here on the Mac with Acrobat Pro 10.1.8. OS X's built-in Preview on the left, Acrobat on the right:



The difference is due to the fact that Acrobat/Reader uses its own PDF rendering engine, not the OS-provided one.

And the difference between the smaller size and the others is caused by the fact that the larger sizes are created as composites, by superpositions of small vertical segments: the superposition looks right in poppler (I've tried with TeXworks which uses it, and all's OK there), but in Acrobat and Preview there are artifacts:

- On Acrobat these appear as outline instead of plain delimiters, as in your screenshot. This varies with the magnification, too.

- In Preview they appear as slight irisations, looking as colored delimiters at smaller magnifications.

This seems to point to anti-aliasing problems, for such composite delimiters.

Unfortunately I've no idea what can be done to circumvent this. That said, I'm surprised when you say printing is affected, too. I would have thought only screen rendering was involved. Here printing your test file from Acrobat looks fine (MacBook Pro, OS X 10.9, Canon iP4500).

An aside, since you seem to prefer \big etc. to \left etc.: recently I needed to use very big delimiters, for multi-line formulas where delimiter-size balancing with \left and \right between lines would have required several \phantom's. Based on the additional size specifications in Y&Y's original lcdplain.tex for plain TeX, and the implementations of \big etc. in LaTeX's exscale.sty and Lucida Type 1's lucidabr.sty, I ended up writing

\makeatletter
\providecommand{\biggg}{\bBigg@{3}}
\providecommand{\Biggg}{\bBigg@{3.5}}
\providecommand{\bigggg}{\bBigg@{4}}
\providecommand{\Bigggg}{\bBigg@{4.5}}
\providecommand{\bigggl}{\mathopen\biggg}
\providecommand{\bigggr}{\mathclose\biggg}
\providecommand{\Bigggl}{\mathopen\Biggg}
\providecommand{\Bigggr}{\mathclose\Biggg}
\providecommand{\biggggl}{\mathopen\bigggg}
\providecommand{\biggggr}{\mathclose\bigggg}
\providecommand{\Biggggl}{\mathopen\Bigggg}
\providecommand{\Biggggr}{\mathclose\Bigggg}
\makeatother

Bruno Voisin
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