[NTG-context] \bigl \bigr \big problems

Mikael Persson mickep at gmail.com
Thu Apr 8 10:37:55 CEST 2010


On Thu, Apr 8, 2010 at 10:37 AM, Mikael Persson <mickep at gmail.com> wrote:
> On Thu, Apr 8, 2010 at 10:31 AM, Hans Hagen <pragma at wxs.nl> wrote:
>> On 8-4-2010 7:40, Mikael Persson wrote:
>>
>>> Ok Hans, with the beta from yesterday the absolute values change size,
>>> but there are some problems still:
>>>
>>> 1) The absolute value bars are not just "straight lines" when using
>>> \big and friends, but som kind of line that is thicker in the middle.
>>> (zoom i on attached pdf)
>>
>> this is because lm has no such characters so they are made from the smaller
>> ones (extensible characters)
>>
>> in traditional lm this can go unniticed (depends a bit in the exact
>> definition but in mkii you will see two stacked | just not touching but in
>> mkiv we use overlap - which is custom in opentype anyway); so what you
>> observe is an artefact of the viewer - it might be that future versions of
>> luatex deal better with this as it relates somewhat with how things are
>> dealt with in the backend but you will observe similar effects in pdftex
>>
>> in an earlier version i used rules but then found out that the | has round
>> tops (ok, i could use pdf literals to draw lines but not today)
>>
>>> 2) The horizontal spacing in the \big version seems to be bigger than
>>> for the \bigl/\bigr version (and similar for \Big vs \Bigl/\Bigr). I'd
>>> expect the same spacing (the l and r are just there for the writer to
>>> easily see what is left and what is right).
>>
>> repaired .. (i also added \plainbigmathmode
>>
>>> 3) I'd expect that \| gives double bars, like the || one get from
>>> \Vert and not |. This is not so (see the attached file). Moreover, it
>>> is not possible to do \bigl\Vert right now to get a bigger ||.
>>
>> i've added double bars so this works:
>>
>> $\biggl\Vert x^n\biggr\Vert$
>> $\biggl{||} x^n\biggr{||}$
>> $\biggl|\biggl| x^n\biggr|\biggr|$
>>
>> there will be a new beta later today or tomorrow
>>
>> Hans

Thanks for you answer and explanation. Is there a reason why you do
not add \| to get double bars? This is the way it is done in LaTeX
(OK, not really an argument). I'm just curious.

Mikael


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