Re: Manually scaling math fences

[Hans Hagen <pragma@wxs.nl>]

On 3/24/2017 8:24 AM, Aditya Mahajan wrote:
> On Thu, 23 Mar 2017, Hans Hagen wrote:
>
>> On 3/8/2017 2:45 AM, Aditya Mahajan wrote:
>>> On Tue, 7 Mar 2017, Hans Hagen wrote:
>>>
>>>>>> \MEAN[delimiter=auto] expands to \left\langle .. \right\langle
>>>>>> \MEAN[delimiter=]     expands to \langle .. \rangle
>>>>>> \MEAN[delimiter=big]  expands to \big\langle  ... \big\rangle
>>>>>> \MEAN[delimiter=Big]  expands to \Big\langle  ... \Big\rangle
>>>>>> \MEAN[delimiter=bigg] expands to \bigg\langle ... \bigg\rangle
>>>>>> \MEAN[delimiter=Bigg] expands to \Bigg\langle ... \Bigg\rangle
>>>>>>
>>>>>> I am not sure whether `delimiter` is the best key. I think that
>> `scale`
>>>> may be better, but using `scale` for specifying the scaling of math
>>>> delimiters will be inconsistent with how `scale` is used everywhere
>>>> else. Another option is to use `alternative` key.
>>>>
>>>> it would be something factor=2 or so, not the funny XxXxxxXX kind of
>>>> flags
>>>
>>> Sure. factor=(auto|none|1|2|3|4) is also ok (and would be directly
>>> mapped to choosemathbig).
>>
>> actually we will hook into a new feature of luatex for specifying the
>> size of delimiters (so no vbox hack) .. factors are multipliers of
>> bodyfontsize
>>
>> \definemathfence [MEAN] [angle] [command=yes, color=blue, factor=2.5]
>>
>> \starttext
>> \startTEXpage \startformula
>>     \MEAN[factor=1]{\sum_{i = 1}^n A_i x_i }
>>     \hbox{ vs. }
>>     \MEAN{ \sum_{i = 1}^n A_i x_i }
>>     \hbox{ vs. }
>>     \bigg\langle \sum_{i=1}^n A_i x_i \bigg\rangle
>> \stopformula \stopTEXpage
>> \stoptext
>
> Thanks.
>
> If I understand the code correctly (sorry, haven't tested it yet),
>
> factor=, factor=none, and factor=auto all behave the same (all insert
> \normalleft ... \normalright)

i prefer empty to be as before we even had factor i.e. same as auto

      \ifx\p_factor\empty
        #2%
      \else\ifx\p_factor\v!auto
        #2%
      \else\ifx\p_factor\v!none
        #3\s!height\zeropoint\s!depth\zeropoint\s!axis
        #2%
      \else
        \scratchdimen\dimexpr\p_factor\bodyfontsize/2\relax
        #3\s!height\scratchdimen\s!depth\scratchdimen\s!axis
      \fi\fi\fi

> I think that it may be more consistent if factor= and factor=none do not
> scale the delimited at all. To maintain backward compatibility, the
> default value of factor can be set to auto.
>
> Also what values of factor give scaling equal to \big, \Big, \bigg, and
> \Bigg?

These values are actually somewhat weird and relate to the design size 
of a font .. derived from plain:

0.85
1.15
1.45
1.75

but ... as these are extensibles a font might have more values. The 
factor is n times the bodyfontsize (50% above and below the axis)

what actually comes out depends on the chosen font

Hans

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                                           Hans Hagen | PRAGMA ADE
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