[NTG-context] Re: weekend update

[Hans Hagen via ntg-context <ntg-context@ntg.nl>]

On 6/23/2024 2:35 PM, Gerion Entrup wrote:
> Am Freitag, 21. Juni 2024, 19:00:03 MESZ schrieb Hans Hagen via ntg-context:
>> -- support for stacking at the tex end (maybe for presentations)
>>
>> \starttext
>>
>> \definestacking[one]
>> \definestacking[two]
>>
>> \startbuffer
>> This is a test \stacking [one] {and a proof} of \stacking [two]
>> {concept} indeed
>> \stacking [one] {\blackrule [width=4cm]} is it and the question is how
>> \stacking
>> [two] {\scale [s=2] {fancy}} we can go
>>
>> \startstacking[one]
>> \startformula
>>       \sqrt{1+x}
>> \stopformula
>> \stopstacking
>>
>> and how useful \stacking[two]{\inframed{it}} is.
>> \stopbuffer
>>
>> \startstackingsteps[one,two,{one,two}]
>>       \startTEXpage[offset=1ts]
>>           \getbuffer
>>       \stopTEXpage
>> \stopstackingsteps
>>
>> \startTEXpage[offset=1ts] \setupstacking[criterium={one}]     \getbuffer
>> \stopTEXpage
>> \startTEXpage[offset=1ts] \setupstacking[criterium={two}]     \getbuffer
>> \stopTEXpage
>> \startTEXpage[offset=1ts] \setupstacking[criterium={one,two}] \getbuffer
>> \stopTEXpage
>>
>> \stoptext
> 
> Very nice, thank you!
> 
> I see some similarities to the "visible on" technique [1], I posted in a previous thread.

You mean the horrible transparency hack there?

> What comes there really handy are range specifiers, what seems not possible with this interface.
> For example: "visible on=<2->" renders the content on every page except the first one
> or "visible on=<1-5,13-15>" on the first page up to the fifth page and from page 13 to 15.
> 
> The mechanism stems from the Beamer overlay specifications, see section 9.3 of the manual [2]
> and can be much more complicated with modes (section 9.6.2).

I don't know beamer other than seeing presentations at meetings but I 
assume that it has some accumulator. We do have steppers in mkii / mkiv 
already in the presentation styles. The conceptual cleanest of them 
depends on the viewer and free ones never catched up so that one is 
acrobat specific. The stacker discussed now is just similar to the 
metapost one but then at the tex end. (A quick hack with room for more a 
bit more effiency if ther ei sneed for it.)

> To add this to the new interface, if you want that, the stack layers above need some kind of order,
> which is implicit for numbers:
> ```
> \definestacking{one}
> \definestacking{two}
> \definestacking{three}
> \definestackingorder{one,two, three}
> ...
> \setupstacking[criterium={one-three}]
> ```
> The order could also be implicitly defined after the order of the \definestacking calls.
> 
> Or would it be possible to have numbers always automatically (additionally) available as stacking layer?
> So that this "just" works:
> ```
> \startbuffer
> This is a test \stacking [1] {and a proof} of \stacking [2] {concept} indeed.
> \stopbuffer
> ...
> \setupstacking[criterium={1-}]
> ```
> 
> I also wondered, if it is possible to define a lot of layers semiautomatically in Lua
> (in some graphics I needed around 20 layers). It seems that numbers in layer names currently are not allowed.
> Is code like this possible somehow?
> 
> ```
> \startluacode
> for i = 1, 20 do
>      context.definestacking(string.format("l\letterpercent.d", i))
> end
> \stopluacode
> ```

The next version already will have this:

%D For Aditya Mahajan: ranges and such.
%D
%D \starttyping
%D \starttext
%D \startstackingsteps[1,{1:2,201},{1:3,301},{1,2,4},{1-5},{1-6},{1-7}]
%D     \startTEXpage
%D         \startstacking[1]   \framed{ONE}    \stopstacking
%D         \startstacking[2]   \framed{TWO}    \stopstacking
%D         \startstacking[201] \framed{MORE}   \stopstacking
%D         \startstacking[3]   \framed{THREE}  \stopstacking
%D         \startstacking[301] \framed{INDEED} \stopstacking
%D         \startstacking[4]   \framed{FOUR}   \stopstacking
%D         \startstacking[5]   \framed{\im {\sqrt {
%D              \stacking[6] { 1 + x ^ {
%D              \stacking[7] { 2 } } } } }}
%D         \stopstacking
%D     \stopTEXpage
%D \stopstackingsteps
%D \stoptext
%D \stoptyping

The range interface is not different from the one we use in other places 
so it was a braindead patch. Numeric stacking id's don't need to be 
allocated. The example shows that it is rather general applicable 
although there are some border cases (that if needed we can intercept 
but I assume sane usage).

No upload yet unless there is a hurry.

Hans


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