Re: Bug in lmt_arrow

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

On 11/15/2021 4:07 AM, Aditya Mahajan wrote:
> On Sun, 14 Nov 2021, Aditya Mahajan via ntg-context wrote:
> 
>> On Sun, 14 Nov 2021, Hans Hagen wrote:
>>
>>> On 11/14/2021 4:33 AM, Aditya Mahajan via ntg-context wrote:
>>>> Hi,
>>>>
>>>> There is a bug in lmt_arrow. If given a "non-cycle" path, lmt_arrow
>>>> completes the cycle.
>>>>
>>>>       \starttext
>>>>
>>>>       \startMPcode
>>>>         newpath p;
>>>>         ahfactor := 5;
>>>>         p := origin .. (1cm, 1cm) .. (2cm, 0);
>>>>         draw lmt_arrow
>>>>              [
>>>>                path = p,
>>>>                location = "percentage",
>>>>                percentage = 50,
>>>>                alternative = "curved",
>>>>              ]
>>>>              withpen pencircle scaled 1bp;
>>>>       \stopMPcode
>>>>       \stoptext
>>>>
>>>> With 2021.11.11, I get the attached file. Note that lmt_arrow has drawn the
>>>> "cycle" version of the path, even though p does not have a cycle.
>>>>
>>>> I have looked at the code and cannot figure out why this is happening.
>>>
>>> it happens in the 'direct' variant (metapost.registerdirect) where a boolean
>>> is passed as signal and that boolean then is also picked up by the (shared)
>>> path injector as (old school) signal that a path is closed while it should
>>> instead consutl the closed field in a path table (sounds more complex than it
>>> is)
>>>
>>> so in the end it is a nasty side effect of the fast inject code path (shared
>>> function with different stack values; i'll probably have to ditch a "low level
>>> backward compatibility feature no one uses anyway" some day)
>>>
>>> i uploaded a fix that you can test when the bins are compiled at
>>>
>>> 	https://build.contextgarden.net/#/waterfall?tags=c.luametatex
>>>
>>> new bins then in:
>>>
>>> 	https://dl.contextgarden.net/build/luametatex/
>>>
>>> (fyi: in the mp code you see that the path p is 'get' from the lua end where
>>> it got passed to by parameter)
>>
>> Thanks! Works perfectly here.
> 
> Spoke too soon. Now straight lines don't work:

new attempt (submitted to build)


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                                           Hans Hagen | PRAGMA ADE
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