From: "Thomas A. Schmitz" <thomas.schmitz@uni-bonn.de>
To: mailing list for ConTeXt users <ntg-context@ntg.nl>
Subject: Re: xml and lua again
Date: Fri, 28 Oct 2011 08:55:18 +0200 [thread overview]
Message-ID: <4EAA51D6.3050909@uni-bonn.de> (raw)
In-Reply-To: <83BD5F74-4BB7-41D2-9C1E-F5F31084E6AC@gundla.ch>
On 10/28/11 08:44, Patrick Gundlach wrote:
>
>
>>>>>
>>>>> context.blackrule{ width = number.topoints(tex.dimen["textwidth"]/2) }
>>>
>>> or just tex.dimen["textwidth"]/2 .. "sp"
>>
>> Wait, just so I understand: your solution would imply that tex.dimen["textwidth"] holds a number, not a dimension, right? (Because you simply concatenate it with a dimension unit). Which makes sense when I think of it because lua has no concept of dimensions, only of strings, functions, tables, numbers... Whereas the Wolfgang implies that the result is already in sp. So who's right?
>
> both :)
>
> tex.dimen holds a number, that is the size in points, multiplied by 65536/1pt, so for example 3pt becomes
>
> 3pt * 65536
> ----------- = 3 * 65536 = 196608
> 1pt
>
>
> This number is also known "sp". So if you store the number 3*65536 in tex.dimen[...], you can say:
>
> my width is \directlua{ tex.dimen[...] / 2}sp (results to "my width is 196608sp", which you can use as an argument to whatever needs a length)
>
> or
>
> my width is \directlua{ number_to_points(tex.dimen[...]) } where number_to_points is something like
>
> number_to_points = function (amount_in_sp)
> in_pt = tostring(amount_in_sp / 65536)
> return in_pt .. "pt"
> end
>
> which gives "3pt".
>
> Patrick
>
Luigi, Patrick,
thanks for your explanations! The point of my question was: can I feed
the content of tex.dimen["textwidth"] directly back to TeX, and the
answer to this appears to be "no"; you need to add some unit to it
(otherwise, you get an error message). Which was a bit confusing to me
at first, because the name tex.dimen implies that it holds a "real"
dimension, like \newdim does.
Thomas
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next prev parent reply other threads:[~2011-10-28 6:55 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-22 16:46 Thomas A. Schmitz
2011-10-23 14:04 ` Peter Rolf
2011-10-23 14:37 ` Thomas A. Schmitz
2011-10-23 15:25 ` Peter Rolf
2011-10-23 18:15 ` Peter Rolf
2011-10-24 10:17 ` Hans Hagen
2011-10-24 12:18 ` Thomas A. Schmitz
2011-10-24 12:26 ` Hans Hagen
2011-10-24 17:00 ` Thomas A. Schmitz
2011-10-24 18:48 ` Hans Hagen
2011-10-25 9:43 ` Thomas A. Schmitz
2011-10-25 10:10 ` Wolfgang Schuster
2011-10-25 10:17 ` Hans Hagen
2011-10-25 10:27 ` Thomas A. Schmitz
2011-10-27 9:23 ` Thomas A. Schmitz
2011-10-27 9:53 ` Wolfgang Schuster
2011-10-27 10:32 ` Thomas A. Schmitz
2011-10-27 11:05 ` Hans Hagen
2011-10-28 6:23 ` Thomas A. Schmitz
2011-10-28 6:37 ` luigi scarso
2011-10-28 6:43 ` luigi scarso
2011-10-28 6:44 ` Patrick Gundlach
2011-10-28 6:55 ` Thomas A. Schmitz [this message]
2011-10-28 8:35 ` Wolfgang Schuster
2011-10-28 8:59 ` Hans Hagen
2011-10-28 8:56 ` Hans Hagen
2011-10-28 10:48 ` Thomas A. Schmitz
2011-10-28 11:23 ` luigi scarso
2011-10-28 11:42 ` Hans Hagen
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