June 2020 - ntg-context - NTG Mailing Lists

explain please
by Hans van der Meer 24 Jun '20

24 Jun '20

How can the crash in the minimal example here be explained? And is there a solution to avoid this and make the crash going away "without having to jump through special hoops"? dr. Hans van der Meer

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Automatic userdata storage between runs
by Lukas/ConTeXt 24 Jun '20

24 Jun '20

Hello, first - thanks for the perfectly synoptical https://wiki.contextgarden.net/Programming_in_LuaTeX#Namespaces ! My question (and the answer sould appear on wiki, too): Is any of the namespaces (userdata, thirddata, moduledata, documentdata, parametersets) automatically serialized between Ctx first(-second(-third)) runs? I'm asking because user may call some (longer) code and put the result into a namespace (be it e.g. "userdata"). And if that namespace was automatically serialized for next run(s), that code could be called conditionally - typically just in first run (= mode "*first" enabled) - as in next runs results of the additional code would be available in a namespace (instead of repetitive call of that (longer) code). Of course, user can perform such evaluation, storage and conditional extra-code-call individually, but maybe there is some support for similar situations in Ctx. Best regards, Lukas

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CMYK workflow. How to set and should I worry about
by Keith McKay 23 Jun '20

23 Jun '20

Colleagues I'm getting ready to send a book to the printers and in their blurb they state "/Ensure that you are using a CMYK workflow and export to PDF/X-1a:2001" . /I can set the pdf format using \setupbackend but I'm unsure as to what to do about CMYK workflow. The book has no colour pages so I'm not sure if I really need to worry about CMYK workflow. Could someone advise? Thanks and Best Wishes Keith McKay //

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METAPOST's uniformdeviate is not truly random (seed)
by Gerben Wierda 23 Jun '20

23 Jun '20

I’m trying to get a real random number in METAPOST MWE: \startMPpage[instance=doublefun] show uniformdeviate 60; \stopMPpage Every time I run this, it shows the same result. I tried playing around with the randomseed, but for instance when I do two runs shortly after each other they still are very predictable. E.g. this in METAPOST: whatever = lua( "math.randomseed( tonumber(tostring(os.time()):reverse():sub(1,6)) )"); randomseed := lua.math.random(); minutespast := uniformdeviate 60; Called shortly after each other (two LMTX runs) gets me the same result. What is a good way to get better random numbers in METAPOST (LMTX)? Thanks, G

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loading xml error
by Hans van der Meer 23 Jun '20

23 Jun '20

Please can someone explain the following error and why the one specific XML input fails? It turns out that a single node <node/> is not accepted by the core whereas others are ok. This is the error message in the log, first line from my debug statement: HVDM-VOC > load vocabulary from buffer "german" xml > core > load error in [buffer: german]: invalid xml file - parsed text Minimal code to explain what is done: % Loading from buffer. \def\loadvocabularyfrombuffer#1{% \writestatus{HVDM-VOC}{load vocabulary from buffer "#1"}% \XMLProcessBuffer{#1}% % simply does an \xmlprocessbuffer{}{}{} } The following buffer gives the error: \startbuffer[german] <vocabulary use="de"/> \stopbuffer \loadvocabularyfrombuffer{german} But the others below are ok and load as expected. \startbuffer[german] <vocabulary use="de"></vocabulary> \stopbuffer and \startbuffer[german] <root><vocabulary use="de"/></root> \stopbuffer dr. Hans van der Meer

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Undefined control sequence: \pdfpxdimen
by Aditya Mahajan 22 Jun '20

22 Jun '20

The drops module uses the primitive \pdfpxdimen in a couple of places, but that is no longer defined in the current beta. What is the equivalent command now? Examples of usage: \pdfpxdimen1in\relax\divide\pdfpxdimen\numexpr\dropsparameter\c! resolution\relax % set actual pixel dimension Aditya

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How to define an array of pens
by Otared Kavian 22 Jun '20

22 Jun '20

Hi Hans, After learning from you how to define an array of colors and paths, I would like to know how is it possible to define a variable pen size. In the following working example below, I would like to replace MyPens[j] := pencircle scaled 2pt ; by something like MyPens[j] := pencircle scaled (2+j) pt ; but this does not work (neither do (2+j)*pt). Is it possible to specify the pen size according to the value of j, without using a structure like if j == -1 : MyPens[j] := pencircle scaled 1pt ; elseif j == 0 : MyPens[j] := pencircle scaled 2pt ; else : MyPens[j] := pencircle scaled 3pt ; fi (In my real example I have more than three values for j). %% begin example-array.tex \startMPpage string MyColors[] ; path MyPaths [] ; pen MyPens[] ; for j = -1 step 1 until 1 : MyPens[j] := pencircle scaled 2pt ; % I would like to say here (2+j) pt endfor MyPaths[-1] := (-1.5cm,1.5cm) -- (1.5cm,1.5cm) ; MyColors[-1] := "magenta" ; MyPaths[0] := (-2cm,2cm) -- (2cm,-2cm) ; MyColors[0] := "darkyellow" ; MyPaths[1] := fullcircle scaled 3cm ; MyColors[1] := "darkred" ; for j = -1 step 1 until 1 : draw MyPaths[j] withpen MyPens[j] withcolor MyColors[j] ; endfor \stopMPpage %% end example-array.tex Best regards: Otared

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How to define an array of colors in Metafun
by Otared Kavian 20 Jun '20

20 Jun '20

Hi all, I have a family of graphs to draw in Metapost and I would like to attribute a different color to each of them according to the value of a certain variable. Assuming that the path mygraph(j) depends on the variable j, which is computed within a lua code and passed to Metapost, I wonder if it is possible to define an array of colors named mycolor, so that I could say draw mygraph(j) withcolor mycolor(j) ; Here the variable j takes integer values (say between 1 and 10), and one would have defined mycolor(1) through mycolor(10). Thanks in advance for any help: Otared K.

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Variables in \useURL
by Nigel King 19 Jun '20

19 Jun '20

Hi Group, I want to insert a variable hyper reference into a pdf document. The following method does not work for some reason. \def\hyperref{http://www.website <http://www.website/>.com/abc/def} show \hyperref Gives the correct answer but \useURL[this_doc][\hyperref][][displayed text] \from[this_doc] Gives hyperef%20 as the url What am I doing wrong? TIA — Nigel nigel(a)nigelking.me.uk m:07917 803879 h:01364 642265 Abbey Moor, Moreleigh, Totnes, TQ9 7JW.

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lmtx
by Hans Hagen 19 Jun '20

19 Jun '20

Hi, Here's an update about what Wolfgang and I are doing in the lmtx code base i.e. where it differs from the mkiv code. Much has to do with cleaner code, less memory usage and less tracing clutter. To some extend it might be more efficient in terms of runtime, but in practice there is not much (measurable) to gain at the macro level wrt speed. Most bottlenecks are at the Lua end anyway. (1) macro arguments: In tex a macro argument is defined with numbers, so \def\foo#1#2{... #2 ... #2 ...} in luametatex we can have some variants #0 : the argument is picked up but not stored #- : the argument is ignored and not even counted #+ : the argument is picked up but no outer braces are removed There is some explanation in the evenmore document, like: \def\foo [#1]{\detokenize{#1}} \def\ofo [#0]{\detokenize{#1}} \def\oof [#+]{\detokenize{#1}} \def\fof[#1#-#2]{\detokenize{#1#2}} \def\fff[#1#0#3]{\detokenize{#1#3}} \meaning\foo\ : <\foo[{123}]> \crlf \meaning\ofo\ : <\ofo[{123}]> \crlf \meaning\oof\ : <\oof[{123}]> \crlf \meaning\fof\ : <\fof[123]> \crlf \meaning\fff\ : <\fof[123]> \crlf I mention this because you may encounter something other than #1 .. #9 in error reports or tracing. (2) interception of unmatched delimiters If you define macros like \def\foo[#1=#2]{...} the brackets and equal had better be there. However there is some trickery in the macro parsing that can be used to intercept cases where they are missing: optional tokens as well as forcing end of scanning (so if you see \ignorearguments and \ifarguments in the code, that is what we're talking about: premature quitting and checking why that happened and acting upon it: less hackery is needed but then of course also less possibility to 'show off how clever one is wrt writing obscure macros' ... so be it. Both (1) and (2) are relatively lightweight extensions that are downward compatible as well as have no impact on performance. We don't expect them to be used at the user level (where one seldom defines macros anyway) but we apply them in some low level macros (and might apply them more). One can measure better performance but only when applied millions of times which is seldom the case in context (we're often more talking thousands there than millions of expansions). (3) There is some more 'matching token sequences' code that is being applied stepwise but again this is normally not seen at the user level. It sometimes permits cleaner fully expandable solutions. (4) There are some additional if tests but these are already around for quite a while and probably went unnoticed anyway. (5) Nested conditions can be flattened by using \orelse and that's what happens now in quite some places in the lmtx code (it's already there for a quite a while and kind of well tested). Again this leads to less tracing, can in priniciple be more efficient, but also demands less multiple expand after situations. It also just looks nicer. (6) Upcoming code can use some more (simplified) grouping magic but that is something we need to test more (which is what we are doing now). Just that you know when you get some error and see unfamiliar primitives, Hans ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl -----------------------------------------------------------------

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