MaTeX stopped accepting certain font sizes

Question

My system: Windows 10, Mathematica 11.2

Problem: I have been using the fine MaTeX paclet to get nice symbols on my plots. As I scale the images in a TeX-document after exporting them in EPS, I need to adjust the FontSize. So far things have worked out the way I wanted them to. But this week Mathematica has been acting up.

A command like

ec = ContourPlot[y^2 == x^3 - 5 x + 6, {x, -3.5, 3.5}, {y, -3.5, 3.5},
   Frame -> False, Axes -> True, 
  AxesLabel -> {MaTeX["x"], MaTeX["y"]}]

works just fine, produces the expected image with nicely rendererd AxesLabels. But when I try

ec = ContourPlot[y^2 == x^3 - 5 x + 6, {x, -3.5, 3.5}, {y, -3.5, 3.5},
   Frame -> False, Axes -> True, 
  AxesLabel -> {MaTeX["x", FontSize -> 18], 
    MaTeX["y", FontSize -> 18]}]

instead, I get a strange message with a tiny garbage image followed by a text like "MapThread[...". Having isolated the problem, the next thing to do was to try the input

MaTeX["x", FontSize -> 18]

This gave the following message that is all Greek to me, but hopefully somebody here can make sense out of it. I omitted most of the contents of the GraphicsBox for it's rather long. If judged essential, I will copy/paste all of it.

MapThread[ Show[#1, ImageSize -> {#2, #3}, BaselinePosition -> Scaled[(#4 + MaTeXPrivate$psfactor)/#3]] &, {{\!\(\* GraphicsBox[ AspectRatio->Automatic, ImageSize->{12., 24.}, PlotRange->{{0., 11.97}, {0., 23.51}}]\)}, 0.996264 (2 + Interpreter`DependentTypes`PackagePrivate`coerced$5234), \ {23.5118}, {6.45585}}]

Search: It is not impossible that my problem is related to that of this question. However, Szabolcs' diagnosis does not seem to fit here given that MaTeX in the exact same notebook worked a week ago. Therefore it is unlikely that for example Scandic letters in the path name would play a role. Furthermore, the path to this notebook is all ASCII-characters anyway.

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Update:

More testing:

It seems to me that the choice of FontSize plays a role.

In a virgin session, the first call to MaTeX, asking for FontSize->16 greeted me with the following:

Fold::normal: Nonatomic expression expected at position 3 in Fold[Insert[#1,{},#2]&,MapThread[Replace[#1,Failure[InterpreterInternalPackagePrivateargs___,InterpreterInternalPackagePrivatea:Blank[<<1>>]]:>Failure[InterpreterInternalPackagePrivateargs,Join[InterpreterInternalPackagePrivatea,Association[<<2>>]]]]&,{<<1>>,{8.90271}}],InterpreterDependentTypesPackagePrivate`pos$3165].

Together with a lot of messages:

Symbol::argx: Symbol called with 0 arguments; 1 argument is expected.

Next, when I asked for an 18-point font, I got the plot together with typeset strings all right. But at the bottom of that cell there was something extra starting with Show[#1, ImageSize->{#2,#3},...

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Next, when I asked for a 20-point font. THERE WERE NO PROBLEMS.

So has something destroyed my collection of fonts this last week?

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A clue to the above test was that copy/pasting the snippet from Szabolcs' page worked as prescribed. So Magnification -> 2 works fine.

Answer 1

This also started happening to me sometime last week. I have no clue what triggered the change, since I have not updated anything manually.

Unfortunately, I don't have a proper fix, but a simple workaround I've found is to run the following snippet once at the beginning of the notebook,

Quiet[MaTeX["x"]];
ClearMaTeXCache[];

MaTeX can be used normally afterwards.