A strange discrepancy between LuaTeX and XeTeX

[Philip Taylor]

On 05/03/2025 15:22, Philip Taylor wrote:

My wine list, previously referred to, include the following font definition —

\font \vfont = "ITC Zapf Chancery"/B:color=007700;embolden=4;slant=-0.1 at 11pt

In XeTeX, characters set in this font appear as intended (green, emboldened, slight slant).  In LuaTeX, they appear green-with-black-stroke, emboldened, slight slant.  Does anyone have any idea from whence cometh the black stroke ?

I should add that, at one additional level of abstraction, I do know from whence comes the black stroke — it comes from the "embolden=4" attribute.  But why should LuaTeX embolden by stroking in black when XeTeX emboldens by stroking in the font's fill colour ?

I still do not know why my (intended-to-be-emboldened-green) characters gain a black stroke when rendered using LuaTeX but not when rendered using XeTeX, but thanks to Zdeněk <https://dml.cz/browse-author-items?id=22042> Wagner<https://dml.cz/browse-author-items?id=22042>’s article Tisk obrysu písma v PDF <https://dml.cz/handle/10338.dmlcz/150078><https://dml.cz/handle/10338.dmlcz/150078> I now think that I know how to resolve the problem.  The following code fragment demonstrates the solution at which I finally arrived —

\def \VeganV {{\ \Vfont \raise 0,2 ex \hbox {(}{V}\raise 0,2 ex \hbox {\kern 0,1 em )}}}

\def \veganv {{\ \vfont \raise 0,2 ex \hbox {(v)}}}


\font \vfont = "Zapf Chancery Medium Italic BT":embolden=4 at 11pt

\font \Vfont = "Zapf Chancery Medium Italic BT":embolden=6 at 11pt


\def \CMYK #1#2#3#4#5%

{%

    \pdfextension literal direct {q #1 #2 #3 #4 k #1 #2 #3 #4 K}%

    #5%

    \pdfextension literal direct {Q}%

}


\def \Green #1{\CMYK 1 0 1 0 {#1}}

\def \v {\Green \veganv}

\def \V {\Green \VeganV}

My sincere thank to Zdeněk for publishing that article.

--
Philip Taylor


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