Extend `\_inkdefs`

[robertbachmann]

Commit: Extend \_inkdefs

• add \textbf
• add \textit
• add \textsc
• add \transparent

These macros may be generated by Inkscape's latex-text-renderer.cpp.

Additional notes

The relevant code can be seen here https://gitlab.com/inkscape/inkscape/-/blob/master/src/extension/internal/latex-text-renderer.cpp#L390

---

Test case:

\fontfam[pagella]

\inkinspic{figure.pdf}

\bye

I'm using Inkscape 1.1.2 (0a00cf5339, 2022-02-04) with inkscape figure.svg --export-type=pdf --export-latex -o figure.pdf

Inkscapes generates

  \begin{picture}(1,0.62019123)%
    \lineheight{1}%
    \setlength\tabcolsep{0pt}%
    \put(0,0){\includegraphics[width=\unitlength,page=1]{figure.pdf}}%
    \put(0.80999305,0.15562135){\color[rgb]{1,0.4,0}\makebox(0,0)[lt]{\lineheight{1.25}\smash{\begin{tabular}[t]{l}Some\\\textbf{\textit{tex}}\textbf{\textit{t}}\end{tabular}}}}%
    \put(0.08211842,0.48438098){\color[rgb]{0,0,0}\makebox(0,0)[lt]{\lineheight{1.25}\smash{\begin{tabular}[t]{l}regular, \textbf{bold},\\\textit{italic}, \textbf{\textit{bold-italic }}\\\end{tabular}}}}%
    \put(0.05959094,0.13101){\color[rgb]{0,0.50196078,0}\makebox(0,0)[lt]{\lineheight{1.25}\smash{\begin{tabular}[t]{l}\textsl{slanted, }\textbf{bold}\\\textbf{\textsl{bold slanted}}\end{tabular}}}}%
    \put(0.60685555,0.51537681){\color[rgb]{0,0,0}\transparent{0.40999392}\makebox(0,0)[lt]{\lineheight{1.25}\smash{\begin{tabular}[t]{l}semi-transparent\end{tabular}}}}%
  \end{picture}%

I've attached the SVG file.

figure.zip

[robertbachmann]

The \transparent macro used by the inkscape generated file is from transparent.sty. http://mirrors.ctan.org/macros/latex/contrib/transparent/transparent.pdf

I takes a number from 0 -- 1, but careful 1 means 100% opaque:

1. User interface The package transparent defines \transparent and \texttransparent. They are used like \color and \textcolor. The first argument is the transparency value between 0 and 1 where 0 is fully transparent and 1 is opaque.

I implemented it like this.

\_def\transparent#1{\_edef\_tmpt{\_expr[0]{(1-#1)*255}}\_transparency=\_tmpt}%

Not sure if there's an easy way to do it without the \_tmpt

---

Test case:

\fontfam[lm]
\OpTeX
\medskip
\inkinspic{figure2.pdf}
\bye

LaTeX test file I used:

\documentclass{article}
\usepackage{graphicx}
\usepackage{xcolor}
\usepackage{transparent}
\begin{document}
\input{figure2.pdf_tex}
\end{document}

Second SVG file figure2.zip

Sceenshot of result:

[olsak]

You can use this code

\_def\transparent#1{\_ea\_transparency\_expanded{\_expr[0]{(1-.5)*255}} }

This is without \_tmpt. If the \expr macro was expandable in classical sense then simply \transparency=\expr... would be enough. But it is not true in this case because \immediateassigment is used in \expr and this LuaTeX primitive is (wrongly) applied to the currently executed assignment \transparency= not to the desired assignment inside the \expr macro. I didn't know about this "feature" yet and I am not sure if it is feature or bug in LuaTeX.

[olsak]

Or we can use

\_def\transparent#1{\_transparency\_exprA[0]{(1-.5)*255} }

but we cannot be sure if the \_exprA "API" will be stable in OpTeX. Maybe yes.

[olsak]

I did a more thorough investigation and I found that the issue is due to \afterassignment used in the \trnasparency macro. This primitive is applied to the first assignment done inside \expr macro and not to the \_transpattr= assignment. Now, I am sure this is feature, not bug.

[robertbachmann]

Thanks for the explanation.