How to make a standalone image with a transparent background

standalonetikz-pgftransparency

When I try to make a PNG image using TikZ by using the convert option for the standalone class, I cannot figure out how to make the background transparent.
I seem to recall some years ago that this happened by default; while I could be misremembering, other questions and answers on here seem to back up that memory (e.g. tikzpicture has clear background by default, this recent question stating that the TikZ standalone picture background was clear and asking how to make it white…).
In any case, the default behavior on my machine currently seems to be a white background.
Using a minimal example,

\documentclass[convert={density=300},tikz]{standalone}

\begin{document}
\begin{tikzpicture}
\draw [ultra thick] (0,0) circle (2.5cm);
\end{tikzpicture}
\end{document}

I get a circle with a white background:

How can I make the background transparent?

It may be that software version details matter; I have the following setup:

OS: Ubuntu 21.10
LaTeX distribution: TeX Live 2020
(can provide other details on request, not sure what else to add)

Best Answer

You could use the command= suboption to convert= to further specify the convert command. Something like this should work:

\documentclass[convert={density=300,command=\unexpanded{{\convertexe\space -density \density\space \infile\space -transparent \space white \outfile}}},tikz]{standalone}

\begin{document}
\begin{tikzpicture}
\draw [ultra thick] (0,0) circle (2.5cm);
\end{tikzpicture}
\end{document}

This is adapted from the example in the standalone documentation you linked to.

Be sure to run with --shell-escape.

Related Solutions

[Tex/LaTex] Semi-transparent background for image

I am not sure of having understood your question correctly. Hence this is shooting blindfolded. Do you mean some thing like this?

You can use opacity=<value>. The MWE is :

\documentclass{beamer}
\usepackage{tikz}
\begin{document} 
\begin{frame}{}
    \begin{itemize}
        \item item
        \begin{tikzpicture}
            \node (img1) {\includegraphics[height=0.4\textwidth]{example-image-a}};
            \visible<2>{\node[opacity=0.7] (img2) at (img1.south east){\includegraphics[height=0.4\textwidth]{example-image-b}};}
        \end{tikzpicture}
    \end{itemize}
\end{frame}
\end{document}

enter image description here

For me both the images A and B do not have transparent background. Since your image is already having a transparent backgound, I have no idea of how it will be. Please feed back.

Edit:

Following the comments, this is the next guess in trying to accomplish the goal.

\documentclass{beamer}
\usepackage{tikz}
\begin{document}
\begin{frame}{}
    \begin{itemize}
        \item item
        \begin{tikzpicture}
            \node (img1) {\includegraphics[height=0.4\textwidth]{example-image-a}};
            \visible<2>{\node[opacity=0.9,fill=red!90] (img2) at (img1.south east) {\phantom{\includegraphics[height=0.4\textwidth]{tansparent}}};
            \node (img2) at (img1.south east) {\includegraphics[height=0.4\textwidth]{tansparent}};}
        \end{tikzpicture}
    \end{itemize}
\end{frame}
\end{document}

Here an articial bounding box is used with the help of \phantom.

enter image description here

[Tex/LaTex] Drawing rectilinear curves in Tikz, aka an Etch-a-Sketch drawing

\draw (20,12) -- ++(2,0) -- ++(0,2) -- ++(-3,0) -- ++(45:3);

Use ++ before each new incremental coordinate to make it relative to the last one and put the pencil there.

Here's a complete example:

\documentclass{article}
\usepackage{tikz}
\begin{document}
\tikz\draw (20,12) -- ++(2,0) -- ++(0,2) -- ++(-3,0) -- ++(30:3) {[rounded corners=10pt]-- ++(5,0) -- ++(0,-6)} -- ++(-7,0) -- cycle;
\end{document}

Of course, combining this with the -| or |- path operators can simplify the code even further; the following two pieces of code produce the same result:

\tikz\draw (20,12) -- ++(2,0) -- ++(0,2) -- ++(3,0) -- ++(0,1) -- ++(1,0) -- ++(0,-3) -- ++(2,0);\par\bigskip

and

\tikz\draw (20,12) -| ++(2,2) -| ++(3,1) -- ++(1,0) |- ++(2,-3);

I don't think that defining commands in this case adds anything; in fact, I think it reduces the functionality of the existing syntax (which is already simple). The example demonstrates that you can use, for example, polar coordinates and modify (up to TikZ limitations) the path attributes midways; even if the current question doesn't require this, it's a good thing to have the possibility to do those kind of modification if they are required.

Best Answer

Related Solutions

[Tex/LaTex] Semi-transparent background for image

[Tex/LaTex] Drawing rectilinear curves in Tikz, aka an Etch-a-Sketch drawing

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