CircuiTikZ over a png image

Question

I want to draw simple CircuiTikZ symbols over a .png image. This is what I want:

This is what I currently get:

Here is my code:

\begin{figure} [!ht]
\begin{tikzpicture}[x=1cm,y=1cm]
\node at (0,0) {\includegraphics[trim={40cm 55cm 40cm 55cm},clip,height=10cm]{images/MecanismoEscala_primer_ensayo_Variables.png}};
\node at (-3.7634,-1.5117){
\begin{circuitikz}
\draw
 (0,0) --++ (-1.0778,0)
        to [open,v=$v$,o-o] ++(0,0.7012)
        to[short,i=$i_{a}$] ++(1.0663,0);
\end{circuitikz}
};
\end{tikzpicture}
\end{figure}\FloatBarrier

I would also like to write the $v$ besides the terminals along with the +- signs (with these two signs a little bit more apart from each other, not like the result I get).

Just a guess: when you add [draw] to your second node to outline its boundaries, you‘ll probably see that the nodes center is at the point you specified. If so, it needs a shift or realignment. — MS-SPO, Oct 09 '22 at 04:04
Thanks for your answer. Is there a way to anchor the first point of the circuitikz drawing to the specified point? — el_maxx, Oct 09 '22 at 10:12
You are nesting tikzictures. Don't do that. https://tex.stackexchange.com/questions/47377/proper-nesting-of-tikzpicture-environments-reset-all-pgf-values-to-their-defaul — Rmano, Oct 09 '22 at 10:48
If you upload/link the base image I can try an answer (later, no time left now). But basically, you can just use the answer from https://tex.stackexchange.com/questions/9559/drawing-on-an-image-with-tikz --- circuitikz is the same as tikzpicture. — Rmano, Oct 09 '22 at 10:51

score 7 · Accepted Answer · answered Oct 09 '22 at 18:05

First of all. Never nest tikzpictures! And post the basic picture, which in this case I managed to concoct with GIMP and saved as uffa.png.

My approach would be:

load the image as a node at the start of the tikzpicture, so that then you can write on top of it.
Set some kind of grid to have an easy reference.
Draw whatever you want, fine tune coordinates.
Remove the grid.

Let's see: step 1 & 2 would be something like this:

\documentclass[tikz]{standalone}
\begin{document}
\begin{tikzpicture}
    \node[anchor=south west,inner sep=0] (image) at (0,0) {%
        \includegraphics[width=10cm]{uffa.png}};
        \draw[red,thin] (0,0) grid[step=1] (10,5);
\end{tikzpicture}
\end{document}

You have 0,0 on the bottom left point, and every grid step is 1cm. Now, the background is not white (I hope you do not print it, otherwise, change it), so I picked the color that results to be a quite dark blue-grey with RGB at 33,40,48 (any color picker will do).

Now I draw the circuit, setting the blue-gray as the fill for open poles.

\documentclass[tikz]{standalone}
\usepackage[RPvoltages, american]{circuitikz}
\begin{document}
\begin{tikzpicture}[color=white]% write in white
    \node[anchor=south west,inner sep=0] (image) at (0,0) {%
        \includegraphics[width=10cm]{uffa.png}};
        \draw[red,thin] (0,0) grid[step=1] (10,5);
        \definecolor{mybg}{RGB}{33,40,48}% with a color picker
        \ctikzset{open poles fill=mybg}% tell circuitikz what is background for you
        \draw (4,4) coordinate(a) to[short, i=$i_a$, o-]  ++(1.8,0);
        \draw (a) ++(0,-1) to[short, o-] ++(1.7,0);
        \draw (a) ++(-0.3,0) to[open, v=$v$] ++(0,-1);
\end{tikzpicture}
\end{document}

I tried to use relative and named coordinates where possible, to minimize the number of numbers you need to tweak to obtain the result. Then, you remove the grid and you'll have:

CircuiTikZ over a png image

1 Answers1