Tikz package. How to build a rectangle centered in one point?

Question

For istance, with Tikz, I can draw a circle centered in the point (0,0) with radius 2. How can I draw a rectangle centerd in (0,0) giving height and basis?

Answer 1

Last but not least, you could use a node, whose shape is rectangle and apply its anchor to its center:

\documentclass[border=2mm]{standalone}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
    % I want to center the rectangle here
    \filldraw (0,0) node [below] {center here} circle (1pt);
    % drawing the node with shape=rectangle and anchor=center
    \node [draw, thick, shape=rectangle, minimum width=3cm, minimum height=2cm, anchor=center] at (0,0) {};
\end{tikzpicture}
\end{document}

Answer 2

You can use the shift key:

 \draw[shift={(2,1)}] (-3,-2) rectangle (3,2);

With this method, you can also rotate the rectangle around the center:

 \draw[shift={(2,1)},rotate=20] (-3,-2) rectangle (3,2);

Answer 3

If you use the tikzpackage calc you can achieve this quite easily.

If A is the center and dim the basis/height of the rectangle

\coordinate (A) at (2,2);
\coordinate (dim) at (3,4);

you could calculate the lower left and upper right coordinate with:

\coordinate (LL) at ($(A)-0.5*(dim)$);
\coordinate (UR) at ($(A)+0.5*(dim)$);

And then draw the rectangle between those two points.

If you need this often I recommend creating a macro for it - se here: A macro of drawing a rectangle with several parameters in TikZ