Graphics, Figures & Tables ⇒ TikZ- extracting coordinate components

[fenn]

This is a question regarding TikZ and PGF. I'm trying to extract the x-, y-, and z-components of a coordinate into a macro so that the values can be manipulated using \pgfmathparse commands. As an example:

Code: Select all

\begin{tikzpicture}
 \coordinate (A) at (2.34, 3.21);
 \pgfmathsetmacro{\Ax}{ "x-component of coordinate (A)" } 
 \Ax
\end{tikzpicture}

I would like this example to output the value 2.34, the (unitless) x-component of coordinate (A). From what I can tell, there is no way to simply define "x-component of coordinate (A)".

I would like to get this information since I am developing a LaTeX tool to perform vector math, and thought it would be convenient to specify vectors using the TikZ coordinate system. I essentially need to find a way to bridge the gap between specifying coordinates and defining macros that work within \pgfmathparse commands.

I have looked into the "let" operation that will pick out the x- and y-component of a coordinate as \x# and \y# macros, but there are several problems with this. First, it contains the "pt" unit, and this value will only exist within a \path or \draw operation. I can use this value to define another coordinate, but then I'm back where I started. Finally, there is no macro for the z-component.

Any suggestions or ideas are welcome!

Jeff

[chandra]

Perhaps the solution at {TeX} SE might give you the solution you seek.

Also, section "78.6 Extracting Coordinates" p 724 of the latest PGF manual.

I was after the same thing and came across your post.

Sorry this answer is more than a year late!