tkz* commands vs draw/path

Question

I am learning TikZ and am confused about two apparent completely different ways to go about things, although they seem completely compatible and intermixable:

\begin{tikzpicture}
\draw[color=black] (20,20) -- (100,20);
% vs
\tkzDrawSegments((20,20),(100,20))
\end{tikzpicture}

I'm quite sure the second thing is wrong (please correct to fix this). The first way seems way more powerful (you've got nodes and all), but the second way has stuff like tkzMarkAngle which seems painful to do the first way.

What is the difference and how would I do a "simple thing" like tkzMarkAngle using paths?

Answer 1

I don't know if it is possible to give a precise consideration on which package is more powerful (TikZ or the tkz bundle): what is true is that they have a different syntax, but I think there are cases in which TikZ provides a simpler programming solution and others when tkz is more straightforward.

For example, the macro \tkzMarkAngle, is one of the latter case. You could find the code of the macro typing in the shell:

gedit $(kpsewhich tkz-obj-angles.tex)

The following document tries to replicate the same picture with both packages and with a similar programming structure:

\documentclass[a4paper,11pt]{article}
\usepackage{tikz}
\usepackage{tkz-euclide}
\usepackage{tkzexample}
% to display picture and code
\usetkzobj{all}

\begin{document}
tkz-based solution:
\begin{center}
\begin{tkzexample}[latex=4.5cm]
\begin{tikzpicture}
\tkzDefPoint(0,0){O} 
\tkzDefPoint(2,2){A}
\tkzDefPoint(-2,3){B}
\tkzDrawSegment[thick](O,A)
\tkzDrawSegment[thick](O,B)
% equivalent: \tkzDrawVectors(O,A O,B)
\tkzMarkAngle[fill= yellow,%
 opacity=.5](A,O,B)
\end{tikzpicture}
\end{tkzexample}
\end{center}

Ti\textit{k}Z-based solution:
\begin{center}
\begin{tkzexample}[latex=4.5cm]
\begin{tikzpicture}
\coordinate (O) at (0,0);
\coordinate (A) at (2,2);
\coordinate (B) at (-2,3);
\draw[thick] (B)--(O) 
 node[coordinate,pos=0.7](x-b){};
\draw[thick] (A)--(O) 
 node[coordinate,pos=0.625](x-a){};
\draw[fill=yellow,opacity=.5] 
 (O)--(x-b)  arc (125:38:0.95cm) -- (O);
\end{tikzpicture}
\end{tkzexample}
\end{center}

\end{document}

which provides:

As you can see, the second picture is not precise as the first one, because inside the definition of \tkzMarkAngle there is the exact computation for that. Not that you couldn't do the calculus with pure TikZ, but you need to complicate the code.