Points and Coordnates

1. \coordinate (A) at (1,2);
\coordinate (B) at (-3,1);
\coordinate (C) at (2,-3);
   
2. Synonimous: \path...
   
3. Linear Combinations:
   \coordinate (D) at ($1/3*(A)+1/3*(B)+1/3*(C)$);
   
4. Convex Combinations: \[ \overrightarrow{OC}= (1-t)\overrightarrow{OA} +t\overrightarrow{OB} \]
   \tikzmath{\t=-1;}
\coordinate (C) at ($(A)!\t!(B)$);
   
5. Polar Coordinates:
   \tikzmath{\Angle=60;}
\tikzmath{\R=2;}
\coordinate (P) at (\Angle:\R);
   
   Angles in degrees!
6. Projection Ortogonal of $C$ on Segment $AB$:
   \coordinate (P) at ($(A)!(C)!(B)$);
   
   Angles in degrees!
7. Relative coordinates:
   \draw[-latex] (A) --+(v);
   
8. Retrieve coordinates (in TikZ preamble):

   LaTeX Listing: h.tex. PDF   ZIP*   \documentclass{article} %%.. %%Usage: \gettikzxy{(P)}{\px}{\py} \makeatletter \newcommand{\gettikzxy}[3]{% \tikz@scan@one@point\pgfutil@firstofone#1\relax \edef#2{\the\pgf@x}% \edef#3{\the\pgf@y}% \tikzmath{\#2=#2/28.3465;}; \tikzmath{\#3=#3/28.3465;}; } \makeatother %%.. \begin{document} %%.. \begin{tikzpicture} \coordinate (A) at (1,1); \coordinate (B) at (3,4); \coordinate (M) at ($(A)!0.5!(B)$); \gettizxy{(A)}{\ax}{\ay}; \gettizxy{(B)}{\bx}{\by}; \gettizxy{(M)}{\mx}{\my}; \node at (A) {$A=(\ax,\ay)$}; \node at (B) {$B=(\bx,\by)$}; \node at (M) {$M=(\mx,\my)$}; \end{tikzpicture} %%.. \end{document}