In the TikZ & PGF Manual for Version 3.1.5b, page 33/1318, section 2.4, we get Curved Path Construction. The general syntax for extending a path in a “curved” way is .. controls and .. .
This curve mathematically is not unique. I like to read the source code for this to understand how exactly they define this controls curve. There are many curves that can be a solution. Do you know where I can get the source code?
\draw (0,0) to[bend left] (1,0) to[bend right=30] (2,0);. – Torbjørn T. Jul 13 '20 at 20:09