These sketches are examples for the
p5.rotate-about library.
This library adds rotateAbout() and scaleAbout() functions to
p5.js.
A minimal example, that uses rotateAbout() to spin a rectangle around the
center of the canvas.
An examples that uses createVector() to create and modify a vector, that is
used as the argument to rotateAbout() instead of supplying separate x and
y values.
The blue rectangle is drawn with rotate(). It spins around the origin (the
upper left corner of the canvas). It is therefore off of the visible canvas
roughly 3/4 of the time.
The green rectangle is drawn with rotateAbout(). It spins around the center of
the canvas.
The first example I wrote. I don't know why I thought this one would be a good example.
The directory can be opened via p5 server. This command knows how to run
JavaScript-only sketches, and recognizes that the sketches in this directory
depend on the p5.vector-arguments library in these sketches.
Or, it can be browsed on the web at https://osteele.github.io/p5.libs/p5.rotate-about/examples/.
The web version was created by the p5 build subcommand of p5 server.