Erica Fischer e-n-f

Experimenting with a rainbow color scale that is cylical but has better perceptual properties. The HCL rainbow has roughly-constant luminance, but is ugly. The cubehelix rainbow, inspired by Matteo Niccoli’s perceptual rainbow but extended to 360°, varies in brightness but is prettier.

Here are the math-y bits, courtesy of @ch402:

// The math-y bits
var a2 = Math.atan2(source.y, source.x);

var angle = function(source, compare) {
    var cross = source.x * compare.y - source.y * compare.x;
    var sd = Math.sqrt(source.x * source.x + source.y * source.y);
    var cd = Math.sqrt(compare.x * compare.x + compare.y * compare.y);

How to install dlib v19.9 or newer (w/ python bindings) from github on macOS and Ubuntu

Pre-reqs:

Have Python 3 installed. On macOS, this could be installed from homebrew or even via standard Python 3.6 downloaded installer from https://www.python.org/download. On Linux, just use your package manager.
On macOS:
- Install XCode from the Mac App Store (or install the XCode command line utils).
- Have homebrew installed
On Linux:

	/* I, Brandon Martin-Anderson, release this into the public domain or whatever. */


	BufferedReader reader;
	double ll, bb, rr, tt;

	float A = 1000.0;

	GlobalMercator proj = new GlobalMercator();

	license: gpl-3.0
	height: 500
	border: no