Matt MattShawPhoto

The dynamic wallpaper in MacOS Mojave is a single 114 MB .heic file that seems to contain 16 embedded images.

It also contains the following binary plist data in its metadata under the key "Solar". It's an array of 16 items, each with four keys:

i (integer). This seems to be the image index.
o (integer). This is always 1 or 0. Stephen Radford thinks it indicates dark mode (0) vs. light mode (1).
a (decimal). I’m pretty sure this is the angle of the sun over the horizon. 0º = sunset/sunrise. 90º = sun directly overhead. Negative values = sun below horizon.
z (decimal). This seems to be the cardinal position of the sun relative to the camera. 0º = sun is directly in front of the camera. 90º = sun is directly to the right of the camera. 180º = sun is directly behind the camera.

gif-from-tweet

There are so many great GIFs out there and I want to have copies of them. Twitter makes that harder than it should be by converting them to MP4 and not providing access to the source material. To make it easier, I made a bash pipeline that takes a tweet URL and a filename, extracts the MP4 from that tweet and uses ffmpeg to convert back to GIF.

Dependencies

ffmpeg
- macOS: brew install ffmpeg
- Ubuntu/Debian: apt install ffmpeg

Marker animation along SVG "path" element with D3.js Based on Mike's example: Point-Along-Path Interpolation.

	var motionQuery = matchMedia('(prefers-reduced-motion)');
	function handleReduceMotionChanged() {
	if (motionQuery.matches) {
	/* adjust motion of 'transition' or 'animation' properties */
	} else {
	/* standard motion */
	}
	}
	motionQuery.addListener(handleReduceMotionChanged);
	handleReduceMotionChanged(); // trigger once on load if needed

	var ctx = document.getElementById('canvas').getContext('2d');
	for (var i = 0; i < 6; i++){
	for (var j = 0; j < 6; j++){
	ctx.fillStyle = 'rgb(' + Math.floor(255 - 42.5 * i) + ',' +
	Math.floor(255 - 42.5 * j) + ',0)';
	ctx.fillRect(j * 25, i * 25, 25, 25);
	}
	}

	/**
	* Converts an RGB color value to HSL. Conversion formula
	* adapted from http://en.wikipedia.org/wiki/HSL_color_space.
	* Assumes r, g, and b are contained in the set [0, 255] and
	* returns h, s, and l in the set [0, 1].
	*
	* @param Number r The red color value
	* @param Number g The green color value
	* @param Number b The blue color value
	* @return Array The HSL representation

	public static bool IsAnAdministrator()
	{
	WindowsIdentity identity = WindowsIdentity.GetCurrent();
	WindowsPrincipal principal = new WindowsPrincipal(identity);
	return principal.IsInRole(WindowsBuiltInRole.Administrator);
	}

	public static bool UserIsAdministrator() {
	WindowsPrincipal currentPrincipal = new WindowsPrincipal(WindowsIdentity.GetCurrent());
	return currentPrincipal.IsInRole(WindowsBuiltInRole.Administrator);

	const all = (...preds) => (obj) => preds.map(f => f(obj)).reduce((a, b) => a && b, true)
	const any = (...preds) => (obj) => preds.map(f => f(obj)).reduce((a, b) => a \|\| b, false)
	const oneOf = (...preds) => (obj) => preds.map(f => f(obj)).reduce((a, b) => a ? !b : b, false)
	const has = (prop) => (obj) => obj[prop] !== undefined
	const not = (pred) => (obj) => !pred(obj)
	const equals = (prop, val) => (obj) => obj[prop] === val
	const implies = (f, g) => (obj) => !f(obj) \|\| g(obj);

	const validate = all(implies(has('selectedIndex'), equals('isOpen', true)))

	// JS array equivalents to C# LINQ methods - by Dan B.

	// Here's a simple array of "person" objects
	var people = [
	{ name: "John", age: 20 },
	{ name: "Mary", age: 35 },
	{ name: "Arthur", age: 78 },
	{ name: "Mike", age: 27 },
	{ name: "Judy", age: 42 },
	{ name: "Tim", age: 8 }

	console.log(1);
	(_ => console.log(2))();
	eval('console.log(3);');
	console.log.call(null, 4);
	console.log.apply(null, [5]);
	new Function('console.log(6)')();
	Reflect.apply(console.log, null, [7])
	Reflect.construct(function(){console.log(8)}, []);
	Function.prototype.apply.call(console.log, null, [9]);
	Function.prototype.call.call(console.log, null, 10);