paulirish

What forces layout / reflow

All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout*. This is also called reflow or layout thrashing, and is common performance bottleneck.

Generally, all APIs that synchronously provide layout metrics will trigger forced reflow / layout. Read on for additional cases and details.

Element APIs

Getting box metrics

• elem.offsetLeft, elem.offsetTop, elem.offsetWidth, elem.offsetHeight, elem.offsetParent

AndyShiue

I think I’ve figured out most parts of the cubical type theory papers; I’m going to take a shot to explain it informally in the format of Q&As. I prefer using syntax or terminologies that fit better rather than the more standard ones.

Q: What is cubical type theory?

A: It’s a type theory giving homotopy type theory its computational meaning.

Q: What is homotopy type theory then?

A: It’s traditional type theory (which refers to Martin-Löf type theory in this Q&A) augmented with higher inductive types and the univalence axiom.

dergachev

OS X Screencast to animated GIF

This gist shows how to create a GIF screencast using only free OS X tools: QuickTime, ffmpeg, and gifsicle.

Instructions

To capture the video (filesize: 19MB), using the free "QuickTime Player" application:

paulirish

/* bling.js */

window.$ = document.querySelectorAll.bind(document);

Node.prototype.on = window.on = function (name, fn) {
  this.addEventListener(name, fn);
}

NodeList.prototype.__proto__ = Array.prototype;

andymatuschak

A composable pattern for pure state machines with effects

State machines are everywhere in interactive systems, but they're rarely defined clearly and explicitly. Given some big blob of code including implicit state machines, which transitions are possible and under what conditions? What effects take place on what transitions?

There are existing design patterns for state machines, but all the patterns I've seen complect side effects with the structure of the state machine itself. Instances of these patterns are difficult to test without mocking, and they end up with more dependencies. Worse, the classic patterns compose poorly: hierarchical state machines are typically not straightforward extensions. The functional programming world has solutions, but they don't transpose neatly enough to be broadly usable in mainstream languages.

Here I present a composable pattern for pure state machiness with effects,

bishboria

These links no longer work. Springer have pulled the free plug.

Graduate texts in mathematics

duplicates = multiple editions

A Classical Introduction to Modern Number Theory, Kenneth Ireland Michael Rosen

A Classical Introduction to Modern Number Theory, Kenneth Ireland Michael Rosen

ericclemmons

Using <details> in GitHub

Suppose you're opening an issue and there's a lot noisey logs that may be useful.

Rather than wrecking readability, wrap it in a <details> tag!

<details>
 Summary Goes Here

NeuroWinter

FFMPEG '-i', file, '-c:v', 'libopenjpeg', "jpeg2000\\" + name + ".jp2"\

Convert image to jpeg2000
	ffmpeg -i in.png -c:v libopenjpeg out.jp2
	Hex Edit out.jp2
	ffmpeg -i in.jp2 -c:v png out.png

General Edit
ffmpeg -i input.avi -c:v mpeg2video -g 999 -q:v 1 output.avi
*edit in avidemux/whatever*

takuma7

OpenCV Video Writer on Mac OS X

Fourcc tests:

• x : not worked
• o: worked (able to open in quicktime but need conversion)
• oo: worked well (preview worked but wrong aspect ratio)
• ooo: worked very well (preview worked, and aspect ratio’s right)

(Codecs are extracted from https://web.archive.org/web/20120722124832/http://opencv.willowgarage.com/wiki/QuickTimeCodecs )

addyosmani

CSS Layout Debugger

A tweet-sized debugger for visualizing your CSS layouts. Outlines every DOM element on your page a random (valid) CSS hex color.

One-line version to paste in your DevTools

Use $$ if your browser aliases it:

~ 108 byte version