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

jsturgis

var mediaJSON = { "categories" : [ { "name" : "Movies",
        "videos" : [ 
		    { "description" : "Big Buck Bunny tells the story of a giant rabbit with a heart bigger than himself. When one sunny day three rodents rudely harass him, something snaps... and the rabbit ain't no bunny anymore! In the typical cartoon tradition he prepares the nasty rodents a comical revenge.\n\nLicensed under the Creative Commons Attribution license\nhttp://www.bigbuckbunny.org",
              "sources" : [ "http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/BigBuckBunny.mp4" ],
              "subtitle" : "By Blender Foundation",
              "thumb" : "images/BigBuckBunny.jpg",
              "title" : "Big Buck Bunny"
            },
            { "description" : "The first Blender Open Movie from 2006",
              "sources" : [ "http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/ElephantsDream.mp4" ],

johnnyclem

CVImageBufferRef cvImage = CMSampleBufferGetImageBuffer(sampleBuffer);
CIImage *ciImage = [[CIImage alloc] initWithCVPixelBuffer:cvImage];

fent

# If in a playlist, play the next video.
tell application "Google Chrome"
  repeat with t in tabs of windows
    tell t
      if URL starts with "http://www.youtube.com/watch" or URL starts with "https://www.youtube.com/watch" then
        execute javascript "
        var player =
          document.getElementById('movie_player') ||
          document.getElementsByTagName('embed')[0];
        var next = document.getElementsByClassName('yt-uix-button-icon-playlist-bar-next')[0];

scy

Opening and closing an SSH tunnel in a shell script the smart way

I recently had the following problem:

• From an unattended shell script (called by Jenkins), run a command-line tool that accesses the MySQL database on another host.
• That tool doesn't know that the database is on another host, plus the MySQL port on that host is firewalled and not accessible from other machines.

We didn't want to open the MySQL port to the network, but it's possible to SSH from the Jenkins machine to the MySQL machine. So, basically you would do something like

ssh -L 3306:localhost:3306 remotehost

dannycroft

// Add the following to your preferences file
"folder_exclude_patterns":[".git","node_modules"]

jadeatucker

Creating a "DMG installer" for OS X

A DMG Installer is convenient way to provide end-users a simple way to install an application bundle. They are basically a folder with a shortcut to the Applications directory but they can be customized with icons, backgrounds, and layout properties. A DMG file (.dmg) is a Mac OS X Disk Image file and it is used to package files or folders providing compression, encryption, and read-only to the package.

##Creating the DMG file #Disk Utility

potch

SVG path data generator

This is excerpted from my work on emilio.js, a d3 plotting library, but useful enough to stand on its own.

• Generators are constructed with new Path().
• Takes two optional arguments, xScale and yScale.
  • Methods for coordinate space translation.
  • Works great with d3.scale() objects!
  • xScale and yScale affect the x and y coordinate spaces, respectively.
• If only xScale is supplied, y values will be in the xScale space.

rnapier

#!/usr/bin/python

# fix-xcode
# 	Rob Napier <robnapier@gmail.com>

# Script to link in all your old SDKs every time you upgrade Xcode
# Create a directory called /SDKs (or modify source_path).
# Under it, put all the platform directories:
# 	MacOSX.platform          iPhoneOS.platform        iPhoneSimulator.platform
# Under those, store the SDKs:

jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD