apburnes

#Topology in Geography

Topology is a broad branch of mathematics used to describe the fundamental structure of a shape or object within a space. Objects can be manipulated by stretching or compressing the shape’s components, but the tearing of or addition to its structure will break topology. According to the rules of topology, a doughnut and a coffee mug are equal.

###Topology example: ![Alt text] (http://i.imgur.com/sBP9p.gif)

Geography utilizes topology to project geometric objects from a 3D sphere onto a 2D coordinate system while allowing the shape to stay intact with some distortion.

###3D Sphere projections to 2D plane:

zziuni

# source : http://code.google.com/p/natvpn/source/browse/trunk/stun_server_list
# A list of available STUN server.

stun.l.google.com:19302
stun1.l.google.com:19302
stun2.l.google.com:19302
stun3.l.google.com:19302
stun4.l.google.com:19302
stun01.sipphone.com
stun.ekiga.net

jareware

⇐ back to the gist-blog at jrw.fi

Advanced SCSS

Or, 16 cool things you may not have known your stylesheets could do. I'd rather have kept it to a nice round number like 10, but they just kept coming. Sorry.

I've been using SCSS/SASS for most of my styling work since 2009, and I'm a huge fan of Compass (by the great @chriseppstein). It really helped many of us through the darkest cross-browser crap. Even though browsers are increasingly playing nice with CSS, another problem has become very topical: managing the complexity in stylesheets as our in-browser apps get larger and larger. SCSS is an indispensable tool for dealing with this.

This isn't an introduction to the language by a long shot; many things probably won't make sense unless you have some SCSS under your belt already. That said, if you're not yet comfy with the basics, check out the aweso

mudge

/* Polyfill indexOf. */
var indexOf;

if (typeof Array.prototype.indexOf === 'function') {
    indexOf = function (haystack, needle) {
        return haystack.indexOf(needle);
    };
} else {
    indexOf = function (haystack, needle) {
        var i = 0, length = haystack.length, idx = -1, found = false;

jackiekazil

How do I round to 2 decimals?

In python, you have floats and decimals that can be rounded. If you care about the accuracy of rounding, use decimal type. If you use floats, you will have issues with accuracy.

All the examples use demical types, except for the original value, which is automatically casted as a float.

To set the context of what we are working with, let's start with an original value.

Original Value

tmcw

Moral Concerns

JSONP is not actually JSON with padding, it's Javascript code that's executed. JSON is not a real subset of Javascript and the way it is not is important to us: via UTFGrid, we are all UTF-8 masters.

JSONP is not safe: it's Javascript that's executed. It's trivial to XSS with JSONP, because JSONP is XSS. Just have a call like mapbox.load('foo.tilejson', …) and if foo.tilejson gets replaced with destroyYoursite(), it gets run. Compare to JSON.parse, which is, on purpose, not eval.

Practical Concerns

JSONP is questionable in terms of performance. To be fast, you want to have the same callback all the time so that you can cache the response. But this leads to a page like

lengstrom

function intersect(x1, y1, x2, y2, x3, y3, x4, y4){
	var a1, a2, b1, b2, c1, c2;
	var r1, r2 , r3, r4;
	var denom, offset, num;

	// Compute a1, b1, c1, where line joining points 1 and 2
	// is "a1 x + b1 y + c1 = 0".
	a1 = y2 - y1;
	b1 = x1 - x2;
	c1 = (x2 * y1) - (x1 * y2);

pbojinov

Two way iframe communication

The main difference between the two pages is the method of sending messages. Recieving messages is the same in both.

Parent

Send messages to iframe using iframeEl.contentWindow.postMessage Recieve messages using window.addEventListener('message')

iframe

deandob

    // Live video stream management for HTML5 video. Uses FFMPEG to connect to H.264 camera stream, 
    // Camera stream is remuxed to a MP4 stream for HTML5 video compatibility and segments are recorded for later playback
var liveStream = function (req, resp) {                                            // handle each client request by instantiating a new FFMPEG instance
    // For live streaming, create a fragmented MP4 file with empty moov (no seeking possible).

    var reqUrl = url.parse(req.url, true)
    var cameraName = typeof reqUrl.pathname === "string" ? reqUrl.pathname.substring(1) : undefined;
    if (cameraName) {
        try {
            cameraName = decodeURIComponent(cameraName);

ichord

<script src="http://cdnjs.cloudflare.com/ajax/libs/processing.js/1.4.1/processing-api.min.js"></script><html>
<!--
  Created using jsbin.com
  Source can be edited via http://jsbin.com/pdfjs-helloworld-v2/8598/edit
-->
<body>
  <canvas id="the-canvas" style="border:1px solid black"></canvas>
  <input id='pdf' type='file'/>

  <!-- Use latest PDF.js build from Github -->