Vjeux

I am in the process of rewriting MMO-Champion Tables and I want a generic way to manage the hash part of the URL (#table__search_results_item=4%3A-slot). I no longer want to write a new parser every time I want to add a new widget.

Why JSON is not suited for URLs

JSON uses characters that are not widely known in the URL. For example, having the double quote character in the URL sucks for HTML embedding. As well, Many of the automated URL insertion will fail at highlighting the whole URL.

MSN Messenger trying to automatically URLify: See the missing last three }.

http://website.com/#{"table":{"achievement":{"column":"instance","ascending":true}}}

As a user, I am also really disturbed when I see this URL. This does not feel like a normal URL. I am a bit suspicious.

A strong requirement for an URL is its small size. JSON representation can be further compressed by removing extra quotes and ending characters such as " and }.

URLON

This is why I made URLON, a new Object Notation intended to be used in URLs. It makes use of URL friendly characters such as = : @ _ &. It is shorter than JSON and should no longer scare your users 🙂

Put some random JSON / URLON / Rison in one of the boxes to see the other notations update.

JSON:

{"table":{"achievement":{"column":"instance","ascending":true}}}

URLON:

Rison:

A reference implementation is available:

It is also available on NPM:

 npm install URLON

var URLON = require('URLON');
console.log(URLON.stringify({URLON: 'works'}));
// _URLON=works

JSON / URLON Comparison

Object

An object starts with an underscore _. All the fields are separated by ampersand & and terminated by a semicolon ;. It makes it feel really url'ish. Note that trailing semicolons can safely be removed.

• JSON: {"first": "value", "second": "value"}
• URLON: _first=value&second=value

String

A string just starts with an equal sign =. A string stop as soon as it reaches a reserved keyword (= : @ _ &). You can escape a character a slash before /.

• JSON: "string"
• URLON: =string

Number, Boolean and null

Sadly, we have to distinguish between Strings and Numbers/Booleans/null. Therefore I chose to use a colon : for those instead.

Array

An array starts with a arobas @ and elements are separated by comma @. The prefix typing does not really fit well with the Array syntax. If you can find something better, I'm open to your suggestions 🙂

• JSON: [1, "vjeux", 3]
• URLON: @:1@=vjeux@:3

URLON / Query String

Query String is a standard for encoding structured data in a URL context. It is implemented natively in PHP and Ruby. However, I strongly believe that URLON is better for several reasons:

• Query String are not typed: Every atomic value is a string. This makes it less expressive than JSON and less easy to work with as numbers and booleans are common in urls.
• Query Strings are big. For every leaf node, the whole identifier is being written, this is a waste of space.

The following example from the PHP Documentation compares JSON, Query String and URLON.

JSON

{
  "user": {
    "name": "Bob Smith",
    "age": 47,
    "sex": "M",
    "dob": "5-12-1956"
  },
  "pastimes": ["golf", "opera", "poker", "rap"],
  "children": {
    "bobby": {
      "age": 12,
      "sex": "M"
    },
    "sally": {
      "age": 8,
      "sex": "F"
    }
  }
}

Minified JSON

{"user":{"name":"Bob Smith","age":47,"sex":"M","dob":"5-12-1956"},"pastimes":
["golf","opera","poker","rap"],"children":{"bobby":{"age":12,"sex":"M"},
"sally":{"age":8,"sex":"F"}}}

Query String

user[name]=Bob+Smith&user[age]=47&user[sex]=M&user[dob]=5-12-1956&pastimes[0]=golf
&pastimes[1]=opera&pastimes[2]=poker&pastimes[3]=rap&children[bobby][age]=12
&children[bobby][sex]=M&children[sally][age]=8&children[sally][sex]=F

URLON

_user_name=Bob%20Smith&age:47&sex=M&dob=5-12-1956;&pastimes@=golf@=opera
@=poker@=rap;&children_bobby_age:12&sex=M;&sally_age:8&sex=F

Rison

(user:(name:'Bob Smith',age:47,sex:M,dob:'5-12-1956'),pastimes:!(golf,opera
,poker,rap),children:(bobby:(age:12,sex:M),sally:(age:8,sex:F)))

Rison is a tiny-bit longer than URLON but is easier to read. However it does not feel like it's part of an URL to me. It is also common for automatic linking to break on parenthesis ( or ), meaning that we are back with the same issues as JSON.

Please, feel free to give your ideas in the comments 🙂

I've always found CSS positioning with both float and position: absolute/relative hard to work with. I want to introduce to you an alternative way borrowed from the World of Warcraft Interface: Anchors.

Anchor

The concept is extremely simple. You can tell where you want the element to be, relative to another. For example, top left of this blog's main content is 10px right relative to the top right of the menu.

<frame name="Content">
  <anchor point="TOP LEFT" relativeTo="Menu" relativePoint="TOP RIGHT" x="10" />
</frame>

• Allowed points:
   TOP LEFT ,  TOP   , TOP RIGHT
       LEFT , CENTER , RIGHT
BOTTOM LEFT , BOTTOM , BOTTOM RIGHT
• Default Values:
  • point, relativePoint: TOP LEFT.
  • relativeTo: Parent of the element.
  • x, y: 0.

Demo

I've made a quick implementation of this behavior in HTML using data-attribute. Check the Javascript tab to see the 35 lines of CoffeeScript that makes the following code work:

<!-- In order to put the sidebar centered at the right of the frame:
  Sidebar.left = Frame.right                                          -->
<div id="sidebar" data-anchor="left, #frame, right"></div>
 
<!-- In order to put the chat at the top right of the screen:
  Chat.topRight = HTML.topRight + {x: -10, y: 10}                       -->
<div id="chat" data-anchor="top right, html, top right, -10, 10"></div>

Limitations

Static

The current code works well for static elements. As there isn't any event for DOM move/resize, the position will not be updated if anything moves 🙁

It might be possible to achieve the same effect by setting properly the position: absolute/relative and top/bottom/right/left CSS properties. I'd be really interested to know if you try to tackle this challenge 🙂

CSS Attribute

It would be more semantically correct to add an anchor CSS attribute instead of an HTML data attribute. However, it's not possible to access the value of a custom CSS property.

#sidebar {
  anchor: bottom left #frame top right 10px 0;
}

Multiple Anchors

World of Warcraft supports multiple anchors. For example if you anchor both the left and right sides, then the width of the element is going to be updated accordingly.

I came across a CSS problem, text-align: justify does not work with only one line.

Justify behavior

The reason is because it has been designed with paragraphs in mind. It justifies all the lines but the last one.

Solution

The solution (given by cam) is to put an extra tag at the end of the paragraph that will be big enough to create a new line. Fortunately, it is possible to do it without affecting the markup using :after. We are going to put an empty tag as big as the line.

.fulljustify {
  text-align: justify;
}
.fulljustify:after {
  content: "";
  display: inline-block;
  width: 100%;
}

Now you can add class="fulljustify" in order to justify your one-line divs 🙂

MMO-Champion is a World of Warcraft news website. When a new patch is released, we want to show what has changed in the game (Post Example). An english summary of each spell change is hand written, but we want to show the exact tooltip changes.

Generate Tooltips

First, we use the database application to generate the tooltips in HTML form.

Tokenize

We are not going to do a full HTML diff which is really difficult. Instead, the trick is to parse the HTML and extract only text nodes. We split them by space to generate a token stream.

Diff

Paul Butler SimpleDiff algorithm is used on the two token streams to label each token with old, new or both.

Combine

We parse the HTML again. This time we pretty-print the HTML while traversing it. As we parse text nodes, we add <ins> tags where we need to. We just make sure to group contiguous insertions.

Text Diff

We would also like to get a text-based diff we can insert in a Patch Note. We combine both token streams into one.

Chestguard of Nature's Fury
Binds when equipped
Chest
1669 Armor
+341+321 Intellect
+512 Stamina
Red Socket
Socket Bonus: +10 Haste Rating
Requires Level 85
Equip: Improves critical strike rating by 205.
Equip: Increases your mastery rating by 241.221.

Chestguard of Nature's Fury Binds when equipped Chest 1669 Armor +341+321 Intellect +512 Stamina Red Socket Socket Bonus: +10 Haste Rating Requires Level 85 Equip: Improves critical strike rating by 205. Equip: Increases your mastery rating by 241.221.

However, the result isn't that readable. There is too much noise. We want to show only the information that has changed! In order to do that, we are going to keep only the lines that contain changes.

+341+321 Intellect
Red Socket
Socket Bonus: +10 Haste Rating
Equip: Increases your mastery rating by 241.221.

+341+321 Intellect Red Socket Socket Bonus: +10 Haste Rating Equip: Increases your mastery rating by 241.221.

And it works a lot better 🙂

Conclusion

This approach is working really well with the World of Warcraft tooltips. After many patches and hundreds of changes, I haven't seen any weird behavior. They were common before using this technique. The only downside: non textual changes such as icons or colors will be completly ignored.

At school we've been studying Lie Algebra and we were asked to make a 3D representation of a Lie Group. We chose to represent Julia Set in the Quaternion domain.

We were really impressed to see that it was possible to generate many different forms given such a simple equation. Feel free to share links with some cool settings in the comments 🙂

The demo has been written in WebGL using ThreeJS.

A bit of Mathematics

Les ensembles de Julia sont des fractales définies par une suite de récurrence \(z_{n+1} = z^{2}_{n} + r\). Avec \(r\) une constante. Si, pour un \(z_{0}\) fixé, \((z_{n})\) converge alors \(z_{0}\) est dans l'ensemble de Julia.

Les ensembles de Julia peuvent être représentés en 2 dimensions en prenant \(r \in \mathbb{C}\) ou alors en 4 dimensions en prenant \(r \in \mathbb{H}\). \(\mathbb{H}\) étant l'ensemble des quaternions. Les quaternions sont des nombres hypercomplexes de la forme: \[a + i \times b + j \times c + k \times d \ \ \ \ \ \ (a, b, c, d) \in \mathbb{R}\] Avec \(i\), \(j\), \(k\) des racines complexes de l'unité, c'est-à-dire: \(i^{2} = j^{2} = k^{2} = ijk = 1\).

Afin d'obtenir une représentation dans un espace à quatre dimensions on représente chaque point de cet espace par un quaternion. À \(r\) fixé on obtient l'ensemble de Julia correspondant en testant la convergence de
\((z_{n})\) pour tous les points de l'espace.

Dans notre démonstration les coefficients de la constante sont modifiables via les curseurs \(a\), \(b\), \(c\) et \(d\). Pour obtenir une représentation en 3D il est nécessaire de réaliser une coupe de l'ensemble de Julia par un hyperplan. Dans la pratique cela signifie que nous assignons une valeur constante à un même coefficient pour tous les quaternions. On assimile alors les 3 coefficients restants aux axes \(x\), \(y\) et \(z\) d'un repère 3D.

Dans notre démonstration on peut choisir quel coefficient fixer et modifier sa valeur avec le curseur Hyperplane. Une fois un coefficient fixé on fait ensuite varier \(x\), \(y\), et \(z\). Par exemple si on a fixé le coefficient de \(k\) à \(W\), la valeur initiale de la suite est donc: \(z_{0} = x + i \times y + j \times z + k \times W\).

Le point \((x, y, z)\) est alors dans l'ensemble de Julia si après un nombre fixé d'itérations la valeur de la suite n'a pas dépassé un certain seuil. Dans notre démonstration, nous avons choisi d'effectuer 10 itérations.