HTML preprocessors can make writing HTML more powerful or convenient. For instance, Markdown is designed to be easier to write and read for text documents and you could write a loop in Pug.
In CodePen, whatever you write in the HTML editor is what goes within the <body>
tags in a basic HTML5 template. So you don't have access to higher-up elements like the <html>
tag. If you want to add classes there that can affect the whole document, this is the place to do it.
In CodePen, whatever you write in the HTML editor is what goes within the <body>
tags in a basic HTML5 template. If you need things in the <head>
of the document, put that code here.
The resource you are linking to is using the 'http' protocol, which may not work when the browser is using https.
CSS preprocessors help make authoring CSS easier. All of them offer things like variables and mixins to provide convenient abstractions.
It's a common practice to apply CSS to a page that styles elements such that they are consistent across all browsers. We offer two of the most popular choices: normalize.css and a reset. Or, choose Neither and nothing will be applied.
To get the best cross-browser support, it is a common practice to apply vendor prefixes to CSS properties and values that require them to work. For instance -webkit-
or -moz-
.
We offer two popular choices: Autoprefixer (which processes your CSS server-side) and -prefix-free (which applies prefixes via a script, client-side).
Any URLs added here will be added as <link>
s in order, and before the CSS in the editor. You can use the CSS from another Pen by using its URL and the proper URL extension.
You can apply CSS to your Pen from any stylesheet on the web. Just put a URL to it here and we'll apply it, in the order you have them, before the CSS in the Pen itself.
You can also link to another Pen here (use the .css
URL Extension) and we'll pull the CSS from that Pen and include it. If it's using a matching preprocessor, use the appropriate URL Extension and we'll combine the code before preprocessing, so you can use the linked Pen as a true dependency.
JavaScript preprocessors can help make authoring JavaScript easier and more convenient.
Babel includes JSX processing.
Any URL's added here will be added as <script>
s in order, and run before the JavaScript in the editor. You can use the URL of any other Pen and it will include the JavaScript from that Pen.
You can apply a script from anywhere on the web to your Pen. Just put a URL to it here and we'll add it, in the order you have them, before the JavaScript in the Pen itself.
If the script you link to has the file extension of a preprocessor, we'll attempt to process it before applying.
You can also link to another Pen here, and we'll pull the JavaScript from that Pen and include it. If it's using a matching preprocessor, we'll combine the code before preprocessing, so you can use the linked Pen as a true dependency.
Search for and use JavaScript packages from npm here. By selecting a package, an import
statement will be added to the top of the JavaScript editor for this package.
Using packages here is powered by esm.sh, which makes packages from npm not only available on a CDN, but prepares them for native JavaScript ESM usage.
All packages are different, so refer to their docs for how they work.
If you're using React / ReactDOM, make sure to turn on Babel for the JSX processing.
If active, Pens will autosave every 30 seconds after being saved once.
If enabled, the preview panel updates automatically as you code. If disabled, use the "Run" button to update.
If enabled, your code will be formatted when you actively save your Pen. Note: your code becomes un-folded during formatting.
Visit your global Editor Settings.
<!--
Instructions
Keyboard Controls:
M: Menu - More controls for pattern
R: Randomize - Randomize pattern
B: Background - Toggle background colour
S: Samples - a few different starting points
E: Export - Export to codepen, svg, and background: url
If you want back and forward buttons please visit here:
https://brandonbrule.github.io/canvas-pattern/
I couldn't keep track of url changes in CodePen.
-->
<div class="utility-nav">
<button id="toggle-menu" data-action="toggle-menu" class="menu">(M)ore Controls</button>
<button data-action="randomize-pattern">(R)andomize</button>
<button data-action="toggle-background">(B)ackground</button>
<button data-action="toggle-samples">(S)amples</button>
<button data-action="export-codepen">(E)xport</button>
</div>
<header class="controls" id="menu">
<hr>
<fieldset>
<div class="pattern-preview">
<canvas id="canvas-pattern" width="10" height="10"></canvas>
</div>
</fieldset>
<fieldset>
<label for="width">Width</label>
<input id="width" type="range" min="1" max="100">
</fieldset>
<fieldset>
<label for="height">Height</label>
<input id="height" type="range" min="1" max="100">
</fieldset>
<fieldset>
<label for="x-lengh">X Length</label>
<input id="x-length" type="range" min="0" max="100">
</fieldset>
<fieldset>
<label for="y-length">Y Length</label>
<input id="y-length" type="range" min="0" max="100">
</fieldset>
<fieldset>
<label for="random">Randomness</label>
<input id="random" type="range" min="1" max="12">
</fieldset>
<fieldset>
<button data-action="randomize-pattern">(R)andomize</button>
<button data-action="toggle-background">(B)ackground</button>
<button data-action="toggle-samples">(S)amples</button>
</fieldset>
<hr>
<div style="display: none;" class="svg-export-container">
<fieldset>
<div class="pattern-preview">
<div id="svg"></div>
</div>
</fieldset>
<fieldset>
<textarea id="svg-data-input"></textarea>
<form id="export-codepen" action="https://codepen.io/pen/define" method="POST" target="_blank">
<!-- We'll populate the value with the data to post to codepen here. -->
<input id="data-input" type="hidden" name="data" value="">
</form>
</fieldset>
</div>
<hr>
<textarea id="pattern-data">{"w":"76","h":"69","x_len":"6","y_len":"48","points":"6","x1":6,"x2":29,"y1":47,"y2":56,"position_data":[{"w":5,"h":34},{"w":72,"h":6},{"w":56,"h":21},{"w":26,"h":47},{"w":48,"h":18},{"w":50,"h":20}],"background_index":0}</textarea>
</header>
<canvas id="canvas-repeat" width="500" height="500"></canvas>
html {
box-sizing: border-box;
}
*, *:before, *:after {
box-sizing: inherit;
}
body {
margin: 0;
}
textarea {
font-size: 8px;
width: 100%;
padding: 5px;
}
#its-wrapper{
width:600px;
position:absolute!important;
right: 0;
font-size: 12px;
}
fieldset{
display: inline-block;
width: 12.5%;
margin-left: 2.5%;
border: none;
padding: 0;
margin: 0;
}
fieldset:first-child{
margin-left: 0;
}
hr{
clear:both;
}
svg{
margin: 0 auto;
display: block;
}
.pattern-preview {
padding: 5px;
box-shadow: inset 2px 2px 5px rgba(154, 147, 140, 0.5), 1px 1px 5px rgba(255, 255, 255, 1);
background: #fff;
}
#canvas-pattern{
display: block;
margin: 0 auto;
}
#canvas-repeat {
display: block;
}
.utility-nav{
position:absolute;
top: 1em;
left: 1em;
}
@media only screen
and (max-device-width: 640px),
only screen and (max-device-width: 667px),
only screen and (max-width: 480px)
{
input[type='range'] {
-webkit-appearance: none;
height: 6.5em;
-webkit-border-radius: 15px;
border-radius: 15px;
padding: 2.5em;
background: #cecece; }
input[type='range']::-webkit-slider-thumb {
-webkit-appearance: none;
width: 6em;
background: #fff;
height: 6em;
-webkit-border-radius: 50%; }
fieldset{
width: 33%;
}
fieldset:first-of-type{
display: none;
}
.pattern-preview, #svg-data-input{
display: none;
}
.utility-nav button{
font-size:2em;
}
}
.controls {
position: absolute;
bottom: 0px;
left: 0;
width: 100%;
box-shadow: -2px -1px 5px -3px rgba(0, 0, 0, 0.8);
padding: 10px;
opacity: 0;
background: #e6e3df;
transition: all 0.5s ease;
}
.controls.active{
opacity: 1;
}
.controls label {
font-size: .875em;
}
.controls input, .controls button {
width: 100%;
}
.controls label {
display: block;
margin-top: 10px;
}
#pattern-data{
background: none;
padding: 0;
border: none;
line-height: 1;
}
var config;
var sample_index=0;
var background_index = 0;
var focus_index = 1;
// Show the pattern repeating
var canvas_repeat = document.getElementById('canvas-repeat');
var ctx_repeat = canvas_repeat.getContext('2d');
// Pattern Canvas
var canvas_pattern = document.getElementById('canvas-pattern');
var ctx_pattern = canvas_pattern.getContext('2d');
// Control Inputs
var sliders = document.getElementsByTagName('input');
var width_input = document.getElementById('width');
var height_input = document.getElementById('height');
var x_len_input = document.getElementById('x-length');
var y_len_input = document.getElementById('y-length');
var random_input = document.getElementById('random');
var pattern_data = document.getElementById('pattern-data');
var svg_data_input = document.getElementById('svg-data-input');
var background_colours = [
{background_colour: 'rgb(255,240,86)'},
{background_colour: 'rgb(254,82,76)'},
{background_colour: 'rgb(97,210,214)'},
{background_colour: 'rgb(160,255,87)'},
{background_colour: 'rgb(255,255,255)'}
];
var sample_examples = [
{"w":"28","h":"45","x_len":"9","y_len":"4","points":"3","position_data":[{"w":15,"h":11},{"w":7,"h":14},{"w":27,"h":34}],"background_index":1},
{"w":"9","h":"49","x_len":6,"y_len":48,"points":"1","position_data":[{"w":2,"h":5}],"background_index":3,"x1":4,"x2":7,"y1":49,"y2":47},
{"w":"28","h":"45","x_len":"9","y_len":"4","points":"3","position_data":[{"w":7,"h":28},{"w":8,"h":32},{"w":24,"h":9}],"background_index":2,"x1":6,"x2":22,"y1":25,"y2":31},
{"w":"76","h":"74","x_len":"7","y_len":"3","points":"1","background_index":4},
{"w":"76","h":"69","x_len":"6","y_len":"48","points":"6","x1":6,"x2":29,"y1":47,"y2":56,"position_data":[{"w":5,"h":34},{"w":72,"h":6},{"w":56,"h":21},{"w":26,"h":47},{"w":48,"h":18},{"w":50,"h":20}],"background_index":0},
{"w":"56","h":"39","x_len":"9","y_len":"0","points":"4","position_data":[{"w":12,"h":35},{"w":49,"h":36},{"w":18,"h":39},{"w":15,"h":38}],"background_index":1},
{"w":"2","h":"33","x_len":"2","y_len":"1","points":"1","background_index":3},
{"w":"90","h":"45","x_len":"9","y_len":"4","points":"8","x1":41,"x2":20,"y1":20,"y2":42,"position_data":[{"w":33,"h":7},{"w":6,"h":4},{"w":41,"h":32},{"w":26,"h":44},{"w":28,"h":17},{"w":50,"h":12},{"w":63,"h":23},{"w":20,"h":25}],"background_index":2},
{"w":"54","h":"38","x_len":"12","y_len":"28","points":"4","position_data":[{"w":12,"h":8},{"w":32,"h":21},{"w":17,"h":15},{"w":44,"h":31}],"background_index":0,"x1":17,"x2":51,"y1":7,"y2":36},
{"w":"90","h":"45","x_len":"9","y_len":"4","points":"8","x1":48,"x2":28,"y1":21,"y2":37,"position_data":[{"w":36,"h":28},{"w":11,"h":36},{"w":34,"h":14},{"w":1,"h":31},{"w":30,"h":24},{"w":65,"h":5},{"w":52,"h":17},{"w":12,"h":31}],"background_index":2},
{"w":"90","h":"45","x_len":"9","y_len":"4","points":"8","x1":15,"x2":62,"y1":44,"y2":5,"position_data":[{"w":51,"h":25},{"w":86,"h":34},{"w":73,"h":27},{"w":66,"h":25},{"w":73,"h":42},{"w":62,"h":44},{"w":43,"h":21},{"w":57,"h":1}],"background_index":3},
];
// Helper Functions
function getQueryVariable(variable){
var query = window.location.search.substring(1);
var vars = query.split("&");
for (var i=0;i<vars.length;i++) {
var pair = vars[i].split("=");
if(pair[0] == variable){return pair[1];}
}
return(false);
}
// General Debounce
function debounce(func, wait, immediate) {
var timeout;
return function() {
var context = this, args = arguments;
var later = function() {
timeout = null;
if (!immediate) func.apply(context, args);
};
var callNow = immediate && !timeout;
clearTimeout(timeout);
timeout = setTimeout(later, wait);
if (callNow) func.apply(context, args);
};
}
function configFromControlValues(){
var config = {
w: width_input.value,
h: height_input.value,
x_len: x_len_input.value,
y_len: y_len_input.value,
points: random_input.value
};
return config;
}
// Set Range Slider Values from Data
function controlValuesFromData(data){
width_input.value = data.w;
height_input.value = data.h;
x_len_input.value = data.x_len;
y_len_input.value = data.y_len;
random_input.value = data.points;
}
function patternData(config){
pattern_data.value = JSON.stringify(config);
window.location.hash = encodeURIComponent(JSON.stringify(config));
if ( background_colours[config.background_index] ){
document.getElementsByTagName('body')[0].style.background = background_colours[config.background_index].background_colour;
}
}
// Background Colour
function setBackgroundColour(){
// Interate Index for background colours by 1
(function(){
background_index = (background_index + 1) % background_colours.length;
config.background_index = background_index;
patternData(config);
})();
}
function exportToCodePen(svg){
var svg_str = svg_data_input.innerHTML.replace(/"/g, '\'');
svg_str = svg_str.replace(/</g, '<');
svg_str = svg_str.replace(/>/g, '>');
var canvas_pattern_data_str = pattern_data.innerHTML;
var html = [
'<div style="position: absolute; bottom: 20px; right: 20px; display: inline-block; padding:5px; background:#fff; border:1px solid #222;">',
svg_str,
'<a style="display:block; text-align: center; color:#222; margin-top:5px;" target="_blank" href="https://brandonbrule.github.io/canvas-pattern/'+ window.location.hash + '">Link</a>',
'</div>',
].join("");
var css = 'body{ background: url("data:image/svg+xml;utf8,' + svg_str + ' "); } svg{display: block}'
var data = {
title : "",
description : "",
html : html,
html_pre_processor : "",
css : css,
css_pre_processor : "",
css_starter : "",
css_prefix : "",
js : '// https://brandonbrule.github.io/canvas-pattern/' + window.location.hash,
js_pre_processor : "",
js_modernizr : "",
js_library : "",
html_classes : "",
css_external : "",
js_external : ""
};
var dataString = JSON.stringify(data);
// Get Input and Append
var data_input = document.getElementById('data-input');
data_input.value = dataString;
}
function drawSVG(){
var svg_ctx = new SVGCanvas( "canvas-pattern" );
var svg_container = document.getElementById('svg');
var svg_element = svg_container.getElementsByTagName('svg')[0];
config = JSON.parse(pattern_data.value);
svg_ctx.beginPath();
svg_ctx.moveTo(config.x1,config.y1);
svg_ctx.lineTo(config.x2, config.y1);
for (var i = 0, len = config.points; i < len; i++){
svg_ctx.lineTo(config.position_data[i].w, config.position_data[i].h);
}
svg_ctx.fill();
svg_container.innerHTML = svg_ctx.toDataURL("image/svg+xml");
if (svg_element){
document.getElementById('svg').getElementsByTagName('svg')[0].setAttribute('height', config.h);
document.getElementById('svg').getElementsByTagName('svg')[0].setAttribute('width', config.w);
svg_container.parentNode.setAttribute('style', 'background: ' + background_colours[config.background_index].background_colour);
document.getElementById('svg').getElementsByTagName('svg')[0].setAttribute('style', 'background: ' + background_colours[config.background_index].background_colour);
svg_data_input.innerHTML = svg_container.innerHTML;
exportToCodePen(svg_element);
}
};
// Refill Canvas with repeating Pattern
function repeatPattern(config){
// Now we draw that pattern to a custom shape:
var pattern = ctx_repeat.createPattern(canvas_pattern, "repeat");
// Clear everytime before redrawing.
ctx_repeat.clearRect(0, 0, canvas_repeat.width, canvas_repeat.height);
// Fill the Repeat Canvas with the Pattern Canvas
ctx_repeat.beginPath();
ctx_repeat.fillStyle = pattern;
ctx_repeat.fillRect(0,0,canvas_repeat.width,canvas_repeat.height);
canvas_pattern.parentNode.setAttribute('style', 'background: ' + background_colours[config.background_index].background_colour);
patternData(config);
}
// Initial Canvas Pattern.
// Makes interesting starting point for random.
function drawPattern(config){
x_len_input.value = config.x_len;
y_len_input.value = config.y_len;
var w = config.w;
var h = config.h;
var x_len = config.x_len;
var y_len = config.y_len;
// Increase range of x-lengh, y-length
// according to height and width sizes
x_len_input.setAttribute('max', w);
x_len = x_len_input.value;
y_len_input.setAttribute('max', h);
y_len = y_len_input.value;
// Update Pattern Preview Window Size
canvas_pattern.width = w;
canvas_pattern.height = h;
// The Pattern that's repeated.
ctx_pattern.fillRect(0, 0, x_len, y_len);
ctx_pattern.clearRect(0, 0, x_len - (x_len / 2), y_len - (y_len / 2));
ctx_pattern.beginPath();
ctx_pattern.moveTo(x_len,y_len);
ctx_pattern.lineTo(y_len + 1,x_len + 1);
ctx_pattern.lineTo(x_len - 1,y_len - 1);
ctx_pattern.fill();
ctx_pattern.beginPath();
ctx_pattern.moveTo(y_len,x_len);
ctx_pattern.lineTo(y_len + 1,x_len + 1);
ctx_pattern.lineTo(x_len - 1,y_len - 1);
ctx_pattern.fill();
repeatPattern(config);
}
// Run Button, Draw Pattern From Data Input
function drawFromData(config){
var w = config.w;
var h = config.h;
var x_len = config.x_len;
var y_len = config.y_len;
var points = config.points;
x_len_input.value = config.x_len;
y_len_input.value = config.y_len;
width_input.value = w;
height_input.value = h;
// Increase range of x-lengh, y-length
// according to height and width sizes
x_len_input.setAttribute('max', w);
x_len = x_len_input.value;
y_len_input.setAttribute('max', h);
y_len = y_len_input.value;
// Update Pattern Preview Window Size
canvas_pattern.width = w;
canvas_pattern.height = h;
// The Pattern that's repeated.
ctx_pattern.beginPath();
ctx_pattern.moveTo(config.x1,config.y1);
ctx_pattern.lineTo(config.x2, config.y1);
for (var i = 0, len = points; i < len; i++){
ctx_pattern.lineTo(config.position_data[i].w, config.position_data[i].h);
}
ctx_pattern.fill();
// Repeat the Pattern.
repeatPattern(config);
}
// Randomize the Pattern
function randomizePattern(config){
x_len_input.value = config.x_len;
y_len_input.value = config.y_len;
var w = config.w;
var h = config.h;
var x_len = config.x_len;
var y_len = config.y_len;
var points = config.points;
var position_data = [];
// Increase range of x-lengh, y-length
// according to height and width sizes
x_len_input.setAttribute('max', w);
x_len = x_len_input.value;
y_len_input.setAttribute('max', h);
y_len = y_len_input.value;
// Update Pattern Preview Window Size
canvas_pattern.width = w;
canvas_pattern.height = h;
config.x1 = Math.floor(Math.random() * w) + 1;
config.x2 = Math.floor(Math.random() * w) + 1;
config.y1 = Math.floor(Math.random() * h) + 1;
config.y2 = Math.floor(Math.random() * h) + 1;
// The Pattern that's repeated.
ctx_pattern.beginPath();
ctx_pattern.moveTo(config.x1,config.y1);
ctx_pattern.lineTo(config.x2, config.y1);
for (var i = 0, len = points; i < len; i++){
var rand_width = Math.floor(Math.random() * w) + 1;
var rand_height = Math.floor(Math.random() * h) + 1;
position_data.push( { w: rand_width, h: rand_height } );
ctx_pattern.lineTo(rand_width, rand_height);
}
ctx_pattern.fill();
config.position_data = position_data;
// Repeat the Pattern.
repeatPattern(config);
}
// Samples Button
function cycleSamples(){
// drawSamples uses the modulus operator
// to continuously go through an array
(function(){
// Draw Random Pattern From Data
if (sample_examples[sample_index].position_data){
drawFromData(sample_examples[sample_index]);
// Draw Original Algorythm Pattern
} else {
controlValuesFromData( sample_examples[sample_index]);
drawPattern(sample_examples[sample_index]);
}
sample_index = (sample_index + 1) % sample_examples.length;
})();
}
// --- Events and Buttons
// Draw Pattern Type
// For Now, There are two algorythms
// Draw starting point, which is drawPattern
// And Randomized Data
function drawPatternType(){
// It'll basically always be from window hash
if ( window.location.hash ){
config = decodeURIComponent(window.location.href.split('#')[1]);
config = JSON.parse(config);
// Else is if we paste date
} else {
config = JSON.parse(pattern_data.value);
}
// Draw Random Pattern From Data
if (config.position_data){
drawFromData(config);
// Draw Original Algorythm Pattern
} else {
drawPattern(config);
}
}
// Slider Events
function controlEvents(){
var sliders = document.getElementsByTagName('input');
var i = 0;
var len = sliders.length;
for (i = 0; i < len; i++){
sliders[i].onchange = debounce(function() {
config = configFromControlValues();
randomizePattern(config);
}, 150);
}
}
// Set Up All Button Events
function buttonEvents(){
var buttons = document.getElementsByTagName('button');
for(var i = 0, len = buttons.length; i < len; i++){
buttons[i].addEventListener('click', function(e){
var data_action = e.target.getAttribute('data-action');
switch (data_action) {
case 'toggle-menu':
document.getElementById('menu').classList.toggle('active');
break;
case 'randomize-pattern':
setBackgroundColour();
config = JSON.parse(pattern_data.value);
randomizePattern(config);
break;
case 'toggle-background':
setBackgroundColour();
break;
case 'toggle-samples':
cycleSamples();
break;
case 'export-codepen':
drawSVG();
drawSVG();
document.getElementById('export-codepen').submit();
break;
default:
console.log('button data-action not found');
}
});
}
}
// Resize Event
// resize the canvas to fill browser window dynamically
var resizeCanvas = debounce(function() {
canvas_repeat.width = window.innerWidth;
canvas_repeat.height = window.innerHeight;
config = JSON.parse(pattern_data.value);
drawPatternType();
}, 250);
// On Resize
window.addEventListener('resize', resizeCanvas, false);
// OnLoad Set Up Slider Events and Default Sample
window.onload = function(){
controlEvents();
buttonEvents();
resizeCanvas();
};
// Back, Forward Button
window.onpopstate=function(){
drawPatternType();
}
// Keyboard Controls
document.onkeydown = function(e) {
e = e || window.event;
key = e.keyCode;
switch (key) {
// R - For Random
case 82:
setBackgroundColour();
config = JSON.parse(pattern_data.value);
randomizePattern(config);
//setBackgroundColour();
break;
// S - For Sample
case 83:
cycleSamples();
break;
// B - For Background
case 66:
setBackgroundColour();
break;
// M - For Menu
case 77:
document.getElementById('menu').classList.toggle('active');
break;
// E - Export SVG
case 69:
drawSVG();
drawSVG();
document.getElementById('export-codepen').submit();
break;
default:
}
}
// NEAT PATTERNS
/*
ctx_pattern.fillRect(0, 0, x_len, y_len);
ctx_pattern.clearRect(0, 0, x_len - (x_len / 2), y_len - (y_len / 2));
ctx_pattern.beginPath();
ctx_pattern.moveTo(x_len,y_len);
ctx_pattern.lineTo(y_len + 1,x_len + 1);
ctx_pattern.lineTo(x_len - 1,y_len - 1);
ctx_pattern.fill();
ctx_pattern.beginPath();
ctx_pattern.moveTo(y_len,x_len);
ctx_pattern.lineTo(y_len + 1,x_len + 1);
ctx_pattern.lineTo(x_len - 1,y_len - 1);
ctx_pattern.fill();
*/
/*
ctx_pattern.beginPath();
ctx_pattern.moveTo(x_len,y_len);
ctx_pattern.lineTo(y_len + 1,x_len + 1);
ctx_pattern.lineTo( (y_len + x_len) ,(y_len + x_len) / 2);
ctx_pattern.fill();
ctx_pattern.beginPath();
ctx_pattern.moveTo(y_len,x_len);
ctx_pattern.lineTo(y_len - 1,x_len + 1);
ctx_pattern.lineTo((y_len + x_len) / 2 ,(y_len + x_len));
ctx_pattern.fill();
*/
/*
ctx_pattern.beginPath();
ctx_pattern.moveTo(x_len,y_len);
ctx_pattern.lineTo(0, 0);
ctx_pattern.lineTo(0, x_len);
ctx_pattern.lineTo(y_len, x_len);
ctx_pattern.lineTo(y_len, 0);
ctx_pattern.fill();
*/
/*
ctx_pattern.beginPath();
ctx_pattern.moveTo(x_len,y_len);
ctx_pattern.lineTo(y_len, x_len);
ctx_pattern.lineTo(x_len + 10, y_len - 10);
ctx_pattern.lineTo(0, 0);
ctx_pattern.lineTo(x_len - 10, y_len + 10);
ctx_pattern.lineTo(x_len, y_len);
ctx_pattern.fill();
*/
Also see: Tab Triggers