Pen Settings

HTML

CSS

CSS Base

Vendor Prefixing

Add External Stylesheets/Pens

Any URL's 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 it's URL and the proper URL extention.

+ add another resource

JavaScript

Babel includes JSX processing.

Add External Scripts/Pens

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.

+ add another resource

Packages

Add Packages

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.

Behavior

Save Automatically?

If active, Pens will autosave every 30 seconds after being saved once.

Auto-Updating Preview

If enabled, the preview panel updates automatically as you code. If disabled, use the "Run" button to update.

Format on Save

If enabled, your code will be formatted when you actively save your Pen. Note: your code becomes un-folded during formatting.

Editor Settings

Code Indentation

Want to change your Syntax Highlighting theme, Fonts and more?

Visit your global Editor Settings.

HTML

              
                <canvas id="c"/>
              
            
!

CSS

              
                
              
            
!

JS

              
                /**
 * Water ripple effect.
 * Original code (Java) by Neil Wallis 
 * @link http://www.neilwallis.com/java/water.html
 * 
 * @author Sergey Chikuyonok (serge.che@gmail.com)
 * @link http://chikuyonok.ru
 */
(function(){
    var canvas = document.getElementById('c'),
        /** @type {CanvasRenderingContext2D} */
        ctx = canvas.getContext('2d'),
        width = 960,
        height = 400,
        half_width = width >> 1,
        half_height = height >> 1,
        size = width * (height + 2) * 2,
        delay = 30,
        oldind = width,
        newind = width * (height + 3),
        riprad = 3,
        ripplemap = [],
        last_map = [],
        ripple,
        texture,
        line_width = 20,
        step = line_width * 2, 
        count = height / line_width;
        
    canvas.width = width;
    canvas.height = height;
    
    /*
     * Water ripple demo can work with any bitmap image
     * (see example here: http://media.chikuyonok.ru/ripple/)
     * But I need to draw simple artwork to bypass 1k limitation
     */
    with (ctx) {
        fillStyle = '#a2ddf8';
        fillRect(0, 0, width, height);
        
        fillStyle = '#07b';
        save();
        rotate(-0.785);
        for (var i = 0; i < count; i++) {
            fillRect(-width, i * step, width * 3, line_width);
        }
        
        restore();
    }
    
    texture = ctx.getImageData(0, 0, width, height);
    ripple = ctx.getImageData(0, 0, width, height);
    
    for (var i = 0; i < size; i++) {
        last_map[i] = ripplemap[i] = 0;
    }
    
    /**
     * Main loop
     */
    function run() {
        newframe();
        ctx.putImageData(ripple, 0, 0);
    }
    
    /**
     * Disturb water at specified point
     */
    function disturb(dx, dy) {
        dx <<= 0;
        dy <<= 0;
        
        for (var j = dy - riprad; j < dy + riprad; j++) {
            for (var k = dx - riprad; k < dx + riprad; k++) {
                ripplemap[oldind + (j * width) + k] += 128;
            }
        }
    }
    
    /**
     * Generates new ripples
     */
    function newframe() {
        var a, b, data, cur_pixel, new_pixel, old_data;
        
        var t = oldind; oldind = newind; newind = t;
        var i = 0;
        
        // create local copies of variables to decrease
        // scope lookup time in Firefox
        var _width = width,
            _height = height,
            _ripplemap = ripplemap,
            _last_map = last_map,
            _rd = ripple.data,
            _td = texture.data,
            _half_width = half_width,
            _half_height = half_height;
        
        for (var y = 0; y < _height; y++) {
            for (var x = 0; x < _width; x++) {
                var _newind = newind + i, _mapind = oldind + i;
                data = (
                    _ripplemap[_mapind - _width] + 
                    _ripplemap[_mapind + _width] + 
                    _ripplemap[_mapind - 1] + 
                    _ripplemap[_mapind + 1]) >> 1;
                    
                data -= _ripplemap[_newind];
                data -= data >> 5;
                
                _ripplemap[_newind] = data;

                //where data=0 then still, where data>0 then wave
                data = 1024 - data;
                
                old_data = _last_map[i];
                _last_map[i] = data;
                
                if (old_data != data) {
                    //offsets
                    a = (((x - _half_width) * data / 1024) << 0) + _half_width;
                    b = (((y - _half_height) * data / 1024) << 0) + _half_height;
    
                    //bounds check
                    if (a >= _width) a = _width - 1;
                    if (a < 0) a = 0;
                    if (b >= _height) b = _height - 1;
                    if (b < 0) b = 0;
    
                    new_pixel = (a + (b * _width)) * 4;
                    cur_pixel = i * 4;
                    
                    _rd[cur_pixel] = _td[new_pixel];
                    _rd[cur_pixel + 1] = _td[new_pixel + 1];
                    _rd[cur_pixel + 2] = _td[new_pixel + 2];
                }
                
                ++i;
            }
        }
    }
    
    canvas.onmousemove = function(/* Event */ evt) {
        disturb(evt.offsetX || evt.layerX, evt.offsetY || evt.layerY);
    };
    
    setInterval(run, delay);
    
    // generate random ripples
    var rnd = Math.random;
    setInterval(function() {
        disturb(rnd() * width, rnd() * height);
    }, 700);
    
})();
              
            
!
999px

Console