HTML5/Canvas很炫的可选色旋转云动画

长按鼠标，会给圆圈施加压力迫使圆圈扩散到预览窗口四周。

Canvas, circle

《three.js如何实现贴图模糊效果 - 使用canvas》申请公开！

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常用链接

HTML
CSS
JavaScript
Result

编译

JavaScript

// Basically all the JS from caleb-miller.com

$(document).ready(function() {
    // custom color picker here on codepen
    var color_picker = document.createElement('div');
    color_picker.classList.add('color-picker');
    document.body.appendChild(color_picker);

var long_side = 300;
    var short_side = 50;
    color_picker.style.width = short_side + 'px';
    color_picker.style.height = long_side + 'px';

// generate color chips
    for (var i = 0; i < 8; i++) {
        var color_chip = document.createElement('div');
        color_picker.appendChild(color_chip);
        var hue = i * 40 + 10;
        color_chip.style.backgroundColor = 'hsl(' + hue + ', 100%, 50%)';
        color_chip.addEventListener('click', (function iife(hue) {
            return function changeColor(evt) {
                BG.setHue(hue);
            };
        })(hue));
    }

resizeColorPicker();
    window.addEventListener('resize', resizeColorPicker);

function resizeColorPicker() {
        color_picker.style.right = '10px';
        color_picker.style.top = (window.innerHeight - long_side) / 2 + 'px';
    }

// setup logo image
    BG.logo = new Image();
    BG.logo.onload = function() {
        BG.logo_loaded = true;
        BG.showLogo();
    }
    BG.logo.setAttribute('id', 'logo');
    BG.logo.setAttribute('width', '100');
    BG.logo.setAttribute('height', '100');
    BG.logo.src = BG.logo_path + BG.logo_ext;
    // setup canvas
    BG.wrapper = document.getElementById('intro');
    $(BG.wrapper).prepend('<canvas id="bg-canvas" width="' + window.innerWidth + '" height="' + window.innerHeight + '">Please use a browser that supports canvas</canvas>');
    BG.canvas = document.getElementById('bg-canvas');
    BG.ctx = BG.canvas.getContext('2d');
    $(BG.wrapper).append(BG.logo);
    // wire ticker listener
    Ticker.addListener(BG.tick);
    // start
    BG.init();

// show initial color (takes a number from 0-360 degrees)
    BG.setHue(210);

// restart on window resize
    window.addEventListener('resize', BG.init);

// input events
    var is_mobile = (/(android|bb\d+|meego).+mobile|avantgo|bada\/|blackberry|blazer|compal|elaine|fennec|hiptop|iemobile|ip(hone|od|ad)|iris|kindle|lge |maemo|midp|mmp|netfront|opera m(ob|in)i|palm( os)?|phone|p(ixi|re)\/|plucker|pocket|psp|series(4|6)0|symbian|treo|up\.(browser|link)|vodafone|wap|windows (ce|phone)|xda|xiino|android|ipad|playbook|silk/i.test(navigator.userAgent || navigator.vendor || window.opera) || /1207|6310|6590|3gso|4thp|50[1-6]i|770s|802s|a wa|abac|ac(er|oo|s\-)|ai(ko|rn)|al(av|ca|co)|amoi|an(ex|ny|yw)|aptu|ar(ch|go)|as(te|us)|attw|au(di|\-m|r |s )|avan|be(ck|ll|nq)|bi(lb|rd)|bl(ac|az)|br(e|v)w|bumb|bw\-(n|u)|c55\/|capi|ccwa|cdm\-|cell|chtm|cldc|cmd\-|co(mp|nd)|craw|da(it|ll|ng)|dbte|dc\-s|devi|dica|dmob|do(c|p)o|ds(12|\-d)|el(49|ai)|em(l2|ul)|er(ic|k0)|esl8|ez([4-7]0|os|wa|ze)|fetc|fly(\-|_)|g1 u|g560|gene|gf\-5|g\-mo|go(\.w|od)|gr(ad|un)|haie|hcit|hd\-(m|p|t)|hei\-|hi(pt|ta)|hp( i|ip)|hs\-c|ht(c(\-| |_|a|g|p|s|t)|tp)|hu(aw|tc)|i\-(20|go|ma)|i230|iac( |\-|\/)|ibro|idea|ig01|ikom|im1k|inno|ipaq|iris|ja(t|v)a|jbro|jemu|jigs|kddi|keji|kgt( |\/)|klon|kpt |kwc\-|kyo(c|k)|le(no|xi)|lg( g|\/(k|l|u)|50|54|\-[a-w])|libw|lynx|m1\-w|m3ga|m50\/|ma(te|ui|xo)|mc(01|21|ca)|m\-cr|me(rc|ri)|mi(o8|oa|ts)|mmef|mo(01|02|bi|de|do|t(\-| |o|v)|zz)|mt(50|p1|v )|mwbp|mywa|n10[0-2]|n20[2-3]|n30(0|2)|n50(0|2|5)|n7(0(0|1)|10)|ne((c|m)\-|on|tf|wf|wg|wt)|nok(6|i)|nzph|o2im|op(ti|wv)|oran|owg1|p800|pan(a|d|t)|pdxg|pg(13|\-([1-8]|c))|phil|pire|pl(ay|uc)|pn\-2|po(ck|rt|se)|prox|psio|pt\-g|qa\-a|qc(07|12|21|32|60|\-[2-7]|i\-)|qtek|r380|r600|raks|rim9|ro(ve|zo)|s55\/|sa(ge|ma|mm|ms|ny|va)|sc(01|h\-|oo|p\-)|sdk\/|se(c(\-|0|1)|47|mc|nd|ri)|sgh\-|shar|sie(\-|m)|sk\-0|sl(45|id)|sm(al|ar|b3|it|t5)|so(ft|ny)|sp(01|h\-|v\-|v )|sy(01|mb)|t2(18|50)|t6(00|10|18)|ta(gt|lk)|tcl\-|tdg\-|tel(i|m)|tim\-|t\-mo|to(pl|sh)|ts(70|m\-|m3|m5)|tx\-9|up(\.b|g1|si)|utst|v400|v750|veri|vi(rg|te)|vk(40|5[0-3]|\-v)|vm40|voda|vulc|vx(52|53|60|61|70|80|81|83|85|98)|w3c(\-| )|webc|whit|wi(g |nc|nw)|wmlb|wonu|x700|yas\-|your|zeto|zte\-/i.test((navigator.userAgent || navigator.vendor || window.opera).substr(0, 4)));
    if (is_mobile) {
        BG.canvas.addEventListener('touchstart', Input.touchHandler);
        BG.canvas.addEventListener('touchmove', Input.touchHandler);
        document.addEventListener('touchend', Input.touchHandler);
    } else {
        BG.canvas.addEventListener('mousedown', Input.mouseHandler);
        BG.canvas.addEventListener('mousemove', Input.mouseHandler);
        document.addEventListener('mouseup', Input.mouseHandler);
    }

// cycle colors
    var event_name = is_mobile ? 'touchstart' : 'mouseenter';
    $('nav a').on(event_name, function() {
        BG.setHue(BG.hues[$(this).index()]);
    });

// smooth scroll to projects section
    $('#nav-projects').click(function() {
        var anchor = $.attr(this, 'href');
        window.history.pushState("Project Section", "Project Section", anchor);
        $('html, body').animate({
            scrollTop: $(anchor).offset().top
        }, 500);
        return false;
    });

// fetch retina versions of project thumbnails if needed
    if (window.devicePixelRatio > 1) {
        $('.project-box').each(function() {
            var image = $(this).css('backgroundImage');
            if (image !== 'none') {
                image = image.substr(0, image.length - 5) + '@2x' + image.substr(-5);
                $(this).css('backgroundImage', image);
            }
        });
    }
});

// wrapper for background animation functionality
var BG = {
    started: false,
    // wrapper element
    wrapper: null,
    // logo image and associated data
    logo_loaded: false,
    logo: null,
    logo_path: 'http://caleb-miller.com/lib/img/c_logo',
    logo_ext: '.svg',
    logo_opacity: '0.85',
    logo_size: 0,
    showLogo: function() {
        if (BG.logo_loaded) setTimeout(function() {
            BG.logo.style.opacity = BG.logo_opacity;
        }, 500);
    },
    // canvas element and context
    canvas: null,
    ctx: null,
    // current hue
    hue: 0,
    // possible hues
    hues: [180, 210, 240],
    // counter for initially adding balls
    init_time: 0,
    // store minimum screen dimension from last initialization
    min_dim: 0,
    // ball arrays
    balls: [],
    ball_pool: [],
    // devicePixelRatio alias
    dpr: window.devicePixelRatio || 1
};
// start/reset animation
BG.init = function() {
    // resize canvas
    BG.canvas.width = window.innerWidth * BG.dpr;
    BG.canvas.height = window.innerHeight * BG.dpr;
    // hide logo with no transition
    BG.logo.style.display = 'none';
    setTimeout(function() {
        BG.logo.style.opacity = '0';
        BG.logo.style.display = 'block';
    }, 0);
    // only restart animation if running for first time, or minimum screen dimension changed
    var current_min_dim = Math.min(window.innerWidth, window.innerHeight);
    if (!BG.started || BG.min_dim !== current_min_dim) {
        BG.started = true;
        BG.min_dim = current_min_dim;
        var balls = BG.balls;
        var ball_pool = BG.ball_pool;
        // recycle any balls that are displayed
        for (var i = balls.length - 1; i >= 0; i--) {
            ball_pool.push(balls.pop());
        }
        // reset initialization frame
        BG.init_time = 0;
        // resize logo
        BG.logo_size = current_min_dim * 0.5;
        BG.logo.style.width = BG.logo_size + 'px';
        BG.logo.style.height = BG.logo_size + 'px';
    }
    // fade logo back in
    BG.showLogo();
    // position logo
    BG.logo.style.left = ((window.innerWidth - BG.logo_size) / 2) + 'px';
    BG.logo.style.top = ((window.innerHeight - BG.logo_size) / 2) + 'px';
}
BG.setHue = function(hue) {
        // store
        BG.hue = hue;
        // color balls
        var balls = BG.balls;
        for (var i = balls.length - 1; i >= 0; i--) {
            balls[i].setColor(hue);
        }
        // color backgrounds
        BG.wrapper.style.backgroundColor = 'hsl(' + hue + ', 85%, 30%)';
        var hsla = 'hsla(' + hue + ', 100%, 40%, 0.85)';
        $('header').css('background-color', hsla);
        $('nav a').css('background-color', hsla);
        $('.angle-right-deco').css('border-top-color', hsla);
        $('.angle-left-deco').css('border-bottom-color', hsla);
    }
    // run animation
BG.tick = function(frame_time, lag) {
    // store some handy references locally
    var Input = window.Input;
    var ctx = BG.ctx;
    var balls = BG.balls;
    var ball_pool = BG.ball_pool;
    var width = BG.canvas.width;
    var height = BG.canvas.height;
    var center_x = width * 0.5;
    var center_y = height * 0.5;
    var radius = Math.min(width, height) * 0.35;
    var max_ball_radius = radius * 0.185;

// start off slowly adding balls (one every ~4 frames)
    if (balls.length < 200) {
        BG.init_time += frame_time;
        if (BG.init_time > 60) {
            BG.init_time = 0;
            var ball = ball_pool.pop() || new BG.Ball();
            ball.init(center_x, center_y, max_ball_radius);
            balls.push(ball);
        }
    }

// wipe canvas
    ctx.fillStyle = '#fff'; // temporary fix for Safari - clearRect() shouldn't need a fillStyle to work
    ctx.clearRect(0, 0, width, height);
    // ensure proper blend mode
    ctx.globalCompositeOperation = "lighter";

// increase input force
    if (Input.touching) {
        if (Input.pointer_force === 0) {
            Input.pointer_force = radius;
        }
        Input.pointer_force += 10 * lag;
        if (Input.pointer_force > radius * 2) {
            Input.pointer_force = radius * 2;
        }
    }

// step through visible balls
    for (var i = balls.length - 1; i >= 0; i--) {
        var ball = balls[i];
        // movement
        ball.position += ball.speed * lag;
        var radius_offset = radius + Math.sin((ball.position + ball.wave_offset) * ball.wave_period) * radius * ball.wave_height;
        ball.x_target = Math.sin(ball.position) * radius_offset - ball.radius + center_x;
        ball.y_target = -Math.cos(ball.position) * radius_offset - ball.radius + center_y;

// apply input force
        if (Input.touching && MyMath.pointDist(Input.pointer_x, Input.pointer_y, ball.x_target, ball.y_target) < Input.pointer_force) {
            var angle = MyMath.pointAngle(Input.pointer_x, Input.pointer_y, ball.x_target, ball.y_target);
            ball.x_target = Input.pointer_x + Math.sin(angle) * Input.pointer_force - ball.radius;
            ball.y_target = Input.pointer_y - Math.cos(angle) * Input.pointer_force - ball.radius;
        }

// approach target
        ball.x_inertia += ((ball.x_target - ball.x) * 0.05 - ball.x_inertia) * 0.05;
        ball.y_inertia += ((ball.y_target - ball.y) * 0.05 - ball.y_inertia) * 0.05;
        // move
        ball.x += ball.x_inertia * lag;
        ball.y += ball.y_inertia * lag;
        // check bounds
        if (ball.x < 0) {
            ball.x = 0;
            ball.x_inertia *= -0.9;
        } else if (ball.x + ball.width > width) {
            ball.x = width - ball.width;
            ball.x_inertia *= -0.9;
        }
        if (ball.y < 0) {
            ball.y = 0;
            ball.y_inertia *= -0.9;
        } else if (ball.y + ball.height > height) {
            ball.y = height - ball.height;
            ball.y_inertia *= -0.9;
        }

// drawing
        ctx.drawImage(ball.canvas, ball.x | 0, ball.y | 0);
    }
}

// Ball definition
BG.Ball = function() {
    // sprite properties
    this.color = "";
    this.radius = 0;
    this.x = 0;
    this.y = 0;
    this.width = 0;
    this.height = 0;
    this.alpha = 1;
    this.canvas = document.createElement('canvas');
    this.ctx = this.canvas.getContext('2d');
    this.redraw = false;
    // track target position separately
    this.x_target = 0;
    this.y_target = 0;
    // track inertia
    this.x_inertia = 0;
    this.y_inertia = 0;
    // position around center circle
    this.position = 0;
    // speed around circle in radians/frame
    this.speed = 0;
    // wave offset params
    this.wave_period = 0;
    this.wave_height = 0;
    this.wave_offset = 0;
}
BG.Ball.prototype.init = function(x, y, max_radius) {
    // size
    this.radius = Math.random() * max_radius * 0.5 + max_radius * 0.5;
    this.width = this.radius * 2 + 1; // without adding a pixel, balls develop a flat edge on bottom and right side... ??
    this.height = this.width;
    this.canvas.width = this.width;
    this.canvas.height = this.height;
    // start position
    this.x = x - this.radius;
    this.y = y - this.radius;
    // set start color
    this.setColor(BG.hue);
    // position on circle
    var PI2 = Math.PI * 2;
    this.position = Math.random() * PI2;
    // 10 - 30 seconds for a full orbit
    this.speed = Math.random() * PI2 / 1000 + PI2 / 1800;
    // reset inertia
    this.x_inertia = 0;
    this.y_inertia = 0;
    // randomize offset wave
    this.wave_period = MyMath.randomInt(1, 6);
    this.wave_height = Math.random() * 0.2;
    this.wave_offset = Math.random() * Math.PI;
}
BG.Ball.prototype.setColor = function(hue) {
    // randomize hue a bit
    hue += (Math.random() * 70 - 35) | 0;
    // set color and render
    this.color = 'hsla(' + hue + ', 100%, 55%, 0.2)';
    this.redraw = true;
    this.render();
}
BG.Ball.prototype.render = function() {
    if (this.redraw) {
        this.redraw = false;
        this.ctx.clearRect(0, 0, this.width, this.height);
        this.ctx.fillStyle = this.color;
        this.ctx.beginPath();
        this.ctx.arc(this.radius, this.radius, this.radius, 0, Math.PI * 2);
        this.ctx.fill();
    }
}

var Input = {
    // user controls
    touching: false,
    pointer_x: 0,
    pointer_y: 0,
    pointer_force: 0,
    // used to get coordinates of a touchend event
    last_pos: null,

// easy window to canvas coordinate conversion
    windowToCanvas: function(canvas, x, y) {
        var bbox = canvas.getBoundingClientRect();
        return {
            x: (x - bbox.left) * (canvas.width / bbox.width),
            y: (y - bbox.top) * (canvas.height / bbox.height)
        };
    }
};

// very simple pointer event
Input.PointerEvent = function(x, y) {
    // "start", "move", "end"
    this.type = null;
    this.x = x;
    this.y = y;
    this.touch_count = 1;
}

Input.mouseHandler = function(evt) {
    var pos = Input.windowToCanvas(BG.canvas, evt.clientX, evt.clientY);
    var dispatch_event = new Input.PointerEvent(pos.x, pos.y);

if (evt.type === 'mousedown') {
        evt.preventDefault();
        dispatch_event.type = 'start';
    } else if (evt.type === 'mousemove') {
        dispatch_event.type = 'move';
    } else if (evt.type === 'mouseup') {
        dispatch_event.type = 'end';
        dispatch_event.touch_count = 0;
    }

Input.pointerHandler(dispatch_event);
}

// native touch handler
Input.touchHandler = function(evt) {
    evt.preventDefault();
    var dispatch_event;
    if (evt.touches.length > 0) {
        var touch = evt.touches[0];
        var pos = Input.windowToCanvas(BG.canvas, touch.clientX, touch.clientY);
        Input.last_pos = pos;
        dispatch_event = new Input.PointerEvent(pos.x, pos.y);
    } else {
        dispatch_event = new Input.PointerEvent(Input.last_pos.x, Input.last_pos.y);
    }

dispatch_event.touch_count = evt.touches.length;

if (evt.type === 'touchmove') {
        dispatch_event.type = 'move';
    } else if (evt.type === 'touchstart') {
        dispatch_event.type = 'start';
    } else if (evt.type === 'touchend') {
        dispatch_event.type = 'end';
    }

Input.pointerHandler(dispatch_event);
}

// synthetic "pointer" handler delegate for mouse and touch
Input.pointerHandler = function(evt) {
    if (evt.type === 'start') {
        if (evt.touch_count === 1) {
            Input.touching = true;
            Input.pointer_x = evt.x;
            Input.pointer_y = evt.y;
        }
    } else if (evt.type === 'move') {
        if (evt.touch_count === 1) {
            Input.pointer_x = evt.x;
            Input.pointer_y = evt.y;
        }
    } else if (evt.type === 'end') {
        if (evt.touch_count === 0) {
            Input.touching = false;
            Input.pointer_force = 0;
        }
    }
}

// Handy math/trig reference (implement complex math directly to reduce overhead of extra convenience function calls)
var MyMath = {
    // degree/radian conversion constants
    toDeg: 180 / Math.PI,
    toRad: Math.PI / 180,
    halfPI: Math.PI / 2,

// Pythagorean Theorem point distance calculation
    pointDist: function(x1, y1, x2, y2) {
        var x_dist = x2 - x1;
        var y_dist = y2 - y1;
        return Math.sqrt(x_dist * x_dist + y_dist * y_dist);
    },
    // Returns the angle (in radians) between two points
    pointAngle: function(x1, y1, x2, y2) {
        return MyMath.halfPI + Math.atan2(y2 - y1, x2 - x1);
    },
    // Splits a speed vector into x and y components (angle needs to be in radians)
    split_vector: function(speed, angle) {
        return {
            x: Math.sin(angle) * speed,
            y: -Math.cos(angle) * speed
        };
    },
    // Generates a random integer between and possibly including min and max values
    randomInt: function(min, max) {
        return ((Math.random() * (max - min + 1)) | 0) + min;
    },
    // Returns a random element from an array, or simply the set of provided arguments when called
    randomChoice: function(choices) {
        if (arguments.length === 1 && Array.isArray(choices))
            return choices[(Math.random() * choices.length) | 0];
        return arguments[(Math.random() * arguments.length) | 0];
    }
};

// Frame ticker helper class
var Ticker = (function() {
    var PUBLIC_API = {};

// public
    // will call function reference repeatedly once registered, passing elapsed time and a lag multiplier as parameters
    PUBLIC_API.addListener = function addListener(fn) {
        if (typeof fn !== 'function') throw ('Ticker.addListener() requires a function reference passed in.');

listeners.push(fn);

// start frame-loop lazily
        if (!started) {
            started = true;
            queueFrame();
        }
    };

// private
    var started = false;
    var last_timestamp = 0;
    var listeners = [];
    // queue up a new frame (calls frameHandler)
    function queueFrame() {
        if (window.requestAnimationFrame) {
            requestAnimationFrame(frameHandler);
        } else {
            webkitRequestAnimationFrame(frameHandler);
        }
    }

function frameHandler(timestamp) {
        var frame_time = timestamp - last_timestamp;
        last_timestamp = timestamp;
        // make sure negative time isn't reported (first frame can be whacky)
        if (frame_time < 0) {
            frame_time = 17;
        }
        // - cap minimum framerate to 15fps[~68ms] (assuming 60fps[~17ms] as 'normal')
        else if (frame_time > 68) {
            frame_time = 68;
        }

// fire custom listeners
        for (var i = 0, len = listeners.length; i < len; i++) {
            listeners[i].call(window, frame_time, frame_time / 16.67);
        }

// always queue another frame
        queueFrame();
    }

return PUBLIC_API;
}());

编译

CSS

/* STYLES */

body {
    font-family: 'Teko', sans-serif;
    letter-spacing: 1px;
    margin: 0;
}
/* color picker for codepen */

.color-picker {
    position: fixed;
    box-sizing: border-box;
    background-color: rgba(0, 0, 0, 0.65);
    padding: 10px 0;
    border-radius: 4px;
}
.color-picker div {
    height: calc( (100% - 6px * 7) / 8);
    margin-left: 14px;
    margin-right: 14px;
    cursor: pointer;
    -webkit-transition: -webkit-transform 500ms;
    transition: -webkit-transform 500ms;
    transition: transform 500ms;
    transition: transform 500ms, -webkit-transform 500ms;
}
.color-picker div + div {
    margin-top: 6px;
}
.color-picker div:hover {
    -webkit-transition: none;
    transition: none;
    -webkit-transform: scale(1.6, 1);
    transform: scale(1.6, 1);
}
/* Intro / Interactive section */

#intro {
    position: relative;
    height: 100vh;
    background-color: #000;
    -webkit-transition: background-color 500ms;
    transition: background-color 500ms;
    /* FF3.6+ */
    
    background-image: -webkit-gradient(radial, center center, 0px, center center, 100%, color-stop(0%, rgba(0, 0, 0, 0)), color-stop(100%, rgba(0, 0, 0, 0.65)));
    /* Chrome,Safari4+ */
    
    background-image: -webkit-radial-gradient(center, ellipse cover, rgba(0, 0, 0, 0) 0%, rgba(0, 0, 0, 0.65) 100%);
    /* Chrome10+,Safari5.1+ */
    /* Opera 12+ */
    /* IE10+ */
    
    background-image: -webkit-radial-gradient(center ellipse, rgba(0, 0, 0, 0) 0%, rgba(0, 0, 0, 0.65) 100%);
    background-image: radial-gradient(ellipse at center, rgba(0, 0, 0, 0) 0%, rgba(0, 0, 0, 0.65) 100%);
    /* W3C */
}
.angle-right-deco,
.angle-left-deco {
    position: absolute;
    top: 0;
    width: 0;
    height: 0;
    transition: border-color 400ms;
    -webkit-transition: border-color 400ms;
}
header {
    position: absolute;
    top: 0;
    left: 0;
    background-color: #333;
    color: #FFF;
    font-size: 60px;
    text-align: center;
    width: 6.67em;
    height: 2.5em;
    padding-left: 0.667em;
    transition: background-color 400ms;
    -webkit-transition: background-color 400ms;
}
header .angle-right-deco {
    left: 100%;
    border-top: 2.5em solid #333;
    border-right: 2.5em solid transparent;
}
header h1 {
    font-size: 1em;
    line-height: 1em;
    font-weight: bold;
    padding-top: 0.55em;
    position: relative;
    left: 0.2em;
    width: 110%;
}
header h1::after {
    content: '.com';
    font-size: 0.4em;
    opacity: 0.5;
    position: relative;
    left: 0.25em;
    z-index: 1;
}
header h2 {
    font-size: 0.4em;
    line-height: 0.4em;
    opacity: 0.75;
    font-weight: normal;
}
nav {
    position: absolute;
    right: 0;
    bottom: 0;
    font-size: 25px;
}
nav .angle-left-deco {
    right: 100%;
    border-bottom: 6em solid #333;
    border-left: 6em solid transparent;
}
nav a {
    position: relative;
    display: block;
    width: 12em;
    height: 2em;
    line-height: 2em;
    font-weight: bold;
    color: rgba(255, 255, 255, 0.75);
    text-align: center;
    text-decoration: none;
    padding-right: 0.8em;
    background-color: #333;
    -webkit-tap-highlight-color: rgba(0, 0, 0, 0);
    transition: background-color 400ms, color 400ms;
    -webkit-transition: background-color 400ms, color 400ms;
}
nav a::after {
    content: '';
    display: block;
    position: absolute;
    top: 0;
    left: 0;
    width: 12em;
    height: 2em;
    /* FF3.6+ */
    
    background: -webkit-gradient(linear, left top, right top, color-stop(0%, rgba(255, 255, 255, 0)), color-stop(50%, rgba(255, 255, 255, 1)), color-stop(100%, rgba(255, 255, 255, 0)));
    /* Chrome,Safari4+ */
    
    background: -webkit-linear-gradient(left, rgba(255, 255, 255, 0) 0%, rgba(255, 255, 255, 1) 50%, rgba(255, 255, 255, 0) 100%);
    /* Chrome10+,Safari5.1+ */
    /* Opera 11.10+ */
    /* IE10+ */
    
    background: linear-gradient(to right, rgba(255, 255, 255, 0) 0%, rgba(255, 255, 255, 1) 50%, rgba(255, 255, 255, 0) 100%);
    /* W3C */
    
    opacity: 0;
    transition: opacity 400ms;
    -webkit-transition: opacity 400ms;
}
nav a:hover {
    color: #FFF;
}
nav a:hover::after {
    opacity: 0.4;
}
nav a:active {
    outline: none;
}
@media (min-width: 420px) and (max-width: 800px) {
    header {
        font-size: 7.5vw;
    }
    nav {
        font-size: 3.125vw;
    }
}
@media (max-width: 420px) {
    header {
        font-size: 31.5px;
    }
    nav {
        font-size: 13.125px;
    }
}
/* go even smaller for small mobile landscapish viewports */

@media (min-width: 420px) and (max-width: 800px) and (max-height: 400px) {
    header {
        font-size: 5vw;
    }
    nav {
        font-size: 2.0833vw;
    }
}
@media (max-width: 420px) and (max-height: 400px) {
    header {
        font-size: 21px;
    }
    nav {
        font-size: 8.75px;
    }
}
/* make sure interactive canvas background is contained */

#bg-canvas {
    position: absolute;
    width: 100%;
    height: 100%;
    -webkit-user-select: none;
}
#logo {
    position: absolute;
    pointer-events: none;
    opacity: 0;
    transition: opacity 4000ms;
    -webkit-transition: opacity 4000ms;
}

HTML

长按鼠标，会给圆圈施加压力迫使圆圈扩散到预览窗口四周。

Canvas, circle

编辑器支持Emmet

快捷键

长按鼠标，会给圆圈施加压力迫使圆圈扩散到预览窗口四周。

Canvas, circle

HTML5/Canvas可以切换日夜模式的挂钟动画

HTML5 Canvas炫酷的线条分形动画特效

编辑器支持Emmet

快捷键

语言：

语言：

导入代码模板：