JavaScript

语言：

JaveScriptBabelCoffeeScript

确定

function Playback(container, progressCheck) {

this.diameter = 100;

this.diameterOnHover = 120;

this.thickness = 5;

this.thicknessOnHover = 3;

this.iconSize = 24;

this.diameterStart = this.diameter;

this.thicknessStart = this.thickness;

// quick intro

this.thickness = 1;

this.diameter = 40;

this.isOver = false;

this.playing = false;

this.progress = 0;

this.progressOffset = 1;

this.container = container;

this.progressCheck = progressCheck;

this.canvas = document.createElement('canvas');

this.canvas.className = 'playback';

this.canvas.width = this.diameterOnHover;

this.canvas.height = this.diameterOnHover;

this.context = this.canvas.getContext('2d');

this.container.appendChild(this.canvas);

this.animate();

this.on('mouseover', function() {

this.isOver = true;

}.bind(this));

this.on('mouseout', function() {

this.isOver = false;

}.bind(this));

}

Playback.prototype.setPlaying = function(value) {

var wasPlaying = this.playing;

this.playing = value;

};

Playback.prototype.isPlaying = function() {

return this.playing;

};

Playback.prototype.animate = function() {

var progressBefore = this.progress;

if (this.playing) {

this.progress = this.progressCheck();

} else {

this.progress += (1 - this.progress) * 0.1;

this.progress = this.progress > 0.99999 ? 0.99999 : this.progress;

}

if (progressBefore > 0.8 && this.progress < 0.2) {

this.progressOffset = this.progress;

}

this.diameter += ((this.isOver ? this.diameterOnHover : this.diameterStart) - this.diameter) * 0.1;

this.thickness += ((this.isOver ? this.thicknessOnHover : this.thicknessStart) - this.thickness) * 0.1;

this.render();

requestAnimationFrame(this.animate.bind(this));

};

Playback.prototype.render = function() {

var progress = this.progress,

radius = (this.diameter / 2) - this.thickness,

x = this.diameter / 2,

y = this.diameter / 2,

iconSize = this.iconSize;

this.progressOffset += (1 - this.progressOffset) * 0.1;

var endAngle = (-Math.PI / 2) + (progress * (Math.PI * 2));

var startAngle = (-Math.PI / 2) + (this.progressOffset * (Math.PI * 2));

this.context.save();

this.context.clearRect(0, 0, this.diameterOnHover, this.diameterOnHover);

this.context.translate((this.diameterOnHover - this.diameter) / 2, (this.diameterOnHover - this.diameter) / 2);

// Solid background color

this.context.beginPath();

this.context.arc(x, y, radius + 2, 0, Math.PI * 2, false);

this.context.fillStyle = 'rgba( 0, 0, 0, 0.3 )';

this.context.fill();

// Draw progress track

this.context.beginPath();

this.context.arc(x, y, radius, 0, Math.PI * 2, false);

this.context.lineWidth = this.thickness;

this.context.strokeStyle = 'rgba(255,255,255,0.3)';

this.context.stroke();

// Draw progress on top of track

this.context.beginPath();

this.context.arc(x, y, radius, startAngle, endAngle, false);

this.context.lineWidth = this.thickness;

this.context.strokeStyle = '#fff';

this.context.stroke();

this.context.translate(x - (iconSize / 2), y - (iconSize / 2));

// Draw play/pause icons

if (this.playing) {

this.context.fillStyle = '#fff';

this.context.fillRect(0, 0, iconSize / 2 - 4, iconSize);

this.context.fillRect(iconSize / 2 + 4, 0, iconSize / 2 - 4, iconSize);

} else {

this.context.beginPath();

this.context.translate(2, 0);

this.context.moveTo(0, 0);

this.context.lineTo(iconSize - 2, iconSize / 2);

this.context.lineTo(0, iconSize);

this.context.fillStyle = '#fff';

this.context.fill();

}

this.context.restore();

};

Playback.prototype.on = function(type, listener) {

this.canvas.addEventListener(type, listener, false);

};

Playback.prototype.off = function(type, listener) {

this.canvas.removeEventListener(type, listener, false);

};

var demoElement = document.querySelector('.playback-demo');

var t = Date.now();

var p = new Playback(demoElement, function() {

return (Date.now() - t) * 0.04 % 100 / 100;

});

p.setPlaying(true);

p.on('click', function() {

t = Date.now();

p.render();

p.setPlaying(!p.isPlaying());

});