165 lines
3.8 KiB
JavaScript
165 lines
3.8 KiB
JavaScript
/**
|
|
* UI component that lets the use control auto-slide
|
|
* playback via play/pause.
|
|
*/
|
|
export default class Playback {
|
|
|
|
/**
|
|
* @param {HTMLElement} container The component will append
|
|
* itself to this
|
|
* @param {function} progressCheck A method which will be
|
|
* called frequently to get the current playback progress on
|
|
* a range of 0-1
|
|
*/
|
|
constructor( container, progressCheck ) {
|
|
|
|
// Cosmetics
|
|
this.diameter = 100;
|
|
this.diameter2 = this.diameter/2;
|
|
this.thickness = 6;
|
|
|
|
// Flags if we are currently playing
|
|
this.playing = false;
|
|
|
|
// Current progress on a 0-1 range
|
|
this.progress = 0;
|
|
|
|
// Used to loop the animation smoothly
|
|
this.progressOffset = 1;
|
|
|
|
this.container = container;
|
|
this.progressCheck = progressCheck;
|
|
|
|
this.canvas = document.createElement( 'canvas' );
|
|
this.canvas.className = 'playback';
|
|
this.canvas.width = this.diameter;
|
|
this.canvas.height = this.diameter;
|
|
this.canvas.style.width = this.diameter2 + 'px';
|
|
this.canvas.style.height = this.diameter2 + 'px';
|
|
this.context = this.canvas.getContext( '2d' );
|
|
|
|
this.container.appendChild( this.canvas );
|
|
|
|
this.render();
|
|
|
|
}
|
|
|
|
setPlaying( value ) {
|
|
|
|
const wasPlaying = this.playing;
|
|
|
|
this.playing = value;
|
|
|
|
// Start repainting if we weren't already
|
|
if( !wasPlaying && this.playing ) {
|
|
this.animate();
|
|
}
|
|
else {
|
|
this.render();
|
|
}
|
|
|
|
}
|
|
|
|
animate() {
|
|
|
|
const progressBefore = this.progress;
|
|
|
|
this.progress = this.progressCheck();
|
|
|
|
// When we loop, offset the progress so that it eases
|
|
// smoothly rather than immediately resetting
|
|
if( progressBefore > 0.8 && this.progress < 0.2 ) {
|
|
this.progressOffset = this.progress;
|
|
}
|
|
|
|
this.render();
|
|
|
|
if( this.playing ) {
|
|
requestAnimationFrame( this.animate.bind( this ) );
|
|
}
|
|
|
|
}
|
|
|
|
/**
|
|
* Renders the current progress and playback state.
|
|
*/
|
|
render() {
|
|
|
|
let progress = this.playing ? this.progress : 0,
|
|
radius = ( this.diameter2 ) - this.thickness,
|
|
x = this.diameter2,
|
|
y = this.diameter2,
|
|
iconSize = 28;
|
|
|
|
// Ease towards 1
|
|
this.progressOffset += ( 1 - this.progressOffset ) * 0.1;
|
|
|
|
const endAngle = ( - Math.PI / 2 ) + ( progress * ( Math.PI * 2 ) );
|
|
const startAngle = ( - Math.PI / 2 ) + ( this.progressOffset * ( Math.PI * 2 ) );
|
|
|
|
this.context.save();
|
|
this.context.clearRect( 0, 0, this.diameter, this.diameter );
|
|
|
|
// Solid background color
|
|
this.context.beginPath();
|
|
this.context.arc( x, y, radius + 4, 0, Math.PI * 2, false );
|
|
this.context.fillStyle = 'rgba( 0, 0, 0, 0.4 )';
|
|
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, 0.2 )';
|
|
this.context.stroke();
|
|
|
|
if( this.playing ) {
|
|
// 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( 4, 0 );
|
|
this.context.moveTo( 0, 0 );
|
|
this.context.lineTo( iconSize - 4, iconSize / 2 );
|
|
this.context.lineTo( 0, iconSize );
|
|
this.context.fillStyle = '#fff';
|
|
this.context.fill();
|
|
}
|
|
|
|
this.context.restore();
|
|
|
|
}
|
|
|
|
on( type, listener ) {
|
|
this.canvas.addEventListener( type, listener, false );
|
|
}
|
|
|
|
off( type, listener ) {
|
|
this.canvas.removeEventListener( type, listener, false );
|
|
}
|
|
|
|
destroy() {
|
|
|
|
this.playing = false;
|
|
|
|
if( this.canvas.parentNode ) {
|
|
this.container.removeChild( this.canvas );
|
|
}
|
|
|
|
}
|
|
|
|
} |