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Using Favicon as progress bar
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| export class FaviconHelper { | |
| private linkEl: HTMLLinkElement; | |
| private canvas: HTMLCanvasElement; | |
| private context: CanvasRenderingContext2D; | |
| public constructor( | |
| public color = '#fff', | |
| public background = '#888', | |
| public text: string | null = '#fff', | |
| public shadow: string | null = '#000', | |
| ) { | |
| this.linkEl = document.createElement('link'); | |
| this.linkEl.rel = 'icon'; | |
| document.head.appendChild(this.linkEl); | |
| this.canvas = document.createElement('canvas'); | |
| this.canvas.width = this.canvas.height = 128; | |
| this.context = this.canvas.getContext('2d')!; | |
| this.linkEl.href = this.canvas.toDataURL('image/png'); | |
| } | |
| public destroy() { | |
| this.linkEl.remove(); | |
| this.canvas.remove(); | |
| } | |
| public render(percent: number) { | |
| this.clear(); | |
| this.renderChart(100, this.background); | |
| this.renderChart(percent, this.color); | |
| this.renderText(percent); | |
| this.linkEl.href = this.canvas.toDataURL('image/png'); | |
| } | |
| public renderMultiple(percents: number[], margin: number = 20) { | |
| this.clear(); | |
| percents.forEach((percent, index) => { | |
| if (index !== 0) { | |
| this.renderChart(100, this.background, margin * index - 3); | |
| } | |
| this.renderChart(100, this.background, margin * index); | |
| this.renderChart(percent, this.color, margin * index); | |
| }); | |
| this.linkEl.href = this.canvas.toDataURL('image/png'); | |
| } | |
| public clear() { | |
| this.context.clearRect(0, 0, this.canvas.width, this.canvas.height); | |
| } | |
| private renderChart(percent: number, background: string, margin: number = 0) { | |
| const context = this.context; | |
| const middle = this.canvas.width / 2; | |
| const radius = this.canvas.width / 2 - margin; | |
| const startAngle = - Math.PI / 2; | |
| const endAngle = startAngle + Math.PI * 2 * percent / 100; | |
| context.fillStyle = background; | |
| context.beginPath(); | |
| context.moveTo(middle, middle); | |
| context.arc(middle, middle, radius, startAngle, endAngle, false); | |
| context.lineTo(middle, middle); | |
| context.closePath(); | |
| context.fill(); | |
| } | |
| private renderText(percent: number) { | |
| if (!this.text || this.text === 'transparent') { | |
| return; | |
| } | |
| const context = this.context; | |
| const middle = this.canvas.width / 2; | |
| const text = percent.toString(); | |
| context.font = '60px monospace'; | |
| context.textAlign = 'center'; | |
| context.textBaseline = 'middle'; | |
| context.strokeStyle = this.shadow ?? '#000'; | |
| context.lineWidth = 4; | |
| context.strokeText(text, middle, middle); | |
| context.fillStyle = this.text; | |
| context.fillText(text, middle, middle); | |
| } | |
| } |
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| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <title>Example Page</title> | |
| </head> | |
| <body> | |
| <p>This page uses the favicon as a progress bar. Try clicking the button.</p> | |
| <button onclick="run()">Do something</button> | |
| <script> | |
| var FaviconProgress = function() { | |
| // Create <link> for favicon | |
| this._linkEl = document.createElement('link'); | |
| this._linkEl.rel = 'icon'; | |
| document.head.appendChild(this._linkEl); | |
| // Initialise canvas | |
| this._canvas = document.createElement('canvas'); | |
| this._canvas.width = this._canvas.height = 32; | |
| this._context = this._canvas.getContext('2d'); | |
| // Clear the favicon by default | |
| this._linkEl.href = this._canvas.toDataURL('image/png'); | |
| }; | |
| FaviconProgress.prototype = { | |
| render: function(percent) { | |
| this.clear(); | |
| this._renderChart(percent); | |
| this._renderText(percent); | |
| this._linkEl.href = this._canvas.toDataURL('image/png'); | |
| }, | |
| clear: function() { | |
| this._context.clearRect(0, 0, this._canvas.width, this._canvas.height); | |
| }, | |
| _renderChart: function(percent) { | |
| var context = this._context; | |
| var middle = this._canvas.width / 2; | |
| // Render progress | |
| // Start from 12 o'clock (-π/2) | |
| var startAngle = -Math.PI / 2; | |
| var endAngle = startAngle + Math.PI * 2 * percent / 100; | |
| context.fillStyle = '#3B5998'; | |
| context.beginPath(); | |
| context.moveTo(middle, middle); | |
| context.arc( | |
| /* x */ middle, | |
| /* y */ middle, | |
| /* radius */ middle, | |
| startAngle, | |
| endAngle, | |
| /* antiClockwise */ false | |
| ); | |
| context.lineTo(middle, middle); | |
| context.closePath(); | |
| context.fill(); | |
| }, | |
| _renderText: function(percent) { | |
| var context = this._context; | |
| var middle = this._canvas.width / 2; | |
| var text = percent + '%'; | |
| context.font = '11px Arial'; | |
| context.textAlign = 'center'; | |
| context.textBaseline = 'middle'; | |
| context.strokeStyle = 'black'; | |
| context.lineWidth = 4; | |
| context.strokeText(text, middle, middle); | |
| context.fillStyle = 'white'; | |
| context.fillText(text, middle, middle); | |
| } | |
| }; | |
| var favicon = new FaviconProgress(); | |
| function run() { | |
| var progress = 0; | |
| favicon.render(0); | |
| var timer = window.setInterval(function() { | |
| progress += 5; | |
| favicon.render(progress); | |
| if (progress >= 100) { | |
| window.clearInterval(timer); | |
| } | |
| }, 150); | |
| } | |
| </script> | |
| </body> | |
| </html> |
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