103 lines
2.6 KiB
JavaScript
103 lines
2.6 KiB
JavaScript
/*
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* favcount.js v1.5.0
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* http://chrishunt.co/favcount
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* Dynamically updates the favicon with a number.
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*
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* Copyright 2013, Chris Hunt
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* Released under the MIT license
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*/
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(function(){
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function Favcount(icon) {
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this.icon = icon;
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this.opacity = 0.4;
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this.canvas = document.createElement('canvas');
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this.font = "Helvetica, Arial, sans-serif";
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}
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Favcount.prototype.set = function(count) {
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var self = this,
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img = document.createElement('img');
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if (self.canvas.getContext) {
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img.crossOrigin = "anonymous";
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img.onload = function() {
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drawCanvas(self.canvas, self.opacity, self.font, img, normalize(count));
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};
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img.src = this.icon;
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}
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};
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function normalize(count) {
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count = Math.round(count);
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if (isNaN(count) || count < 1) {
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return '';
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} else if (count < 10) {
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return ' ' + count;
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} else if (count > 99) {
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return '99';
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} else {
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return count;
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}
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}
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function drawCanvas(canvas, opacity, font, img, count) {
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var head = document.getElementsByTagName('head')[0],
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favicon = document.createElement('link'),
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multiplier, fontSize, context, xOffset, yOffset, border, shadow;
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favicon.rel = 'icon';
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// Scale canvas elements based on favicon size
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multiplier = img.width / 16;
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fontSize = multiplier * 11;
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xOffset = multiplier;
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yOffset = multiplier * 11;
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border = multiplier;
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shadow = multiplier * 2;
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canvas.height = canvas.width = img.width;
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context = canvas.getContext('2d');
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context.font = 'bold ' + fontSize + 'px ' + font;
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// Draw faded favicon background
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if (count) { context.globalAlpha = opacity; }
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context.drawImage(img, 0, 0);
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context.globalAlpha = 1.0;
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// Draw white drop shadow
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context.shadowColor = '#FFF';
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context.shadowBlur = shadow;
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context.shadowOffsetX = 0;
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context.shadowOffsetY = 0;
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// Draw white border
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context.fillStyle = '#FFF';
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context.fillText(count, xOffset, yOffset);
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context.fillText(count, xOffset + border, yOffset);
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context.fillText(count, xOffset, yOffset + border);
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context.fillText(count, xOffset + border, yOffset + border);
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// Draw black count
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context.fillStyle = '#000';
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context.fillText(count,
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xOffset + (border / 2.0),
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yOffset + (border / 2.0)
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);
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// Replace favicon with new favicon
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favicon.href = canvas.toDataURL('image/png');
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head.removeChild(document.querySelector('link[rel=icon]'));
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head.appendChild(favicon);
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}
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this.Favcount = Favcount;
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}).call(this);
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(function(){
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Favcount.VERSION = '1.5.0';
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}).call(this);
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