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/**********************************************************************************
*
* Copyright (C) 2017 MuK IT GmbH
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
**********************************************************************************/
window.AudioContext = window.AudioContext || window.webkitAudioContext || window.mozAudioContext;
function Visualizer($audio, $container, $canvas) {
var _this = this;
this.$audio = $audio;
this.$container = $container;
this.$canvas = $canvas;
this.audio = $audio.get(0);
this.canvas = $canvas.get(0);
this.audioCtx = new AudioContext();
this.analyser = this.audioCtx.createAnalyser();
this.audioSrc = this.audioCtx.createMediaElementSource(this.audio);
this.frequencyData = new Uint8Array(this.analyser.frequencyBinCount);
this.smoothEndingCounter = 0;
this.audioSrc.connect(this.analyser);
this.analyser.connect(this.audioCtx.destination);
this.ctx = this.canvas.getContext('2d'),
this.capYPositionArray = [];
this.$audio.bind('play', function (e) {
_this.smoothEndingCounter = 0;
_this.calcCanvas();
_this.renderFrame();
});
this.map = function (num, in_min, in_max, out_min, out_max) {
return (num - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}
this.calcCanvas = function() {
_this.canvas.width = _this.$container.width() !== 0 ? _this.$container.width() : 650;
_this.canvas.height = _this.$container.height() !== 0 ? _this.$container.height() : 360;
_this.cwidth = _this.canvas.width;
_this.cheight = _this.canvas.height - 4;
_this.meterWidth = 10;
_this.capHeight = 4;
_this.capStyle = '#FFF';
_this.meterNum = (_this.$container.width() !== 0 ? _this.$container.width() : 650) / (10 + 2);
_this.gradient = _this.ctx.createLinearGradient(0, 0, 0, _this.cheight);
_this.gradient.addColorStop(1, '#1CD5FB');
_this.gradient.addColorStop(0.75, '#19DECA');
_this.gradient.addColorStop(0.5, '#28F5A6');
_this.gradient.addColorStop(0.25, '#19DE5A');
_this.gradient.addColorStop(0, '#1CFB27');
}
this.renderFrame = function() {
if(_this.$container.width() !== _this.cwidth) {
_this.calcCanvas();
}
_this.ctx.clearRect(0, 0, _this.cwidth, _this.cheight);
_this.analyser.getByteFrequencyData(_this.frequencyData);
var step = Math.round(_this.frequencyData.length / _this.meterNum);
for (var i = 0; i < _this.meterNum; i++) {
var valueBar = _this.map(_this.frequencyData[i * step], 0, 255, 0, _this.cheight);
var valueCap = _this.map(_this.frequencyData[i * step], 0, 255, 0, _this.canvas.height);
if (_this.capYPositionArray.length < Math.round(_this.meterNum)) {
_this.capYPositionArray.push(valueCap);
};
_this.ctx.fillStyle = _this.gradient;
_this.ctx.fillRect(i * 12, _this.cheight - valueBar, _this.meterWidth, _this.cheight);
_this.ctx.fillStyle = _this.capStyle;
if (valueCap < _this.capYPositionArray[i]) {
_this.ctx.fillRect(i * 12, _this.canvas.height - (--_this.capYPositionArray[i]), _this.meterWidth, _this.capHeight);
} else {
_this.ctx.fillRect(i * 12, _this.canvas.height - valueCap, _this.meterWidth, _this.capHeight);
_this.capYPositionArray[i] = valueCap;
};
}
if(!_this.audio.paused) {
requestAnimationFrame(_this.renderFrame);
} else {
if(_this.smoothEndingCounter < 500) {
requestAnimationFrame(_this.renderFrame);
}
_this.smoothEndingCounter++;
}
}
};