1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 | 31x 31x 31x 31x 31x | /** * Imports the config module * @module config */ import config from "../config.js"; /** * Builds a waveform for the current audio. * Help from: https://robots.thoughtbot.com/javascript-audio-api * https://stackoverflow.com/questions/21347833/html-svg-not-drawing-works-in-other-pages */ let WaveForm = (function() { /* Initialize the local variables used in the Waveform. */ let buffer = ""; let sampleRate = config.waveforms.sample_rate; let peaks = ""; function init() { /* Grabs all of the waveform elements on the page. */ let waveforms = document.querySelectorAll(".amplitude-wave-form"); /* If there are waveforms, we iterate over them and set them up to display properly. */ if (waveforms.length > 0) { /* Iterate over all of the waveforms and build the SVG parts. */ for (let i = 0; i < waveforms.length; i++) { /* Clear the inner HTML of the element if we are replacing the waveform. */ waveforms[i].innerHTML = ""; /* Inserts an SVG into the element. */ let svg = document.createElementNS("http://www.w3.org/2000/svg", "svg"); svg.setAttribute("viewBox", "0 -1 " + sampleRate + " 2"); svg.setAttribute("preserveAspectRatio", "none"); /* Add a g component to the SVG */ let g = document.createElementNS("http://www.w3.org/2000/svg", "g"); svg.appendChild(g); /* Add a path component to the g */ let path = document.createElementNS( "http://www.w3.org/2000/svg", "path" ); path.setAttribute("d", ""); path.setAttribute("id", "waveform"); g.appendChild(path); /* Append the SVG to the waveform. */ waveforms[i].appendChild(svg); } } } /** * Builds each waveform for the page. */ function build() { if (config.web_audio_api_available) { /* If we don't have the wave form built, we need to build the waveform by loading the src with an array buffer. */ if ( config.waveforms.built[ Math.abs( config.audio.src.split("").reduce(function(a, b) { a = (a << 5) - a + b.charCodeAt(0); return a & a; }, 0) ) ] == undefined ) { /* Initializes a new XML Http Request. */ var req = new XMLHttpRequest(); /* Opens the src parameter for the audio file to read in. */ req.open("GET", config.audio.src, true); req.responseType = "arraybuffer"; /* When the ready state changes, check to see if we can render the wave form. */ req.onreadystatechange = function(e) { /* When the request is complete, then we begin decoding the audio to build the waveform. */ if (req.readyState == 4) { /* If the status is 200 means the response is a success and we decode the audio data. */ if (req.status == 200) { /* Decode the audio data and process the waveform. */ config.context.decodeAudioData(req.response, function( bufferedAudio ) { /* Set the buffer to the audio returned. */ buffer = bufferedAudio; /* Get the peaks in the audio. */ peaks = getPeaks(sampleRate, buffer); /* Build the SVG */ process(sampleRate, buffer, peaks); }); } } }; req.send(); } else { /* If we already have a waveform, we grab the waveform that was created for the song and display it. We do a simple hash of the song URL so it's already unique. */ displayWaveForms( config.waveforms.built[ Math.abs( config.audio.src.split("").reduce(function(a, b) { a = (a << 5) - a + b.charCodeAt(0); return a & a; }, 0) ) ] ); } } } /** * Processes the audio and generates the waveform. * * @param {sampleRate} sampleRate - The rate we should sample the audio. * @param {arraybuffer} buffer - The Web Audio API * @param {array} peaks - The peaks in the audio. */ function process(sampleRate, buffer, peaks) { /* If we have a buffer, we find the peaks in the audio. */ if (buffer) { /* Get the total peaks in the song. */ let totalPeaks = peaks.length; /* Figure out the depth of the peak. */ let d = ""; for (let peakNumber = 0; peakNumber < totalPeaks; peakNumber++) { if (peakNumber % 2 === 0) { d += ` M${~~(peakNumber / 2)}, ${peaks.shift()}`; } else { d += ` L${~~(peakNumber / 2)}, ${peaks.shift()}`; } } /* Add the waveform to the built waveforms array. */ config.waveforms.built[ Math.abs( config.audio.src.split("").reduce(function(a, b) { a = (a << 5) - a + b.charCodeAt(0); return a & a; }, 0) ) ] = d; /* Display the waveform. */ displayWaveForms( config.waveforms.built[ Math.abs( config.audio.src.split("").reduce(function(a, b) { a = (a << 5) - a + b.charCodeAt(0); return a & a; }, 0) ) ] ); } } /** * Get the peaks of the audio for the waveform. * * @param {number} length - The sample size of the audio. * @param {array} buffer - The array buffer used to find the peaks in the audio. */ function getPeaks(length, buffer) { /* Set the parameters needed to build the SVG. */ const sampleSize = buffer.length / length; const sampleStep = ~~(sampleSize / 10) || 1; const numberOfChannels = buffer.numberOfChannels; const mergedPeaks = []; /* Iterate over the channels and find the peaks. */ for ( let channelNumber = 0; channelNumber < numberOfChannels; channelNumber++ ) { /* Initialize the peaks array and set the channel data to what the buffer has in its channel data. */ const peaks = []; const channelData = buffer.getChannelData(channelNumber); /* Iterate over peaks with respect to the sample size. */ for (let peakNumber = 0; peakNumber < length; peakNumber++) { /* Gt the start and end peak. */ const start = ~~(peakNumber * sampleSize); const end = ~~(start + sampleSize); /* Set min and max to the channel data first peak. */ let min = channelData[0]; let max = channelData[0]; /* Iterate over the parts of the song starting to the ending to display the waveform. */ for ( let sampleIndex = start; sampleIndex < end; sampleIndex += sampleStep ) { const value = channelData[sampleIndex]; if (value > max) { max = value; } if (value < min) { min = value; } } /* Set the max and min for the peak. */ peaks[2 * peakNumber] = max; peaks[2 * peakNumber + 1] = min; /* Merge the peaks */ if (channelNumber === 0 || max > mergedPeaks[2 * peakNumber]) { mergedPeaks[2 * peakNumber] = max; } if (channelNumber === 0 || min < mergedPeaks[2 * peakNumber + 1]) { mergedPeaks[2 * peakNumber + 1] = min; } } } /* Returns the merged peaks. */ return mergedPeaks; } /** * Displays all of the waveforms necessary. * * @param {path} svg - The drawing of the waveform. */ function displayWaveForms(svg) { let waveformElements = document.querySelectorAll(".amplitude-wave-form"); /* Iterate over all of the waveform elements and display the waveform. */ for (let i = 0; i < waveformElements.length; i++) { /* Get the playlist attribute of the waveform element. */ let playlist = waveformElements[i].getAttribute( "data-amplitude-playlist" ); /* Get the song index attribute of the waveform element. */ let song = waveformElements[i].getAttribute("data-amplitude-song-index"); /* If the playlist is null and the song is null it's a global element. */ if (playlist == null && song == null) { displayGlobalWaveform(waveformElements[i], svg); } /* If the playlist is defined but the song is null it's a playlist element. */ if (playlist != null && song == null) { displayPlaylistWaveform(waveformElements[i], svg, playlist); } /* If the playlist is not defined and the song is not null it's a song element. */ if (playlist == null && song != null) { displaySongWaveform(waveformElements[i], svg, song); } /* If the playlist and song are defined it's a song in the playlist element. */ if (playlist != null && song != null) { displaySongInPlaylistWaveform(waveformElements[i], svg, playlist, song); } } } /** * Displays a global wave form. * * @param {Node} element - Element to display the waveform in. * @param {SVG} svg - The waveform path. */ function displayGlobalWaveform(element, svg) { let waveformPath = element.querySelector("svg g path"); waveformPath.setAttribute("d", svg); } /** * Displays a playlist wave form. * * @param {Node} element - Element to display the waveform in. * @param {SVG} svg - The waveform path. * @param {string} playlist - The playlist we are displaying the waveform for. */ function displayPlaylistWaveform(element, svg, playlist) { /* Ensure the playlist is the active playlist. */ if (config.active_playlist == playlist) { let waveformPath = element.querySelector("svg g path"); waveformPath.setAttribute("d", svg); } } /** * Displays a song wave form. * * @param {Node} element - Element to display the waveform in. * @param {SVG} svg - The waveform path. * @param {Integer} song - The index of the song we are displaying the * waveform for. */ function displaySongWaveform(element, svg, song) { /* Ensure it's the active song being displayed. */ if (config.active_index == song) { let waveformPath = element.querySelector("svg g path"); waveformPath.setAttribute("d", svg); } } /** * Displays a song in playlist waveform. * * @param {Node} element - Element to display the waveform in. * @param {SVG} svg - The waveform path. * @param {String} playlist - The playlist the waveform is in. * @param {Integer} song - The index of the song we are displaying the waveform for. */ function displaySongInPlaylistWaveform(element, svg, playlist, song) { /* Ensure it's the active song in the active playlist. */ if ( config.active_playlist == playlist && config.playlists[config.active_playlist].active_index == song ) { let waveformPath = element.querySelector("svg g path"); waveformPath.setAttribute("d", svg); } } /* Return the public methods. */ return { init: init, build: build }; })(); export default WaveForm; |