1 files changed, 139 insertions, 0 deletions
diff --git a/client/lib/util.js b/client/lib/util.js
new file mode 100644
index 0000000..c2483eb
--- /dev/null
+++ b/client/lib/util.js
@@ -0,0 +1,139 @@
+export const isIphone = (navigator.userAgent.match(/iPhone/i)) || (navigator.userAgent.match(/iPod/i))
+export const isIpad = (navigator.userAgent.match(/iPad/i))
+export const isAndroid = (navigator.userAgent.match(/Android/i))
+export const isMobile = isIphone || isIpad || isAndroid
+export const isDesktop = ! isMobile
+
+document.body.classList.add(isMobile ? 'mobile' : 'desktop')
+
+export const browser = { isIphone, isIpad, isMobile, isDesktop }
+
+export function choice (a){ return a[ Math.floor(Math.random() * a.length) ] }
+export function mod(n,m){ return n-(m * Math.floor(n/m)) }
+export function norm(n, min, max){ return (n - min) / (max - min) }
+
+export function requestAudioContext (fn) {
+	if (isMobile) {
+    const container = document.createElement('div')
+    const button = document.createElement('div')
+    button.innerHTML = 'Tap to start - please unmute your phone'
+    Object.assign(container.style, {
+      position: 'absolute',
+      width: '100%',
+      height: '100%',
+      zIndex: '10000',
+      top: '0px',
+      left: '0px',
+      backgroundColor: 'rgba(0, 0, 0, 0.8)',
+    })
+		Object.assign(button.style, {
+		  position: 'absolute',
+		  left: '50%',
+		  top: '50%',
+			padding: '20px',
+		  backgroundColor: '#7F33ED',
+		  color: 'white',
+		  fontFamily: 'monospace',
+		  borderRadius: '3px',
+		  transform: 'translate3D(-50%,-50%,0)',
+		  textAlign: 'center',
+			lineHeight: '1.5',
+    })
+    container.appendChild(button)
+    document.body.appendChild(container)
+    StartAudioContext.setContext(Tone.context)
+    StartAudioContext.on(button)
+    StartAudioContext.onStarted(_ => {
+      container.remove()
+			fn()
+  	})
+	} else {
+		fn()
+	}
+}
+
+export function dataURItoBlob(dataURI) {
+  // convert base64 to raw binary data held in a string
+  // doesn't handle URLEncoded DataURIs - see SO answer #6850276 for code that does this
+  var byteString = atob(dataURI.split(',')[1]);
+
+  // separate out the mime component
+  var mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0]
+
+  // write the bytes of the string to an ArrayBuffer
+  var ab = new ArrayBuffer(byteString.length);
+
+  // create a view into the buffer
+  var ia = new Uint8Array(ab);
+
+  // set the bytes of the buffer to the correct values
+  for (var i = 0; i < byteString.length; i++) {
+      ia[i] = byteString.charCodeAt(i);
+  }
+
+  // write the ArrayBuffer to a blob, and you're done
+  var blob = new Blob([ab], {type: mimeString});
+  return blob;
+
+}
+export function ftom(f) {
+  // return (Math.log(f) - Math.log(261.626)) / Math.log(2) + 4.0
+  return 69 + 12 * Math.log2(f / 440)
+}
+export function mtof(m) {
+  return 440 * Math.pow(2, (m - 69) / 12)
+}
+export function tap (fn) {
+  return (e) => {
+    if (browser.isMobile) fn()
+    else if (e.press) fn()
+  }
+}
+
+/* get minimum and maximum variance from row-to-row */
+
+export function get_diff_bounds(rows){
+  const diffs = rows.map(row => {
+    const row_min = Math.min.apply(Math, row)
+    const row_max = Math.max.apply(Math, row)
+    return row_max - row_min
+  })
+  const min = Math.min.apply(Math, diffs)
+  const max = Math.max.apply(Math, diffs)
+  return { min, max }
+}
+
+/* get minimum and maximum values from a dataset */
+
+export function get_bounds(dataset){
+  let rows = dataset.lines
+  // rows.forEach(row => row.shift())
+  rows = rows.map(a => a.map(n => parseFloat(n)))
+  const max = rows.reduce((a,b) => {
+    return b.reduce((z,bb) => {
+      return Math.max(z, bb)
+    }, a)
+  }, -Infinity)
+  const min = rows.reduce((a,b) => {
+    return b.reduce((z,bb) => {
+      return Math.min(z, bb)
+    }, a)
+  }, Infinity)
+  return { rows, max, min }
+}
+
+/* transpose a 2D array */
+
+export function transpose(a) {
+  let i_len = a[0].length
+  let j_len = a.length
+  let T = new Array(i_len)
+  for (let i = 0; i < i_len; i++) {
+    T[i] = new Array(j_len)
+    for (var j = 0; j < j_len; j++) {
+      T[i][j] = a[j][i]
+    }
+  }
+  return T
+}
+