Add extracted source directory and README navigation

extracted-source/node_modules/qrcode/lib/renderer/canvas.js

@@ -0,0 +1,63 @@
+const Utils = require('./utils')
+
+function clearCanvas (ctx, canvas, size) {
+  ctx.clearRect(0, 0, canvas.width, canvas.height)
+
+  if (!canvas.style) canvas.style = {}
+  canvas.height = size
+  canvas.width = size
+  canvas.style.height = size + 'px'
+  canvas.style.width = size + 'px'
+}
+
+function getCanvasElement () {
+  try {
+    return document.createElement('canvas')
+  } catch (e) {
+    throw new Error('You need to specify a canvas element')
+  }
+}
+
+exports.render = function render (qrData, canvas, options) {
+  let opts = options
+  let canvasEl = canvas
+
+  if (typeof opts === 'undefined' && (!canvas || !canvas.getContext)) {
+    opts = canvas
+    canvas = undefined
+  }
+
+  if (!canvas) {
+    canvasEl = getCanvasElement()
+  }
+
+  opts = Utils.getOptions(opts)
+  const size = Utils.getImageWidth(qrData.modules.size, opts)
+
+  const ctx = canvasEl.getContext('2d')
+  const image = ctx.createImageData(size, size)
+  Utils.qrToImageData(image.data, qrData, opts)
+
+  clearCanvas(ctx, canvasEl, size)
+  ctx.putImageData(image, 0, 0)
+
+  return canvasEl
+}
+
+exports.renderToDataURL = function renderToDataURL (qrData, canvas, options) {
+  let opts = options
+
+  if (typeof opts === 'undefined' && (!canvas || !canvas.getContext)) {
+    opts = canvas
+    canvas = undefined
+  }
+
+  if (!opts) opts = {}
+
+  const canvasEl = exports.render(qrData, canvas, opts)
+
+  const type = opts.type || 'image/png'
+  const rendererOpts = opts.rendererOpts || {}
+
+  return canvasEl.toDataURL(type, rendererOpts.quality)
+}