1 files changed, 117 insertions, 0 deletions
diff --git a/public/assets/js/vendor/renderToCanvas.js b/public/assets/js/vendor/renderToCanvas.js
new file mode 100644
index 0000000..376e61a
--- /dev/null
+++ b/public/assets/js/vendor/renderToCanvas.js
@@ -0,0 +1,117 @@
+function renderToCanvas(img, options) {
+  if (!img) return
+  options = options || {}
+
+  // Canvas max size for any side
+  var maxSize = 2000
+  var canvas = document.createElement('canvas')
+  var ctx = canvas.getContext('2d')
+  var initialScale = options.scale || 1
+  // Scale to needed to constrain canvas to max size
+  var scale = getScale(img.width * initialScale,
+      img.height * initialScale, maxSize, maxSize)
+  // Still need to apply the user defined scale
+  scale *= initialScale
+  var width = canvas.width = Math.round(img.width * scale)
+  var height = canvas.height = Math.round(img.height * scale)
+  var correctOrientation = options.correctOrientation
+  var jpeg = !!img.src.match(/data:image\/jpeg|\.jpeg$|\.jpg$/i)
+  var dataURI = !!img.src.match(/^data:/)
+
+  ctx.save()
+
+  // Can only correct orientation on JPEGs represented as dataURIs
+  // for the time being
+  if (correctOrientation && jpeg && dataURI) {
+    applyOrientationCorrection()
+  }
+  // Resize image if too large
+  if (scale !== 1) {
+    ctx.scale(scale, scale)
+  }
+
+  ctx.drawImage(img, 0, 0)
+  ctx.restore()
+
+  return canvas
+
+  function applyOrientationCorrection() {
+    var orientation = getOrientation(img.src)
+    // Only apply transform if there is some non-normal orientation
+    if (orientation && orientation !== 1) {
+      var transform = orientationToTransform[orientation]
+      var rotation = transform.rotation
+      var mirror = transform.mirror
+      var flipAspect = rotation === 90 || rotation === 270
+      if (flipAspect) {
+        // Fancy schmancy swap algo
+        canvas.width = canvas.height + canvas.width
+        canvas.height = canvas.width - canvas.height
+        canvas.width -= canvas.height
+      }
+      if (rotation > 0) {
+        applyRotation(rotation)
+      }
+      if (mirror) {
+        // TODO This is broken. Not sure how to apply this transform
+        //      No biggie, we don't run into this case ATM
+        // applyMirror()
+      }
+    }
+  }
+
+  /**
+   * Some images are friggin rotated n shit! (iOS)
+   * wut the heck
+   * dang it
+   * man
+   * read the EXIF data
+   * return EXIF orientation value
+   */
+  function getOrientation(uri) {
+    var exif = new ExifReader
+    // Split off the base64 data
+    var base64String = uri.split(',')[1]
+    // Read off first 128KB, which is all we need to
+    // get the EXIF data
+    var arr = base64ToUint8Array(base64String, 0, Math.pow(2, 17))
+    try {
+      exif.load(arr.buffer)
+      return exif.getTagValue('Orientation')
+    } catch (err) {
+      return 1
+    }
+  }
+
+  /**
+   * Apply rotation such that rotated image will be
+   * centered in canvas
+   */
+  function applyRotation(deg) {
+    var radians = deg * (Math.PI / 180)
+    if (deg === 90) {
+      ctx.translate(canvas.width, 0)
+    } else if (deg === 180) {
+      ctx.translate(canvas.width, canvas.height)
+    } else if (deg == 270) {
+      ctx.translate(0, canvas.height)
+    }
+    ctx.rotate(radians)
+  }
+
+  function applyMirror() {
+    ctx.scale(-1, 1)
+  }
+}
+
+function base64ToUint8Array(string, start, finish) {
+  var start = start || 0
+  var finish = finish || string.length
+  // atob that shit
+  var binary = atob(string)
+  var buffer = new Uint8Array(binary.length)
+  for (var i = start; i < finish; i++) {
+    buffer[i] = binary.charCodeAt(i)
+  }
+  return buffer
+}