P5-1511: Fix for losing image position after navigating back in browser

src/Viewport.js

@@ -84,14 +84,17 @@ function Viewport(canvas) {
         _rect.addTo(canvas).center().setCoords();
 
         if (cropData) {
+            var viewportBounds = _rect.getInsideBoundingRect();
+
             // Calculate the new position after screenresize and when the
             // image already has been cropped to a certain position.
-            var left = _rect.left + _rect.strokeWidth - (canvas.getImage().width * canvas.getImage().scaleX * cropData.x);
-            var top = _rect.top + _rect.strokeWidth - (canvas.getImage().height * canvas.getImage().scaleY * cropData.y);
+            var left = viewportBounds.left - (canvas.getImage().width * canvas.getImage().scaleX * cropData.x);
+            var top = viewportBounds.top - (canvas.getImage().height * canvas.getImage().scaleY * cropData.y);
 
             canvas.getImage().set({ left: left, top: top }).setCoords();
         } else {
             canvas.getImage().center().setCoords();
+            canvas.getImageData().setCropData();
         }
 
         canvas.getImage().drag.enable(calcMinMaxBoundsForRect(_rect.getInsideBoundingRect(), canvas.getImage()));
@@ -112,7 +115,7 @@ function Viewport(canvas) {
     this.canvas = canvas;
 
     this.getBounds = function () {
-        return _rect.getInsideBoundingRect();
+        return _rect ? _rect.getInsideBoundingRect() : null;
     };
 
     /**
@@ -132,20 +135,24 @@ function Viewport(canvas) {
      * @return {Viewport}
      */
     this.set = function (width, height, units) {
-        var oldData = _data;
+        if (!width || !height) {
+            return this;
+        }
 
         _data = util.calcCrop(canvas.getImage(), width, height, units);
 
-        var keepCropping = (oldData && !util.isAspectChanged(oldData.dim.width, oldData.dim.height, width, height));
-        if (keepCropping) {
-            canvas.getImageData().setCropData();
+        var cropData = canvas.getImageData().getCropData();
+        var isAspectTheSame = !!(cropData && !util.isAspectChanged(cropData.viewportWidth, cropData.viewportHeight, width, height));
+
+        if (!isAspectTheSame) {
+            canvas.getImageData().removeCropData();
         }
 
         apply();
         this.getGores().reset();
         this.getRulers().reset();
 
-        if (canvas.getImage().__cropped && !keepCropping) {
+        if (canvas.getImage().__cropped && !isAspectTheSame) {
             canvas.getApertures().setTransparent(true);
 
             // Trigger event to tell the image needs to be dragged.
@@ -154,6 +161,7 @@ function Viewport(canvas) {
 
         canvas.getButtonMenu().bringToFront();
 
+        return this;
     };
 
     /**