release 0.8.3: fix safari zoom issue

package.json

@@ -1,6 +1,6 @@
 {
   "name": "piskel",
-  "version": "0.8.2",
+  "version": "0.8.3",
   "description": "Pixel art editor",
   "author": "Julian Descottes <julian.descottes@gmail.com>",
   "contributors": [

src/css/layout.css

@@ -3,7 +3,7 @@
  */
 
 .main-wrapper {
-  position: absolute;
+  position: fixed;
   top: 5px;
   right: 0;
   bottom: 5px;
@@ -26,6 +26,7 @@
   vertical-align: top;
   height: 100%;
   margin-right: 7px;
+  flex-shrink: 0;
 }
 
 .main-column {
@@ -37,6 +38,7 @@
   box-sizing: border-box;
   vertical-align: top;
   height: 100%;
+  flex-shrink: 0;
 
   display: flex;
   flex-direction: column;

src/js/controller/DrawingController.js

@@ -238,13 +238,15 @@
     var evt = jQueryEvent.originalEvent;
     // Ratio between wheelDeltaY (mousewheel event) and deltaY (wheel event) is -40
     var delta;
-    if (pskl.utils.UserAgent.isChrome) {
+    if (pskl.utils.UserAgent.isIE11) {
-      delta = evt.wheelDeltaY;
-    } else if (pskl.utils.UserAgent.isIE11) {
       delta = evt.wheelDelta;
     } else if (pskl.utils.UserAgent.isFirefox) {
       delta = -40 * evt.deltaY;
+    } else {
+      delta = evt.wheelDeltaY;
     }
+
+    delta = delta || 0;
     var modifier = (delta / 120);
 
     if (pskl.utils.UserAgent.isMac ? evt.metaKey : evt.ctrlKey) {
@@ -278,7 +280,7 @@
     var step = zoomMultiplier * this.getZoomStep_();
     this.setZoom_(this.renderer.getZoom() + step);
 
-    if (centerCoords) {
+    if (typeof centerCoords === 'object') {
       var xRatio = (centerCoords.x - off.x) / oldWidth;
       var yRatio = (centerCoords.y - off.y) / oldHeight;
       var newWidth = this.getContainerWidth_() / this.renderer.getZoom();