Make it easier to pan images in the lightbox

Previously, if you were dragging an image and your cursor outpaced the
edge of the image as it was moving, panning would abruptly stop. This
moves a few of the lightbox event listeners one level up to the image
wrapper to ensure that all drag movements are detected, even if they
don't end over the image's current position.

Signed-off-by: Robin Townsend <robin@robin.town>

res/css/views/elements/_ImageView.scss

@@ -22,6 +22,7 @@ limitations under the License.
 }
 
 .mx_ImageView_image_wrapper {
+    pointer-events: initial;
     display: flex;
     justify-content: center;
     align-items: center;
@@ -30,7 +31,6 @@ limitations under the License.
 }
 
 .mx_ImageView_image {
-    pointer-events: all;
     flex-shrink: 0;
 }
 
@@ -43,7 +43,7 @@ limitations under the License.
 }
 
 .mx_ImageView_info_wrapper {
-    pointer-events: all;
+    pointer-events: initial;
     padding-left: 32px;
     display: flex;
     flex-direction: row;
@@ -63,7 +63,7 @@ limitations under the License.
 
 .mx_ImageView_toolbar {
     padding-right: 16px;
-    pointer-events: all;
+    pointer-events: initial;
     display: flex;
     align-items: center;
 }

src/components/views/elements/ImageView.tsx

@@ -471,7 +471,12 @@ export default class ImageView extends React.Component<IProps, IState> {
                 </div>
                 <div
                     className="mx_ImageView_image_wrapper"
-                    ref={this.imageWrapper}>
+                    ref={this.imageWrapper}
+                    onMouseDown={this.props.onFinished}
+                    onMouseMove={this.onMoving}
+                    onMouseUp={this.onEndMoving}
+                    onMouseLeave={this.onEndMoving}
+                >
                     <img
                         src={this.props.src}
                         title={this.props.name}
@@ -480,9 +485,6 @@ export default class ImageView extends React.Component<IProps, IState> {
                         className="mx_ImageView_image"
                         draggable={true}
                         onMouseDown={this.onStartMoving}
-                        onMouseMove={this.onMoving}
-                        onMouseUp={this.onEndMoving}
-                        onMouseLeave={this.onEndMoving}
                     />
                 </div>
             </FocusLock>