Implement horizontal scrolling

Limelight/Input/StreamView.m

@@ -474,11 +474,23 @@ static const double X1_MOUSE_SPEED_DIVISOR = 2.5;
     }
     
     CGPoint currentScrollTranslation = [gesture translationInView:self];
+    
+    {
         short translationDeltaY = ((currentScrollTranslation.y - lastScrollTranslation.y) / self.bounds.size.height) * 120; // WHEEL_DELTA
         if (translationDeltaY != 0) {
             LiSendHighResScrollEvent(translationDeltaY * 20);
             lastScrollTranslation = currentScrollTranslation;
         }
+    }
+
+    {
+        short translationDeltaX = ((currentScrollTranslation.x - lastScrollTranslation.x) / self.bounds.size.width) * 120; // WHEEL_DELTA
+        if (translationDeltaX != 0) {
+            // Direction is reversed from vertical scrolling
+            LiSendHighResHScrollEvent(-translationDeltaX * 20);
+            lastScrollTranslation = currentScrollTranslation;
+        }
+    }
 }
 
 - (void)mouseWheelMovedDiscrete:(UIPanGestureRecognizer *)gesture {
@@ -497,10 +509,21 @@ static const double X1_MOUSE_SPEED_DIVISOR = 2.5;
     // Using velocityInView is 0 for discrete scroll events
     // when scrolling very slowly, but translationInView does work.
     CGPoint currentScrollTranslation = [gesture translationInView:self];
+    
+    {
         short translationDeltaY = currentScrollTranslation.y - lastScrollTranslation.y;
         if (translationDeltaY != 0) {
             LiSendScrollEvent(translationDeltaY > 0 ? 1 : -1);
         }
+    }
+
+    {
+        short translationDeltaX = currentScrollTranslation.x - lastScrollTranslation.x;
+        if (translationDeltaX != 0) {
+            // Direction is reversed from vertical scrolling
+            LiSendHScrollEvent(translationDeltaX < 0 ? 1 : -1);
+        }
+    }
     
     lastScrollTranslation = currentScrollTranslation;
 }