Update GTK smooth scrolling support and enable it

2 files changed, 21 insertions, 40 deletions

diff --git a/main/src/addins/VersionControl/MonoDevelop.VersionControl/MonoDevelop.VersionControl.Views/BlameWidget.cs b/main/src/addins/VersionControl/MonoDevelop.VersionControl/MonoDevelop.VersionControl.Views/BlameWidget.cs
index 48b4165c79..3147c6850b 100644
--- a/main/src/addins/VersionControl/MonoDevelop.VersionControl/MonoDevelop.VersionControl.Views/BlameWidget.cs
+++ b/main/src/addins/VersionControl/MonoDevelop.VersionControl/MonoDevelop.VersionControl.Views/BlameWidget.cs
@@ -259,31 +259,19 @@ namespace MonoDevelop.VersionControl.Views
 			}
 		}
 		
-		static double GetWheelDelta (Scrollbar scrollbar, ScrollDirection direction)
-		{
-			double delta = System.Math.Pow (scrollbar.Adjustment.PageSize, 2.0 / 3.0);
-			if (direction == ScrollDirection.Up || direction == ScrollDirection.Left)
-				delta = -delta;
-			if (scrollbar.Inverted)
-				delta = -delta;
-			return delta;
-		}
-		
 		protected override bool OnScrollEvent (EventScroll evnt)
 		{
-			var direction = evnt.Direction;
-			Scrollbar scrollWidget = (direction == ScrollDirection.Up || direction == ScrollDirection.Down)
-				? (Scrollbar)vScrollBar
-				: hScrollBar;
-			
-			if (!scrollWidget.Visible)
-				return base.OnScrollEvent (evnt);
-			
-			var adj = scrollWidget.Adjustment;
-			double newValue = adj.Value + GtkWorkarounds.GetScrollWheelDelta (evnt, adj.PageSize, scrollWidget.Inverted);
-			newValue = System.Math.Max (System.Math.Min (adj.Upper - adj.PageSize, newValue), adj.Lower);
-			adj.Value = newValue;
-			return true;
+			var alloc = Allocation;
+			double dx, dy;
+			evnt.GetPageScrollPixelDeltas (alloc.Width, alloc.Height, out dx, out dy);
+			
+			if (dx != 0.0 && hScrollBar.Visible)
+				hAdjustment.AddValueClamped (dx);
+			
+			if (dy != 0.0 && vScrollBar.Visible)
+				vAdjustment.AddValueClamped (dy);
+			
+			return (dx != 0.0 || dy != 0.0) || base.OnScrollEvent (evnt);
 		}
 		
 		protected override void OnSizeRequested (ref Gtk.Requisition requisition)
diff --git a/main/src/addins/VersionControl/MonoDevelop.VersionControl/MonoDevelop.VersionControl.Views/EditorCompareWidgetBase.cs b/main/src/addins/VersionControl/MonoDevelop.VersionControl/MonoDevelop.VersionControl.Views/EditorCompareWidgetBase.cs
index 79dd6c2ad5..6a12147b2d 100644
--- a/main/src/addins/VersionControl/MonoDevelop.VersionControl/MonoDevelop.VersionControl.Views/EditorCompareWidgetBase.cs
+++ b/main/src/addins/VersionControl/MonoDevelop.VersionControl/MonoDevelop.VersionControl.Views/EditorCompareWidgetBase.cs
@@ -514,24 +514,17 @@ namespace MonoDevelop.VersionControl.Views
 
 		protected override bool OnScrollEvent (EventScroll evnt)
 		{
-			double pageSizePx;
-			Adjustment adj;
-			if (evnt.Direction == ScrollDirection.Up || evnt.Direction == ScrollDirection.Down)  {
-				pageSizePx = Allocation.Height;
-				adj = vAdjustment;
-			} else  {
-				pageSizePx = Allocation.Width;
-				adj = hAdjustment;
-			}
-
-			if (adj.PageSize >= (adj.Upper - adj.Lower))
-				return base.OnScrollEvent (evnt);
+			var alloc = Allocation;
+			double dx, dy;
+			evnt.GetPageScrollPixelDeltas (alloc.Width, alloc.Height, out dx, out dy);
+			
+			if (dx != 0.0 && hAdjustment.PageSize < (hAdjustment.Upper - hAdjustment.Lower))
+				hAdjustment.AddValueClamped (dx / (alloc.Width / hAdjustment.PageSize));
+			
+			if (dy != 0.0 && vAdjustment.PageSize < (vAdjustment.Upper - vAdjustment.Lower))
+				vAdjustment.AddValueClamped (dy / (alloc.Height / vAdjustment.PageSize));
 			
-			double deltaPx = GtkWorkarounds.GetScrollWheelDelta (evnt, pageSizePx, false);
-			double newValue = adj.Value + adj.PageSize * (deltaPx / pageSizePx);
-			newValue = System.Math.Max (System.Math.Min (1.0 - adj.PageSize, newValue), 0.0);
-			adj.Value = newValue;
-			return true;
+			return (dx != 0.0 || dy != 0.0) || base.OnScrollEvent (evnt);
 		}
 
 		protected override void OnSizeRequested (ref Gtk.Requisition requisition)