Mouse Drag Distance Threshold

- Added a mouse drag distance threshold value to allow tuning whether a small or accidental drag operation should still count towards a click event or not.

Assets/Impossible Odds/MouseEvents/Runtime/MouseButtonEvent.cs

@@ -160,7 +160,7 @@ public bool IsDrag
 		public bool IsSingleClick => buttonState == MouseButtonEventType.SingleClick;
 
 		/// <summary>
-		/// Is this event a double-click event?
+		/// Is this event a double click event?
 		/// </summary>
 		public bool IsDoubleClick => buttonState == MouseButtonEventType.DoubleClick;
 

Assets/Impossible Odds/MouseEvents/Runtime/MouseButtonEventType.cs

@@ -3,36 +3,40 @@
 	/// <summary>
 	/// States a mouse button can reside in.
 	/// </summary>
-	public enum MouseButtonEventType : int
+	public enum MouseButtonEventType
 	{
 		/// <summary>
 		/// No current event of interest has happened.
 		/// </summary>
-		None = 0,
+		None,
 		/// <summary>
 		/// When the mouse button performed a single click, but is waiting for a follow-up action.
 		/// </summary>
-		SingleClickPending = 1,
+		SingleClickPending,
 		/// <summary>
 		/// When the mouse button performed a single click.
 		/// </summary>
-		SingleClick = 2,
+		SingleClick,
 		/// <summary>
 		/// When the mouse button performed a double click.
 		/// </summary>
-		DoubleClick = 3,
+		DoubleClick,
+		/// <summary>
+		/// When the mouse button is being dragged, but the threshold for a drag action has not been met yet.
+		/// </summary>
+		DragPending,
 		/// <summary>
 		/// When the mouse button is being used to initiate a drag action.
 		/// </summary>
-		DragStart = 4,
+		DragStart,
 		/// <summary>
 		/// When the mouse button is being used for dragging.
 		/// </summary>
-		Dragging = 5,
+		Dragging,
 		/// <summary>
 		/// When the mouse button completed a drag action.
 		/// </summary>
-		DragComplete = 6,
+		DragComplete,
 
 		Idle = None
 	}

Assets/Impossible Odds/MouseEvents/Runtime/MouseButtonStateTracker.cs

@@ -8,7 +8,8 @@ public class MouseButtonStateTracker
 		public event Action<MouseButtonStateTracker> onStateUpdated;
 
 		private readonly MouseButton button;
-		private readonly Func<float> multiClickTimeThreshold = null;
+		private readonly Func<float> multiClickTimeThreshold;
+		private readonly Func<float> dragDistanceThreshold;
 
 		private MouseButtonEventType state = MouseButtonEventType.None;
 		private EventModifiers lastModifiers = EventModifiers.None;
@@ -42,10 +43,11 @@ public class MouseButtonStateTracker
 		/// </summary>
 		public Vector2 MousePosition => mousePosition;
 
-		public MouseButtonStateTracker(MouseButton button, Func<float> multiClickTimeThreshold)
+		public MouseButtonStateTracker(MouseButton button, Func<float> multiClickTimeThreshold, Func<float> dragDistanceThreshold)
 		{
 			this.button = button;
 			this.multiClickTimeThreshold = multiClickTimeThreshold;
+			this.dragDistanceThreshold = dragDistanceThreshold;
 			ClearState();
 		}
 
@@ -95,7 +97,7 @@ internal void ProcessEvent(Event mouseEvent)
 		internal void Suspend(Event mouseEvent)
 		{
 			// If the button doesn't match, don't bother.
-			if ((MouseButton)mouseEvent.button != (MouseButton)button)
+			if (mouseEvent.button != button)
 			{
 				return;
 			}
@@ -128,6 +130,7 @@ private void ProcessMouseUpEvent(Event mouseEvent)
 			switch (state)
 			{
 				case MouseButtonEventType.None:
+				case MouseButtonEventType.DragPending:
 					state = MouseButtonEventType.SingleClickPending;
 					lastModifiers = mouseEvent.modifiers;
 					mousePosition = mouseEvent.mousePosition;
@@ -163,19 +166,29 @@ private void ProcessMouseDragEvent(Event mouseEvent)
 				return;
 			}
 
-			// If a single click was still pending,
-			// then perform the click before getting to the drag operation.
+			// If a single click was still pending, then perform the click before getting to the drag operation.
 			if (state == MouseButtonEventType.SingleClickPending)
 			{
 				state = MouseButtonEventType.SingleClick;
 				lastClickAction = 0f;
 			}
-			else if ((state != MouseButtonEventType.DragStart) && (state != MouseButtonEventType.Dragging))
+			else if ((state != MouseButtonEventType.DragPending) &&
+			         (state != MouseButtonEventType.DragStart) &&
+			         (state != MouseButtonEventType.Dragging))
 			{
-				state = MouseButtonEventType.DragStart; // The first of such events initiates the drag start.
+				state = MouseButtonEventType.DragPending; // The first of such events declares that drag is pending, until the drag threshold is exceeded.
 				dragStartPosition = mouseEvent.mousePosition;
 				mousePosition = mouseEvent.mousePosition;
 			}
+			else if (state == MouseButtonEventType.DragPending)
+			{
+				if (Vector2.Distance(mouseEvent.mousePosition, dragStartPosition) > dragDistanceThreshold())
+				{
+					state = MouseButtonEventType.DragStart; // The first of such events initiates the drag start.
+				}
+
+				mousePosition = mouseEvent.mousePosition;
+			}
 			else
 			{
 				state = MouseButtonEventType.Dragging;

Assets/Impossible Odds/MouseEvents/Runtime/MouseEventMonitor.cs

@@ -43,6 +43,8 @@ public class MouseEventMonitor : MonoBehaviour
 		private List<MouseButton> monitoredButtons = new List<MouseButton>();
 		[SerializeField, Tooltip("How long (in seconds) should it wait for registering a multi-click event?"), Range(0.1f, 1f)]
 		private float multiClickTimeThreshold = 0.3f;
+		[SerializeField, Tooltip("How far can the mouse move (in pixels) before it is considered a drag movement?"), Range(0, 50)]
+		private float dragDistanceThreshold = 0f;
 		[SerializeField, Tooltip("When the cursor is over UI, should the mouse event monitor suspend operations?")]
 		private bool suspendWhenOverUI;
 		[SerializeField, Tooltip("Should the cursor coordinates be reported in pixel coordinates (as reported by Input.mousePosition), or in GUI coordinates (as reported by OnGUI events)?")]
@@ -74,6 +76,23 @@ public float MultiClickTimeThreshold
 			}
 		}
 
+		/// <summary>
+		/// How far can the mouse cursor be dragged (in pixels) before it registers the start of a drag operation?
+		/// </summary>
+		public float DragDistanceThreshold
+		{
+			get => dragDistanceThreshold;
+			set
+			{
+				if (value < 0f)
+				{
+					throw new ArgumentOutOfRangeException(nameof(value), "The drag distance threshold should be greater than or equal to 0.");
+				}
+
+				dragDistanceThreshold = value;
+			}
+		}
+
 		/// <summary>
 		/// When the cursor is over UI, should the mouse event monitor suspend operations?
 		/// </summary>
@@ -160,12 +179,17 @@ public void StartMonitoring(MouseButton mouseButton)
 
 			monitoredButtons.Add(mouseButton);
 
-			if (enabled)
+			if (!enabled)
 			{
-				MouseButtonStateTracker stateTracker = new MouseButtonStateTracker(mouseButton, () => multiClickTimeThreshold);
-				stateTrackers[mouseButton] = stateTracker;
-				stateTracker.onStateUpdated += OnMouseKeyStateUpdate;
+				return;
 			}
+
+			MouseButtonStateTracker stateTracker = new MouseButtonStateTracker(
+				mouseButton, 
+				() => multiClickTimeThreshold,
+				() => dragDistanceThreshold);
+			stateTrackers[mouseButton] = stateTracker;
+			stateTracker.onStateUpdated += OnMouseKeyStateUpdate;
 		}
 
 		/// <summary>
@@ -185,7 +209,10 @@ private void OnEnable()
 		{
 			foreach (MouseButton key in monitoredButtons)
 			{
-				MouseButtonStateTracker state = new MouseButtonStateTracker(key, () => multiClickTimeThreshold);
+				MouseButtonStateTracker state = new MouseButtonStateTracker(
+					key,
+					() => multiClickTimeThreshold,
+					() => dragDistanceThreshold);
 				stateTrackers[key] = state;
 				state.onStateUpdated += OnMouseKeyStateUpdate;
 			}

Assets/Impossible Odds/MouseEvents/Samples/MouseEventsDemo.cs

@@ -87,6 +87,11 @@ private void OnMouseEvent(MouseButtonEvent mouseEvent)
 					break;
 			}
 
+			if (display != null)
+			{
+				Debug.Log(display.text);
+			}
+
 			// The dragging event is not send out each frame if there's not mouse movement.
 			// So don't clear it when this state is detected.
 			if (!mouseEvent.IsDragging && (display != null))

Assets/Impossible Odds/MouseEvents/Samples/MouseEventsDemo.unity

@@ -1747,6 +1747,7 @@ MonoBehaviour:
   m_EditorClassIdentifier: 
   monitoredButtons: 000000000200000001000000
   multiClickTimeThreshold: 0.3
+  dragDistanceThreshold: 0
   suspendWhenOverUI: 1
   cursorPositionInPixelCoordinates: 1
 --- !u!1 &1158115896
@@ -1973,7 +1974,7 @@ Camera:
   m_Enabled: 1
   serializedVersion: 2
   m_ClearFlags: 2
-  m_BackGroundColor: {r: 0.19215687, g: 0.3019608, b: 0.4745098, a: 0}
+  m_BackGroundColor: {r: 0.35, g: 0.35, b: 0.35, a: 1}
   m_projectionMatrixMode: 1
   m_GateFitMode: 2
   m_FOVAxisMode: 0

Assets/Impossible Odds/MouseEvents/package.json

@@ -1,6 +1,6 @@
 {
 	"name": "com.impossibleodds.mousevents",
-	"version": "1.2.0",
+	"version": "1.3.0",
 	"displayName": "Impossible Odds - Mouse Events",
 	"unity": "2019.4",
 	"documentationUrl": "https://github.com/juniordiscart/ImpossibleOdds-MouseEvents/blob/master/README.md",

README.md

@@ -36,7 +36,7 @@ Additionally, you can also query the state of a specific mouse button on the mou
 
 ## Advanced
 
-The main point of entry is the `MouseEventMonitor` script. It requires to be placed on a game object in your scene and will monitor the mouse inputs you set it up to be: left, right and/or middle mouse buttons. Apart from which mouse buttons it should monitor, you can also adjust the time threshold for registering multi-clicks (double click). Unity does not allow to transparently distinguish between single click and double click without always invoking the single click event. This multi-click time threshold is the time limit it will delay a single click event while listening in for a secondary click or other event.
+The main point of entry is the `MouseEventMonitor` script. It requires to be placed on a game object in your scene and will monitor the mouse inputs you set it up to be: left, right and/or middle mouse buttons. Apart from which mouse buttons it should monitor, you can also adjust the time threshold for registering multi-clicks (double click). Unity does not allow to transparently distinguish between single click and double click without always invoking the single click event. This multi-click time threshold is the time limit it will delay a single click event while listening in for a secondary click or other event. Additionally, you can also set a drag distance threshold for when you want to let small or accidental drag operations to still count as a click event instead.
 
 You can listen for events of the registered mouse buttons as well as querying the current state of a particular button using the `CurrentEvent` method. When a new mouse button requires monitoring, you can add it using the `StartMonitoring` method. Conversely, you can also stop monitoring events for a specific mouse button by calling the `StopMonitoring` method.
 
@@ -126,6 +126,11 @@ This package is provided under the [MIT][License] license.
 
 * Fixed a runtime issue where clicks would be invalidated due to using Unity's built-in `Event` struct. This structure would put the event type to `Ignore` while it was actually a mouse button up/down event.
 
+### v1.3.0
+
+* Added a `DragDistanceThreshold` to the the `MouseEventMonitor` to allow small/accidental drag operations to still register as a click.
+* Updated the sample scene to also log the performed actions to the console.
+
 [License]: ./LICENSE.md
 [Changelog]: ./CHANGELOG.md
 [Logo]: ./Docs/Images/ImpossibleOddsLogo.png