From: Mikko Rasa <tdb@tdb.fi>
Date: Mon, 19 Sep 2016 20:31:45 +0000 (+0300)
Subject: Implement three-finger tap and drag gestures
X-Git-Url: http://git.tdb.fi/?p=libs%2Fgui.git;a=commitdiff_plain;h=301e09d687a1217130fbb2240b7a80f1a00aacdc

Implement three-finger tap and drag gestures
---

diff --git a/source/input/gesturedetector.cpp b/source/input/gesturedetector.cpp
index 26968c0..62ac3f0 100644
--- a/source/input/gesturedetector.cpp
+++ b/source/input/gesturedetector.cpp
@@ -31,10 +31,14 @@ string GestureDetector::get_button_name(unsigned btn) const
 		return "Tap";
 	else if(btn==GESTURE_TAP_2)
 		return "Two-finger tap";
+	else if(btn==GESTURE_TAP_3)
+		return "Three-finger tap";
 	else if(btn==GESTURE_DRAG)
 		return "Drag";
 	else if(btn==GESTURE_DRAG_2)
 		return "Two-finger drag";
+	else if(btn==GESTURE_DRAG_3)
+		return "Three-finger drag";
 	else if(btn==GESTURE_PINCH)
 		return "Pinch";
 	else if(btn==GESTURE_ROTATE)
@@ -76,6 +80,8 @@ void GestureDetector::touch_down(unsigned btn)
 			pending_tap = GESTURE_TAP;
 		else if(btn==1)
 			pending_tap = GESTURE_TAP_2;
+		else if(btn==2)
+			pending_tap = GESTURE_TAP_3;
 	}
 }
 
@@ -153,7 +159,21 @@ void GestureDetector::start_gesture()
 		return;
 
 	invalid_gesture = false;
-	if(points[1].down)
+	if(points[2].down)
+	{
+		bool same_direction = true;
+		for(unsigned i=0; (same_direction && i<2); ++i)
+			for(unsigned j=i+1; (same_direction && j<3); ++j)
+			{
+				TouchPoint &pi = points[i];
+				TouchPoint &pj = points[j];
+				same_direction = ((pi.x*pj.x+pi.y*pj.y)>2*abs(pi.x*pj.y-pi.y*pj.x));
+			}
+
+		if(same_direction)
+			current_gesture = GESTURE_DRAG_3;
+	}
+	else if(points[1].down)
 	{
 		TouchPoint &p2 = points[1];
 		float ddx = p.down_x-p2.down_x;
@@ -217,7 +237,7 @@ void GestureDetector::set_gesture_delta(unsigned n_points)
 
 void GestureDetector::update_progress()
 {
-	if(current_gesture>=GESTURE_DRAG && current_gesture<=GESTURE_DRAG_2)
+	if(current_gesture>=GESTURE_DRAG && current_gesture<=GESTURE_DRAG_3)
 		set_gesture_delta(gesture_points(current_gesture));
 	else if(current_gesture==GESTURE_PINCH || current_gesture==GESTURE_ROTATE)
 	{
diff --git a/source/input/gesturedetector.h b/source/input/gesturedetector.h
index f39fdce..51af312 100644
--- a/source/input/gesturedetector.h
+++ b/source/input/gesturedetector.h
@@ -13,8 +13,10 @@ enum Gesture
 	GESTURE_NONE,
 	GESTURE_TAP,
 	GESTURE_TAP_2,
+	GESTURE_TAP_3,
 	GESTURE_DRAG,
 	GESTURE_DRAG_2,
+	GESTURE_DRAG_3,
 	GESTURE_PINCH,
 	GESTURE_ROTATE
 };