From: Mikko Rasa <tdb@tdb.fi>
Date: Sat, 21 Nov 2015 08:34:01 +0000 (+0200)
Subject: Combine swipe gestures into a single drag gesture
X-Git-Url: http://git.tdb.fi/?a=commitdiff_plain;h=a5be5c703808817dda8feafb03b0aec04b20afbb;p=libs%2Fgui.git

Combine swipe gestures into a single drag gesture

This makes them more versatile for different kinds of control schemes.
Directional swipes can still be approximated through the Control
interface.  Capturing swipe gestures is no longer easily possible, but
the capture interface is due for a rewrite to support activator controls
anyway.
---

diff --git a/source/input/gesturedetector.cpp b/source/input/gesturedetector.cpp
index d626c5d..cc02797 100644
--- a/source/input/gesturedetector.cpp
+++ b/source/input/gesturedetector.cpp
@@ -26,14 +26,8 @@ GestureDetector::GestureDetector(Touchscreen &ts):
 
 string GestureDetector::get_button_name(unsigned btn) const
 {
-	if(btn==GESTURE_SWIPE_DOWN)
-		return "Swipe down";
-	else if(btn==GESTURE_SWIPE_UP)
-		return "Swipe up";
-	else if(btn==GESTURE_SWIPE_LEFT)
-		return "Swipe left";
-	else if(btn==GESTURE_SWIPE_RIGHT)
-		return "Swipe right";
+	if(btn==GESTURE_DRAG)
+		return "Drag";
 	else if(btn==GESTURE_PINCH)
 		return "Pinch";
 	else
@@ -153,20 +147,10 @@ void GestureDetector::start_gesture()
 	}
 	else
 	{
-		// Allow a maximum deviation of about 26° to recognize a swipe gesture.
-		if(abs(p.x)>2*abs(p.y))
-			current_gesture = (p.x>0 ? GESTURE_SWIPE_RIGHT : GESTURE_SWIPE_LEFT);
-		else if(abs(p.y)>2*abs(p.x))
-			current_gesture = (p.y>0 ? GESTURE_SWIPE_UP : GESTURE_SWIPE_DOWN);
-		else
-			invalid_gesture = true;
-
-		if(current_gesture!=GESTURE_NONE)
-		{
-			active_points = 1;
-			set_axis_value(0, p.down_x, true);
-			set_axis_value(1, p.down_y, true);
-		}
+		current_gesture = GESTURE_DRAG;
+		active_points = 1;
+		set_axis_value(0, p.down_x, true);
+		set_axis_value(1, p.down_y, true);
 	}
 
 	update_progress();
@@ -179,14 +163,11 @@ void GestureDetector::update_progress()
 {
 	TouchPoint &p = points[0];
 
-	if(current_gesture==GESTURE_SWIPE_DOWN)
-		set_axis_value(2, -p.y, true);
-	else if(current_gesture==GESTURE_SWIPE_UP)
-		set_axis_value(2, p.y, true);
-	else if(current_gesture==GESTURE_SWIPE_LEFT)
-		set_axis_value(2, -p.x, true);
-	else if(current_gesture==GESTURE_SWIPE_RIGHT)
+	if(current_gesture==GESTURE_DRAG)
+	{
 		set_axis_value(2, p.x, true);
+		set_axis_value(3, p.y, true);
+	}
 	else if(current_gesture==GESTURE_PINCH)
 	{
 		TouchPoint &p2 = points[1];
@@ -197,6 +178,7 @@ void GestureDetector::update_progress()
 		float dx = ddx+p.x-p2.x;
 		float dy = ddy+p.y-p2.y;
 		set_axis_value(2, sqrt(dx*dx+dy*dy)/sqrt(ddx*ddx+ddy*ddy)-1, true);
+		set_axis_value(3, 0, true);
 	}
 }
 
diff --git a/source/input/gesturedetector.h b/source/input/gesturedetector.h
index b2d0d4f..fdd083d 100644
--- a/source/input/gesturedetector.h
+++ b/source/input/gesturedetector.h
@@ -11,17 +11,14 @@ class Touchscreen;
 enum Gesture
 {
 	GESTURE_NONE,
-	GESTURE_SWIPE_DOWN,
-	GESTURE_SWIPE_UP,
-	GESTURE_SWIPE_LEFT,
-	GESTURE_SWIPE_RIGHT,
+	GESTURE_DRAG,
 	GESTURE_PINCH
 };
 
 /**
 Interprets events from a Touchscreen as high-level gestures.  One button is
 provided for each type of gesture.  Axes 0 and 1 indicate the starting position
-of the gesture; axis 2 tracks its progress.  The progress axis may exhibit
+of the gesture; axes 2 and 3 track its progress.  The progress axis may exhibit
 absolute values greater than one.
 */
 class GestureDetector: public Device