Disable motion with resting thumbs

Disable motion gestures whenever one of the pointing fingers is a
thumb. Movement is skipped rather than held, minimizing unpredictable
movement after thumb release.

Signed-off-by: Henrik Rydberg <rydberg@euromail.se>

3 files changed, 20 insertions, 5 deletions

diff --git a/src/gestures.c b/src/gestures.c
index b6c3bf4..d061f93 100644
--- a/src/gestures.c
+++ b/src/gestures.c
@@ -25,6 +25,7 @@
 
 #include "gestures.h"
 
+static const int FINGER_THUMB_MS = 400;
 /**
  * extract_buttons
  *
@@ -83,11 +84,19 @@ static void extract_movement(struct Gestures *gs, struct MTouch* mt)
 	ymove /= nmove;
 
 	if (nmove == 1) {
+		if (mt->mem.moving & mt->mem.thumb) {
+			mt_skip_movement(mt, FINGER_THUMB_MS);
+			return;
+		}
 		gs->dx = xmove;
 		gs->dy = ymove;
 		if (gs->dx || gs->dy)
 			SETBIT(gs->type, GS_MOVE);
 	} else {
+		if (mt->mem.moving & mt->mem.thumb) {
+			mt_skip_movement(mt, FINGER_THUMB_MS);
+			return;
+		}
 		gs->dx = xmove;
 		gs->dy = ymove;
 		if (abs(gs->dx) > abs(gs->dy)) {
diff --git a/src/memory.c b/src/memory.c
index 7d8cda8..9084502 100644
--- a/src/memory.c
+++ b/src/memory.c
@@ -46,11 +46,11 @@ void init_memory(struct Memory *mem)
 /**
  * update_configuration
  *
- * Update the same, fingers, added memory variables.
+ * Update the same, fingers, added, and thumb memory variables.
  *
  * Precondition: none
  *
- * Postcondition: same, fingers, added are set
+ * Postcondition: same, fingers, added, thumb are set
  *
  */
 static void update_configuration(struct Memory *m,
@@ -66,6 +66,11 @@ static void update_configuration(struct Memory *m,
 			SETBIT(m->added, i);
 	m->same = m->fingers == fingers && m->added == 0;
 	m->fingers = fingers;
+	if (!m->same)
+		m->thumb = 0;
+	foreach_bit(i, fingers)
+		if (f[i].thumb)
+			SETBIT(m->thumb, i);
 }
 
 /**
@@ -73,7 +78,7 @@ static void update_configuration(struct Memory *m,
  *
  * Update the pointing and ybar memory variables.
  *
- * Precondition: fingers, added are set
+ * Precondition: fingers, added, thumb are set
  *
  * Postcondition: pointing, ybar are set
  *
@@ -121,7 +126,7 @@ static void update_pointers(struct Memory *m,
  * When moving is nonzero, gestures can be extracted from the dx and dy
  * variables. These variables should be cleared after use.
  *
- * Precondition: fingers, added, pointing are set
+ * Precondition: fingers, added, thumb, pointing are set
  *
  * Postcondition: pending, moving, mvhold, mvforget, dx, dy are set
  *
diff --git a/src/memory.h b/src/memory.h
index cc7bf55..8ffbdab 100644
--- a/src/memory.h
+++ b/src/memory.h
@@ -31,6 +31,7 @@
  * @same: true if the finger configuration is unchanged
  * @fingers: bitmask of fingers on the pad
  * @added: bitmask of new fingers on the pad
+ * @thumb: bitmask of thumbs on the pad
  * @pointing: bitmask of pointing fingers
  * @pending: bitmask of tentatively moving fingers
  * @moving: bitmask of moving fingers
@@ -43,7 +44,7 @@
  */
 struct Memory {
 	unsigned btdata, same;
-	unsigned fingers, added;
+	unsigned fingers, added, thumb;
 	unsigned pointing, pending, moving;
 	int ybar;
 	mstime_t mvhold, mvforget;