Add scale gesture

Moving two fingers apart or closer together will trigger the gesture.
This patch computes the scaling gesture and maps it to mouse buttons
12 and 13.

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

1 files changed, 33 insertions, 1 deletions

diff --git a/src/gestures.c b/src/gestures.c
index 977655c..03ec96d 100644
--- a/src/gestures.c
+++ b/src/gestures.c
@@ -70,22 +70,32 @@ static void extract_movement(struct Gestures *gs, struct MTouch* mt)
         int npoint = bitcount(mt->mem.pointing);
         int nmove = bitcount(mt->mem.moving);
         int i;
+        float xp[DIM_FINGER], yp[DIM_FINGER];
         float xm[DIM_FINGER], ym[DIM_FINGER];
-        float xmove = 0, ymove = 0;
+        float xpos = 0, ypos = 0;
+        float move, xmove = 0, ymove = 0;
+        float rad, rad2 = 0, scale = 0;
 
         if (!nmove || nmove != npoint)
                 return;
 
         foreach_bit(i, mt->mem.moving) {
+                xp[i] = mt->state.finger[i].hw.position_x - xpos;
+                yp[i] = mt->state.finger[i].hw.position_y - ypos;
                 xm[i] = mt->mem.dx[i];
                 ym[i] = mt->mem.dy[i];
                 mt->mem.dx[i] = 0;
                 mt->mem.dy[i] = 0;
+                xpos += xp[i];
+                ypos += yp[i];
                 xmove += xm[i];
                 ymove += ym[i];
         }
+        xpos /= nmove;
+        ypos /= nmove;
         xmove /= nmove;
         ymove /= nmove;
+        move = sqrt(xmove * xmove + ymove * ymove);
 
         if (nmove == 1) {
                 if (mt->mem.moving & mt->mem.thumb) {
@@ -96,6 +106,28 @@ static void extract_movement(struct Gestures *gs, struct MTouch* mt)
                 gs->dy = ymove;
                 if (gs->dx || gs->dy)
                         SETBIT(gs->type, GS_MOVE);
+                return;
+        }
+
+        foreach_bit(i, mt->mem.moving) {
+                xp[i] -= xpos;
+                yp[i] -= ypos;
+                rad2 += xp[i] * xp[i];
+                rad2 += yp[i] * yp[i];
+                scale += xp[i] * xm[i];
+                scale += yp[i] * ym[i];
+        }
+        rad2 /= nmove;
+        scale /= nmove;
+        rad = sqrt(rad2);
+        scale /= rad;
+
+        if (abs(scale) > move) {
+                gs->scale = scale;
+                if (gs->scale) {
+                        if (nmove == 2)
+                                SETBIT(gs->type, GS_SCALE);
+                }
         } else {
                 if (mt->mem.moving & mt->mem.thumb) {
                         mt_skip_movement(mt, FINGER_THUMB_MS);