Keep both raw and action delta in move model

Accumulated values can be obtained either by using the raw_delta,
which is the actual (filtered) change between frames, or by using
the action delta, which sums up to the same position, but in a non-
linear fashion. Use the raw delta for pointer gestures.

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

1 files changed, 21 insertions, 18 deletions

diff --git a/src/grail-gestures.c b/src/grail-gestures.c
index 3daeaec..eda1d38 100644
--- a/src/grail-gestures.c
+++ b/src/grail-gestures.c
@@ -83,23 +83,25 @@ static float compute_rotation(float x, float y, float r,
         return da;
 }
 
+/* Response-augmented EWMA filter, courtesy of Vojtech Pavlik */
 static float move_filter(const struct filter_model *m, float val)
 {
-        if (val > m->val - m->fuzz / 2 && val < m->val + m->fuzz / 2)
-                return m->val;
-        if (val > m->val - m->fuzz && val < m->val + m->fuzz)
-                return (m->val * 3 + val) / 4;
-        if (val > m->val - m->fuzz * 2 && val < m->val + m->fuzz * 2)
-                return (m->val + val) / 2;
+        if (val > m->value - m->fuzz / 2 && val < m->value + m->fuzz / 2)
+                return m->value;
+        if (val > m->value - m->fuzz && val < m->value + m->fuzz)
+                return (m->value * 3 + val) / 4;
+        if (val > m->value - m->fuzz * 2 && val < m->value + m->fuzz * 2)
+                return (m->value + val) / 2;
         return val;
 }
 
 static void move_reset(struct move_model *m, int i, float val)
 {
         struct filter_model *fm = &m->fm[i];
-        fm->delta = 0;
-        fm->val = val;
-        fm->orig = val;
+        fm->raw_delta = 0;
+        fm->action_delta = 0;
+        fm->value = val;
+        fm->original = val;
         m->tickle &= ~(1 << i);
         m->active &= ~(1 << i);
 }
@@ -107,19 +109,20 @@ static void move_reset(struct move_model *m, int i, float val)
 static void move_update(struct move_model *m, int i, float val)
 {
         struct filter_model *fm = &m->fm[i];
-        fm->delta = val - fm->val;
-        fm->val = val;
-        if (fabs(fm->delta) > 0.5)
+        fm->raw_delta = val - fm->value;
+        fm->action_delta = fm->raw_delta;
+        fm->value = val;
+        if (fabs(fm->raw_delta) > 0.5)
                 m->tickle |= (1 << i);
         else
                 m->tickle &= ~(1 << i);
         if (m->active & (1 << i))
                 return;
-        fm->delta = val - fm->orig;
-        if (fabs(fm->delta) > fm->bar)
+        fm->action_delta = val - fm->original;
+        if (fabs(fm->action_delta) > fm->bar)
                 m->active |= (1 << i);
         else
-                fm->delta = 0;
+                fm->action_delta = 0;
 }
 
 void gru_init_motion(struct grail *ge)
@@ -170,7 +173,7 @@ void gru_motion(struct grail *ge,
                 y = move_filter(&m->fm[FM_Y], y);
                 r = compute_radius(x, y, frame);
                 r = move_filter(&m->fm[FM_R], r);
-                a = m->fm[FM_A].val;
+                a = m->fm[FM_A].value;
                 a += compute_rotation(x, y, r, &gru->frame, frame);
                 a = move_filter(&m->fm[FM_A], a);
                 move_update(m, FM_X, x);
@@ -188,12 +191,12 @@ void gru_event(struct grail *ge, int gid,
                const struct move_model *m,
                const grail_prop_t *prop, int nprop)
 {
-        gin_gid_event(ge, gid, m->fm[FM_X].val, m->fm[FM_Y].val, m->ntouch,
+        gin_gid_event(ge, gid, m->fm[FM_X].value, m->fm[FM_Y].value, m->ntouch,
                       prop, nprop, 0);
 }
 
 void gru_end(struct grail *ge, int gid, const struct move_model *m)
 {
-        gin_gid_end(ge, gid, m->fm[FM_X].val, m->fm[FM_Y].val, m->ntouch);
+        gin_gid_end(ge, gid, m->fm[FM_X].value, m->fm[FM_Y].value, m->ntouch);
 }