Introduce tapping

Simplify some common parts of the recognizer code and add tapping
to the gesture suite.

Signed-off-by: Henrik Rydberg <rydberg@bitmath.org>

1 files changed, 96 insertions, 0 deletions

diff --git a/src/gestures-tapping.c b/src/gestures-tapping.c
new file mode 100644
index 0000000..453f77c
--- /dev/null
+++ b/src/gestures-tapping.c
@@ -0,0 +1,96 @@
+/*****************************************************************************
+ *
+ * grail - Gesture Recognition And Instantiation Library
+ *
+ * Copyright (C) 2010 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors:
+ *      Henrik Rydberg <rydberg@bitmath.org>
+ *
+ ****************************************************************************/
+
+#include "grail-recognizer.h"
+#include <math.h>
+
+static const int TAP_INIT = 0;
+static const int TAP_BEGIN = 1;
+static const int TAP_END = 2;
+static const int TAP_CANCEL = 3;
+
+static const int TAP_MIN_GAP_MS = 25;
+static const int TAP_MAX_GAP_MS = 400;
+
+int gru_tapping(struct grail *ge,
+              const struct touch_frame *frame)
+{
+        struct gesture_recognizer *gru = ge->gru;
+        struct tapping_model *state = &gru->tapping;
+        struct move_model *move = &gru->move;
+        grail_prop_t prop[DIM_GRAIL_PROP];
+        if (state->status == TAP_CANCEL) {
+                if (move->ntouch)
+                        return 0;
+                else
+                        state->status = TAP_INIT;
+        }
+        if (move->ntouch > state->ntouch) {
+                if (!state->ntouch) {
+                        state->start = frame->time;
+                        state->status = TAP_BEGIN;
+                }
+                state->ntouch = move->ntouch;
+        } else if (move->ntouch < state->ntouch) {
+                if (!move->ntouch)
+                        state->status = TAP_END;
+        }
+        if (state->status == TAP_INIT)
+                return 0;
+        if (state->ntouch < 1 || state->ntouch > 5) {
+                state->status = TAP_CANCEL;
+        }
+        if (frame->time - state->start > TAP_MAX_GAP_MS) {
+                state->status = TAP_CANCEL;
+        }
+        if (state->status == TAP_END &&
+            frame->time - state->start < TAP_MIN_GAP_MS) {
+                state->status = TAP_CANCEL;
+        }
+        if (state->status == TAP_CANCEL) {
+                if (state->active) {
+                        gru_end(ge, state->gid, move);
+                        state->active = 0;
+                }
+                state->ntouch = 0;
+                return 0;
+        }
+        if (frame->time - state->start < TAP_MIN_GAP_MS)
+                return 0;
+        if (!state->active) {
+                int type = GRAIL_TYPE_TAP1 + state->ntouch - 1;
+                state->gid = gin_gid_begin(ge, type, frame);
+                state->active = 1;
+        }
+        if (state->status != TAP_END)
+                return 0;
+        prop[0] = frame->time - state->start;
+        gin_gid_event(ge, state->gid,
+                      move->x.val, move->y.val, state->ntouch,
+                      prop, 1, GRAIL_STATUS_END);
+        state->status = TAP_INIT;
+        state->ntouch = 0;
+        state->active = 0;
+        return 1;
+}