Add grail_contact and a method to retrieve the current contacts

This patch adds the possibility to extract the current set of
contacts from the grail state.

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

1 files changed, 38 insertions, 0 deletions

diff --git a/include/grail.h b/include/grail.h
index ae3a73f..40cf22f 100644
--- a/include/grail.h
+++ b/include/grail.h
@@ -49,6 +49,32 @@ struct grail_coord {
         float x, y;
 };
 
+/**
+ * struct grail_contact - MT event information in bounding box units
+ * @id: Contact tracking id
+ * @tool_type: Tool type (ABS_MT_TOOL_TYPE)
+ * @pos: Position of contact (bbox units)
+ * @touch_major: Major axis of contact shape (bbox units)
+ * @touch_minor: Minor axis of contact shape (bbox units)
+ * @width_major: Major axis of perimeter (bbox units)
+ * @width_minor: Minor axis of perimeter (bbox units)
+ * @angle: Angle of orientation (vertical: 0 horizontal: +-M_PI_2)
+ * @pressure: Pressure of contact (min: 0 max: 1)
+ *
+ * Depending on the native support of the underlying device, some or all of
+ * the listed properties may be computed.
+ */
+struct grail_contact {
+        int id;
+        int tool_type;
+        struct grail_coord pos;
+        float touch_major;
+        float touch_minor;
+        float width_major;
+        float width_minor;
+        float angle;
+        float pressure;
+};
 
 /**
  * struct grail_client_id - Gesture client information
@@ -228,4 +254,16 @@ void grail_filter_abs_events(struct grail *ge, int usage);
 void grail_get_units(const struct grail *ge,
                      struct grail_coord *min, struct grail_coord *max);
 
+/**
+ * grail_get_contacts - get current contact state
+ * @ge: the grail device in use
+ * @touch: array of contacts to be filled in
+ * @max_touch: maximum number of contacts supported by the array
+ *
+ * Extract the contact state as currently seen by grail.
+ *
+ */
+int grail_get_contacts(const struct grail *ge,
+                       struct grail_contact *touch, int max_touch);
+
 #endif