3 files changed, 27 insertions, 0 deletions

diff --git a/src/capabilities.c b/src/capabilities.c
index 9879ddf..cd96e8e 100644
--- a/src/capabilities.c
+++ b/src/capabilities.c
@@ -128,6 +128,16 @@ int get_cap_wsize(const struct Capabilities *cap)
         return cap->abs_touch_major.maximum - cap->abs_touch_major.minimum;
 }
 
+int get_cap_xmid(const struct Capabilities *cap)
+{
+        return (cap->abs_position_x.maximum + cap->abs_position_x.minimum) >> 1;
+}
+
+int get_cap_ymid(const struct Capabilities *cap)
+{
+        return (cap->abs_position_y.maximum + cap->abs_position_y.minimum) >> 1;
+}
+
 void output_capabilities(const struct Capabilities *cap)
 {
         char line[1024];
diff --git a/src/capabilities.h b/src/capabilities.h
index 402d297..23086bd 100644
--- a/src/capabilities.h
+++ b/src/capabilities.h
@@ -49,6 +49,9 @@ int get_cap_xsize(const struct Capabilities *cap);
 int get_cap_ysize(const struct Capabilities *cap);
 int get_cap_wsize(const struct Capabilities *cap);
 
+int get_cap_xmid(const struct Capabilities *cap);
+int get_cap_ymid(const struct Capabilities *cap);
+
 void output_capabilities(const struct Capabilities *cap);
 
 #endif
diff --git a/src/mtstate.h b/src/mtstate.h
index fa297cd..a8feaa4 100644
--- a/src/mtstate.h
+++ b/src/mtstate.h
@@ -44,5 +44,19 @@ void output_mtstate(const struct MTState *s);
 
 const struct MTFinger *find_finger(const struct MTState *s, int id);
 
+
+static inline int center_dist2(const struct MTFinger *a,
+                               const struct Capabilities *caps)
+{
+        return dist2(a->hw.position_x - get_cap_xmid(caps),
+                     a->hw.position_y - get_cap_ymid(caps));
+}
+
+static inline int center_maxdist2(const struct Capabilities *caps)
+{
+        return dist2(caps->abs_position_x.maximum - get_cap_xmid(caps),
+                     caps->abs_position_y.maximum - get_cap_ymid(caps));
+}
+
 #endif