animation_lib: add get_start_xy function

Drone/animation_lib.py

@@ -37,9 +37,43 @@ def get_id(filepath="animation.csv"):
                 anim_id = row_0[0]
                 print("Got animation_id: {}".format(anim_id))
             else:
+                anim_id = "Empty id"
                 print("No animation id in file")
     return anim_id
 
+def get_start_xy(filepath="animation.csv"):
+    try:
+        animation_file = open(filepath)
+    except IOError:
+        logging.error("File {} can't be opened".format(filepath))
+        anim_id = "No animation"
+        return float('nan'), float('nan')
+    else:
+        with animation_file:
+            csv_reader = csv.reader(
+                animation_file, delimiter=',', quotechar='|'
+            )
+            try:
+                row_0 = csv_reader.next()
+            except:
+                return float('nan'), float('nan')
+            if len(row_0) == 1:
+                anim_id = row_0[0]
+                print("Got animation_id: {}".format(anim_id))
+                try:
+                    frame_number, x, y, z, yaw, red, green, blue = csv_reader.next()
+                except:
+                    return float('nan'), float('nan')
+            else:
+                anim_id = "Empty id"
+                print("No animation id in file")
+                try:
+                    frame_number, x, y, z, yaw, red, green, blue = row_0
+                except:
+                    return float('nan'), float('nan')
+    return float(x), float(y)
+
+
 def load_animation(filepath="animation.csv", x0=0, y0=0, z0=0, x_ratio=1, y_ratio=1, z_ratio=1):
     imported_frames = []
     global anim_id