upd xlib.image.sd

xlib/image/sd/calc.py

@@ -0,0 +1,25 @@
+import numpy as np
+import numpy.linalg as npla
+
+def dist_to_edges(pts, pt, is_closed=False):
+    """
+    returns array of dist from pt to edge and projection pt to edges
+    """
+    if is_closed:
+        a = pts
+        b = np.concatenate( (pts[1:,:], pts[0:1,:]), axis=0 )
+    else:
+        a = pts[:-1,:]
+        b = pts[1:,:]
+
+    pa = pt-a
+    ba = b-a
+    
+    div = np.einsum('ij,ij->i', ba, ba)
+    div[div==0]=1
+    h = np.clip( np.einsum('ij,ij->i', pa, ba) / div, 0, 1 )
+    
+    x = npla.norm ( pa - ba*h[...,None], axis=1 )
+    
+    return x, a+ba*h[...,None]
+