Add box function to create the corners of 2d and3d box

poisson/continuous/shapes.py

@@ -820,6 +820,62 @@ class InHull(Shape):
 
 #####################
 
+def box(length, corner=None, center=None):
+    '''
+        Returns points of a 2d of 3d box
+
+        Parameters:
+        -----------
+        length = (Lx, Ly, Lz): numbers
+            the lengths of the sides
+            if Ly (Lz) is None, Ly (Lz) will be equal to Lx
+            (usefull to quickly draw cubes)
+
+        corner = (x0, y0, z0) : numbers
+            the lower left corner of the (if z0 si None will be 2d)
+
+        center = (x0, y0, z0) : numbers
+            overwrites the corner argument
+            if center=None the corner will be used
+            the lower left corner of the (if z0 si None will be 2d)
+
+        Returns:
+        --------
+        points: np.ndarray
+            the points defining the box
+    '''
+    if isinstance(length, (int, float)):
+        length = (length, length)
+
+    length = np.asarray(length)
+    ndim = len(length)
+
+    if corner is None:
+        corner = np.zeros(ndim)
+    elif isinstance(corner, int):
+        corner = corner * np.ones(ndim)
+
+    corner = np.asarray(corner)
+
+    if center is not None:
+        center = np.asarray(center)
+
+    assert len(length) == len(corner), (
+            'The corner does not have the same'
+            + ' size as length / or a corner has'
+            + ' been given and length is an int')
+
+    points = np.array([[0, 0], [0, length[1]], length[:2], [length[0], 0]])
+    if ndim == 3:
+        points = np.vstack((np.c_[points, np.zeros(4)], np.c_[points, np.ones(4) * length[2]]))
+
+    if center is None:
+        points = points + corner
+    else:
+        points = points - length / 2 + center
+
+    return points
+
 def translate(x, vect):
     '''
     Translate a point or a list of points by a vector vect