Bézier curves, PCell

* bezier bend, sbend, taper
* Update __init__.py
* bezier update
* fix menu Layout > Show selected components

klayout_dot_config/grain.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <salt-grain>
  <name>siepic_tools</name>
- <version>0.5.11</version>
+ <version>0.5.12</version>
  <api-version>0.27</api-version>
  <title>SiEPIC Tools</title>
  <doc>Tools for designing Silicon Photonic Integrated Circuits, including waveguides, component simulations, functional verification, DRC verification, Functional verification, netlist extraction, circuit simulations. Layout can be implemented graphically or by programming in Python using the SiEPIC functions and KLayout Python API. Framework and examples for creating layouts using scripts. Includes a generic PDK (GSiP). Other PDKs are installed separately, and depend on SiEPIC-Tools.</doc>

klayout_dot_config/pymacros/Keybindings/Layout/Show component information.lym

@@ -77,7 +77,7 @@ def show_component_info():
     text += ('<br>')
     text += "  selected cell name: %s" % obj.inst().cell.name
     text += ('<br>')
-    c = cell.find_components(cell_selected=[obj.inst().cell],verbose=True)
+    c = cell.find_components(cell_selected=tuple([obj.inst().cell]),verbose=True, raiseException = False)
     if c and c[0].cell:
       text += c[0].display().replace(';','<br>   ')
       if c[0].cell.is_pcell_variant():

klayout_dot_config/python/SiEPIC/__init__.py

@@ -2,7 +2,7 @@
 SiEPIC-Tools package for KLayout
 '''
 
-__version__ = '0.5.11'
+__version__ = '0.5.12'
 
 print("KLayout SiEPIC-Tools version %s" %__version__)
 

klayout_dot_config/python/SiEPIC/extend.py

@@ -702,6 +702,11 @@ def find_pins(self, verbose=False, polygon_devrec=None, GUI=False):
     Electrical Pins have:
      1) box on layer PinRec
      2) text on layer PinRec, inside the box
+     
+    Returns:
+        pins: SiEPIC.core.Pin
+        pin_errors: text
+
     '''
 
     if verbose:
@@ -946,7 +951,7 @@ def find_pins_component(self, component):
 '''
 from functools import lru_cache
 @lru_cache(maxsize=None)
-def find_components(self, cell_selected=None, inst=None, verbose=False):
+def find_components(self, cell_selected=None, inst=None, verbose=False, raiseException = True):
     '''
     Function to traverse the cell's hierarchy and find all the components
     returns list of components (class Component)
@@ -963,13 +968,15 @@ def find_components(self, cell_selected=None, inst=None, verbose=False):
     
     inst: return only the component that matches the instance inst
     
+    raiseException: False turns of exception handling, and returns None instead
+    
     limitation:
      - flat components only. doesn't find the component if it is buried in a hierarchy
      - no function for instance.find_components.  Instead we find based on cell, then try to match it to the requested instance.
 
     '''
 
-    if cell_selected != None and type(cell_selected) != type([]):
+    if cell_selected != None and type(cell_selected) != type([]) and type(cell_selected) != tuple:
           cell_selected=[cell_selected]
 
     if verbose:
@@ -1143,8 +1150,10 @@ def find_components(self, cell_selected=None, inst=None, verbose=False):
         return component_matched
 
     if components == []:
-        raise Exception ('SiEPIC.extend.find_components: No component found for cell_selected=%s' % (cell_selected[0].name if cell_selected else None))
-
+        if raiseException:
+            raise Exception ('SiEPIC.extend.find_components: No component found for cell_selected=%s' % (cell_selected[0].name if cell_selected else None))
+        else:
+            return None
     return components
 # end def find_components
 

klayout_dot_config/python/SiEPIC/scripts.py

@@ -349,7 +349,7 @@ def connect_pins_with_waveguide(instanceA, pinA, instanceB, pinB, waveguide = No
             else:
                 waveguide = waveguides[0]
                 print('error: waveguide type not found in PDK waveguides')
-                raise Exception('error: waveguide type (%s) not found in PDK waveguides' % waveguide_type)
+                raise Exception('error: waveguide type (%s) not found in PDK. Waveguides available: %s' % (waveguide_type, [w['name'] for w in waveguides]))
         # check if the waveguide type is compound waveguide
         if 'compound_waveguide' in waveguide:
             waveguide = [w for w in waveguides if w['name']==waveguide['compound_waveguide']['singlemode']]
@@ -1780,7 +1780,8 @@ def connect_cell(instanceA, pinA, cellB, pinB, mirror = False, verbose=False, tr
 
   if type(componentA) == type([]):
     componentA = componentA[0]
-  componentB = componentB[0]
+  if type(componentB) == type([]):
+    componentB = componentB[0]
   if verbose:
     componentA.display()
     componentB.display()
@@ -1794,9 +1795,11 @@ def connect_cell(instanceA, pinA, cellB, pinB, mirror = False, verbose=False, tr
       import re
       try:
           if cpinA==[]:
-              cpinA = [p for p in componentA.pins if re.findall(r'\d+', pinA)[0] in p.pin_name]
+              if re.findall(r'\d+', pinA):
+                  cpinA = [p for p in componentA.pins if re.findall(r'\d+', pinA)[0] in p.pin_name]
           if cpinB==[]:
-              cpinB = [p for p in componentB.pins if re.findall(r'\d+', pinB)[0] in p.pin_name]
+              if re.findall(r'\d+', pinB):
+                  cpinB = [p for p in componentB.pins if re.findall(r'\d+', pinB)[0] in p.pin_name]
       except:
           print('error in siepic.scripts.connect_cell')      
 

klayout_dot_config/python/SiEPIC/utils/__init__.py

@@ -1119,9 +1119,25 @@ def arc_to_waveguide(pts, width):
 
 
 def translate_from_normal(pts, trans):
-    '''Translate each point by its normal a distance 'trans' '''
+    '''Translate each point by its normal a distance 'trans' 
+    
+    Args:
+        pts: list of pya.Point (nanometers)
+            or       pya.DPoint (microns)
+        trans: <float> (matching pts, either nm or microns)
+
+    Returns:
+        list of pya.Point or pya.DPoint, matching Arg pts type.
+    '''
     #  pts = [pya.DPoint(pt) for pt in pts]
-    pts = [pt.to_dtype(1) for pt in pts]
+    if type(pts[0]) == pya.Point:
+        # convert to float pya.DPoint
+        pts = [pt.to_dtype(1) for pt in pts]
+        in_type = 'Point'
+    elif type(pts[0]) == pya.DPoint:
+        in_type = 'DPoint'
+    else:
+        raise Exception('SiEPIC.utils.translate_from_normal expects pts=[pya.Point,...] or [pya.DPoint,...]')
     if len(pts) < 2:
         return pts    
     from math import cos, sin, pi
@@ -1146,8 +1162,10 @@ def translate_from_normal(pts, trans):
     else:
         tpts[-1].x = pts[-1].x
 #  return [pya.Point(pt) for pt in tpts]
-    return [pt.to_itype(1) for pt in tpts]
-
+    if in_type == 'Point':
+        return [pt.to_itype(1) for pt in tpts]
+    else:
+        return tpts
 
 
 def pt_intersects_segment(a, b, c):

klayout_dot_config/python/SiEPIC/utils/geometry.py

@@ -61,8 +61,12 @@ def __str__(self):
         return str(Point({self.x}, {self.y}))
 
     def norm(self):
+        '''Euclidean length'''
         return sqrt(self.x**2 + self.y**2)
 
+    def long_edge_length(self):
+        '''return the longest segment of a Manhattan distance'''
+        return max(self.x, self.y)
 
 class Line(Point):
     """ Defines a line """
@@ -150,6 +154,13 @@ def max_curvature(P0, P1, P2, P3):
     max_curv = np.max(np.abs(curv.flatten()))
     return max_curv
 
+def min_curvature(P0, P1, P2, P3):
+    """Gets the minimum curvature of Bezier curve"""
+    t = np.linspace(0, 1, 300)
+    curv = curvature_bezier(P0, P1, P2, P3)(t)
+    min_curv = np.min(np.abs(curv.flatten()))
+    return min_curv
+
 
 def _curvature_penalty(P0, P1, P2, P3):
     """Penalty on the curvyness of Bezier curve"""
@@ -377,6 +388,71 @@ def bezier_optimal(P0, P3, *args, **kwargs):
 except ImportError:
     pass
 
+def bezier_cubic(P0, P3, angle0, angle3, a, b, accuracy = 0.001, verbose=False, plot=False, *args, **kwargs):
+    '''
+    Calculate a cubic Bezier curve between Points P0 and P3, 
+    where the control point positions P1 and P2 are determined by
+    the angles at P0 (angle0) and P3 (angle3), 
+    at a distance of a * scale from P0, and b * scale from P3,
+    where scale is the longest segment in a Manhattan route between P0 and P3.
+
+    Args:
+        P0, P3: pya.DPoint (in microns)
+        angle0, angle3: radians
+        a, b: <float>. 0 corresponds to P1=P0, and 1 corresponds to P1 at the corner of a 90º bend
+        accuracy: 0.001 = 1 nm
+
+    Returns:
+        list of pya.DPoint
+
+    Example:
+        Bezier curve can approximate a 1/4 circle (arc) for a=b=0.553
+            # https://stackoverflow.com/questions/1734745/how-to-create-circle-with-b%C3%A9zier-curves
+    '''
+
+    P0 = Point(P0.x, P0.y)
+    P3 = Point(P3.x, P3.y)
+    scale = (P3 - P0).long_edge_length()  # longest distance between the two end points
+    P1 = a * scale * Point(np.cos(angle0), np.sin(angle0)) + P0
+    P2 = P3 - b * scale * Point(np.cos(angle3), np.sin(angle3))
+    new_bezier_line = bezier_line(P0, P1, P2, P3)
+    # new_bezier_line = _bezier_optimal_pure(P0, P3, *args, **kwargs)
+    bezier_point_coordinates = lambda t: np.array([new_bezier_line(t).x, new_bezier_line(t).y])
+
+    _, bezier_point_coordinates_sampled = \
+        sample_function(bezier_point_coordinates, [0, 1], tol=accuracy / scale) 
+
+    # # This yields a better polygon
+    bezier_point_coordinates_sampled = \
+        np.insert(bezier_point_coordinates_sampled, 1, bezier_point_coordinates(accuracy / scale),
+                    axis=1)  # add a point right after the first one
+    bezier_point_coordinates_sampled = \
+        np.insert(bezier_point_coordinates_sampled, -1, bezier_point_coordinates(1 - accuracy / scale),
+                    axis=1)  # add a point right before the last one
+
+    if verbose:
+        # print the minimum/maximum curvature
+        print ('SiEPIC.utils.geometry.bezier_cubic: minimum radius of curvature = %0.3g' % (1/max_curvature(P0, P1, P2, P3)))
+        print ('SiEPIC.utils.geometry.bezier_cubic: maximum radius of curvature = %0.3g' % (1/min_curvature(P0, P1, P2, P3)))
+    if plot:
+        t = np.linspace(0, 1, 300)
+        curv = curvature_bezier(P0, P1, P2, P3)(t)
+        rc = 1./curv.flatten()
+        import matplotlib.pyplot as plt
+        plt.plot(t, rc, '--pb', label='a=%3g, b=%3g' % (a,b), linewidth=1.5)
+        SizeFont = 19
+        plt.xlabel('Position along path (t)', fontsize=SizeFont)
+        plt.ylabel('Radius of curvature (microns)', fontsize=SizeFont)
+        plt.legend(fontsize=SizeFont)
+        plt.xticks(fontsize=SizeFont)
+        plt.ylim(bottom=0)
+        plt.yticks(fontsize=SizeFont)
+        plt.show()
+
+    return [pya.DPoint(x, y) for (x, y) in zip(*(bezier_point_coordinates_sampled))]
+
+
+
 # ####################### SIEPIC EXTENSION ##########################
 
 

klayout_dot_config/python/pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "SiEPIC"
-version = "0.5.11"
+version = "0.5.12"
 authors = [
   { name="Lukas Chrostowski", email="lukasc@ece.ubc.ca" },
 ]