sfc/slicer.py: new option -o to add an offset to the last layer

sfc/slicer.py

@@ -33,6 +33,7 @@ height = None		# height of the workpiece above the Z plane (can be
 			# negative). Default: use model dimensions.
 align_top = None	# align the Z position of the model to the workpiece
 align_bottom = None
+end = 0			# Z adjustment of final layer
 
 
 def dist(a, b):
@@ -92,7 +93,7 @@ def dump_level(wires, z):
 def usage():
 	print >>sys.stderr, "usage:", sys.argv[0], \
 	    "[-a (top|bottom)(+|-)offset] [-f] [-h height]" + \
-	    "\t[-b piece_distance] [-s max_step] file.stl"
+	    "\t[-b piece_distance] [-o z_offset] [-s max_step] file.stl"
 	sys.exit(1)
 
 
@@ -105,7 +106,7 @@ stdout = os.dup(1)
 os.dup2(2, 1)
 sys.stdout = os.fdopen(stdout, "w")
 
-opts, args = getopt.getopt(sys.argv[1:], "a:fh:p:s:")
+opts, args = getopt.getopt(sys.argv[1:], "a:e:fh:p:s:")
 for opt, arg in opts:
 	if opt == "-a":
 		if arg[0:3] == "top":
@@ -114,6 +115,8 @@ for opt, arg in opts:
 			align_bottom = float(arg[6:])
 		else:
 			usage()
+	elif opt == "-o":
+		end = float(arg)
 	elif opt == "-f":
 		flip = True
 	elif opt == "-h":
@@ -213,7 +216,9 @@ else:
 	last_z = None
 if height is not None and height < 0 and z_levels[-1] > height:
 	z_levels.append(height - z_off)
-	
+
+z_levels[-1] += end
+
 for next_z in z_levels:
 	wires = shape.slice(Base.Vector(0, 0, 1), next_z + epsilon)
 	if z_step is None or last_z is None or last_z - z_step <= next_z: