added convertToGrayscale() method; overlays seam

Author: LeslieK

SeamCarverUtilities.py

@@ -1,3 +1,5 @@
+import png, array
+
 def printVerticalSeam(sc):
 	"vertical seam is a list of cols"
 	seam = sc.findVerticalSeam()
@@ -39,4 +41,60 @@ def printVerticalSeamEnergy(sc):
 		for col in range(sc.width()):
 			if col == seam[row]:
 				totalSeamEnergy += sc.energy(col, row)
-	print "\nTotal seam energy: {:d}".format(totalSeamEnergy)
+	print "\nTotal seam energy: {:d}".format(totalSeamEnergy)
+
+def printHorizontalSeamEnergy(sc):
+	"horizontal seam is a list of rows"
+	seam = sc.findHorizontalSeam()
+	totalSeamEnergy = 0
+	for row in range(sc.height()):
+		for col in range(sc.width()):
+			if row == seam[col]:
+				totalSeamEnergy += sc.energy(col, row)
+	print "\nTotal seam energy: {:d}".format(totalSeamEnergy)
+
+
+def distToArray(sc):
+	"displays distTo in matrix format"
+	print "sc._distTo array\n"
+	for r in range(sc.height()):
+		for c in range(sc.width()):
+			print '{:>8d}'.format(sc._distTo[r * sc.width() + c]),
+		print
+
+def _normalize(data):
+	"normalize values in data collection"
+	maxVal = max(data)
+	normal_data = map(lambda x: x/float(maxVal), data)
+	return normal_data
+
+def convertToGrayscale(sc, filename_out, seam=None, horizontal=True):
+	"converts sc.energy array to png image of grayscale values"
+	w = png.Writer(width=sc.width(), height=sc.height(), bitdepth=8, greyscale=True)
+	normal_energy = [int(round(x * 255)) for x in _normalize(sc._energy)]
+	if seam:
+		# write energy png with seam overlay
+		_RED = 255
+		if horizontal:
+			# horizontal seam
+			for col, row in enumerate(seam):
+				index = row * sc.width() + col
+				normal_energy[index] = _RED
+		else:
+			# vertical seam
+			for row, col in enumerate(seam):
+				index = row * sc.width() + col
+				normal_energy[index] = _RED
+		# write png 
+		
+		with open(filename_out, 'wb') as f:
+			w.write_array(f, normal_energy)
+
+
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