improve performance by using more sets

sprite-optimizer.py

@@ -32,8 +32,9 @@ def print_stats(img):
 
 def get_lines(img):
 	"""Generate all potential lines the image contains"""
-	lines = []
-	pixels = [(x, y) for x in range(img.width) for y in range(img.height) if img.getpixel((x, y)) == 0]
+	lines = set()
+	lines_uniq = set()
+	pixels = {(x, y) for x in range(img.width) for y in range(img.height) if img.getpixel((x, y)) == 0}
 
 	i, n = 0, len(pixels) * len(pixels)
 
@@ -42,53 +43,21 @@ def get_lines(img):
 	# for each pair of pixels, get the line
 	for a in pixels:
 		for b in pixels:
-			line = list(bresenham(a[0], a[1], b[0], b[1]))
-			is_in = True
-			for p in line:
-				if p not in pixels:
-					is_in = False
-					break
+			line = tuple(bresenham(*a, *b))
+			line_uniq = tuple(sorted(line))
+
 			# if image contains the line, put it on the array
-			if is_in:
-				lines.append(line)
+			if set(line).issubset(pixels) and line_uniq not in lines_uniq:
+				lines.add(line)
+				lines_uniq.add(line_uniq)
 			i += 1
 			if progress:
 				print("\rGet lines: {:.1%}".format(i / n), end = "")
+
 	if progress:
 		print("\rGet lines: complete")
-
-	if progress:
 		print("{} lines found".format(len(lines)))
-	return lines
-
-
-def removing_doubles(lines):
-	"""Remove lines that are symetric"""
-	results = []
-	n = len(lines)
-
-	if progress:
-		print("Remove duplicated lines:", end = "")
-	# for each line, see if it's already in the output array
-	# beware not to change the orientation of the line (bresenham is not symetric)
-	# TODO: optimize a bit this operation
-	for i, l in enumerate(lines):
-		s = sorted(l)
-		same = False
-		for o in results:
-			if sorted(o) == s:
-				same = True
-				break
-		if same == False:
-			results.append(l)
-		if progress:
-			print("\rRemove double lines: {:.1%}".format(i / n), end = "")
-	if progress:
-		print("\rRemove double lines: complete")
-
-	if progress:
-		print("{} lines kept".format(len(results)))
-	return results
+	return list(lines)
 
 
 def removing_useless(lines):
@@ -99,18 +68,20 @@ def removing_useless(lines):
 	if progress:
 		print("Remove useless lines:", end = "")
 	# for each line, see if there is a line that contains every pixel of it
-	for i, l in enumerate(lines):
+	lines_set = [ set(l) for l in lines ]
+
+	for i, l in enumerate(lines_set):
 		inclusions = 0
 		# others are all lines that are not l
-		others = (x for x in lines if x != l)
-		for k in others:
-			if len(list(set(l).intersection(set(k)))) == len(l):
+		for j, k in enumerate(lines_set):
+			if i == j: continue
+			if l.issubset(k):
 				inclusions += 1
 				break
 		# or len(l) == 1 : we keep single pixels to complete the image if necessary
 		# TODO: do some tests to see if it's worth or not
 		if inclusions == 0 or len(l) == 1:
-			results.append((len(l), l))
+			results.append((len(l), lines[i], l))
 		if progress:
 			print("\rRemove useless lines: {:.1%}".format(i / n), end = "")
 	if progress:
@@ -123,22 +94,24 @@ def removing_useless(lines):
 
 def get_best_solution(img, lines):
 	"""Compute an optimized solution. The magic part of the algorithm"""
-	px_left = [(x, y) for x in range(img.width) for y in range(img.height) if img.getpixel((x, y)) == 0]
+	px_left = {(x, y) for x in range(img.width) for y in range(img.height)
+	           if img.getpixel((x, y)) == 0}
 	results = []
 	n = len(px_left)
 
 	if progress:
 		print("Draw:", end = "")
 	# while the entier image has not been drown
-	while len(px_left):
+	while px_left:
 		# define the length of lines
-		lines = [(sum([1 for p in l if p in px_left]) - len(l)/(2*max(img.size)), l) for n, l in lines]
+		lines = [(len(l_set.intersection(px_left)) - len(l)/(2*max(img.size)),
+			      l, l_set) for n, l, l_set in lines]
 		# sort them by length
 		lines = sorted(lines)
 		# pop the longest
-		(p, line) = lines.pop()
+		(p, line, line_set) = lines.pop()
 		# define the pixels that are not covered by any lines
-		px_left = [p for p in px_left if p not in line]
+		px_left = px_left.difference(line_set)
 		results.append((line[0], line[-1]))
 		if progress:
 			print("\rDraw: {:.0%}".format(1 - len(px_left)/n), end="")
@@ -222,7 +195,6 @@ if __name__ == "__main__":
 	if args.info:
 		print_stats(image)
 	lines = get_lines(image)
-	lines = removing_doubles(lines)
 	lines = removing_useless(lines)
 	lines = get_best_solution(image, lines)
 	code = generate_code(lines, args)