Add: support num_plays (#5)

apng/__init__.py

@@ -214,14 +214,18 @@ def from_bytes(cls, b):
 
 class APNG:
 	"""Represent APNG image."""
-	def __init__(self):
+	def __init__(self, num_plays=0):
 		"""APNG is composed by multiple PNGs, which can be inserted with 
 		:meth:`append`.
+		
+		:arg int num_plays: Number of times to loop. 0 = infinite.
 			
 		:var frames: Frames of APNG, a list of ``(png, control)`` tuple.
 		:vartype frames: list[tuple(PNG, FrameControl)]
+		:var int num_plays: same as ``num_plays``.
 		"""
 		self.frames = []
+		self.num_plays = num_plays
 
 	def append(self, png, **options):
 		"""Read a PNG file and append one frame.
@@ -258,7 +262,7 @@ def to_bytes(self):
 		out.append(png.hdr)
 
 		# acTL
-		out.append(make_chunk("acTL", struct.pack("!II", len(self.frames), 0)))
+		out.append(make_chunk("acTL", struct.pack("!II", len(self.frames), self.num_plays)))
 
 		# fcTL
 		if control:
@@ -337,6 +341,7 @@ def open(cls, file):
 
 		frame_chunks = []
 		frames = []
+		num_plays = 0
 
 		control = None
 
@@ -345,6 +350,7 @@ def open(cls, file):
 				hdr = data
 				frame_chunks.append((type, data))
 			elif type == "acTL":
+				num_frames, num_plays = struct.unpack("!II", data[8:-4])
 				continue
 			elif type == "fcTL":
 				if any(type == "IDAT" for type, data in frame_chunks):
@@ -376,6 +382,7 @@ def open(cls, file):
 
 		o = cls()
 		o.frames = frames
+		o.num_plays = num_plays
 		return o
 
 	def save(self, file):

test.py

@@ -47,7 +47,11 @@ def iter_frames(dir):
 
 		for dir in pathlib.Path("test").iterdir():
 			with self.subTest("dir: {}".format(dir.name)):
-				im = APNG()
+				try:
+					property = json.loads(dir.joinpath("property.json").read_text())
+				except OSError:
+					property = {}
+				im = APNG(**property)
 				for png, ctrl in iter_frames(dir):
 					im.append(png, **ctrl)
 				filename = "{}-animated.png".format(dir.stem)
@@ -61,6 +65,11 @@ def test_disassemble(self):
 		for dir in pathlib.Path("test").iterdir():
 			with self.subTest(dir.stem):
 				im = APNG.open(dir.joinpath("animated.png"))
+				property = dir.joinpath("property.json")
+				if property.exists():
+					property = json.loads(property.read_text())
+					for key, value in property.items():
+						assert getattr(im, key) == value
 				for i, (png, ctrl) in enumerate(im.frames):
 					filename = "{}-{}.png".format(dir.stem, i + 1)
 					png.save(pathlib.Path("build").joinpath(filename))

test/num_plays/property.json

@@ -0,0 +1,3 @@
+{
+	"num_plays": 3
+}