make apng support more robust by using delay denominator

apng_test.py

@@ -0,0 +1,28 @@
+from apng import APNG
+
+print "image1"
+
+img = APNG.open("image.apng")
+
+for png, control in img.frames:
+    print "---------"
+    print control.delay
+    print control.delay_den
+    
+print "image2"
+    
+img = APNG.open("shocked.apng")
+
+for png, control in img.frames:
+    print "---------"
+    print control.delay
+    print control.delay_den
+    
+print "image3"
+    
+img = APNG.open("(a)mad.apng")
+
+for png, control in img.frames:
+    print "---------"
+    print control.delay
+    print control.delay_den

images.py

@@ -34,8 +34,6 @@ def load_apng(file): # this one was hell to implement compared to the three func
         i = img.frames.index((frame, frame_info))
         pilframe = Image.open(io.BytesIO(frame.to_bytes())).convert("RGBA")
 
-        #print str(i)+"\t"+disposes[dispose_op]+"\t\t"+blends[frame_info.blend_op]
-
         if dispose_op == APNG_DISPOSE_OP_BACKGROUND or (i == 0 and dispose_op == APNG_DISPOSE_OP_PREVIOUS):
             prev_frame = outputbuf.copy()
             emptyrect = Image.new("RGBA", (img.frames[i-1][0].width, img.frames[i-1][0].height), (255,255,255,0))
@@ -55,14 +53,18 @@ def load_apng(file): # this one was hell to implement compared to the three func
         final_frame = outputbuf.copy()
         pilframes.append(final_frame)
         if frame_info:
-            frames.append([final_frame.toqimage(), frame_info.delay*10]) # convert delay from centiseconds to milliseconds
+            # convert delay from centiseconds to milliseconds
+            if frame_info.delay_den == 100:
+                delay = frame_info.delay * 10
+            else:
+                delay = frame_info.delay * (1000.0 / frame_info.delay_den) 
+            frames.append([final_frame.toqimage(), delay]) 
             dispose_op = frame_info.depose_op
         else:
             frames.append([final_frame.toqimage(), 0])
 
     for frame in pilframes: frame.close()
     return frames
-    #return pilframes
 
 def load_webp(file):
     img = Image.open(file)