fix a few bugs in python3

screen.py

@@ -1,13 +1,24 @@
 # -*- coding: utf-8 -*-
 
-import threading, StringIO, time, base64
+import threading, time, base64
 import pyscreenshot as ig
 
+import sys
+
+ver = sys.version_info.major
+if ver==2:
+    import StringIO
+elif ver==3:
+    import io
+
 class Screen():
     def __init__(self):
         self.FPS = 10
         self.screenbuf = ""
-        self.screenfile = StringIO.StringIO()
+        if ver==2:
+            self.screenfile = StringIO.StringIO()
+        elif ver==3:
+            self.screenfile = io.BytesIO()
         threading.Thread(target=self.getframes).start()
 
     def __del__(self):
@@ -15,13 +26,19 @@ class Screen():
 
     def getframes(self):
         while True:
-            im = ig.grab(childprocess=False)
+            im = ig.grab(childprocess=False,backend="pygdk3")
+            self.screenfile.seek(0)
             self.screenfile.truncate(0)
             im.save(self.screenfile, format="jpeg", quality=75, progressive=True)
             self.screenbuf = base64.b64encode(self.screenfile.getvalue())
             time.sleep(1.0/self.FPS)
     
     def gen(self):
-        return self.screenbuf
+        s = ''
+        if ver==2:
+            s = self.screenbuf
+        elif ver==3:
+            s = self.screenbuf.decode()
+        return s
     
-screenlive = Screen()
+screenlive = Screen()