Add inputhook for pyglet

IPython/terminal/pt_inputhooks/pyglet.py

@@ -0,0 +1,68 b''
+"""Enable pyglet to be used interacively with prompt_toolkit
+"""
+from __future__ import absolute_import
+
+import os
+import sys
+import time
+from timeit import default_timer as clock
+import pyglet
+
+# On linux only, window.flip() has a bug that causes an AttributeError on
+# window close.  For details, see:
+# http://groups.google.com/group/pyglet-users/browse_thread/thread/47c1aab9aa4a3d23/c22f9e819826799e?#c22f9e819826799e
+
+if sys.platform.startswith('linux'):
+    def flip(window):
+        try:
+            window.flip()
+        except AttributeError:
+            pass
+else:
+    def flip(window):
+        window.flip()
+
+
+def inputhook(context):
+    """Run the pyglet event loop by processing pending events only.
+
+    This keeps processing pending events until stdin is ready.  After
+    processing all pending events, a call to time.sleep is inserted.  This is
+    needed, otherwise, CPU usage is at 100%.  This sleep time should be tuned
+    though for best performance.
+    """
+    # We need to protect against a user pressing Control-C when IPython is
+    # idle and this is running. We trap KeyboardInterrupt and pass.
+    try:
+        t = clock()
+        while not context.input_is_ready():
+            pyglet.clock.tick()
+            for window in pyglet.app.windows:
+                window.switch_to()
+                window.dispatch_events()
+                window.dispatch_event('on_draw')
+                flip(window)
+
+            # We need to sleep at this point to keep the idle CPU load
+            # low.  However, if sleep to long, GUI response is poor.  As
+            # a compromise, we watch how often GUI events are being processed
+            # and switch between a short and long sleep time.  Here are some
+            # stats useful in helping to tune this.
+            # time    CPU load
+            # 0.001   13%
+            # 0.005   3%
+            # 0.01    1.5%
+            # 0.05    0.5%
+            used_time = clock() - t
+            if used_time > 10.0:
+                # print 'Sleep for 1 s'  # dbg
+                time.sleep(1.0)
+            elif used_time > 0.1:
+                # Few GUI events coming in, so we can sleep longer
+                # print 'Sleep for 0.05 s'  # dbg
+                time.sleep(0.05)
+            else:
+                # Many GUI events coming in, so sleep only very little
+                time.sleep(0.001)
+    except KeyboardInterrupt:
+        pass