Lib/lib-stdwin/stdwinq.py

   1 # Replacements for getevent() and pollevent(),
   2 # and new functions ungetevent() and sync().
   3
   4
   5 # Every library module should ideally use this instead of
   6 # stdwin.{get,poll}event(), so applications can use the services
   7 # of ungetevent() and sync().
   8
   9
  10 import stdwin
  11
  12
  13 # Events read ahead are stored in this queue.
  14 #
  15 queue = []
  16
  17
  18 # Replacement for getevent().
  19 #
  20 def getevent():
  21         if queue:
  22                 event = queue[0]
  23                 del queue[0]
  24                 return event
  25         else:
  26                 return stdwin.getevent()
  27
  28
  29 # Replacement for pollevent().
  30 #
  31 def pollevent():
  32         if queue:
  33                 return getevent()
  34         else:
  35                 return stdwin.pollevent()
  36
  37
  38 # Push an event back in the queue.
  39 #
  40 def ungetevent(event):
  41         queue.insert(0, event)
  42
  43
  44 # Synchronize the display.  It turns out that this is the way to
  45 # force STDWIN to call XSync(), which some (esoteric) applications need.
  46 # (This is stronger than just flushing -- it actually waits for a
  47 # positive response from the X server on the last command issued.)
  48 #
  49 def sync():
  50         while 1:
  51                 event = stdwin.pollevent()
  52                 if not event: break
  53                 queue.append(event)