wxPython/demo/Threads.py

   1
   2 import  random
   3 import  time
   4 import  thread
   5
   6 import  wx
   7 import  wx.lib.newevent
   8
   9 #----------------------------------------------------------------------
  10
  11 # This creates a new Event class and a EVT binder function
  12 (UpdateBarEvent, EVT_UPDATE_BARGRAPH) = wx.lib.newevent.NewEvent()
  13
  14
  15 #----------------------------------------------------------------------
  16
  17 class CalcBarThread:
  18     def __init__(self, win, barNum, val):
  19         self.win = win
  20         self.barNum = barNum
  21         self.val = val
  22
  23     def Start(self):
  24         self.keepGoing = self.running = True
  25         thread.start_new_thread(self.Run, ())
  26
  27     def Stop(self):
  28         self.keepGoing = False
  29
  30     def IsRunning(self):
  31         return self.running
  32
  33     def Run(self):
  34         while self.keepGoing:
  35             evt = UpdateBarEvent(barNum = self.barNum, value = int(self.val))
  36             wx.PostEvent(self.win, evt)
  37
  38             sleeptime = (random.random() * 2) + 0.5
  39             time.sleep(sleeptime/4)
  40
  41             sleeptime = sleeptime * 5
  42             if int(random.random() * 2):
  43                 self.val = self.val + sleeptime
  44             else:
  45                 self.val = self.val - sleeptime
  46
  47             if self.val < 0: self.val = 0
  48             if self.val > 300: self.val = 300
  49
  50         self.running = False
  51
  52 #----------------------------------------------------------------------
  53
  54
  55 class GraphWindow(wx.Window):
  56     def __init__(self, parent, labels):
  57         wx.Window.__init__(self, parent, -1)
  58
  59         self.values = []
  60         for label in labels:
  61             self.values.append((label, 0))
  62
  63         font = wx.Font(12, wx.SWISS, wx.NORMAL, wx.BOLD)
  64         self.SetFont(font)
  65
  66         self.colors = [ wx.RED, wx.GREEN, wx.BLUE, wx.CYAN,
  67                         "Yellow", "Navy" ]
  68
  69         self.Bind(wx.EVT_ERASE_BACKGROUND, self.OnEraseBackground)
  70         self.Bind(wx.EVT_PAINT, self.OnPaint)
  71
  72
  73     def SetValue(self, index, value):
  74         assert index < len(self.values)
  75         cur = self.values[index]
  76         self.values[index:index+1] = [(cur[0], value)]
  77
  78
  79     def SetFont(self, font):
  80         wx.Window.SetFont(self, font)
  81         wmax = hmax = 0
  82         for label, val in self.values:
  83             w,h = self.GetTextExtent(label)
  84             if w > wmax: wmax = w
  85             if h > hmax: hmax = h
  86         self.linePos = wmax + 10
  87         self.barHeight = hmax
  88
  89
  90     def GetBestHeight(self):
  91         return 2 * (self.barHeight + 1) * len(self.values)
  92
  93
  94     def Draw(self, dc, size):
  95         dc.SetFont(self.GetFont())
  96         dc.SetTextForeground(wx.BLUE)
  97         dc.SetBackground(wx.Brush(self.GetBackgroundColour()))
  98         dc.Clear()
  99         dc.SetPen(wx.Pen(wx.BLACK, 3, wx.SOLID))
 100         dc.DrawLine(self.linePos, 0, self.linePos, size.height-10)
 101
 102         bh = ypos = self.barHeight
 103         for x in range(len(self.values)):
 104             label, val = self.values[x]
 105             dc.DrawText(label, 5, ypos)
 106
 107             if val:
 108                 color = self.colors[ x % len(self.colors) ]
 109                 dc.SetPen(wx.Pen(color))
 110                 dc.SetBrush(wx.Brush(color))
 111                 dc.DrawRectangle(self.linePos+3, ypos, val, bh)
 112
 113             ypos = ypos + 2*bh
 114             if ypos > size[1]-10:
 115                 break
 116
 117
 118     def OnPaint(self, evt):
 119         dc = wx.BufferedPaintDC(self)
 120         self.Draw(dc, self.GetSize())
 121
 122
 123     def OnEraseBackground(self, evt):
 124         pass
 125
 126
 127
 128
 129 #----------------------------------------------------------------------
 130
 131 class TestFrame(wx.Frame):
 132     def __init__(self, parent, log):
 133         wx.Frame.__init__(self, parent, -1, "Thread Test", size=(450,300))
 134         self.log = log
 135
 136         #self.CenterOnParent()
 137
 138         panel = wx.Panel(self, -1)
 139         panel.SetFont(wx.Font(10, wx.SWISS, wx.NORMAL, wx.BOLD))
 140         wx.StaticText(panel, -1,
 141                      "This demo shows multiple threads interacting with this\n"
 142                      "window by sending events to it, one thread for each bar.",
 143                      (5,5))
 144         panel.Fit()
 145
 146         self.graph = GraphWindow(self, ['Zero', 'One', 'Two', 'Three', 'Four',
 147                                         'Five', 'Six', 'Seven'])
 148         self.graph.SetSize((450, self.graph.GetBestHeight()))
 149
 150         sizer = wx.BoxSizer(wx.VERTICAL)
 151         sizer.Add(panel, 0, wx.EXPAND)
 152         sizer.Add(self.graph, 1, wx.EXPAND)
 153
 154         self.SetSizer(sizer)
 155         self.SetAutoLayout(True)
 156         sizer.Fit(self)
 157
 158         self.Bind(EVT_UPDATE_BARGRAPH, self.OnUpdate)
 159
 160         self.threads = []
 161         self.threads.append(CalcBarThread(self, 0, 50))
 162         self.threads.append(CalcBarThread(self, 1, 75))
 163         self.threads.append(CalcBarThread(self, 2, 100))
 164         self.threads.append(CalcBarThread(self, 3, 150))
 165         self.threads.append(CalcBarThread(self, 4, 225))
 166         self.threads.append(CalcBarThread(self, 5, 300))
 167         self.threads.append(CalcBarThread(self, 6, 250))
 168         self.threads.append(CalcBarThread(self, 7, 175))
 169
 170         for t in self.threads:
 171             t.Start()
 172
 173         self.Bind(wx.EVT_CLOSE, self.OnCloseWindow)
 174
 175
 176     def OnUpdate(self, evt):
 177         self.graph.SetValue(evt.barNum, evt.value)
 178         self.graph.Refresh(False)
 179
 180
 181     def OnCloseWindow(self, evt):
 182         busy = wx.BusyInfo("One moment please, waiting for threads to die...")
 183         wx.Yield()
 184
 185         for t in self.threads:
 186             t.Stop()
 187
 188         running = 1
 189
 190         while running:
 191             running = 0
 192
 193             for t in self.threads:
 194                 running = running + t.IsRunning()
 195
 196             time.sleep(0.1)
 197
 198         self.Destroy()
 199
 200
 201
 202 #---------------------------------------------------------------------------
 203
 204 class TestPanel(wx.Panel):
 205     def __init__(self, parent, log):
 206         self.log = log
 207         wx.Panel.__init__(self, parent, -1)
 208
 209         b = wx.Button(self, -1, "Show Threads sample", (50,50))
 210         self.Bind(wx.EVT_BUTTON, self.OnButton, b)
 211
 212
 213     def OnButton(self, evt):
 214         win = TestFrame(self, self.log)
 215         win.Show(True)
 216
 217
 218 #---------------------------------------------------------------------------
 219
 220
 221 def runTest(frame, nb, log):
 222     win = TestPanel(nb, log)
 223     return win
 224
 225 #----------------------------------------------------------------------
 226
 227
 228
 229
 230
 231 overview = """\
 232 The main issue with multi-threaded GUI programming is the thread safty
 233 of the GUI itself.  On most platforms the GUI is not thread safe and
 234 so any cross platform GUI Toolkit and applications written with it
 235 need to take that into account.
 236
 237 The solution is to only allow interaction with the GUI from a single
 238 thread, but this often severely limits what can be done in an
 239 application and makes it difficult to use additional threads at all.
 240
 241 Since wxPython already makes extensive use of event handlers, it is a
 242 logical extension to allow events to be sent to GUI objects from
 243 alternate threads.  A function called wx.PostEvent allows you to do
 244 this.  It accepts an event and an event handler (window) and instead
 245 of sending the event immediately in the current context like
 246 ProcessEvent does, it processes it later from the context of the GUI
 247 thread.
 248
 249 """
 250
 251
 252
 253 if __name__ == '__main__':
 254     import sys,os
 255     import run
 256     run.main(['', os.path.basename(sys.argv[0])] + sys.argv[1:])
 257