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.GetEventHandler(), evt)
  37             #del evt
  38
  39             sleeptime = (random.random() * 2) + 0.5
  40             time.sleep(sleeptime/4)
  41
  42             sleeptime = sleeptime * 5
  43             if int(random.random() * 2):
  44                 self.val = self.val + sleeptime
  45             else:
  46                 self.val = self.val - sleeptime
  47
  48             if self.val < 0: self.val = 0
  49             if self.val > 300: self.val = 300
  50
  51         self.running = False
  52
  53 #----------------------------------------------------------------------
  54
  55
  56 class GraphWindow(wx.Window):
  57     def __init__(self, parent, labels):
  58         wx.Window.__init__(self, parent, -1)
  59
  60         self.values = []
  61         for label in labels:
  62             self.values.append((label, 0))
  63
  64         font = wx.Font(12, wx.SWISS, wx.NORMAL, wx.BOLD)
  65         self.SetFont(font)
  66
  67         self.colors = [ wx.RED, wx.GREEN, wx.BLUE, wx.CYAN,
  68                         "Yellow", "Navy" ]
  69
  70         self.Bind(wx.EVT_ERASE_BACKGROUND, self.OnEraseBackground)
  71         self.Bind(wx.EVT_PAINT, self.OnPaint)
  72
  73
  74     def SetValue(self, index, value):
  75         assert index < len(self.values)
  76         cur = self.values[index]
  77         self.values[index:index+1] = [(cur[0], value)]
  78
  79
  80     def SetFont(self, font):
  81         wx.Window.SetFont(self, font)
  82         wmax = hmax = 0
  83         for label, val in self.values:
  84             w,h = self.GetTextExtent(label)
  85             if w > wmax: wmax = w
  86             if h > hmax: hmax = h
  87         self.linePos = wmax + 10
  88         self.barHeight = hmax
  89
  90
  91     def GetBestHeight(self):
  92         return 2 * (self.barHeight + 1) * len(self.values)
  93
  94
  95     def Draw(self, dc, size):
  96         dc.SetFont(self.GetFont())
  97         dc.SetTextForeground(wx.BLUE)
  98         dc.SetBackground(wx.Brush(self.GetBackgroundColour()))
  99         dc.Clear()
 100         dc.SetPen(wx.Pen(wx.BLACK, 3, wx.SOLID))
 101         dc.DrawLine((self.linePos, 0), (self.linePos, size.height-10))
 102
 103         bh = ypos = self.barHeight
 104         for x in range(len(self.values)):
 105             label, val = self.values[x]
 106             dc.DrawText(label, (5, ypos))
 107
 108             if val:
 109                 color = self.colors[ x % len(self.colors) ]
 110                 dc.SetPen(wx.Pen(color))
 111                 dc.SetBrush(wx.Brush(color))
 112                 dc.DrawRectangle((self.linePos+3, ypos), (val, bh))
 113
 114             ypos = ypos + 2*bh
 115             if ypos > size[1]-10:
 116                 break
 117
 118
 119     def OnPaint(self, evt):
 120         width, height = size =self.GetSize()
 121         bmp = wx.EmptyBitmap(width, height)
 122
 123         dc = wx.MemoryDC()
 124         dc.SelectObject(bmp)
 125
 126
 127         self.Draw(dc, size)
 128
 129         wdc = wx.PaintDC(self)
 130         wdc.BeginDrawing()
 131         wdc.Blit((0,0), size, dc, (0,0))
 132         wdc.EndDrawing()
 133
 134         dc.SelectObject(wx.NullBitmap)
 135
 136
 137     def OnEraseBackground(self, evt):
 138         pass
 139
 140
 141
 142
 143 #----------------------------------------------------------------------
 144
 145 class TestFrame(wx.Frame):
 146     def __init__(self, parent, log):
 147         wx.Frame.__init__(self, parent, -1, "Thread Test", size=(450,300))
 148         self.log = log
 149
 150         #self.CenterOnParent()
 151
 152         panel = wx.Panel(self, -1)
 153         panel.SetFont(wx.Font(10, wx.SWISS, wx.NORMAL, wx.BOLD))
 154         wx.StaticText(panel, -1,
 155                      "This demo shows multiple threads interacting with this\n"
 156                      "window by sending events to it, one thread for each bar.",
 157                      (5,5))
 158         panel.Fit()
 159
 160         self.graph = GraphWindow(self, ['Zero', 'One', 'Two', 'Three', 'Four',
 161                                         'Five', 'Six', 'Seven'])
 162         self.graph.SetSize((450, self.graph.GetBestHeight()))
 163
 164         sizer = wx.BoxSizer(wx.VERTICAL)
 165         sizer.Add(panel, 0, wx.EXPAND)
 166         sizer.Add(self.graph, 1, wx.EXPAND)
 167
 168         self.SetSizer(sizer)
 169         self.SetAutoLayout(True)
 170         sizer.Fit(self)
 171
 172         self.Bind(EVT_UPDATE_BARGRAPH, self.OnUpdate)
 173
 174         self.threads = []
 175         self.threads.append(CalcBarThread(self, 0, 50))
 176         self.threads.append(CalcBarThread(self, 1, 75))
 177         self.threads.append(CalcBarThread(self, 2, 100))
 178         self.threads.append(CalcBarThread(self, 3, 150))
 179         self.threads.append(CalcBarThread(self, 4, 225))
 180         self.threads.append(CalcBarThread(self, 5, 300))
 181         self.threads.append(CalcBarThread(self, 6, 250))
 182         self.threads.append(CalcBarThread(self, 7, 175))
 183
 184         for t in self.threads:
 185             t.Start()
 186
 187         self.Bind(wx.EVT_CLOSE, self.OnCloseWindow)
 188
 189
 190     def OnUpdate(self, evt):
 191         self.graph.SetValue(evt.barNum, evt.value)
 192         self.graph.Refresh(False)
 193
 194
 195     def OnCloseWindow(self, evt):
 196         busy = wx.BusyInfo("One moment please, waiting for threads to die...")
 197         wx.Yield()
 198
 199         for t in self.threads:
 200             t.Stop()
 201
 202         running = 1
 203
 204         while running:
 205             running = 0
 206
 207             for t in self.threads:
 208                 running = running + t.IsRunning()
 209
 210             time.sleep(0.1)
 211
 212         self.Destroy()
 213
 214
 215
 216 #----------------------------------------------------------------------
 217
 218 def runTest(frame, nb, log):
 219     win = TestFrame(frame, log)
 220     frame.otherWin = win
 221     win.Show(True)
 222     return None
 223
 224 #----------------------------------------------------------------------
 225
 226
 227
 228
 229 overview = """\
 230 The main issue with multi-threaded GUI programming is the thread safty
 231 of the GUI itself.  On most platforms the GUI is not thread safe and
 232 so any cross platform GUI Toolkit and applications written with it
 233 need to take that into account.
 234
 235 The solution is to only allow interaction with the GUI from a single
 236 thread, but this often severely limits what can be done in an
 237 application and makes it difficult to use additional threads at all.
 238
 239 Since wxPython already makes extensive use of event handlers, it is a
 240 logical extension to allow events to be sent to GUI objects from
 241 alternate threads.  A function called wx.PostEvent allows you to do
 242 this.  It accepts an event and an event handler (window) and instead
 243 of sending the event immediately in the current context like
 244 ProcessEvent does, it processes it later from the context of the GUI
 245 thread.
 246
 247 """
 248
 249
 250
 251 if __name__ == '__main__':
 252     import sys,os
 253     import run
 254     run.main(['', os.path.basename(sys.argv[0])])
 255