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         width, height = size =self.GetSize()
 120         bmp = wx.EmptyBitmap(width, height)
 121
 122         dc = wx.MemoryDC()
 123         dc.SelectObject(bmp)
 124
 125
 126         self.Draw(dc, size)
 127
 128         wdc = wx.PaintDC(self)
 129         wdc.BeginDrawing()
 130         wdc.Blit((0,0), size, dc, (0,0))
 131         wdc.EndDrawing()
 132
 133         dc.SelectObject(wx.NullBitmap)
 134
 135
 136     def OnEraseBackground(self, evt):
 137         pass
 138
 139
 140
 141
 142 #----------------------------------------------------------------------
 143
 144 class TestFrame(wx.Frame):
 145     def __init__(self, parent, log):
 146         wx.Frame.__init__(self, parent, -1, "Thread Test", size=(450,300))
 147         self.log = log
 148
 149         #self.CenterOnParent()
 150
 151         panel = wx.Panel(self, -1)
 152         panel.SetFont(wx.Font(10, wx.SWISS, wx.NORMAL, wx.BOLD))
 153         wx.StaticText(panel, -1,
 154                      "This demo shows multiple threads interacting with this\n"
 155                      "window by sending events to it, one thread for each bar.",
 156                      (5,5))
 157         panel.Fit()
 158
 159         self.graph = GraphWindow(self, ['Zero', 'One', 'Two', 'Three', 'Four',
 160                                         'Five', 'Six', 'Seven'])
 161         self.graph.SetSize((450, self.graph.GetBestHeight()))
 162
 163         sizer = wx.BoxSizer(wx.VERTICAL)
 164         sizer.Add(panel, 0, wx.EXPAND)
 165         sizer.Add(self.graph, 1, wx.EXPAND)
 166
 167         self.SetSizer(sizer)
 168         self.SetAutoLayout(True)
 169         sizer.Fit(self)
 170
 171         self.Bind(EVT_UPDATE_BARGRAPH, self.OnUpdate)
 172
 173         self.threads = []
 174         self.threads.append(CalcBarThread(self, 0, 50))
 175         self.threads.append(CalcBarThread(self, 1, 75))
 176         self.threads.append(CalcBarThread(self, 2, 100))
 177         self.threads.append(CalcBarThread(self, 3, 150))
 178         self.threads.append(CalcBarThread(self, 4, 225))
 179         self.threads.append(CalcBarThread(self, 5, 300))
 180         self.threads.append(CalcBarThread(self, 6, 250))
 181         self.threads.append(CalcBarThread(self, 7, 175))
 182
 183         for t in self.threads:
 184             t.Start()
 185
 186         self.Bind(wx.EVT_CLOSE, self.OnCloseWindow)
 187
 188
 189     def OnUpdate(self, evt):
 190         self.graph.SetValue(evt.barNum, evt.value)
 191         self.graph.Refresh(False)
 192
 193
 194     def OnCloseWindow(self, evt):
 195         busy = wx.BusyInfo("One moment please, waiting for threads to die...")
 196         wx.Yield()
 197
 198         for t in self.threads:
 199             t.Stop()
 200
 201         running = 1
 202
 203         while running:
 204             running = 0
 205
 206             for t in self.threads:
 207                 running = running + t.IsRunning()
 208
 209             time.sleep(0.1)
 210
 211         self.Destroy()
 212
 213
 214
 215 #----------------------------------------------------------------------
 216
 217 def runTest(frame, nb, log):
 218     win = TestFrame(frame, log)
 219     frame.otherWin = win
 220     win.Show(True)
 221     return None
 222
 223 #----------------------------------------------------------------------
 224
 225
 226
 227
 228 overview = """\
 229 The main issue with multi-threaded GUI programming is the thread safty
 230 of the GUI itself.  On most platforms the GUI is not thread safe and
 231 so any cross platform GUI Toolkit and applications written with it
 232 need to take that into account.
 233
 234 The solution is to only allow interaction with the GUI from a single
 235 thread, but this often severely limits what can be done in an
 236 application and makes it difficult to use additional threads at all.
 237
 238 Since wxPython already makes extensive use of event handlers, it is a
 239 logical extension to allow events to be sent to GUI objects from
 240 alternate threads.  A function called wx.PostEvent allows you to do
 241 this.  It accepts an event and an event handler (window) and instead
 242 of sending the event immediately in the current context like
 243 ProcessEvent does, it processes it later from the context of the GUI
 244 thread.
 245
 246 """
 247
 248
 249
 250 if __name__ == '__main__':
 251     import sys,os
 252     import run
 253     run.main(['', os.path.basename(sys.argv[0])] + sys.argv[1:])
 254