wxPython/demo/Threads.py

   1
   2 from wxPython.wx import *
   3 from wxPython.lib import newevent
   4
   5 import thread
   6 import time
   7 from   whrandom import random
   8
   9 #----------------------------------------------------------------------
  10
  11 # This creates a new Event class and a EVT binder function
  12 UpdateBarEvent, EVT_UPDATE_BARGRAPH = 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             wxPostEvent(self.win, evt)
  37             #del evt
  38
  39             sleeptime = (random() * 2) + 0.5
  40             time.sleep(sleeptime/4)
  41
  42             sleeptime = sleeptime * 5
  43             if int(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(wxWindow):
  57     def __init__(self, parent, labels):
  58         wxWindow.__init__(self, parent, -1)
  59
  60         self.values = []
  61         for label in labels:
  62             self.values.append((label, 0))
  63
  64         font = wxFont(12, wxSWISS, wxNORMAL, wxBOLD)
  65         self.SetFont(font)
  66
  67         self.colors = [ wxRED, wxGREEN, wxBLUE, wxCYAN,
  68                         "Yellow", "Navy" ]
  69
  70         EVT_ERASE_BACKGROUND(self, self.OnEraseBackground)
  71         EVT_PAINT(self, 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         wxWindow.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(wxBLUE)
  98         dc.SetBackground(wxBrush(self.GetBackgroundColour()))
  99         dc.Clear()
 100         dc.SetPen(wxPen(wxBLACK, 3, wxSOLID))
 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(wxPen(color))
 111                 dc.SetBrush(wxBrush(color))
 112                 dc.DrawRectangle((self.linePos+3, ypos), (val, bh))
 113
 114             ypos = ypos + 2*bh
 115             if ypos > size.height-10:
 116                 break
 117
 118
 119     def OnPaint(self, evt):
 120         size = self.GetSize()
 121         bmp = wxEmptyBitmap(size.width, size.height)
 122         dc = wxMemoryDC()
 123         dc.SelectObject(bmp)
 124         self.Draw(dc, size)
 125
 126         wdc = wxPaintDC(self)
 127         wdc.BeginDrawing()
 128         wdc.Blit((0,0), size, dc, (0,0))
 129         wdc.EndDrawing()
 130
 131         dc.SelectObject(wxNullBitmap)
 132
 133
 134     def OnEraseBackground(self, evt):
 135         pass
 136
 137
 138
 139
 140 #----------------------------------------------------------------------
 141
 142 class TestFrame(wxFrame):
 143     def __init__(self, parent, log):
 144         wxFrame.__init__(self, parent, -1, "Thread Test", size=(450,300))
 145         self.log = log
 146
 147         #self.CenterOnParent()
 148
 149         panel = wxPanel(self, -1)
 150         panel.SetFont(wxFont(10, wxSWISS, wxNORMAL, wxBOLD))
 151         wxStaticText(panel, -1,
 152                      "This demo shows multiple threads interacting with this\n"
 153                      "window by sending events to it, one thread for each bar.",
 154                      wxPoint(5,5))
 155         panel.Fit()
 156
 157         self.graph = GraphWindow(self, ['Zero', 'One', 'Two', 'Three', 'Four',
 158                                         'Five', 'Six', 'Seven'])
 159         self.graph.SetSize((450, self.graph.GetBestHeight()))
 160
 161         sizer = wxBoxSizer(wxVERTICAL)
 162         sizer.Add(panel, 0, wxEXPAND)
 163         sizer.Add(self.graph, 1, wxEXPAND)
 164
 165         self.SetSizer(sizer)
 166         self.SetAutoLayout(True)
 167         sizer.Fit(self)
 168
 169         EVT_UPDATE_BARGRAPH(self, self.OnUpdate)
 170         self.threads = []
 171         self.threads.append(CalcBarThread(self, 0, 50))
 172         self.threads.append(CalcBarThread(self, 1, 75))
 173         self.threads.append(CalcBarThread(self, 2, 100))
 174         self.threads.append(CalcBarThread(self, 3, 150))
 175         self.threads.append(CalcBarThread(self, 4, 225))
 176         self.threads.append(CalcBarThread(self, 5, 300))
 177         self.threads.append(CalcBarThread(self, 6, 250))
 178         self.threads.append(CalcBarThread(self, 7, 175))
 179
 180         for t in self.threads:
 181             t.Start()
 182
 183         EVT_CLOSE(self, self.OnCloseWindow)
 184
 185
 186     def OnUpdate(self, evt):
 187         self.graph.SetValue(evt.barNum, evt.value)
 188         self.graph.Refresh(False)
 189
 190
 191     def OnCloseWindow(self, evt):
 192         busy = wxBusyInfo("One moment please, waiting for threads to die...")
 193         wxYield()
 194         for t in self.threads:
 195             t.Stop()
 196         running = 1
 197         while running:
 198             running = 0
 199             for t in self.threads:
 200                 running = running + t.IsRunning()
 201             time.sleep(0.1)
 202         self.Destroy()
 203
 204
 205
 206 #----------------------------------------------------------------------
 207
 208 def runTest(frame, nb, log):
 209     win = TestFrame(frame, log)
 210     frame.otherWin = win
 211     win.Show(True)
 212     return None
 213
 214 #----------------------------------------------------------------------
 215
 216
 217
 218
 219 overview = """\
 220 The main issue with multi-threaded GUI programming is the thread safty
 221 of the GUI itself.  On most platforms the GUI is not thread safe and
 222 so any cross platform GUI Toolkit and applications written with it
 223 need to take that into account.
 224
 225 The solution is to only allow interaction with the GUI from a single
 226 thread, but this often severely limits what can be done in an
 227 application and makes it difficult to use additional threads at all.
 228
 229 Since wxPython already makes extensive use of event handlers, it is a
 230 logical extension to allow events to be sent to GUI objects from
 231 alternate threads.  A function called wxPostEvent allows you to do
 232 this.  It accepts an event and an event handler (window) and instead
 233 of sending the event immediately in the current context like
 234 ProcessEvent does, it processes it later from the context of the GUI
 235 thread.
 236
 237 """
 238
 239
 240
 241 if __name__ == '__main__':
 242     import sys,os
 243     import run
 244     run.main(['', os.path.basename(sys.argv[0])])
 245