wxPython/demo/Threads.py

   1
   2 from wxPython.wx import *
   3
   4 import thread
   5 import time
   6 from   whrandom import random
   7
   8 #----------------------------------------------------------------------
   9
  10 wxEVT_UPDATE_BARGRAPH = 25015
  11
  12 def EVT_UPDATE_BARGRAPH(win, func):
  13     win.Connect(-1, -1, wxEVT_UPDATE_BARGRAPH, func)
  14
  15
  16 class UpdateBarEvent(wxPyEvent):
  17     def __init__(self, barNum, value):
  18         wxPyEvent.__init__(self)
  19         self.SetEventType(wxEVT_UPDATE_BARGRAPH)
  20         self.barNum = barNum
  21         self.value = value
  22
  23
  24 #----------------------------------------------------------------------
  25
  26 class CalcBarThread:
  27     def __init__(self, win, barNum, val):
  28         self.win = win
  29         self.barNum = barNum
  30         self.val = val
  31
  32     def Start(self):
  33         self.keepGoing = self.running = true
  34         thread.start_new_thread(self.Run, ())
  35
  36     def Stop(self):
  37         self.keepGoing = false
  38
  39     def IsRunning(self):
  40         return self.running
  41
  42     def Run(self):
  43         while self.keepGoing:
  44             evt = UpdateBarEvent(self.barNum, int(self.val))
  45             wxPostEvent(self.win, evt)
  46             del evt
  47
  48             sleeptime = (random() * 2) + 0.5
  49             #print self.barNum, 'sleeping for', sleeptime
  50             time.sleep(sleeptime)
  51
  52             sleeptime = sleeptime * 5
  53             if int(random() * 2):
  54                 self.val = self.val + sleeptime
  55             else:
  56                 self.val = self.val - sleeptime
  57
  58             if self.val < 0: self.val = 0
  59             if self.val > 300: self.val = 300
  60
  61         self.running = false
  62
  63 #----------------------------------------------------------------------
  64
  65
  66 class GraphWindow(wxWindow):
  67     def __init__(self, parent, labels):
  68         wxWindow.__init__(self, parent, -1)
  69
  70         self.values = []
  71         for label in labels:
  72             self.values.append((label, 0))
  73
  74         font = wxFont(12, wxSWISS, wxNORMAL, wxBOLD)
  75         self.SetFont(font)
  76
  77         self.colors = [ wxRED, wxGREEN, wxBLUE, wxCYAN,
  78                         "Yellow", "Navy" ]
  79
  80         EVT_ERASE_BACKGROUND(self, self.OnEraseBackground)
  81         EVT_PAINT(self, self.OnPaint)
  82
  83
  84     def SetValue(self, index, value):
  85         assert index < len(self.values)
  86         cur = self.values[index]
  87         self.values[index:index+1] = [(cur[0], value)]
  88
  89
  90     def SetFont(self, font):
  91         wxWindow.SetFont(self, font)
  92         wmax = hmax = 0
  93         for label, val in self.values:
  94             w,h = self.GetTextExtent(label)
  95             if w > wmax: wmax = w
  96             if h > hmax: hmax = h
  97         self.linePos = wmax + 10
  98         self.barHeight = hmax
  99
 100
 101     def GetBestHeight(self):
 102         return 2 * (self.barHeight + 1) * len(self.values)
 103
 104
 105     def Draw(self, dc, size):
 106         dc.SetFont(self.GetFont())
 107         dc.SetTextForeground(wxBLUE)
 108         dc.SetBackground(wxBrush(self.GetBackgroundColour()))
 109         dc.Clear()
 110         dc.SetPen(wxPen(wxBLACK, 3, wxSOLID))
 111         dc.DrawLine(self.linePos, 0, self.linePos, size.height-10)
 112
 113         bh = ypos = self.barHeight
 114         for x in range(len(self.values)):
 115             label, val = self.values[x]
 116             dc.DrawText(label, 5, ypos)
 117
 118             if val:
 119                 color = self.colors[ x % len(self.colors) ]
 120                 dc.SetPen(wxPen(color))
 121                 dc.SetBrush(wxBrush(color))
 122                 dc.DrawRectangle(self.linePos+3, ypos, val, bh)
 123
 124             ypos = ypos + 2*bh
 125             if ypos > size.height-10:
 126                 break
 127
 128
 129     def OnPaint(self, evt):
 130         size = self.GetSize()
 131         bmp = wxEmptyBitmap(size.width, size.height)
 132         dc = wxMemoryDC()
 133         dc.SelectObject(bmp)
 134         self.Draw(dc, size)
 135
 136         wdc = wxPaintDC(self)
 137         wdc.BeginDrawing()
 138         wdc.Blit(0,0, size.width, size.height, dc, 0,0)
 139         wdc.EndDrawing()
 140
 141         dc.SelectObject(wxNullBitmap)
 142
 143
 144     def OnEraseBackground(self, evt):
 145         pass
 146
 147
 148
 149
 150 #----------------------------------------------------------------------
 151
 152 class TestFrame(wxFrame):
 153     def __init__(self, parent, log):
 154         wxFrame.__init__(self, parent, -1, "Thread Test", size=(450,300))
 155         self.log = log
 156
 157         #self.CenterOnParent()
 158
 159         panel = wxPanel(self, -1)
 160         panel.SetFont(wxFont(10, wxSWISS, wxNORMAL, wxBOLD))
 161         wxStaticText(panel, -1,
 162                      "This demo shows multiple threads interacting with this\n"
 163                      "window by sending events to it.", wxPoint(5,5))
 164         panel.Fit()
 165
 166         self.graph = GraphWindow(self, ['Zero', 'One', 'Two', 'Three', 'Four',
 167                                         'Five', 'Six', 'Seven'])
 168         self.graph.SetSize((450, self.graph.GetBestHeight()))
 169
 170         sizer = wxBoxSizer(wxVERTICAL)
 171         sizer.Add(panel, 0, wxEXPAND)
 172         sizer.Add(self.graph, 1, wxEXPAND)
 173
 174         self.SetSizer(sizer)
 175         self.SetAutoLayout(true)
 176         sizer.Fit(self)
 177
 178         EVT_UPDATE_BARGRAPH(self, self.OnUpdate)
 179         self.threads = []
 180         self.threads.append(CalcBarThread(self, 0, 50))
 181         self.threads.append(CalcBarThread(self, 1, 75))
 182         self.threads.append(CalcBarThread(self, 2, 100))
 183         self.threads.append(CalcBarThread(self, 3, 150))
 184         self.threads.append(CalcBarThread(self, 4, 225))
 185         self.threads.append(CalcBarThread(self, 5, 300))
 186         self.threads.append(CalcBarThread(self, 6, 250))
 187         self.threads.append(CalcBarThread(self, 7, 175))
 188
 189         for t in self.threads:
 190             t.Start()
 191
 192         EVT_CLOSE(self, self.OnCloseWindow)
 193
 194
 195     def OnUpdate(self, evt):
 196         self.graph.SetValue(evt.barNum, evt.value)
 197         self.graph.Refresh(false)
 198
 199
 200     def OnCloseWindow(self, evt):
 201         busy = wxBusyInfo("One moment please, waiting for threads to die...")
 202         wxYield()
 203         for t in self.threads:
 204             t.Stop()
 205         running = 1
 206         while running:
 207             running = 0
 208             for t in self.threads:
 209                 running = running + t.IsRunning()
 210             time.sleep(0.1)
 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 severly 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 wxPostEvent 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 """