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 = wxNewEventType()
  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             time.sleep(sleeptime/4)
  50
  51             sleeptime = sleeptime * 5
  52             if int(random() * 2):
  53                 self.val = self.val + sleeptime
  54             else:
  55                 self.val = self.val - sleeptime
  56
  57             if self.val < 0: self.val = 0
  58             if self.val > 300: self.val = 300
  59
  60         self.running = false
  61
  62 #----------------------------------------------------------------------
  63
  64
  65 class GraphWindow(wxWindow):
  66     def __init__(self, parent, labels):
  67         wxWindow.__init__(self, parent, -1)
  68
  69         self.values = []
  70         for label in labels:
  71             self.values.append((label, 0))
  72
  73         font = wxFont(12, wxSWISS, wxNORMAL, wxBOLD)
  74         self.SetFont(font)
  75
  76         self.colors = [ wxRED, wxGREEN, wxBLUE, wxCYAN,
  77                         "Yellow", "Navy" ]
  78
  79         EVT_ERASE_BACKGROUND(self, self.OnEraseBackground)
  80         EVT_PAINT(self, self.OnPaint)
  81
  82
  83     def SetValue(self, index, value):
  84         assert index < len(self.values)
  85         cur = self.values[index]
  86         self.values[index:index+1] = [(cur[0], value)]
  87
  88
  89     def SetFont(self, font):
  90         wxWindow.SetFont(self, font)
  91         wmax = hmax = 0
  92         for label, val in self.values:
  93             w,h = self.GetTextExtent(label)
  94             if w > wmax: wmax = w
  95             if h > hmax: hmax = h
  96         self.linePos = wmax + 10
  97         self.barHeight = hmax
  98
  99
 100     def GetBestHeight(self):
 101         return 2 * (self.barHeight + 1) * len(self.values)
 102
 103
 104     def Draw(self, dc, size):
 105         dc.SetFont(self.GetFont())
 106         dc.SetTextForeground(wxBLUE)
 107         dc.SetBackground(wxBrush(self.GetBackgroundColour()))
 108         dc.Clear()
 109         dc.SetPen(wxPen(wxBLACK, 3, wxSOLID))
 110         dc.DrawLine(self.linePos, 0, self.linePos, size.height-10)
 111
 112         bh = ypos = self.barHeight
 113         for x in range(len(self.values)):
 114             label, val = self.values[x]
 115             dc.DrawText(label, 5, ypos)
 116
 117             if val:
 118                 color = self.colors[ x % len(self.colors) ]
 119                 dc.SetPen(wxPen(color))
 120                 dc.SetBrush(wxBrush(color))
 121                 dc.DrawRectangle(self.linePos+3, ypos, val, bh)
 122
 123             ypos = ypos + 2*bh
 124             if ypos > size.height-10:
 125                 break
 126
 127
 128     def OnPaint(self, evt):
 129         size = self.GetSize()
 130         bmp = wxEmptyBitmap(size.width, size.height)
 131         dc = wxMemoryDC()
 132         dc.SelectObject(bmp)
 133         self.Draw(dc, size)
 134
 135         wdc = wxPaintDC(self)
 136         wdc.BeginDrawing()
 137         wdc.Blit(0,0, size.width, size.height, dc, 0,0)
 138         wdc.EndDrawing()
 139
 140         dc.SelectObject(wxNullBitmap)
 141
 142
 143     def OnEraseBackground(self, evt):
 144         pass
 145
 146
 147
 148
 149 #----------------------------------------------------------------------
 150
 151 class TestFrame(wxFrame):
 152     def __init__(self, parent, log):
 153         wxFrame.__init__(self, parent, -1, "Thread Test", size=(450,300))
 154         self.log = log
 155
 156         #self.CenterOnParent()
 157
 158         panel = wxPanel(self, -1)
 159         panel.SetFont(wxFont(10, wxSWISS, wxNORMAL, wxBOLD))
 160         wxStaticText(panel, -1,
 161                      "This demo shows multiple threads interacting with this\n"
 162                      "window by sending events to it, one thread for each bar.",
 163                      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 """