utils/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         self.font = wxFont(12, wxSWISS, wxNORMAL, wxBOLD)
  75         self.SetFont(self.font)
  76
  77         self.colors = [ wxRED, wxGREEN, wxBLUE, wxCYAN] #, wxNamedColour("Yellow") ]
  78
  79
  80     def SetValue(self, index, value):
  81         assert index < len(self.values)
  82         cur = self.values[index]
  83         self.values[index:index+1] = [(cur[0], value)]
  84
  85
  86     def SetFont(self, font):
  87         wxWindow.SetFont(self, font)
  88         wmax = hmax = 0
  89         for label, val in self.values:
  90             w,h = self.GetTextExtent(label)
  91             if w > wmax: wmax = w
  92             if h > hmax: hmax = h
  93         self.linePos = wmax + 10
  94         self.barHeight = hmax
  95
  96
  97     def OnPaint(self, evt):
  98         size = self.GetSize()
  99         dc = wxPaintDC(self)
 100         dc.BeginDrawing()
 101         dc.SetFont(self.font)
 102         dc.SetTextForeground(wxBLUE)
 103         dc.SetPen(wxPen(wxBLACK, 3, wxSOLID))
 104         dc.DrawLine(self.linePos, 0, self.linePos, size.height-10)
 105
 106         bh = ypos = self.barHeight
 107         for x in range(len(self.values)):
 108             label, val = self.values[x]
 109             dc.DrawText(label, 5, ypos)
 110
 111             if val:
 112                 color = self.colors[ x % len(self.colors) ]
 113                 dc.SetPen(wxPen(color))
 114                 dc.SetBrush(wxBrush(color))
 115                 dc.DrawRectangle(self.linePos+3, ypos, val, bh)
 116
 117             ypos = ypos + 2*bh
 118             if ypos > size.height-10:
 119                 break
 120
 121         dc.EndDrawing()
 122
 123
 124 #----------------------------------------------------------------------
 125
 126 class TestFrame(wxFrame):
 127     def __init__(self, parent, log):
 128         wxFrame.__init__(self, parent, -1, "Thread Test", size=(450,300))
 129         self.log = log
 130
 131         #self.CenterOnParent()
 132
 133         panel = wxPanel(self, -1)
 134         panel.SetFont(wxFont(10, wxSWISS, wxNORMAL, wxBOLD))
 135         wxStaticText(panel, -1,
 136                      "This demo shows multiple threads interacting with this\n"
 137                      "window by sending events to it.", wxPoint(5,5))
 138         panel.Fit()
 139
 140         self.graph = GraphWindow(self, ['Zero', 'One', 'Two', 'Three'])
 141
 142         sizer = wxBoxSizer(wxVERTICAL)
 143         sizer.Add(panel, 0, wxEXPAND)
 144         sizer.Add(self.graph, 1, wxEXPAND)
 145
 146         self.SetSizer(sizer)
 147         self.SetAutoLayout(true)
 148
 149         #self.graph.SetValue(0, 25)
 150         #self.graph.SetValue(1, 50)
 151         #self.graph.SetValue(2, 75)
 152         #self.graph.SetValue(3, 100)
 153
 154         EVT_UPDATE_BARGRAPH(self, self.OnUpdate)
 155         self.threads = []
 156         self.threads.append(CalcBarThread(self, 0, 25))
 157         self.threads.append(CalcBarThread(self, 1, 50))
 158         self.threads.append(CalcBarThread(self, 2, 75))
 159         self.threads.append(CalcBarThread(self, 3, 100))
 160
 161         for t in self.threads:
 162             t.Start()
 163
 164
 165
 166     def OnUpdate(self, evt):
 167         self.graph.SetValue(evt.barNum, evt.value)
 168         self.graph.Refresh()
 169
 170
 171     def OnCloseWindow(self, evt):
 172         busy = wxBusyInfo("One moment please, waiting for threads to die...")
 173         for t in self.threads:
 174             t.Stop()
 175         running = 1
 176         while running:
 177             running = 0
 178             for t in self.threads:
 179                 running = running + t.IsRunning()
 180             time.sleep(0.1)
 181         self.Destroy()
 182
 183
 184
 185 #----------------------------------------------------------------------
 186
 187 def runTest(frame, nb, log):
 188     win = TestFrame(frame, log)
 189     frame.otherWin = win
 190     win.Show(true)
 191     return None
 192
 193 #----------------------------------------------------------------------
 194
 195
 196
 197
 198 overview = """\
 199 The main issue with multi-threaded GUI programming is the thread safty
 200 of the GUI itself.  On most platforms the GUI is not thread safe and
 201 so any cross platform GUI Toolkit and applications written with it
 202 need to take that into account.
 203
 204 The solution is to only allow interaction with the GUI from a single
 205 thread, but this often severly limits what can be done in an
 206 application and makes it difficult to use additional threads at all.
 207
 208 Since wxPython already makes extensive use of event handlers, it is a
 209 logical extension to allow events to be sent to GUI objects from
 210 alternate threads.  A function called wxPostEvent allows you to do
 211 this.  It accepts an event and an event handler (window) and instead
 212 of sending the event immediately in the current context like
 213 ProcessEvent does, it processes it later from the context of the GUI
 214 thread.
 215
 216 """