wxPython/wx/lib/ticker.py

   1 #----------------------------------------------------------------------
   2 # Name:        wx.lib.ticker
   3 # Purpose:     A news-ticker style scrolling text control
   4 #
   5 # Author:      Chris Mellon
   6 #
   7 # Created:     29-Aug-2004
   8 # RCS-ID:      $Id$
   9 # Copyright:   (c) 2004 by Chris Mellon
  10 # Licence:     wxWindows license
  11 #----------------------------------------------------------------------
  12
  13 """News-ticker style scrolling text control
  14
  15     * Can scroll from right to left or left to right.
  16
  17     * Speed of the ticking is controlled by two parameters:
  18
  19       - Frames per Second(FPS): How many times per second the ticker updates
  20
  21       - Pixels per Frame(PPF): How many pixels the text moves each update
  22
  23 Low FPS with high PPF will result in "jumpy" text, lower PPF with higher FPS
  24 is smoother (but blurrier and more CPU intensive) text.
  25 """
  26
  27 import wx
  28
  29 #----------------------------------------------------------------------
  30
  31 class Ticker(wx.PyControl):
  32     def __init__(self,
  33             parent,
  34             id=-1,
  35             text=wx.EmptyString,        #text in the ticker
  36             fgcolor = wx.BLACK,         #text/foreground color
  37             bgcolor = wx.WHITE,         #background color
  38             start=True,                 #if True, the ticker starts immediately
  39             ppf=2,                      #pixels per frame
  40             fps=20,                     #frames per second
  41             direction="rtl",            #direction of ticking, rtl or ltr
  42             pos=wx.DefaultPosition, size=wx.DefaultSize, style=wx.NO_BORDER,
  43             name="Ticker"
  44         ):
  45         wx.PyControl.__init__(self, parent, id=id, pos=pos, size=size, style=style, name=name)
  46         self.timer = wx.Timer(owner=self)
  47         self._extent = (-1, -1)  #cache value for the GetTextExtent call
  48         self._offset = 0
  49         self._fps = fps  #frames per second
  50         self._ppf = ppf  #pixels per frame
  51         self.SetDirection(direction)
  52         self.SetText(text)
  53         self.SetInitialSize(size)
  54         self.SetForegroundColour(fgcolor)
  55         self.SetBackgroundColour(bgcolor)
  56         wx.EVT_TIMER(self, -1, self.OnTick)
  57         wx.EVT_PAINT(self, self.OnPaint)
  58         wx.EVT_ERASE_BACKGROUND(self, self.OnErase)
  59         if start:
  60             self.Start()
  61
  62
  63     def Stop(self):
  64         """Stop moving the text"""
  65         self.timer.Stop()
  66
  67
  68     def Start(self):
  69         """Starts the text moving"""
  70         if not self.timer.IsRunning():
  71             self.timer.Start(1000 / self._fps)
  72
  73
  74     def IsTicking(self):
  75         """Is the ticker ticking? ie, is the text moving?"""
  76         return self.timer.IsRunning()
  77
  78
  79     def SetFPS(self, fps):
  80         """Adjust the update speed of the ticker"""
  81         self._fps = fps
  82         self.Stop()
  83         self.Start()
  84
  85
  86     def GetFPS(self):
  87         """Update speed of the ticker"""
  88         return self._fps
  89
  90
  91     def SetPPF(self, ppf):
  92         """Set the number of pixels per frame the ticker moves - ie, how "jumpy" it is"""
  93         self._ppf = ppf
  94
  95
  96     def GetPPF(self):
  97         """Pixels per frame"""
  98         return self._ppf
  99
 100
 101     def SetFont(self, font):
 102         self._extent = (-1, -1)
 103         wx.Control.SetFont(self, font)
 104
 105
 106     def SetDirection(self, dir):
 107         """Sets the direction of the ticker: right to left(rtl) or left to right (ltr)"""
 108         if dir == "ltr" or dir == "rtl":
 109             if self._offset <> 0:
 110                 #Change the offset so it's correct for the new direction
 111                 self._offset = self._extent[0] + self.GetSize()[0] - self._offset
 112             self._dir = dir
 113         else:
 114             raise TypeError
 115
 116
 117     def GetDirection(self):
 118         return self._dir
 119
 120
 121     def SetText(self, text):
 122         """Set the ticker text."""
 123         self._text = text
 124         self._extent = (-1, -1)
 125         if not self._text:
 126             self.Refresh() #Refresh here to clear away the old text.
 127
 128
 129     def GetText(self):
 130         return self._text
 131
 132
 133     def UpdateExtent(self, dc):
 134         """Updates the cached text extent if needed"""
 135         if not self._text:
 136             self._extent = (-1, -1)
 137             return
 138         if self._extent == (-1, -1):
 139             self._extent = dc.GetTextExtent(self.GetText())
 140
 141
 142     def DrawText(self, dc):
 143         """Draws the ticker text at the current offset using the provided DC"""
 144         dc.SetTextForeground(self.GetForegroundColour())
 145         dc.SetFont(self.GetFont())
 146         self.UpdateExtent(dc)
 147         if self._dir == "ltr":
 148             offx = self._offset - self._extent[0]
 149         else:
 150             offx = self.GetSize()[0] - self._offset
 151         offy = (self.GetSize()[1] - self._extent[1]) / 2 #centered vertically
 152         dc.DrawText(self._text, offx, offy)
 153
 154
 155     def OnTick(self, evt):
 156         self._offset += self._ppf
 157         w1 = self.GetSize()[0]
 158         w2 = self._extent[0]
 159         if self._offset >= w1+w2:
 160             self._offset = 0
 161         self.Refresh()
 162
 163
 164     def OnPaint(self, evt):
 165         dc = wx.BufferedPaintDC(self)
 166         brush = wx.Brush(self.GetBackgroundColour())
 167         dc.SetBackground(brush)
 168         dc.Clear()
 169         self.DrawText(dc)
 170
 171
 172     def OnErase(self, evt):
 173         """Noop because of double buffering"""
 174         pass
 175
 176
 177     def AcceptsFocus(self):
 178         """Non-interactive, so don't accept focus"""
 179         return False
 180
 181
 182     def DoGetBestSize(self):
 183         """Width we don't care about, height is either -1, or the character
 184         height of our text with a little extra padding
 185         """
 186         if self._extent == (-1, -1):
 187             if not self._text:
 188                 h = self.GetCharHeight()
 189             else:
 190                 h = self.GetTextExtent(self.GetText())[1]
 191         else:
 192             h = self._extent[1]
 193         return (100, h+5)
 194
 195
 196     def ShouldInheritColours(self):
 197         """Don't get colours from our parent..."""
 198         return False
 199
 200
 201
 202 #testcase/demo
 203 if __name__ == '__main__':
 204     app = wx.PySimpleApp()
 205     f = wx.Frame(None)
 206     p = wx.Panel(f)
 207     t = Ticker(p, text="Some sample ticker text")
 208     #set ticker properties here if you want
 209     s = wx.BoxSizer(wx.VERTICAL)
 210     s.Add(t, flag=wx.GROW, proportion=0)
 211     p.SetSizer(s)
 212     f.Show()
 213     app.MainLoop()
 214
 215