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