wxPython/demo/AlphaDrawing.py

   1
   2 import wx
   3
   4 #----------------------------------------------------------------------
   5
   6 class TestPanel(wx.Panel):
   7     def __init__(self, parent, log):
   8         self.log = log
   9         wx.Panel.__init__(self, parent, -1)
  10         self.Bind(wx.EVT_PAINT, self.OnPaint)
  11
  12         txt = """\
  13 If this build of wxPython includes the new wx.GCDC class (which
  14 provides the wx.DC API on top of the new wx.GraphicsContext class)
  15 then these squares should be transparent.
  16 """
  17         wx.StaticText(self, -1, txt, (20, 20))
  18
  19
  20     def OnPaint(self, evt):
  21         pdc = wx.PaintDC(self)
  22         try:
  23             dc = wx.GCDC(pdc)
  24         except:
  25             dc = pdc
  26         rect = wx.Rect(0,0, 100, 100)
  27         for RGB, pos in [((178,  34,  34), ( 50,  90)),
  28                          (( 35, 142,  35), (110, 150)),
  29                          ((  0,   0, 139), (170,  90))
  30                          ]:
  31             r, g, b = RGB
  32             penclr   = wx.Colour(r, g, b, wx.ALPHA_OPAQUE)
  33             brushclr = wx.Colour(r, g, b, 128)   # half transparent
  34             dc.SetPen(wx.Pen(penclr))
  35             dc.SetBrush(wx.Brush(brushclr))
  36             rect.SetPosition(pos)
  37             dc.DrawRoundedRectangleRect(rect, 8)
  38
  39
  40 #----------------------------------------------------------------------
  41
  42 def runTest(frame, nb, log):
  43     win = TestPanel(nb, log)
  44     return win
  45
  46 #----------------------------------------------------------------------
  47
  48
  49
  50 overview = """<html><body>
  51 <h2><center>Alpha Drawing</center></h2>
  52
  53 The wx.DC on Mac now supports alpha transparent drawing using pens and
  54 brushes.  This is accomplished by enabling the wx.Colour class to have
  55 a fourth component for the alpha value, where 0 is fully transparent,
  56 and 255 is fully opaque.
  57
  58 <p>You can consider this a \"preview of coming attractions\" for the
  59 other platforms.
  60
  61 </body></html>
  62 """
  63
  64
  65
  66 if __name__ == '__main__':
  67     import sys,os
  68     import run
  69     run.main(['', os.path.basename(sys.argv[0])] + sys.argv[1:])
  70