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         # some additional testing stuff
  40         #dc.SetPen(wx.Pen(wx.Colour(0,0,255, 196)))
  41         #dc.SetBrush(wx.Brush(wx.Colour(0,0,255, 64)))
  42         #dc.DrawCircle(50, 275, 25)
  43         #dc.DrawEllipse(100, 275, 75, 50)
  44
  45
  46 #----------------------------------------------------------------------
  47
  48 def runTest(frame, nb, log):
  49     win = TestPanel(nb, log)
  50     return win
  51
  52 #----------------------------------------------------------------------
  53
  54
  55
  56 overview = """<html><body>
  57 <h2><center>Alpha Drawing</center></h2>
  58
  59 The wx.GCDC class is a class that implemented the wx.DC API using the
  60 new wx.GraphicsContext class, and so it supports anti-aliased drawing
  61 using pens and brushes, that can optionally also be drawn using an
  62 alpha transparency.  (On the Mac all the DC classes are using this new
  63 implementation.)  This is accomplished by enabling the wx.Colour class
  64 to have a fourth component for the alpha value, where 0 is fully
  65 transparent, and 255 is fully opaque.
  66
  67 </body></html>
  68 """
  69
  70
  71
  72 if __name__ == '__main__':
  73     import sys,os
  74     import run
  75     run.main(['', os.path.basename(sys.argv[0])] + sys.argv[1:])
  76