import wx

print wx.version()

DIM = 100

POS = 20

class TestPanel(wx.Panel):

def __init__(self, *args, **kw):

wx.Panel.__init__(self, *args, **kw)

self.Bind(wx.EVT_PAINT, self.OnPaint)

self.bmps = []

self.bmps.append( self.MakeBitmap(blue=128, alpha=128) )

self.bmps.append( self.MakeBitmap() )

self.bmps.append( self.MakeBitmap(blue=255, alpha=255) )

def MakeBitmap(self, red=0, green=0, blue=0, alpha=0):

bmp = wx.EmptyBitmapRGBA(DIM, DIM, red, green, blue, alpha)

dc = wx.MemoryDC(bmp)

gc = wx.GraphicsContext.Create(dc)

path = gc.CreatePath()

path.MoveToPoint(POS,POS)

path.AddLineToPoint(DIM-POS, DIM-POS)

gc.SetPen(wx.Pen("red", 8))

gc.StrokePath(path)

return bmp

def OnPaint(self, evt):

dc = wx.PaintDC(self)

sz = self.GetSize()

dc.SetPen(wx.Pen("navy", 1))

x = y = 0

while x < sz.width * 2 or y < sz.height * 2:

x += 20

y += 20

dc.DrawLine(x, 0, 0, y)

x, y = 25,25

for bmp in self.bmps:

dc.DrawBitmap(bmp, x, y, True)

x += DIM + 25

app = wx.App(redirect=False)

frm = wx.Frame(None, title="EmptyBitmapRGBA")

pnl = TestPanel(frm)

frm.Show()

app.MainLoop()