I'm trying to make a wx.Frame with variable transparancy (based on the png mapped in the erase bk event)

Question

I'm trying to make a special splash screen that is displayed while the application is loading, it outputs messages of the various components loading and features a progress bar.

The first job I am tackling is mapping a .png image to the frame that will host the splash screen.

import wx

class edSplash(wx.Frame):
    def __init__(self, parent, title):
        wx.Frame.__init__(self, parent, -1, title, size=(410, 410), style=wx.NO_BORDER)
        self.SetBackgroundStyle(wx.BG_STYLE_CUSTOM)
        self.Center()
        self.Bind(wx.EVT_ERASE_BACKGROUND, self.OnEraseBackground)
        return

    def OnEraseBackground(self, evt):
        dc = evt.GetDC() 
        if not dc:
            dc = wx.ClientDC(self)
            rect = self.GetUpdateRegion().GetBox()
            dc.SetClippingRect(rect)

        tempBrush = wx.Brush((0,0,0,0),wx.TRANSPARENT)
        print tempBrush
        dc.SetBackground(tempBrush)
        dc.SetBackgroundMode(wx.TRANSPARENT)
        #dc.Clear()
        img = wx.Image("splash.png", wx.BITMAP_TYPE_PNG, -1)
        bmp = wx.BitmapFromImage(img)
        dc.DrawBitmap(bmp, 0, 0, True)

    def PushMessage(self, mesage):
        print mesage


class edApp(wx.App):
    def OnInit(self):
        splash = edSplash(None, 'Ed')
        self.SetTopWindow(splash)
        splash.Show(True)
        return True

if __name__ == '__main__':
    edApp(redirect=False).MainLoop()

The problem is that dc.Clear() clears to an opaque rectangle, although i have set it's brush and mode to transparent (I think :D). Commenting out dc.Clear() gives me the desired variable transparency based on the .png's alpha channel but the window gathers image noise from the neighboring windows.

How could I get both the .png's transparency and have the background clearing to an transparent brush to keep from gathering image noise?

Answer 1

Maybe you should try putting the background image onto a panel rather than the frame. Here's one way to do it:

http://www.blog.pythonlibrary.org/2010/03/18/wxpython-putting-a-background-image-on-a-panel/