pit.grinja@[...].de wrote:
>  Hello,
>  I have recently started to explore the wxPython opportunities to generate
>  small graphics. As a very first example, I wrote the following:
>  import wx
>  #____________________________
>  
>  class MainWindow(wx.Frame):
>      def __init__(self,parent,id,title):
>          wx.Frame.__init__(self,parent,-1, title,
>  style=wx.DEFAULT_FRAME_STYLE)
>          self.panel = wx.Panel(self,-1)
>          self.sizer = wx.BoxSizer(wx.HORIZONTAL)
>          self.sizer.Add(self.panel,1,wx.ALL)
>          self.SetSize(wx.Size(400,400))
>          self.SetSizer(self.sizer)
>          self.SetAutoLayout(True)
>          self.sizer.Fit(self)
>          dc = wx.ClientDC(self.panel)
>          dc.BeginDrawing()
>          dc.SetPen(wx.Pen(wx.RED,20))
>          dc.DrawLine(5,200,50,300)
>          dc.EndDrawing()
>          self.Refresh()
>  
>  
>  app = wx.PySimpleApp()
>  frame = MainWindow(None, -1, "Draw Demo")
>  frame.Show(True)
>  app.MainLoop()
>  
>  But I cannot see the expected line. What have I missed?

When you draw on a window it is not persistent.  You have to catch the 
EVT_PAINT event and  redraw at least the portions of the window that the 
OS tells you needs refreshing (or just do the whole thing.)  In your 
example you are drawing to a window that has not been shown yet so none 
of your drawing will be seen, and then when it is shown the system is 
sending a EVT_PAINT and since you are not catching it the window will 
just be cleared using the backgroudn colour. Look at the ScrolledWindow 
sample in the demo, it is an example of painting custom things on a window.

-- 
Robin Dunn
Software Craftsman
http://wxPython.org  Java give you jitters?  Relax with wxPython!


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