ScrolledPanel and repaint issues...

wxPython Users
1

Hello all,

Below you will find a test case that exhibits some weird behaviour. There are a couple of issues that I would like to get some guidance on.

NOTE…the first issue only occurs on Windows for me. Linux works fine.

First, when the SHOW_PROGRESS flag is true a progress dialog will be presented and destroyed which causes my ScrolledPanel that contains 10 lines of text to be drawn oddly in the upper-left portion of the main ScrolledPanel. Resizing this Frame will cause things to snap back to normal. Now, if you set the flag to false everything works fine. Any ideas or suggestions?

The second issue is the difference in behaviour between Windows and Linux. In Linux, if you shrink the Frame the inner ScrolledPanel does not resize properly and scrollbars are hidden by the Frame. In Windows it resizes the way I expect it to. Regardless of which behaviour is correct, the two are different. Is this behaviour documented and/or expected? It doesn’t exactly seem cross-platform to me…

Thanks,

AM

BEGIN CODE

import wx
import wx.lib.scrolledpanel as ScrolledPanel

SHOW_PROGRESS = 1

class TestFrame(wx.Frame):
def init(self, parent, title):
wx.Frame._init
_(self, parent, title=title, style=wx.DEFAULT_FRAME_STYLE|wx.CENTRE)

    size = self.GetClientSize()
    self._panel = ScrolledPanel.ScrolledPanel(self, -1, size=size, style=wx.SUNKEN_BORDER)
    self._sizer = wx.BoxSizer(wx.VERTICAL)
    self._panel.SetSizer(self._sizer)
    self._panel.SetupScrolling()

    sp = ScrolledPanel.ScrolledPanel(self._panel, -1, size=(-1,100), style=wx.SUNKEN_BORDER)
    spsizer = wx.BoxSizer(wx.VERTICAL)
    sp.SetSizer(spsizer)
    sp.SetupScrolling()

    # this does not need to be a progress dialog. it has the same behaviour with a message dialog
    if SHOW_PROGRESS:

        pd = wx.ProgressDialog("Fooooo", "Barrrr", maximum=10,
             style=wx.PD_APP_MODAL|wx.PD_ELAPSED_TIME|wx.PD_ESTIMATED_TIME|wx.PD_REMAINING_TIME|wx.PD_AUTO_HIDE)
    v = 0

    for i in xrange(10):
        spsizer.Add(wx.StaticText(sp, wx.ID_ANY, "Whatever goes here!"), flag=wx.EXPAND|wx.ALL)
        v += 1

        if SHOW_PROGRESS:

pd.Update(v)

    if SHOW_PROGRESS:
        pd.Destroy()

    self._sizer.Add(sp, 0, wx.EXPAND)

    self.Center()
    self.Show(1)

class App(wx.App):
def OnInit(self):

    TestFrame(None, "Test")
    return True

if name == “main”:
app = App()
app.MainLoop()

END CODE

2

A.M. wrote:

NOTE...the first issue only occurs on Windows for me. Linux works fine.
First, when the SHOW_PROGRESS flag is true a progress dialog will be presented and destroyed which causes my ScrolledPanel that contains 10 lines of text to be drawn oddly in the upper-left portion of the main ScrolledPanel. Resizing this Frame will cause things to snap back to normal. Now, if you set the flag to false everything works fine. Any ideas or suggestions?

It probably has something to do with the dialog doing a yield when it is shown/updated, and so the initial size events happen before the nested panel has it's items, so it does the layout assuming that it doesn't need anything but minimal size. When you resize the frame then you trigger another size event and so the layout is calculated again. If you don't set the initial size of the outer panel when it is created (the client size is minimal sized at that point in time) then this problem goes away.

The second issue is the difference in behaviour between Windows and Linux. In Linux, if you shrink the Frame the inner ScrolledPanel does not resize properly and scrollbars are hidden by the Frame. In Windows it resizes the way I expect it to. Regardless of which behaviour is correct, the two are different. Is this behaviour documented and/or expected? It doesn't exactly seem cross-platform to me...

There are two different implementations of wxScrolledWindow in play here. I'll take a look at this and see if I can get the Linux one to play nicer.

···

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