wx.lib.editor.Editor gets stuck in a loop generating "drawing failure for widget" messages

[reticulatus]

Operating system: Linux Mint 22 wxPython version & source: wxPython 4.2.2 gtk3 (phoenix) wxWidgets 3.2.6 from pypi Python version & source: 3.12.3 from distro

It also occurs with wxPython 4.2.1 gtk3 (phoenix) wxWidgets 3.2.2.1 + Python 3.10.12 + Linux Mint 21.3

Description of the problem:

In the wxPython demo, the Editor control never fully appears. Continuous warning messages are output to the command line.

As a side effect, entries in the demo's tree control for other recently used examples turn invisible on a grey background.

See this animated gif (click the play button, if necessary):

Code Example (click to expand)

This is the example from the demo, modified to run stand-alone: ```python import wx import wx.lib.editor as editor class TestFrame(wx.Frame): def __init__(self, parent): wx.Frame.__init__(self, parent) win = wx.Panel(self, -1) ed = editor.Editor(win, -1, style=wx.SUNKEN_BORDER) box = wx.BoxSizer(wx.VERTICAL) box.Add(ed, 1, wx.ALL|wx.GROW, 1) win.SetSizer(box) win.SetAutoLayout(True) ed.SetText(["", "This is a simple text editor, the class name is", "Editor. Type a few lines and try it out.", "", "It uses Windows-style key commands that can be overridden by subclassing.", "Mouse select works. Here are the key commands:", "", "Cursor movement: Arrow keys or mouse", "Beginning of line: Home", "End of line: End", "Beginning of buffer: Control-Home", "End of the buffer: Control-End", "Select text: Hold down Shift while moving the cursor", "Copy: Control-Insert, Control-C", "Cut: Shift-Delete, Control-X", "Paste: Shift-Insert, Control-V", ""]) if __name__ == '__main__': app = wx.App() frame = TestFrame(None) frame.Show() app.MainLoop() ``` The first few error message on the command line: ``` (Editor_2.py:8883): Gtk-WARNING **: 13:25:30.814: drawing failure for widget 'wxPizza': invalid value for an input cairo_format_t (Editor_2.py:8883): Gtk-WARNING **: 13:25:30.815: drawing failure for widget 'GtkScrolledWindow': invalid value for an input cairo_format_t (Editor_2.py:8883): Gtk-WARNING **: 13:25:30.815: drawing failure for widget 'wxPizza': invalid value for an input cairo_format_t (Editor_2.py:8883): Gtk-WARNING **: 13:25:30.815: drawing failure for widget 'wxPizza': invalid value for an input cairo_format_t (Editor_2.py:8883): Gtk-WARNING **: 13:25:30.815: drawing failure for widget 'GtkBox': invalid value for an input cairo_format_t (Editor_2.py:8883): Gtk-WARNING **: 13:25:30.815: drawing failure for widget 'GtkWindow': invalid value for an input cairo_format_t (Editor_2.py:8883): Gtk-WARNING **: 13:25:30.824: drawing failure for widget 'wxPizza': invalid value for an input cairo_format_t (Editor_2.py:8883): Gtk-WARNING **: 13:25:30.824: drawing failure for widget 'GtkScrolledWindow': invalid value for an input cairo_format_t (Editor_2.py:8883): Gtk-WARNING **: 13:25:30.824: drawing failure for widget 'wxPizza': invalid value for an input cairo_format_t (Editor_2.py:8883): Gtk-WARNING **: 13:25:30.824: drawing failure for widget 'wxPizza': invalid value for an input cairo_format_t (Editor_2.py:8883): Gtk-WARNING **: 13:25:30.824: drawing failure for widget 'GtkBox': invalid value for an input cairo_format_t ```

[reticulatus]

Further experiments with the Code Example indicate that the OnPaint() method is repeatedly being called.

If I drag the editor's vertical scrollbar to the bottom and the horizontal scrollbar to the right, then the messages stop being generated. However, the text is never displayed.

[swt2c]

Interestingly, I can't reproduce it, at least on Fedora 40.

[reticulatus]

Is Fedora 40 using Wayland?

Edit: I have checked my other machines.

The bug occurs with:

• wxPython 4.2.2 gtk3 (phoenix) wxWidgets 3.2.6 + Python 3.12.3 + Linux Mint 22
• wxPython 4.2.1 gtk3 (phoenix) wxWidgets 3.2.2.1 + Python 3.10.12 + Linux Mint 21.3

But not with:

• wxPython 4.2.2 osx-cocoa (phoenix) wxWidgets 3.2.6 + Python 3.12.6 + macOS Sequoia 15.1

[swt2c]

Is Fedora 40 using Wayland?

Yes, my test was with Wayland. Are you using Wayland also?

[reticulatus]

Is Fedora 40 using Wayland?

Yes, my test was with Wayland. Are you using Wayland also?

No, I'm using X11 which is standard on Mint.

[reticulatus]

If I add a call to self.Layout() in TestFrame.__init__(), the the program only outputs a small number of Gtk-WARNING messages (i.e. it doesn't get stuck in a loop). However, the Editor control is still not displayed.

In wx/lib/editor/editor.py the following method is defined:

    def DrawSimpleCursor(self, xp, yp, dc = None, old=False):
        if not dc:
            dc = wx.ClientDC(self)

        if old:
            xp = self.sco_x
            yp = self.sco_y

        szx = self.fw
        szy = self.fh
        x = xp * szx
        y = yp * szy
        dc.Blit(x,y, szx,szy, dc, x,y, wx.XOR)
        self.sco_x = xp
        self.sco_y = yp

If I comment out the call to dc.Blit() then the Gtk-WARNING messages are not output and the Editor control and its content are displayed as expected.

If I comment out the dc.Blit() call without adding the call to self.Layout() to TestFrame.__init__() then the Editor control does appear, but the text contents flicker rapidly until I click in the control.

[swt2c]

Indeed, I can reproduce this under X11.