Waved underline in RichTextCtrl

I have been trying to get a waved underline in a RichTextCtrl which is typically used by spell checkers.

In the documentation for wx.TextAttr.SetFontUnderlineType() it says:

Note On wxGTK, underline colour is only supported by GTK3. wx.TEXT_ATTR_UNDERLINE_SPECIAL is shown as a waved line. GTK might overrule the colour of wx.TEXT_ATTR_UNDERLINE_SPECIAL.

I have not found any examples of using that method with a RichTextCtrl and have not yet had any success using it. The following code only produced a straight grey/black underline.

import wx
import wx.richtext as rt

class MyFrame(wx.Frame):
    def __init__(self, *args, **kwds):
        kwds["style"] = kwds.get("style", 0) | wx.DEFAULT_FRAME_STYLE
        wx.Frame.__init__(self, *args, **kwds)
        self.SetSize((300, 200))

        self.main_panel = wx.Panel(self, wx.ID_ANY)
        main_sizer = wx.BoxSizer(wx.VERTICAL)
        self.rtc = rt.RichTextCtrl(self.main_panel, wx.ID_ANY, style=rt.RE_MULTILINE)
        main_sizer.Add(self.rtc, 1, wx.EXPAND, 0)

        self.rtc.WriteText("What can you do with this thing? ")

        # Apply waved underline?
        attr = rt.RichTextAttr()
        attr.SetFontUnderlineType(wx.TEXT_ATTR_UNDERLINE_SPECIAL, colour=wx.RED)
        self.rtc.SetStyle(13, 20, attr)

class MyApp(wx.App):
    def OnInit(self):
        self.frame = MyFrame(None, wx.ID_ANY, "")
        return True

if __name__ == "__main__":
    app = MyApp(0)

Any advice on the correct way to get a waved underline will be much appreciated!

[I am using Python 3.8.10 + wxPython 4.1.1 gtk3 (phoenix) wxWidgets 3.1.5 + Linux Mint 20.2].


I just hacked the above code to use a wx.TextCtrl instead of the RichTextCtrl and the red waved underline does appear. However, the amplitude of the waves is very small so, even if I could get it to work in a RichTextCtrl, I don’t think the effect would be sufficiently obvious.

I think the example given by @komoto48g using the StyledTextCtrl in https://discuss.wxpython.org/t/spell-check-as-you-type-with-pyenchant/35585 looks better, so I will investigate using an STC instead.

1 Like

I have now raised this as an issue on the GitHub Repository