wxPython：带有背景图像的框架无法正确显示圆角边框按钮

Question

我需要在具有背景图像的框架中显示带有圆边的按钮。该按钮带有圆形边缘，但我仍然看到按钮外面的矩形框架与背景图像重叠：

正如你所看到的那样，按钮边缘是白色的 - 无论我使用的是什么按钮类型都是wxPython提供的。我不能删除背景图像，因为它需要在那里：

#!/usr/bin/python
import wx
import wx.lib.agw.gradientbutton as GB
import wx.lib.platebtn as platebtn

class MainPanel(wx.Frame):
    def __init__(self):
        super(MainPanel, self).__init__(None, title='Medical App', size=(800, 480))
        self.image = 'image0.png'
        self.sizer = wx.BoxSizer(wx.VERTICAL)
        self.hSizer = wx.BoxSizer(wx.HORIZONTAL)
        self.SetBackgroundStyle(wx.BG_STYLE_CUSTOM)
        self.chopbmp = wx.Bitmap("images1.png",wx.BITMAP_TYPE_PNG)
        self.statbmp = wx.Bitmap("images2.png", wx.BITMAP_TYPE_PNG)
        self.backbmp = wx.Bitmap("images3.png", wx.BITMAP_TYPE_PNG)
        self.chopBtn = GB.GradientButton(self, bitmap=self.chopbmp, size=(410, 90))
        #self.chopBtn = platebtn.PlateButton(self, label="Press Me", style=platebtn.PB_STYLE_NOBG)
        #self.chopBtn = wx.BitmapButton(self, bitmap=self.chopbmp, size=(410, 90))
        self.statBtn = GB.GradientButton(self, bitmap=self.statbmp, size=(410, 90))
        self.backBtn = GB.GradientButton(self, bitmap=self.backbmp, size=(207,90))
        #self.backBtn = wx.BitmapButton(self, bitmap=self.backbmp, size = (150, 50))
        self.backBtn.Bind(wx.EVT_LEFT_DCLICK, self.buttonClick)
        self.Bind(wx.EVT_ERASE_BACKGROUND, self.OnEraseBackground)
        self.sizer.Add(self.chopBtn, 0, wx.ALL | wx.ALIGN_RIGHT, 0)
        self.sizer.Add(self.statBtn, 0, wx.ALL | wx.ALIGN_RIGHT, 5)
        self.sizer.Add(self.backBtn, 0, wx.ALL | wx.ALIGN_RIGHT, 5)
        self.hSizer.Add((1,1), 5, wx.EXPAND)
        self.hSizer.Add(self.sizer, 0, wx.TOP, 150)
        self.hSizer.Add((1,1), 0, wx.ALL, 5)
        self.SetSizer(self.hSizer)
        self.SetPosition(wx.Point(0,0))
        self.ShowFullScreen(True)

    def buttonClick(self, evt):
        self.Destroy()


    def OnEraseBackground(self, evt):
        dc = evt.GetDC()
        if not dc:
            dc = wx.ClientDC(self)
            rect = self.GetUpdateRegion().GetBox()
            dc.SetClippingRect(rect)
        dc.Clear()
        self.bg = wx.Image(self.image, wx.BITMAP_TYPE_PNG).ConvertToBitmap()
        dc.DrawBitmap(self.bg, 0, 0)

if __name__ == "__main__":
   application = wx.App()
   MainPanel()
   application.MainLoop()

有没有办法可以摆脱按钮边缘的额外像素并使其完全看起来有圆角？