如何创建圆角的wxBitmap按钮？

#include <wx/wx.h>
#include <wx/bitmap.h>
#include <wx/dcclient.h>

class RoundedBitmapButton : public wxButton
{
public:
    RoundedBitmapButton(wxWindow* parent, wxBitmap bitmap) : wxButton(parent, wxID_ANY, wxDefaultPosition, wxDefaultSize)
    {
        m_bitmap = bitmap;
    }

    void OnPaint(wxPaintEvent& event)
    {
        wxAutoBufferedPaintDC dc(this);
        wxSize size = GetClientSize();

        // 生成圆角位图
        wxBitmap roundedBitmap = CreateRoundedBitmap(m_bitmap, size);

        // 绘制圆角位图
        dc.DrawBitmap(roundedBitmap, wxPoint(0, 0));
    }

private:
    wxBitmap m_bitmap;

    wxDECLARE_EVENT_TABLE();
};

wxBEGIN_EVENT_TABLE(RoundedBitmapButton, wxButton)
    EVT_PAINT(RoundedBitmapButton::OnPaint)
wxEND_EVENT_TABLE()

wxBitmap CreateRoundedBitmap(const wxBitmap& bitmap, const wxSize& size)
{
    wxImage image = bitmap.ConvertToImage();

    int radius = size.GetWidth() / 2; // 圆角半径
    int diameter = radius * 2;

    // 创建一个新的位图，并设置透明背景
    wxBitmap roundedBitmap(size, 32);
    wxMemoryDC dc(roundedBitmap);
    dc.SetBackground(*wxTRANSPARENT_BRUSH);
    dc.Clear();

    // 创建一个蒙版，用于指定圆角的区域
    wxRegion roundedRegion(wxPoint(0, 0), size);
    roundedRegion.Subtract(wxRegion(wxRect(wxPoint(radius, 0), wxSize(diameter, radius))));
    roundedRegion.Subtract(wxRegion(wxRect(wxPoint(0, radius), wxSize(radius, diameter))));
    roundedRegion.Subtract(wxRegion(wxRect(wxPoint(radius, radius), wxSize(diameter, diameter))));
    dc.SetDeviceClippingRegion(roundedRegion);

    // 绘制圆角矩形
    dc.SetPen(*wxTRANSPARENT_PEN);
    dc.SetBrush(wxBrush(wxColour(0, 0, 0))); // 圆角背景颜色为黑色，可以根据需要修改
    dc.DrawRoundedRectangle(wxPoint(0, 0), size, radius);

    // 在蒙版上绘制位图
    dc.DrawBitmap(bitmap, wxPoint(0, 0));

    return roundedBitmap;
}

// 创建圆角按钮
wxBitmap buttonBitmap = wxBitmap("button.png", wxBITMAP_TYPE_PNG);
RoundedBitmapButton* button = new RoundedBitmapButton(this, buttonBitmap);

// 添加按钮到窗口
wxSizer* sizer = new wxBoxSizer(wxVERTICAL);
sizer->Add(button, 0, wxALIGN_CENTER, 0);
SetSizer(sizer);