Memory leak when drawing with pangomm/cairomm (MSYS2)

[廖骏轩 <mikeljx 126 com>]

I have just found out that the Windows version of my project has a massive memory leak, while on Linux it 
seems alright. It uses pangomm and cairomm to display text, and I believe it’s similar to the examples in the 
online book, “Programming with gtkmm4”. queue_draw() is called every 100 ms, and in a few minutes, the memory 
usage would reach several GB. If I don’t call queue_draw(), the memory used stays around 100 MB.
Does anyone know what caused the memory leak? Thanks！
Here is what the code looks like:
--------------------------
#include "KbiDraw.h"
#include <glibmm/main.h>
#include <sstream>


KbiDraw::KbiDraw(Player* p_player)
        :
        player(p_player)
{
    set_content_width(300);
    set_content_height(300);
    set_expand(true);
    set_draw_func(sigc::mem_fun(*this, &KbiDraw::on_draw));
    Glib::signal_timeout().connect(sigc::mem_fun(*this, &KbiDraw::refresh), 100);
}


KbiDraw::~KbiDraw()
= default;


void KbiDraw::on_draw(const Cairo::RefPtr<Cairo::Context>& cr, int width, int height)
{




    // Draw a black rectangle
    cr->set_source_rgb(0.0, 0.0, 0.0);
    draw_rectangle(cr, width, height);


    // and some white text
    cr->set_source_rgb(1.0, 1.0, 1.0);
    draw_text(cr, width, height);


    Cairo::Matrix matrix(1.0, 0.0, 0.0, -1.0, 0.0, height);


    // apply the matrix
    cr->transform(matrix);


}


void KbiDraw::draw_rectangle(const Cairo::RefPtr<Cairo::Context>& cr, int width, int height)
{


    cr->rectangle(0, 0, width, height);
    cr->fill();


}


void KbiDraw::draw_text(const Cairo::RefPtr<Cairo::Context>& cr, int rectangle_width, int rectangle_height)
{


    Pango::FontDescription font;


    font.set_family("Serif");
    font.set_weight(Pango::Weight::BOLD);
    font.set_size(35000);


    std::stringstream draw_note;
    auto current_notes = player->get_current_notes();
    for (const auto& note : current_notes) {
        draw_note << note << " ";
    }


    auto layout = create_pango_layout(draw_note.str());
    layout->set_font_description(font);


    int text_width;
    int text_height;


    //get the text dimensions (it updates the variables -- by reference)
    layout->get_pixel_size(text_width, text_height);


    // Position the text in the middle
    cr->move_to((rectangle_width - text_width)/2, (rectangle_height - text_height)/2);


    layout->show_in_cairo_context(cr);


}


bool KbiDraw::refresh()
{
    queue_draw();
    return true;
}
------------------------------------------------------