c++在gtk+中使用cairo打印更多页面

#include <gtk/gtk.h>
#include <cairo.h>

GtkWidget *window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
GtkPrintSettings *print_settings = gtk_print_settings_new();
GtkPageSetup *page_setup = gtk_page_setup_new();

void print_callback(GtkWidget *widget, gpointer data)
{
    GtkPrintOperation *print_operation = gtk_print_operation_new();
    gtk_print_operation_set_print_settings(print_operation, print_settings);
    gtk_print_operation_set_default_page_setup(print_operation, page_setup);
    gtk_print_operation_set_n_pages(print_operation, num_pages); // 设置打印的总页数

    g_signal_connect(print_operation, "draw_page", G_CALLBACK(draw_page_callback), data);

    gtk_print_operation_run(print_operation, GTK_PRINT_OPERATION_ACTION_PRINT_DIALOG, GTK_WINDOW(window), NULL);
}

void draw_page_callback(GtkPrintOperation *operation, GtkPrintContext *context, gint page_number, gpointer data)
{
    cairo_t *cr = gtk_print_context_get_cairo_context(context);

    // 在每一页上进行绘制操作
    cairo_move_to(cr, x, y);
    cairo_show_text(cr, "Hello, World!");

    // 绘制完当前页后，判断是否还有下一页需要打印
    if (page_number < num_pages - 1)
        gtk_print_operation_set_n_pages(operation, num_pages); // 更新打印的总页数
    else
        gtk_print_operation_set_n_pages(operation, page_number + 1); // 设置打印的总页数为当前页数加1
}

gtk_widget_show_all(window);
gtk_main();