GDK获得各种scale factor

#include <gtk/gtk.h>
#include <gdk/gdk.h>
#define  FIRST_LABEL "first label"
int main(int argc, char *argv[]) 
{ 
  gtk_init(NULL, NULL);
  GtkWidget *window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
    gtk_window_set_default_size(GTK_WINDOW(window), 300, 200);
  GtkWidget *vbox = gtk_vbox_new(TRUE, 10);
  gtk_container_add(GTK_CONTAINER(window), vbox);
  GtkWidget *label_one = gtk_label_new(FIRST_LABEL);
  gtk_container_add(GTK_CONTAINER(vbox), label_one);
  gtk_widget_show_all(window);
  int scale_factor = 0;
  scale_factor = gtk_widget_get_scale_factor (GTK_WIDGET (window));
  printf("gtk_widget_get_scale_factor=%d\n", scale_factor);
  GdkDisplay* display = gdk_display_get_default();
  printf("display=0x%08X\n", display);
  GdkScreen* screen = gdk_screen_get_default();
  printf("screen=0x%08X\n", screen);
  scale_factor = gdk_screen_get_monitor_scale_factor(screen, 0);
  printf("gdk_screen_get_monitor_scale_factor=%d\n", scale_factor);
  GdkMonitor* monitor = gdk_display_get_primary_monitor(display);
  printf("monitor=0x%08X\n", monitor);
  scale_factor = gdk_monitor_get_scale_factor(monitor);
  printf("gdk_monitor_get_scale_factor=%d\n", scale_factor);
  gtk_main();
    return 0; 
} 

#!/bin/bash
COMPILE_INCLUDE=${COMPILE_INCLUDE}" -I/usr/include/gtk-3.0"
OUTPUT_FILE=test
if [ -f ${OUTPUT_FILE} ]; then
    rm ${OUTPUT_FILE}
fi
echo ${COMPILE_INCLUDE_LINK}
gcc \
    -o ${OUTPUT_FILE} \
    test.c \
    ${COMPILE_INCLUDE} \
    ${COMPILE_LINK} \
    `pkg-config --cflags --libs gtk+-3.0 gtk+-x11-3.0 gdk-3.0 gdk-x11-3.0`