GTK在drawable区域绘图

gtk不使用cairo库的绘图方式：

#include <gtk/gtk.h>
static gboolean on_expose(GtkWidget *drawArea,GdkEventExpose *event,gpointer data)
{
    
	GdkGC *gc_0, *gc_1, *gc_2; 
	GdkColor color;

	gc_0 = gdk_gc_new(drawArea->window);
	color.red = 0;
	color.green = 30000;
	color.blue = 0;
	gdk_gc_set_rgb_fg_color( gc_0, &color );

	gc_1= gdk_gc_new( drawArea->window );
	color.red = 65535;
	color.green = 0;
	color.blue = 65535;
	gdk_gc_set_rgb_fg_color( gc_1, &color );

	gc_2= gdk_gc_new( drawArea->window );
	color.red = 0;
	color.green = 65522;
	color.blue = 33333;
	gdk_gc_set_rgb_fg_color( gc_2, &color );

	//画矩形
    gdk_draw_rectangle( drawArea->window,gc_0,TRUE,5, 5, 100, 100 ); 
	//画圆弧
    gdk_draw_arc( drawArea->window,gc_1,FALSE, 150, 50, 100, 100, 0, 64*180);
	//写字
	PangoLayout *layout = gtk_widget_create_pango_layout( drawArea, "hello world!" );
	PangoFontDescription *fontdesc = pango_font_description_from_string( "Comic Sans 24" );
	pango_layout_set_font_description( layout, fontdesc ); 
	gdk_draw_layout( drawArea->window,gc_2,50, 150, layout );

	//释放资源
	pango_font_description_free( fontdesc );
	g_object_unref( layout );
	g_object_unref( G_OBJECT(gc_0) );
	g_object_unref( G_OBJECT(gc_1) );
   
    return TRUE;


}


int main(int argc,char *argv[])
{
    
	GtkWidget *window;
	GtkWidget *drawArea; 

	gtk_init(&argc, &argv);
	window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
	gtk_window_set_title(GTK_WINDOW(window), "Center");
	gtk_window_set_default_size(GTK_WINDOW(window), 300, 200);
	gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER);

	drawArea = gtk_drawing_area_new();
	gtk_widget_set_size_request(drawArea, 300, 200);
	gtk_container_add(GTK_CONTAINER(window), drawArea);
	g_signal_connect(drawArea, "expose_event",G_CALLBACK(on_expose), NULL);
	g_signal_connect_swapped(G_OBJECT(window), "destroy",G_CALLBACK(gtk_main_quit), NULL);

	gtk_widget_show_all(window); 

	gtk_main();
	return 0;
}

效果：

参考：
gtk画矩形