diff --git a/src/frame.c b/src/frame.c
index 9b56080..f0c0d34 100644
--- a/src/frame.c
+++ b/src/frame.c
@@ -3508,6 +3508,67 @@ bottom edge of FRAME's display.  */)
 
   return Qt;
 }
+
+#ifdef HAVE_WINDOW_SYSTEM
+static
+#if ! (defined HAVE_GTK3 || defined USE_CAIRO)
+_Noreturn
+#endif
+Lisp_Object
+export_frame (Lisp_Object frame, Lisp_Object type, Lisp_Object fname)
+{
+  struct frame *f = decode_window_system_frame (frame);
+
+  if (!FRAME_VISIBLE_P (f))
+    error ("Frames to be exported must be visible");
+
+  if (FRAME_OBSCURED_P (f))
+    error ("Frames to be exported must not be obscured");
+
+  if (!NILP(fname))
+      CHECK_STRING(fname);
+
+  // Stefan, is this what you had in mind?
+  switch (f->output_method)
+    {
+    case output_x_window:
+#ifdef USE_CAIRO
+      // FIXME: save output when FNAME is non-nil
+      /* Question: Is it OK to reuse FRAME here? */
+      return Fx_export_frames(frame, type);
+#elif HAVE_GTK3
+      return x_gtk3_export_frame(f, type, fname);
+#endif
+      /* Fall through */
+    case output_initial:
+    case output_termcap:
+    case output_w32:
+    case output_msdos_raw:
+    case output_ns:
+    default:
+      error ("Unsupported toolkit");
+    }
+}
+
+DEFUN ("export-frame", Fexport_frame,
+       Sexport_frame, 0, 3, 0,
+       doc: /* Capture a screenshot of FRAME in TYPE format.
+Available formats depend on the graphic toolkit in use.
+Currently, this function only works with Cairo and GTK3.
+
+FRAME must be a live, visible, and unobscured frame.  It defaults to
+the selected one.  TYPE is a symbol: on Cairo, valid formats may
+include `pdf', `png', `postscript', and `svg', depending on
+compilation options; on GTK3, valid formats are `png' and `bmp'.
+
+If FNAME is non-nil, save the resulting capture under FNAME; if
+FNAME is nil, return the captured data as a unibyte string.  */)
+     (Lisp_Object frame, Lisp_Object type, Lisp_Object fname)
+{
+  return export_frame(frame, type, fname);
+}
+#endif // HAVE_WINDOW_SYSTEM
+
 
 /***********************************************************************
 				Frame Parameters
@@ -6141,6 +6202,7 @@ iconify the top level frame instead.  */);
   defsubr (&Sframe_pointer_visible_p);
 
 #ifdef HAVE_WINDOW_SYSTEM
+  defsubr (&Sexport_frame);
   defsubr (&Sx_get_resource);
   defsubr (&Sx_parse_geometry);
 #endif
diff --git a/src/xfns.c b/src/xfns.c
index 43c55cc..dc4ef8d 100644
--- a/src/xfns.c
+++ b/src/xfns.c
@@ -7419,6 +7419,48 @@ present and mapped to the usual X keysyms.  */)
 			       Printing
  ***********************************************************************/
 
+#ifdef HAVE_GTK3
+Lisp_Object
+x_gtk3_export_frame (struct frame* frame, Lisp_Object type, Lisp_Object fname)
+{
+  int width = FRAME_PIXEL_WIDTH (frame);
+  int height = FRAME_PIXEL_HEIGHT (frame);
+
+  const char* stype;
+  if (NILP (type) || EQ (type, Qpng))
+    stype = "png";
+  else if (EQ (type, Qbmp))
+    stype = "bmp";
+  else
+    error("Unsupported image type");
+
+  GdkWindow *w = gtk_widget_get_window (FRAME_GTK_WIDGET (frame));
+  if (!w)
+    error("Could not retrieve a GTK window for this frame");
+
+  // gdk_pixbuf_xlib_get_from_drawable(NULL, w, NULL, NULL, 0, 0, 0, 0, width, height);
+  GdkPixbuf *pb = gdk_pixbuf_get_from_window(w, 0, 0, width, height);
+  if (!pb)
+    error("Could not capture a screenshot of this frame");
+
+  if (NILP(fname))
+    {
+      char* buf;
+      long unsigned int buf_size;
+      if (!gdk_pixbuf_save_to_buffer (pb, &buf, &buf_size, stype, NULL, NULL))
+        error ("Could not convert the frame data");
+      return make_unibyte_string (buf, buf_size);
+    }
+  else
+    {
+      Lisp_Object encoded_fname = ENCODE_FILE (fname);
+      if (!gdk_pixbuf_save (pb, SSDATA (encoded_fname), stype, NULL, NULL))
+        error ("Could not save the frame data");
+      return Qnil;
+    }
+}
+#endif // HAVE_GTK3
+
 #ifdef USE_CAIRO
 DEFUN ("x-export-frames", Fx_export_frames, Sx_export_frames, 0, 2, 0,
        doc: /* Return image data of FRAMES in TYPE format.
@@ -7443,7 +7485,7 @@ compile-time configuration of cairo.  */)
 
       XSETFRAME (frame, f);
       if (!FRAME_VISIBLE_P (f))
-	error ("Frames to be exported must be visible.");
+	error ("Frames to be exported must be visible");
       tmp = Fcons (frame, tmp);
     }
   frames = Fnreverse (tmp);
@@ -7457,7 +7499,7 @@ compile-time configuration of cairo.  */)
   if (EQ (type, Qpng))
     {
       if (!NILP (XCDR (frames)))
-	error ("PNG export cannot handle multiple frames.");
+	error ("PNG export cannot handle multiple frames");
       surface_type = CAIRO_SURFACE_TYPE_IMAGE;
     }
   else
@@ -7472,7 +7514,7 @@ compile-time configuration of cairo.  */)
     {
       /* For now, we stick to SVG 1.1.  */
       if (!NILP (XCDR (frames)))
-	error ("SVG export cannot handle multiple frames.");
+	error ("SVG export cannot handle multiple frames");
       surface_type = CAIRO_SURFACE_TYPE_SVG;
     }
   else
@@ -7545,7 +7587,7 @@ visible.  */)
 
       XSETFRAME (frame, f);
       if (!FRAME_VISIBLE_P (f))
-	error ("Frames to be printed must be visible.");
+	error ("Frames to be printed must be visible");
       tmp = Fcons (frame, tmp);
     }
   frames = Fnreverse (tmp);
@@ -7633,6 +7675,7 @@ syms_of_xfns (void)
   DEFSYM (Qmono, "mono");
   DEFSYM (Qassq_delete_all, "assq-delete-all");
 
+  DEFSYM (Qbmp, "bmp");
 #ifdef USE_CAIRO
   DEFSYM (Qpdf, "pdf");
 
diff --git a/src/xterm.h b/src/xterm.h
index 1849a5c..267ade6 100644
--- a/src/xterm.h
+++ b/src/xterm.h
@@ -1082,6 +1082,9 @@ extern void x_real_pos_and_offsets (struct frame *f,
                                     int *xptr,
                                     int *yptr,
                                     int *outer_border);
+extern Lisp_Object x_gtk3_export_frame (struct frame* frame,
+                                        Lisp_Object fname,
+                                        Lisp_Object type);
 
 /* From xrdb.c.  */