MetadataSidebar: Change layout of the data values

Move the value labels in their own line below their key labels.
That improves the visibility of the values and takes away less
horizontal space for image viewing. Unfortunately scrolling could be
necessary now as the vertical space requirement increased.

origin commit:
https://gitlab.gnome.org/GNOME/eog/commit/00aad08

Author: fxri

src/eom-metadata-sidebar.c

@@ -127,22 +127,30 @@ _gtk_grid_append_prop_line (GtkGrid *grid, GtkWidget *sibling,
 			    GtkWidget **data_label, const gchar *text)
 {
 	GtkWidget *label;
+	gchar *markup;
+	GtkWidget *box;
 
-	label = gtk_label_new (text);
-	gtk_misc_set_alignment (GTK_MISC (label), 0.0, 0.5);
+	box = gtk_box_new (GTK_ORIENTATION_VERTICAL, 0);
+	label = gtk_label_new (NULL);
+	markup = g_markup_printf_escaped("<b>%s</b>", text);
+	gtk_label_set_markup (GTK_LABEL(label), markup);
+	g_free (markup);
 
-	gtk_grid_attach_next_to (grid, label, sibling, GTK_POS_BOTTOM,  1, 1);
+	gtk_misc_set_alignment (GTK_MISC (label), 0.0, 1.0);
+	gtk_box_pack_start (GTK_BOX (box), label, FALSE, FALSE, 0);
 
 	if (G_LIKELY (data_label != NULL)) {
 		*data_label = gtk_label_new (NULL);
 		gtk_label_set_selectable (GTK_LABEL (*data_label), TRUE);
-		gtk_label_set_ellipsize (GTK_LABEL (*data_label), PANGO_ELLIPSIZE_END);
-		gtk_misc_set_alignment (GTK_MISC (*data_label), 0.0, 0.5);
-		gtk_grid_attach_next_to (grid, *data_label, label,
-					 GTK_POS_RIGHT, 1, 1);
+		gtk_label_set_line_wrap (GTK_LABEL(*data_label), TRUE);
+		gtk_misc_set_alignment (GTK_MISC (*data_label), 0.0, 0.0);
+		// Add a small margin to make it a sublabel to the first label
+		gtk_widget_set_margin_left (*data_label, 12);
+		gtk_box_pack_end (GTK_BOX(box), *data_label, FALSE, FALSE, 0);
 	}
+	gtk_grid_attach_next_to (grid, box, sibling, GTK_POS_BOTTOM,  2, 1);
 
-	return label;
+	return box;
 }
 
 #if HAVE_EXEMPI
@@ -499,11 +507,15 @@ eom_metadata_sidebar_init (EomMetadataSidebar *sidebar)
 	label = _gtk_grid_append_prop_line (GTK_GRID (priv->grid), label,
 					    NULL, _("Folder:"));
 
+{
 	priv->folder_button = gtk_button_new_with_label ("");
 	g_signal_connect (priv->folder_button, "clicked",
 			  G_CALLBACK (_folder_button_clicked_cb), sidebar);
-	gtk_grid_attach_next_to (GTK_GRID (priv->grid), priv->folder_button,
-				 label, GTK_POS_RIGHT, 1, 1);
+	gtk_widget_set_margin_left (priv->folder_button, 12);
+	gtk_widget_set_margin_right (priv->folder_button, 12);
+	gtk_widget_set_margin_top (priv->folder_button, 3);
+	gtk_box_pack_end (GTK_BOX (label), priv->folder_button, FALSE, FALSE, 0);
+}
 
 #if HAVE_METADATA	
 	label = _gtk_grid_append_title_line (GTK_GRID (priv->grid),