draw_layer

The draw_layer vfunc is called before and after the text view is drawing its own text.

Applications can override this vfunc in a subclass to draw customized content underneath or above the text. In the gtk_text_view_layer_below_text and gtk_text_view_layer_above_text the drawing is done in the buffer coordinate space, but the older (deprecated) layers gtk_text_view_layer_below and gtk_text_view_layer_above work in viewport coordinates, which makes them unnecessarily hard to use. Since: 3.14