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.types.TextViewLayer.BelowText and gtk.types.TextViewLayer.AboveText
the drawing is done in the buffer coordinate space, but the older (deprecated)
layers gtk.types.TextViewLayer.Below and gtk.types.TextViewLayer.Above work in viewport
coordinates, which makes them unnecessarily hard to use. Since: 3.14
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.types.TextViewLayer.BelowText and gtk.types.TextViewLayer.AboveText the drawing is done in the buffer coordinate space, but the older (deprecated) layers gtk.types.TextViewLayer.Below and gtk.types.TextViewLayer.Above work in viewport coordinates, which makes them unnecessarily hard to use. Since: 3.14