Emits the #GtkSourceGutterRenderer::activate signal of the renderer. This is called from #GtkSourceGutter and should never have to be called manually.
a #GtkTextIter at the start of the line where the renderer is activated
a #GdkRectangle of the cell area where the renderer is activated
the event that triggered the activation
Emits the #GtkSourceGutterRenderer::activate signal of the renderer. This is called from #GtkSourceGutter and should never have to be called manually.