void pango_renderer_part_changed ( PangoRenderer* renderer, PangoRenderPart part )
Informs Pango that the way that the rendering is done
part has changed.
This should be called if the rendering changes in a way that would
prevent multiple pieces being joined together into one drawing call.
For instance, if a subclass of
PangoRenderer was to add a stipple
option for drawing underlines, it needs to call
pango_renderer_part_changed (render, PANGO_RENDER_PART_UNDERLINE);
When the stipple changes or underlines with different stipples
might be joined together. Pango automatically calls this for
changes to colors. (See
the part for which rendering has changed.