body_add_vg             vml graph code
dml_docx                DrawingML graphic device for Microsoft Word
dml_pptx                DrawingML graphic device for Microsoft
                        PowerPoint
dml_xlsx                DrawingML graphic device for Microsoft Excel
dsvg                    SVG Graphics Driver
dsvg_view               Run plotting code and view svg in RStudio
                        Viewer or web broswer.
ph_with_vg              pml graph code
rvg_tracer_off          trace off id colection
rvg_tracer_on           trace on id colection
set_attr                set attributes to graphical elements
