### Name: grid.ls
### Title: List the names of grobs or viewports
### Aliases: grid.ls nestedListing pathListing grobPathListing
### Keywords: dplot

### ** Examples

# A gTree, called "parent", with childrenvp vpTree (vp2 within vp1)
# and child grob, called "child", with vp vpPath (down to vp2)
sampleGTree <- gTree(name="parent",
                     children=gList(grob(name="child", vp="vp1::vp2")),
                     childrenvp=vpTree(parent=viewport(name="vp1"),
                                       children=vpList(viewport(name="vp2"))))
grid.ls(sampleGTree)
# Show viewports too
grid.ls(sampleGTree, view=TRUE)
# Only show viewports
grid.ls(sampleGTree, view=TRUE, grob=FALSE)
# Alternate displays
# nested listing, custom indent
grid.ls(sampleGTree, view=TRUE, print=nestedListing, gindent="--")
# path listing
grid.ls(sampleGTree, view=TRUE, print=pathListing)
# path listing, without grobs aligned
grid.ls(sampleGTree, view=TRUE, print=pathListing, gAlign=FALSE)
# grob path listing 
grid.ls(sampleGTree, view=TRUE, print=grobPathListing)
# path listing, grobs only
grid.ls(sampleGTree, print=pathListing)
# path listing, viewports only
grid.ls(sampleGTree, view=TRUE, grob=FALSE, print=pathListing)
# raw flat listing
str(grid.ls(sampleGTree, view=TRUE, print=FALSE))