Hi R-devel, It seems that grobX and grobY (from the grid package) do not refer to the bounding box of a grid.points object.
library(grid) library(lattice) xyplot(1:10 ~ 1:10) downViewport("plot1.panel.1.1.vp") grob <- grid.get("GRID.points", grep=TRUE) convertX(grobWidth(grob), "cm") # 10.3430190058480cm # (correct, but:) convertX(grobX(grob, "west"), "cm") # 5.89552083333333cm convertX(grobX(grob, "east"), "cm") # 5.89552083333334cm So grobX is returning the midpoint, rather than the bounding box. This is surprising, given that ?grobX says "If the grob describes multiple shapes, in most cases, the boundary value will correspond to the edge of a bounding box around all of the shapes." > sessionInfo() R version 2.7.1 (2008-06-23) i386-pc-mingw32 locale: LC_COLLATE=English_Australia.1252;LC_CTYPE=English_Australia.1252;LC_MONETARY=English_Australia.1252;LC_NUMERIC=C;LC_TIME=English_Australia.1252 attached base packages: [1] grid stats graphics grDevices utils datasets methods base other attached packages: [1] playwith_0.9-10 cairoDevice_2.8 gWidgetsRGtk2_0.0-36 RGtk2_2.12.5-3 gWidgets_0.0-28 [6] lattice_0.17-10 loaded via a namespace (and not attached): [1] gridBase_0.4-3 tools_2.7.1 -- Felix Andrews / 安福立 PhD candidate Integrated Catchment Assessment and Management Centre The Fenner School of Environment and Society The Australian National University (Building 48A), ACT 0200 Beijing Bag, Locked Bag 40, Kingston ACT 2604 http://www.neurofractal.org/felix/ 3358 543D AAC6 22C2 D336 80D9 360B 72DD 3E4C F5D8 ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel