Hi
Gabor Grothendieck wrote: > On Jan 23, 2008 9:38 PM, Paul Murrell <[EMAIL PROTECTED]> wrote: >> Hi >> >> >> Gabor Grothendieck wrote: >>> Why does the seekViewport at the bottom give an error? >> >> Because the viewport is popped after GRID.cellGrob.84 is drawn. >> >> grid.ls() shows the viewport because it recurses down into the legend >> frame grob. Compare your output with (grid-generated numbering differs) >> ... >> >> > grid.ls(recurs=FALSE, view=TRUE) >> ROOT >> GRID.rect.28 >> plot1.toplevel.vp >> plot1.xlab.vp >> plot1.xlab >> 1 >> plot1.ylab.vp >> plot1.ylab >> 1 >> plot1.strip.1.1.off.vp >> GRID.segments.29 >> 1 >> plot1.strip.left.1.1.off.vp >> GRID.segments.30 >> GRID.text.31 >> 1 >> plot1.panel.1.1.off.vp >> GRID.segments.32 >> GRID.text.33 >> GRID.segments.34 >> 1 >> plot1.panel.1.1.vp >> GRID.points.35 >> GRID.points.36 >> GRID.points.37 >> 1 >> plot1.panel.1.1.off.vp >> GRID.rect.38 >> 1 >> plot1.legend.top.vp >> GRID.frame.9 >> 1 >> plot1. >> 1 >> 1 >> >> If you look at what viewports are actually available, via >> current.vpTree(), you'll see that GRID.VP.24 is not there. >> >> The problem (see also >> https://stat.ethz.ch/pipermail/r-help/2008-January/151655.html) is that >> cellGrobs (children of frame grobs) use their 'vp' component to store >> the viewport that positions them within the parent frame. This means >> that the viewport is pushed and then popped (as per normal behaviour for >> 'vp' components). >> >> A possible solution that I am currently trialling uses a special >> 'cellvp' slot instead so that the cellGrob viewports are pushed and then >> "upped". That way they remain available after the cellGrob has drawn, >> so you can downViewport() to them. >> >> The disadvantage of this approach is that the viewports no longer appear >> in the grid.ls() listing (because grid.ls() has no way of knowing about >> special components of grobs that contain viewports). This effect can >> already be seen by the fact that the viewport for the frame grob >> (GRID.frame.70) is not shown in the grid.ls() output. On the other >> hand, the viewports will be visible via current.vpTree() ... > > Perhaps some convention could be adopted which, if followed, would > let grid.ls know? If that worked at least for graphics generated from > lattice and ggplot2 that would likely satisfy a significant percentage > of uses. The gridList() function used by grid.ls() is generic, so a solution is to simply write a method for frames and cellGrobs. I have committed a fix along these lines. Paul -- Dr Paul Murrell Department of Statistics The University of Auckland Private Bag 92019 Auckland New Zealand 64 9 3737599 x85392 [EMAIL PROTECTED] http://www.stat.auckland.ac.nz/~paul/ ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
