Customising grid Drawing

Description

These generic hook functions are called whenever a grid grob is drawn. They provide an opportunity for customising the drawing of a new class derived from grob (or gTree).

Usage

drawDetails(x, recording)
preDrawDetails(x)
postDrawDetails(x)

Arguments

Details

NOTE: these functions have been largely superceded by the makeContent and makeContext functions, though they are still run and may still be useful in some contexts.

These functions are called by the grid.draw methods for grobs and gTrees.

preDrawDetails is called first during the drawing of a grob. This is where any additional viewports should be pushed. Note that the default behaviour for grobs is to push any viewports in the vp slot, and for gTrees is to also push and up any viewports in the childrenvp slot so there is typically nothing to do here.

drawDetails is called next and is where any additional calculations and graphical output should occur. Note that the default behaviour for gTrees is to draw all grobs in the children slot so there is typically nothing to do here.

postDrawDetails is called last and should reverse anything done in preDrawDetails (i.e., pop or up any viewports that were pushed). Note that the default behaviour for grobs is to pop any viewports that were pushed so there is typically nothing to do here.

Note that preDrawDetails and postDrawDetails are also called in the calculation of "grobwidth" and "grobheight" units.

Value

None of these functions are expected to return a value.

Author(s)

Paul Murrell

References

"Changes to grid for R 3.0.0", Paul Murrell, The R Journal (2013) 5:2, pages 148-160.

See Also

grid.draw and makeContent