Optimal Shape Parameter for Hexbin Viewport

Takes a viewport or a given height and width and returns the shape parameter that will fill the specified plotting region with the appropriately shaped hexagons. If margins are specified the margins are subtracted from height and width before the shape parameter is specified.

Usage

optShape(vp, height = NULL, width = NULL, mar = NULL)

Arguments

vp: a viewport object, optional see details
height: the height of the plotting region, can be numeric or units
width: The width of the plotting region, can be numeric or units
mar: A four element numeric or units vector describing the margins in the order c(bottom, left, top, right)

Value

a scalar numeric value specifiyng shape.

Author

Nicholas Lewin-Koh

Warning

If a viewport is given as an argument it should already be pushed on the graphics device or it will have null units and a meaningless shape parameter will be returned.

Examples

x <- rgamma(10000,.9)
m <- as.logical(rbinom(10000,1,.17))
x[m] <- -x[m]
y <- rnorm(x,abs(x))
library("grid")
vp <- plotViewport(xscale= range(x)+c(-.5,.5),
                   yscale= range(y)+c(-.5,.5),
             default.units = "native")
grid.newpage()
pushViewport(vp)
grid.rect()
shape <- optShape(vp)
shape
#> [1] 0.8566879
hb <- hexbin(x,y,xbins=40,shape=shape)
grid.hexagons(hb,colramp=BTY)