testAlpha {PBSmodelling}R Documentation

Test Various Alpha Transparency Values

Description

Display how the alpha transparency for rgb() varies.

Usage

testAlpha(alpha=seq(0,1,len=25), fg="blue", bg="yellow",
      border="black", grid=FALSE, ...)

Arguments

alpha numeric vector of alpha transparency values values from 0 to 1.
fg forground colour of the top shape that varies in trnasparency.
bg background colour (remains constant) of the underlying shape.
border border colour (which also changes in transparency) of the foreground polygon.
grid logical: if TRUE, lay a grey grid on the background colour.
... additional graphical arguments to send to the the ploting functions.

Value

Invisibly returns the compound RGB matrix for fg, alpha, bg, and border.

Author(s)

Rowan Haigh, Pacific Biological Station, Nanaimo BC

See Also

testCol, testPch, testLty, testLwd


[Package PBSmodelling version 2.06 Index]