PBSmodelling (version 2.68.8)

testAlpha: 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, ...)

Value

Invisibly returns the compound RGB matrix for fg, alpha,

bg, and border.

Arguments

alpha

numeric vector of alpha transparency values values from 0 to 1.

fg

foreground colour of the top shape that varies in transparency.

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.

Author

Jon T. Schnute, Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo BC

See Also

testCol, testPch, testLty, testLwd