Display how the alpha transparency for rgb()
varies.
testAlpha(alpha=seq(0,1,len=25), fg="blue", bg="yellow",
border="black", grid=FALSE, ...)
Invisibly returns the compound RGB matrix for fg
, alpha
,
bg
, and border
.
numeric vector of alpha transparency values values from 0 to 1.
foreground colour of the top shape that varies in transparency.
background colour (remains constant) of the underlying shape.
border colour (which also changes in transparency) of the foreground polygon.
logical: if TRUE
, lay a grey grid on the background colour.
additional graphical arguments to send to the the ploting functions.
Jon T. Schnute, Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo BC
testCol
, testPch
, testLty
, testLwd