testAlpha {PBSmodelling} | R Documentation |
Display how the alpha transparency for rgb()
varies.
testAlpha(alpha=seq(0,1,len=25), fg="blue", bg="yellow", border="black", grid=FALSE, ...)
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. |
Invisibly returns the compound RGB matrix for fg
, alpha
,
bg
, and border
.
Rowan Haigh, Pacific Biological Station, Nanaimo BC
testCol
, testPch
, testLty
, testLwd