search for: scgradient

Hi all, Is there a way to fill a rectangle or polygon with a color and/or transparency gradient? This would be extremely useful for me in terms of adding some additional information to some plots I'm making, especially if I could define the gradient on my own by putting functions into rgb something like rgb( r=f(x,y), g=f(x,y), b=f(x,y), alpha=f(x,y) ). Not so important whether the

Dear R-helpers, I'm plotting geophysical data in the form of contours using "filled.contour". The display would be much more effective if the areas with negative values could be color coded by -- say -- "cold colors" in the range of blue to green, and conversely the areas with positive values got plotted with "warm colors", from yellow to red. Right now if I use