alpha {plotfunctions}

Adjusting the transparency of colors.

Description

Wrapper around adjustcolor.

Usage

alpha(x, f = 0.5)

Arguments

x

A color or a vector with color values.

f

A number for adjusting the transparency ranging from 0 (completely transparent) to 1 (not transparent).

Note

Does not always work for x11 panels.

See Also

Other Functions for plotting: addInterval(), add_bars(), add_n_points(), alphaPalette(), check_normaldist(), color_contour(), dotplot_error(), drawDevArrows(), emptyPlot(), errorBars(), fill_area(), getCoords(), getFigCoords(), getProps(), gradientLegend(), legend_margin(), marginDensityPlot(), plot_error(), plot_image(), plotsurface(), sortBoxplot()

Examples

emptyPlot(100,100, h=50, v=50)
rect(25,25,75,75, col=alpha('red',f=1))
rect(35,41,63,81, col=alpha(rgb(0,1,.5),f=.25), 
   border=alpha(rgb(0,1,.5), f=.65), lwd=4)

emptyPlot(1,1, axes=FALSE, main='Tunnel of 11 squares')
center <- c(.75, .25)
mycol <- 'steelblue'
for(i in seq(0,1,by=.1)){
    rect(center[1]-center[1]*(1.1-i), center[2]-center[2]*(1.1-i), 
        center[1]+(1-center[1])*(1.1-i), center[2]+(1-center[2])*(1.1-i), 
        col=alpha(mycol, f=i), border=mycol, lty=1, lwd=.5, xpd=TRUE)
}
axis(1, at=center[1]-center[1]*(1.1-seq(0,1,by=.1)), labels=seq(0,1,by=.1))

# see alphaPalette for an elaboration of this example