getRGB.Colors: Create RGB colors from data

In HenrikBengtsson/R.graphics: [R] Class Library - Graphics classes

Description

Generated colors in RGB units using either a one, two or three columns matrix of values specified by argument x. Each row in the matrix corresponds to one color and each column to either R (red), G (green) or B (blue). Which column that corresponds to which channel can be controlled by the argument dim. The intervals the values in each column span can be specified by the argument x.range. Everything outside the range is safely thresholded. If x.range is NULL, the range of each column in x will be used. The interval of each channel the input values should map into can be specified by the argument dim.range. By default this is the full range of each channel, i.e. [0,1].

Usage

Colors$getRGB(x, x.range=NULL, dim=c("r", "g", "b"), dim.range=NULL, ...)

Arguments

x	A matrix of size Nx1, Nx2 or Nx3, where N is the number of data values.
x.range	A matrix of size 2x1, 2x2 or 2x3.
dim	A vector specifying what channel each columns controls.
dim.range	A matrix of size 2x1, 2x2 or 2x3.
...	Not used.

Value

Returns a vector of character strings of length equal to the number of rows (or the length) of x. The resulting vector contains character strings of format "#nnnnnn" where n is a hexadecimal digit.

Author(s)

Henrik Bengtsson (http://www.braju.com/R/)

See Also

*getHSV(), *getGray(). For more information see Colors.

Examples

r <- 1:5;
g <- 1:5;
b <- 1:5;

x <- 1:5; y <- rep(1,5);
plot(NA, xlim=c(1,5), ylim=c(1,5), xlab="", ylab="");

# Generate full-range red colors
colors <- Colors$getRGB(r);
# "#000000" "#400000" "#800000" "#BF0000" "#FF0000"
points(x,1*y, col=colors, pch=19, cex=5);

colors <- Colors$getRGB(matrix(c(r,g), ncol=2));
# "#000000" "#404000" "#808000" "#BFBF00" "#FFFF00"
points(x,2*y, col=colors, pch=19, cex=5);

# Threshold the "g" channel to the interval [2,4].
data <- matrix(c(r,b,g), ncol=3);
data.range <- matrix(c(range(r), range(b), 2,4), ncol=2);
colors <- Colors$getRGB(data, data.range, dim=c("r","b","g"));
# "#000000" "#404000" "#808080" "#BFBFFF" "#FFFFFF"
points(x,3*y, col=colors, pch=19, cex=5);

# Generate light red colors
colors <- Colors$getRGB(r, dim.range=c(0.5,1));
# "#800000" "#9F0000" "#BF0000" "#DF0000" "#FF0000"
points(x,4*y, col=colors, pch=19, cex=5);

# Generate dark red colors
colors <- Colors$getRGB(r, dim.range=c(0.2, 0.7));
# "#330000" "#530000" "#730000" "#930000" "#B30000"
points(x,5*y, col=colors, pch=19, cex=5);

HenrikBengtsson/R.graphics documentation built on May 6, 2019, 11:53 p.m.