Colors  R Documentation 
jet.col
generates the matlabtype colors.
jet2.col
is similar but lacks the deep blue colors
gg.col
and gg2.col
generate ggplotlike colors.
ramp.col
creates color schemes by interpolation.
alpha.col
creates transparent colors.
jet.col (n = 100, alpha = 1)
jet2.col (n = 100, alpha = 1)
gg.col (n = 100, alpha = 1)
gg2.col (n = 100, alpha = 1)
ramp.col (col = c("grey", "black"), n = 100, alpha = 1)
alpha.col (col = "grey", alpha = 0.5)
n 
Number of colors to generate. 
alpha 
Value in the range [0, 1] for alpha
transparency channel (0 means transparent and 1 means opaque).
Transparency defined in the color palette is overruled when

col 
Colors to interpolate, change. 
In addition to the color functions described here, colors
can also be adapted by shading and lighting, or made transparent.
Shading will be overruled if lighting is not FALSE
.
To make colors transparent, use argument alpha
, with a value inbetween 0 and 1.
To switch on shading, the argument shade
should be given a value inbetween 0 and 1.
To switch on lighting, the argument lighting
should be either set to TRUE
(in which case default settings will be used) or should be a list with specifications of
one of the following: ambient, diffuse, specular, exponent, sr
and alpha
.
The defaults are:
ambient = 0.3, diffuse = 0.6, specular = 1., exponent = 20, sr = 0, alpha = 1
Lighting is defined as the sum of ambient, diffuse and specular light.
If N
is the normal vector on the facets (3values, x, y, z direction)
and I
is the light vector, then
col = (ambient + Id + sr * Is) * col + (1  sr) * Is
, where
Is = specular * abs(Light) ^ exponent
, Id = diffuse * Light
and
Light = sum(N*I)
.
The lighting algorithm is very simple, i.e. it is flat shading, no interpolation.
Toggling on lighting or shading also requires the input of the angles of the
light source, as ltheta
and lphi
, whose defaults are:
ltheta = 135, lphi = 0
. This usually works well for shading, but may
not be optimal for lighting.
A list with colors.
Karline Soetaert <karline.soetaert@nioz.nl>
The ggplot type of colors gg.plot
is a colorblind friendly palette from
http://wiki.stdout.org/rcookbook/Graphs
.
colorRamp and colorRampPalette for comparable (and more elaborate) Rfunctions.
# save plotting parameters
pm < par("mfrow")
pmar < par("mar")
## =======================================================================
## Transparency and various color schemes
## =======================================================================
par(mfrow = c(3, 3))
for (alph in c(0.25, 0.75))
image2D(volcano, alpha = alph,
main = paste("jet.col, alpha = ", alph))
image2D(volcano, main = "jet.col")
image2D(volcano, col = jet2.col(100), main = "jet2.col")
image2D(volcano, col = gg.col(100), main = "gg.col")
image2D(volcano, col = gg2.col(100), main = "gg2.col")
image2D(volcano, col = rainbow(100), main = "rainbow")
image2D(volcano, col = terrain.colors(100), main = "terrain.colors")
image2D(volcano, col = ramp.col(c("blue", "yellow", "green", "red")),
main = "ramp.col")
## =======================================================================
## Shading, lighting  one color
## =======================================================================
# create grid matrices
X < seq(0, pi, length.out = 50)
Y < seq(0, 2*pi, length.out = 50)
M < mesh(X, Y)
phi < M$x
theta < M$y
# x, y and z grids
x < sin(phi) * cos(theta)
y < cos(phi)
z < sin(phi) * sin(theta)
# these are the defaults
p < list(ambient = 0.3, diffuse = 0.6, specular = 1.,
exponent = 20, sr = 0, alpha = 1)
par(mfrow = c(3, 3), mar = c(0, 0, 0, 0))
Col < "red"
surf3D(x, y, z, box = FALSE, col = Col, shade = 0.9)
surf3D(x, y, z, box = FALSE, col = Col, lighting = TRUE)
surf3D(x, y, z, box = FALSE, col = Col, lighting = list(ambient = 0))
surf3D(x, y, z, box = FALSE, col = Col, lighting = list(diffuse = 0))
surf3D(x, y, z, box = FALSE, col = Col, lighting = list(diffuse = 1))
surf3D(x, y, z, box = FALSE, col = Col, lighting = list(specular = 0))
surf3D(x, y, z, box = FALSE, col = Col, lighting = list(exponent = 5))
surf3D(x, y, z, box = FALSE, col = Col, lighting = list(exponent = 50))
surf3D(x, y, z, box = FALSE, col = Col, lighting = list(sr = 1))
## =======================================================================
## Shading, lighting with default colors
## =======================================================================
x < seq(pi, pi, len = 100)
y < seq(pi, pi, len = 100)
grid < mesh(x, y)
z < with(grid, cos(x) * sin(y))
cv < with(grid, cos(y) * sin(x))
# lphi = 180, ltheta = 130  good for shade
# lphi = 90, ltheta = 0  good for lighting
par(mfrow = c(2, 2))
persp3D(z = z, x = x, y = y, colvar = cv, zlim = c(3, 3), colkey = FALSE)
persp3D(z = z, x = x, y = y, colvar = cv, zlim = c(3, 3),
lighting = TRUE, colkey = FALSE)
persp3D(z = z, x = x, y = y, colvar = cv, zlim = c(3, 3),
shade = 0.25, colkey = FALSE)
persp3D(z = z, x = x, y = y, colvar = cv, zlim = c(3, 3),
lighting = TRUE, lphi = 90, ltheta = 0, colkey = FALSE)
## =======================================================================
## transparency of a vector of colors
## =======================================================================
par(mfrow = c(1, 1))
x < runif(19)
y < runif(19)
z < runif(19)
# split into 5 sections (polygons)
ii < seq(4, 19, by = 4)
x[ii] < y[ii] < z[ii] < NA
polygon3D(x, y, z, border = "black", lwd = 2,
col = alpha.col(c("red", "lightblue", "yellow", "green", "black"),
alpha = 0.4))
# the same, now passing alpha as an argument to polygon3D:
## Not run:
polygon3D(x, y, z, border = "black", lwd = 2,
col = c("red", "lightblue", "yellow", "green", "black"),
alpha = 0.4)
## End(Not run)
# reset plotting parameters
par(mfrow = pm)
par(mar = pmar)
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