Use this function to rescale a palette function, for example: clip a certain part of it.
rescaler_x(range)
rescaler_lum(range, pal_luv)numeric values, in x or in luminance, to correspond with x = c(0, 1)
cpath_pal_luv, palette function on which the
luminance range will operate
A function with S3 class cpath_rescaler.
A rescaler function:
must accept input between zero and one.
must provide an output between zero and one.
the output must to vary monotonically with the input.
Use rescaler_linear() create a new palette-function that uses part
of the range of an existing palette-function.
Use rescaler_bezier() to rescale a Bézier palette-function to be more
perceptually uniform. This uses fits a spline to equally-spaced points on
the colorpath. The Bézier function makes some optimization calculations,
so it may take a few seconds to run.
# Input rescaler
rlin <- rescaler_x(c(0.25, 0.75))
# print for a preview
print(rlin)
#> Rescaler function:
#> input: 0.000 0.200 0.400 0.600 0.800 1.000
#> output: 0.250 0.350 0.450 0.550 0.650 0.750
# evaluate
rlin(c(0, 0.5, 1))
#> [1] 0.25 0.50 0.75
# Luminance rescaler
pal_luv_blues <- pal_luv_bezier(mat_luv_blues)
rlum <- rescaler_lum(c(40, 70), pal_luv_blues)
# print for a preview
print(rlum)
#> Rescaler function:
#> input: 0.000 0.200 0.400 0.600 0.800 1.000
#> output: 0.257 0.322 0.386 0.451 0.516 0.580
# evaluate
rlum(c(0, 0.5, 1))
#> [1] 0.2569183 0.4187022 0.5804860