README.md

In coolbutuseless/displease: Numeric and Color Sequences with Non-Linear Interpolation

displease

The displease package provides non-linear interpolation between numeric values.

It is a replacement for seq() for when you want a sequence between two values which is not equally spaced.

Easing can look much better than strict linear interpolation when applied to objects moving spatially.

displease = displ + ease. The results are often used for animating visual displacement, and the non-linear interpolation is performed by applying an easing function.

Installation

This package can be installed from CRAN

install.packages('displease')

You can install the latest development version from GitHub with:

# install.package('remotes')
remotes::install_github('coolbutuseless/displease')

Pre-built source/binary versions can also be installed from R-universe

install.packages('displease', repos = c('https://coolbutuseless.r-universe.dev', 'https://cloud.r-project.org'))

What’s in the box?

• seq_ease(x1, x2, n, type, direction) - create a sequence of length n between x1 and x2. Apply the easing function given by type.
• type is one of: sine, quad, cubic, quart, quint, exp, circle, back, elastic
• direction is one of: in, out, in-out
• seq_color(col1, col2, ...) non-linear interpolation between two colors.

The following graph shows the seq_ease() output for n = 100 for all the different easing functions with given extents of x1 = 0 and x2 = 1

Displacement Easing

library(displease)

# normal linear interpolation using seq()
(y_linear       <- seq(1, 10, length.out = 10))
#>  [1]  1  2  3  4  5  6  7  8  9 10

# Non-linear interpolation using {displease}
(y_cubic_in     <- seq_ease(1, 10, n=10, type = 'cubic', direction = 'in'))
#>  [1]  1.000000  1.012346  1.098765  1.333333  1.790123  2.543210  3.666667
#>  [8]  5.234568  7.320988 10.000000
(y_cubic_in_out <- seq_ease(1, 10, n=10, type = 'cubic', direction = 'in-out'))
#>  [1]  1.000000  1.049383  1.395062  2.333333  4.160494  6.839506  8.666667
#>  [8]  9.604938  9.950617 10.000000

plot(1:10, y_linear      , type = 'b')

plot(1:10, y_cubic_in    , type = 'b')

plot(1:10, y_cubic_in_out, type = 'b')

Illustration of supported easings

Easing between two colors

When easing between two colors, the colorspace where the interpolation takes place will have a large effect on the final result.

The examples below show the interpolation from ‘red’ to ‘blue’. The only difference between the examples is the colorspace where the interpolation occurs.

n <- 100
cols <- seq_color('red', 'blue', n = n, direction = 'in-out', type = 'cubic',
                  colorspace = 'hcl')
head(cols)
#> [1] "#FF0000" "#FF0000" "#FF0000" "#FF0000" "#FF0100" "#FF0200"
grid::grid.rect(x = seq(0, 0.95, length.out = n), width = 0.1, 
                gp = grid::gpar(fill = cols, col = NA))

n <- 100
cols <- seq_color('red', 'blue', n = n, direction = 'in-out', type = 'cubic', 
                  colorspace = 'lab')
head(cols)
#> [1] "#FF0000" "#FF0000" "#FF0000" "#FF0000" "#FF0000" "#FF0000"
grid::grid.rect(x = seq(0, 0.95, length.out = n), width = 0.1, 
                gp = grid::gpar(fill = cols, col = NA))

Animated example

This animation shows each of the easing types.

coolbutuseless/displease documentation built on Dec. 26, 2024, 3:14 p.m.