Assign a 2D matrix of pixels to specified colors

Assign a 2D matrix of pixels to specified colors

Usage

assignPixels(
  centers,
  pixel_matrix,
  color_space = "Lab",
  ref_white = "D65",
  adjust_centers = TRUE
)

Arguments

centers

Matrix of color centers (rows = colors, columns = channels).

pixel_matrix

Matrix of pixel colors (rows = pixels, columns = channels).

color_space

Color space in which to minimize distances, passed to [grDevices]{convertColor}. One of "sRGB", "Lab", "Luv", or "XYZ". Default is "Lab", a perceptually uniform (for humans) color space.

ref_white

Reference white for converting to different color spaces. D65 (the default) corresponds to standard daylight.

adjust_centers

Logical. Should the returned color clusters be the average value of the pixels assigned to that cluster? See details.

Value

A list of class color_clusters, containing:

1. pixel_assignments: The color center assignment for each pixel.

2. centers: A matrix of color centers. If adjust_centers = FALSE, this will be identical to the input of centers.

3. sizes: The number of pixels assigned to each cluster.

Details

This is a largely internal function called by imposeColors() for recoloring an image based on extrinsic colors. If adjust_centers = TRUE, then after assigning pixels to given color centers, the location of each color center is replaced by the average color of all the pixels assigned to that center.

Examples

# RGB extremes (white, black, red, green, blue, yellow, magenta, cyan)
ctrs <- matrix(c(1, 1, 1,
                 0, 0, 0,
                 1, 0, 0,
                 0, 1, 0,
                 0, 0, 1,
                 1, 1, 0,
                 1, 0, 1,
                 0, 1, 1), byrow = TRUE, ncol = 3)

# plot it
recolorize::plotColorPalette(ctrs)


# create a pixel matrix of random colors
pixel_matrix <- matrix(runif(3000), ncol = 3)

# assign pixels
reassigned <- recolorize::assignPixels(ctrs, pixel_matrix, adjust_centers = TRUE)
recolorize::plotColorPalette(reassigned$centers)


# if we turn off adjust_centers, the colors remain the same as the inputs:
keep.centers <- recolorize::assignPixels(ctrs, pixel_matrix, adjust_centers = FALSE)
recolorize::plotColorPalette(keep.centers$centers)