The default is to create a mosaic with 48 knobs (brick studs) on each side. Change this using the
img_size input. A single value will create a square mosaic, while an array of two values represent the width and length.
A key feature in
image_to_mosaic() is the conversion of the original image into colors produced by LEGO. The default is to map each individual pixel to any of the 41 solid brick colors currently produced by LEGO useing the CIE94 algorithm. These defaults can be changed.
There are currently 2 main ways to control the color palettes to build mosaics in brickr.
color_paletteinput takes a list of pre-defined palettes to create the mosaic.
color_tableinput can take a data frame of specific colors. Usually a subset of the included
Each of the 41 colors belongs to one of three categories. These categories are mutually exclusive and can be used together.
color_palette input in the
image_to_mosaic() function to limit the bricks used to any combination of these three categories.
p1 <- png::readPNG(demo_img) %>% image_to_mosaic(32, color_palette = c('universal', 'generic')) %>% build_mosaic(title = "universal & generic") p2 <- png::readPNG(demo_img) %>% image_to_mosaic(32, color_palette = c('universal')) %>% build_mosaic(title = "universal") gridExtra::grid.arrange(p1, p2, layout_matrix = matrix(c(1,2), ncol=2))
For grayscale or black and white mosaics, use
color_palette = 'bw'. This creates the mosaic by measuring the brightness of each pixel in the image and mapping it one of the four shades of gray. Use the contrast input to adjust the relative brightness of the pixels.
color_table input, it is possible to restrict the colors in the mosaic to a custom palette.
The default algorithm is ‘cie94’, though the other farver options are available using the
method input. The farver ‘euclidean’ is not very accurate, so ‘brickr_classic’ returns a manually calculated version for Euclidean RGB distance matching.
When rendering a mosaic from a photographic with many shades of similar colors, using dithering by setting
dithering = TRUE will help to add texture to the mosaic and avoid large areas of the same color. This works particularly well for large mosaics, but is purely a stylist preference.
gg_img = tempfile() download.file("http://ryantimpe.com/files/goldengirls.JPG", gg_img, mode="wb") c(FALSE, TRUE) %>% purrr::map(~jpeg::readJPEG(gg_img) %>% image_to_mosaic(dithering = .x) %>% build_mosaic(title = paste("dithering =", .x))) -> mosaics_by_dither gridExtra::grid.arrange(grobs = mosaics_by_dither, layout_matrix = matrix(c(1,2), ncol=2))
With rayshader installed, passing the mosaic object to
bricks_from_mosaic() will render a 3D object, stacking layers of bricks on each other to create an elevated mosaic. By default, the lightest color bricks will be on top, but this can be changed using the
highest_el = 'dark' option.
png::readPNG(demo_img) %>% image_to_mosaic(32) %>% bricks_from_mosaic(highest_el = "dark") %>% build_bricks() #From dput(round(rgl::par3d("userMatrix"),1)) after manual rotation custom_rotation <- structure(c(0.9, 0.3, -0.3, 0, -0.3, 0.9, -0.3, 0, 0.2, 0.4, 0.9, 0, 0, 0, 0, 1), .Dim = c(4L, 4L)) rgl::par3d(userMatrix = rgl::rotate3d(custom_rotation, 0, 0, pi/4 ,1))