Rasterize the input object

The function rasterizes input graphical objects (e.g., grob, layer, ggplot) and optionally processes the resulting raster using magick, a powerful image manipulation library. This allows for advanced graphical transformations directly within the plotting pipeline.

Usage

raster_magick(x, magick = NULL, ..., res = NULL, interpolate = FALSE)

Arguments

x

An object to rasterize, can be a grob(), layer(), ggplot(), or a list of such objects.

magick

A function (purrr-style formula is accepted) that takes an image_read() object as input and returns an object compatible with as.raster(). You can use any of the image_*() functions from the magick package to process the raster image.

...

Not used currently.

res

An integer sets the desired resolution in pixels.

interpolate

A logical value indicating whether to linearly interpolate the image (the alternative is to use nearest-neighbour interpolation, which gives a more blocky result).

Value

An object with the same class of the input.

Examples

# data generated code was copied from `ComplexHeatmap`
set.seed(123)
small_mat <- matrix(rnorm(56), nrow = 7)
rownames(small_mat) <- paste0("row", seq_len(nrow(small_mat)))
colnames(small_mat) <- paste0("column", seq_len(ncol(small_mat)))
ggheatmap(small_mat, aes(.x, .y), filling = NULL) +
    raster_magick(geom_tile(aes(fill = value)), res = 20)


ggheatmap(small_mat, aes(.x, .y), filling = NULL) +
    # Use `magick::filter_types()` to check available `filter` arguments
    raster_magick(geom_tile(aes(fill = value)),
        magick = function(image) {
            magick::image_resize(image,
                geometry = "50%x", filter = "Lanczos"
            )
        }
    )