raster_magick: Rasterize the ggplot layers

In ggalign: A 'ggplot2' Extension for Composable Visualization

Rasterize the ggplot layers

Description

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, ...)

Arguments

x	An object to rasterize, can be a grob(), layer(), ggplot(), or a list of such objects.
...	Additional arguments passed on to magickGrob().

Value

An object with the same class of the input.

See Also

magickGrob()

Examples

# Currently, `magick` package require R >= 4.1.0
if (requireNamespace("magick")) {
    # 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"
                )
            }
        )
}

ggalign documentation built on Nov. 5, 2025, 7:16 p.m.