Save fixed-size glycan cartoon image to local device.

This function saves the glycan cartoon to a file, with a suitable size.

Usage

save_cartoon(cartoon, file, ..., dpi = 300, scale = 1)

Arguments

cartoon

A ggplot2 object returned by draw_cartoon().

file

File name of glycan cartoon.

...

Ignored.

dpi

Deprecated and ignored. Use scale to change the output size.

scale

Numeric output-size multiplier. The default 1 saves the cartoon at its natural fixed size; 2 saves the same cartoon with twice the pixel width and height.

Why not width and height?

The familiar ggplot2::ggsave() interface uses width, height, and dpi because ordinary ggplot2 plots are drawn into a user-chosen device size. glydraw cartoons are different: the natural width and height are calculated from the glycan structure so residues, linkages, labels, and borders stay comparable across different glycans. If users supplied arbitrary width and height, glydraw would either distort that structure-derived layout or need to guess how to reconcile one requested size with the other.

dpi is also not the right control here because changing it alters how point- and inch-based ggplot2 elements are rasterized relative to the fixed cartoon canvas. glydraw therefore keeps an internal fixed design scale and uses scale as a single multiplier for the final pixel dimensions. This preserves the cartoon's aspect ratio and relative appearance while still allowing larger or smaller output files.

Examples

if (FALSE) { # \dontrun{
cartoon <- draw_cartoon("Gal(b1-3)GalNAc(a1-")
save_cartoon(cartoon, "p1.png", scale = 2)
} # }