Gtk.IconSet.prototype.render_icon

function render_icon(style:Gtk.Style, direction:Gtk.TextDirection, state:Gtk.StateType, size:Number, widget:Gtk.Widget, detail:String):GdkPixbuf.Pixbuf {
    // Gjs wrapper for gtk_icon_set_render_icon()
}

Renders an icon using render_icon. In most cases, render_icon is better, since it automatically provides most of the arguments from the current widget settings. This function never returns null; if the icon can't be rendered (perhaps because an image file fails to load), a default "missing image" icon will be returned instead.

style: a Gtk.Style associated with widget, or null
direction: text direction
state: widget state
size: icon size. A size of (GtkIconSize)-1 means render at the size of the source and don't scale.
widget: widget that will display the icon, or null. The only use that is typically made of this is to determine the appropriate Gdk.Screen.
detail: detail to pass to the theme engine, or null. Note that passing a detail of anything but null will disable caching.
Returns: a GdkPixbuf.Pixbuf to be displayed