Snap overlays to a grid

Use this function as the snap parameter of overlayServer() to enable a simple snap-to-grid behaviour for your overlay. It will ensure your overlays stay within the bounds of the plot, and snap both position and width of each overlay to the specified grid.

Usage

snap_grid(anchor = 0, step = 1, min_width = NA, max_width = NA)

Arguments

anchor

The location of any specific gridline.

step

The space between gridlines.

min_width

(optional) Minimum width of an overlay; default (NA) sets to step. Use NULL for no minimum.

max_width

(optional) Maximum width of an overlay; default (NA) sets to the largest size that accommodates the width of the overlay bounds, accounting for the grid. Use NULL for no maximum.

Note that the default values snap overlays to whole numbers.

Value

A snapping function suitable to pass to overlayServer() as the snap argument.

See also

overlayServer(), for a complete example.

Examples

server <- function(input, output) {
    ov <- overlayServer("my_plot", 8, snap = snap_grid())
    # further server code here . . .
}