connectGrob {Gmisc}

Connect boxes with an arrow

Description

The function creates a grob that links two boxes together. It looks for which side it should attach the arrow, e.g. if the start is on top of the bottom it should attach to the bottom edge of ther start box and then to the top at the end.

Usage

connectGrob(
  start,
  end,
  type = c("vertical", "horizontal", "L", "-", "Z", "N"),
  subelmnt = c("right", "left"),
  lty_gp = getOption("connectGrob", default = gpar(fill = "black")),
  arrow_obj = getOption("connectGrobArrow", default = arrow(ends = "last", type =
    "closed"))
)

## S3 method for class 'connect_boxes'
print(x, ...)

## S3 method for class 'connect_boxes'
plot(x, ...)

Arguments

start

The start box

end

The end box

type

How the boxes are stacked. The L alternative generates a straight line up/down and then turns to righT/left for connecting with the end. The - generates a straight horizontal arrow. The Z creates a horizontal line that looks like a Z with 90 degree turns. The option N allows for vertical lines.

subelmnt

If we have a split box we can specify the right/left x as the connector point.

lty_gp

The gpar for the line. Set connectGrob option if you want to customize all the arrows at once.

arrow_obj

The arrow spec according to arrow. Set connectGrobArrow option if you want to customize all the arrows at once.

x

The grob to print/plot

...

Passed to grid.draw

Details

The exact positions of the line is stored at the attr(..., "line"). If you want to draw your own custom line all you need to do is check which attr(my_line, "line")$x and attr(my_line, "line")$y you want to attach to and then create your own custom linesGrob.

Value

grob with an arrow

See Also

Other flowchart components: align, boxGrob(), boxPropGrob(), coords(), distance(), moveBox(), spread

Examples

library(grid)
grid.newpage()

# Initiate the boxes that we want to connect
start <- boxGrob("Top", x = .5, y = .8)
end <- boxGrob("Bottom", x = .5, y = .2)
side <- boxPropGrob("Side", "Left", "Right", prop = .3, x = .2, y = .8)
sub_side_left <- boxGrob("Left", x = attr(side, "coords")$left_x, y = .5)
sub_side_right <- boxGrob("Right", x = attr(side, "coords")$right_x, y = .5)
exclude <- boxGrob("Exclude:\n - Too sick\n - Prev. surgery", x = .8, y = .5, just = "left")

# Connect the boxes and print/plot them
connectGrob(start, end, "vertical")
connectGrob(start, side, "horizontal")
connectGrob(side, sub_side_left, "v", "l")
connectGrob(side, sub_side_right, "v", "r")
connectGrob(start, exclude, "L")

# Print the grobs
start
end
side
exclude
sub_side_left
sub_side_right