Scale points

Scales points by sx/sy along the x/y axes, about the pivot (about_x, about_y).

Usage

trans_scale(sx = 1, sy = sx, about_x = 0, about_y = 0)

Arguments

sx

Scale factor along the x axis. Default 1.

sy

Scale factor along the y axis. Default sx (a uniform scale).

about_x, about_y

Pivot point coordinates. Default 0.

See also

Other transform helpers: trans(), trans_affine(), trans_chain(), trans_fn(), trans_identity(), trans_reflect(), trans_rotate(), trans_shear(), trans_translate(), trans_warp()

Examples

draw(shape_square(side = 1, trans = trans_scale(2)))

draw(shape_square(side = 1, trans = trans_scale(2, 0.5)))


# overlay the original (faded) with the scaled copy (solid)
original <- shape_rectangle(
  width = 1.5,
  height = 0.6,
  fill_alpha = 0.3,
  color_alpha = 0.3
)
draw(sketch() + original + (original + trans_scale(1.5, 0.7)))


# scaling about a pivot other than the shape's own centroid also moves
# it, since distance from the pivot is what gets scaled -- shown here
# against a fixed frame, with a small marker at the pivot
square <- shape_square(
  x = 1,
  side = 0.5,
  fill_alpha = 0.3,
  color_alpha = 0.3
)
pivot <- shape_circle(radius = 0.05, fill = "tomato", color = NA_character_)
draw(
  sketch() + square +
    (square + trans_scale(2, about_x = 0, about_y = 0)) +
    pivot,
  xlim = c(-3, 3), ylim = c(-3, 3)
)