Affine Transformation

Wrapper functions for transformations, rotate: tf_rotate, flip: tf_flip, shift: tf_shift shear: tf_shear, scale: tf_scale and tf_scale_xy

tf_affine(
  object,
  type = c("none", "translate", "scale", "rotate", "shear", "reflect"),
  by.each.cross = F,
  x = 0,
  y = 0,
  angle = NA,
  scale.x = NA,
  scale.y = NA,
  counterclockwise = FALSE,
  relative = T,
  crosses = NULL,
  layout = "transforming"
)

tf_rotate(object, x = 0, y = 0, angle = 90, ...)

tf_flip(object, axis = c("x", "y"), ...)

tf_shift(object, x = 0, y = 0, ...)

tf_shear(object, axis = c("x", "y"), angle = 15, ...)

tf_scale(object, x = 0, y = 0, scale.x = 1, scale.y = 1, ...)

Arguments

object

a CrossLink object
type

affine type
by.each.cross

transformation to be performed by each cross
x, y

coordiantes of transformation center for tf_rotate; offset in x,y axies for tf_shift; scale about this position for tf_scale; scale x and y along x, y axies, respectively, for tf_scale_xy
angle

transformation angle in degree
scale.x, scale.y

scale size for type scale
counterclockwise

angle in counterclockwise for transformation
relative

x,y is relative coordinates in range c(0,1)
crosses

only these crosses will be transformed
layout

layout name to save
...

other parameters passed to tf_affine
axis

along which axis to flip or shear

Value

an updated CrossLink object

Details

learn more about 2D affine and perspective tranformation matrix:

  • https://en.wikipedia.org/wiki/Transformation_matrix

  • https://www.cnblogs.com/bnuvincent/p/6691189.html

  • Rconic::`Affine planar transformations matrix`

Examples