invert: Invert and shift colors of an image

In graphx: Graphics Routines for Scientific Research

Description

Invert the brightness of each color channel in an image and/or circularly shifts the hue value. Optionally, a Gaussian blur can be applied.

Usage

invert(
  img = NULL,
  invert = TRUE,
  colshift = 0,
  blur = 0,
  file.in = "",
  file.out = "",
  format = "png",
  show.image = TRUE
)

Arguments

img	n-by-m-by-3 array or n-by-m-by-4 array representing an rgb(+alpha) image
invert	logical flag indicating whether the channel-brightness should be inverted
colshift	numerical value between 0 and 1 setting the circular shift of the hue value. If invert=TRUE, choosing colshift=0.5 preserves the colors, while inverting black and white.
blur	numerical value >=0 defining the standard deviation of an optional Gaussian blur.
file.in	optional input filename, which can be used to load an image instead of providing it via img. This filename is ignored if img is specified.
file.out	optional output filename.
format	one of "png" or "jpg" specifying the file format of the input and output image.
show.image	logical flag specifying whether the image is displayed in the R console.

Value

Returns an n-by-m-by-3 array or n-by-m-by-4 array of the processed image.

Author(s)

Danail Obreschkow

Examples

img = yinyangyong # this is an example image included in the package

# invert brightness of all channels
invert(img)

# invert brightness, but preserve hue
invert(img, colshift=0.5)

graphx documentation built on Feb. 3, 2022, 5:07 p.m.