imager (version 0.42.19)

pixel.grid: Return the pixel grid for an image

Description

The pixel grid for image im gives the (x,y,z,c) coordinates of each successive pixel as a data.frame. The c coordinate has been renamed 'cc' to avoid conflicts with R's c function. NB: coordinates start at (x=1,y=1), corresponding to the top left corner of the image, unless standardise == TRUE, in which case we use the usual Cartesian coordinates with origin at the center of the image and scaled such that x varies between -.5 and .5, and a y arrow pointing up

Usage

pixel.grid(im, standardise = FALSE, drop.unused = TRUE, dim = NULL)

Value

a data.frame

Arguments

im

an image

standardise

If TRUE use a centered, scaled coordinate system. If FALSE use standard image coordinates (default FALSE)

drop.unused

if TRUE ignore empty dimensions, if FALSE include them anyway (default TRUE)

dim

a vector of image dimensions (optional, may be used instead of "im")

Examples

im <- as.cimg(array(0,c(10,10))) #A 10x10 image
pixel.grid(im) %>% head
pixel.grid(dim=dim(im)) %>% head #Same as above
pixel.grid(dim=c(10,10,3,2)) %>% head 
pixel.grid(im,standardise=TRUE) %>% head
pixel.grid(im,drop.unused=FALSE) %>% head