Aligns an Image object by hand

image_align() rotate an image given a line of desired aligment along the y axis that corresponds to the alignment of the objects (e.g., field plots). By default, the aligment will be to the vertical, which means that if the drawed line have an angle < 90º parallel to the x axis, the rotation angle wil be negative (anticlocwise rotation).

Usage

image_align(
  img,
  align = c("vertical", "horizontal"),
  viewer = get_pliman_viewer(),
  plot = TRUE
)

Arguments

img

An Image object

align

The desired alignment. Either "vertical" (default) or "horizontal".

viewer

The viewer option. If not provided, the value is retrieved using get_pliman_viewer(). This option controls the type of viewer to use for interactive plotting. The available options are "base" and "mapview". If set to "base", the base R graphics system is used for interactive plotting. If set to "mapview", the mapview package is used. To set this argument globally for all functions in the package, you can use the set_pliman_viewer() function. For example, you can run set_pliman_viewer("mapview") to set the viewer option to "mapview" for all functions.

plot

Plots the aligned image? Defaults to TRUE.

Value

The img aligned

Details

The image_align function aligns an image along the vertical or horizontal axis based on user-selected points. The alignment can be performed in either the base plotting system or using the mapview package for interactive visualization. If the viewer option is set to "base", the function prompts the user to select two points on the image to define the alignment line. If the viewer option is set to "mapview", the function opens an interactive map where the user can draw a polyline to define the alignment line. The alignment angle is calculated based on the selected points, and the image is rotated accordingly using the image_rotate function. The function returns the aligned image object.

Examples

if (interactive() && requireNamespace("EBImage")) {
library(pliman)
flax <- image_pliman("flax_leaves.jpg", plot = TRUE)
aligned <- image_align(flax)
}
#> Select 2 points drawing a line of desired aligment along the y axis.

#> Error in do.call(rbind, cord): second argument must be a list