Package {screenshot}

Type:	Package
Title:	Take Screenshots (Screen Capture) from R Command
Version:	0.9.3
Description:	Take screenshots from R command and locate an image position.
URL:	https://github.com/matutosi/screenshot, https://matutosi.github.io/screenshot/
License:	MIT + file LICENSE
Encoding:	UTF-8
LazyData:	true
Imports:	dplyr, fs, imager, magick, purrr, rlang, stringr, tibble, utils
Suggests:	knitr, rmarkdown, spelling, testthat (≥ 3.0.0)
Config/testthat/edition:	3
Language:	en-US
Depends:	R (≥ 4.1.0)
Config/roxygen2/version:	8.1.0
NeedsCompilation:	no
Packaged:	2026-08-22 09:03:36 UTC; matutosi
Author:	Toshikazu Matsumura [aut, cre]
Maintainer:	Toshikazu Matsumura <matutosi@gmail.com>
Repository:	CRAN
Date/Publication:	2026-08-22 09:20:02 UTC

Converts a bitmap image to PNG using

Description

Converts a bitmap image to PNG using

Usage

bitmap2png(path)

Arguments

Value

The result of the system call.

Examples

## Not run: 
bitmap2png("path/to/image.bmp")

## End(Not run)

Save clipboard image to temporary BMP file

Description

This function works only on windows. This function saves the image currently in the clipboard to a temporary BMP file.

Usage

clipboard2bitmap()

Value

Path to the temporary BMP file.

Examples

## Not run: 
clipboard2bitmap()

## End(Not run)

Sample data of clipboard bitmap array

Description

Sample data of clipboard bitmap array

Usage

clipboard_sample

Format

raw data of bitmap array with 246292 length

Examples

data(clipboard_sample)

Compare values within tow arrays or matrices. Helper function for locate_ndl_in_hay().

Description

Compare values within tow arrays or matrices. Helper function for locate_ndl_in_hay().

Usage

compare_table(ndl_mt, hay_mt)

Arguments

Value

A tibble.

Examples

val <- seq(from = 0, to = 1, by = 0.1)
mt_1 <- matrix(sample(val,  20, replace = TRUE))
mt_2 <- matrix(sample(val, 100, replace = TRUE))
compare_table(mt_1, mt_2)

Helper function for compare_table().

Description

Helper function for compare_table().

Usage

count_val_freq(mt, colname)

Arguments

Value

    A dataframe.

Examples

mt <- sample(1:10, 30, replace = TRUE)
count_val_freq(mt, "freq")

Create a BMP header

Description

Create a BMP header

Usage

create_header(clipboard)

Arguments

Value

A raw vector of the BMP header.

Examples

data(clipboard_sample)
create_header(clipboard_sample)

Cut off a part of image from a whole image.

Description

Cut off a part of image from a whole image.

Usage

crop_image(image, pos_x, pos_y, w = 50, h = 20)

hay2needle(image, pos_x, pos_y, w = 50, h = 20)

Arguments

Value

          An image of cimg object.

Examples

image <- imager::load.example("parrots")
croped_image <- crop_image(image, 200, 250, 100, 50)
layout(c(1:2))
plot(image)
plot(croped_image)

Get display corner of screen

Description

This function returns the coordinates of the specified corner of the display. This function works only on windows.

Usage

display_corner(size, corner = "bottom_left", width = 600, height = 600)

Arguments

Value

A numeric vector of length 4 representing the coordinates of the specified corner.

Examples

## Not run: 
size <- display_size()
display_corner(size, "top_left", 800, 800)

## End(Not run)

Get the size of the display.

Description

This function works only on windows.

Usage

display_size()

Value

A list with two elements, width and height, which are the width and height of the display.

Examples

## Not run: 
display_size()

## End(Not run)

Retrieves the image from the clipboard

Description

This function works only on windows.

Usage

get_clipboard_image()

Value

A raw vector containing the image data.

Examples

## Not run: 
get_clipboard_image()

## End(Not run)

data(clipboard_sample)
head(clipboard_sample, 100)
header <- create_header(clipboard_sample)
image_data <- c(header, clipboard_sample)
path <- fs::path_temp(ext = "bmp")
save_bmp(image_data, path)
 # shell.exec(path)
fs::file_delete(path)

Get OS name

Description

Get OS name

Usage

get_os()

Value

A string of OS name

Examples

get_os()

Convert hexadecimal string to little-endian

Description

Convert hexadecimal string to little-endian

Usage

hex2little_endian(x)

Arguments

Value

Little-endian hexadecimal string

Examples

hex2little_endian("01234567")
hex2little_endian("012345")

Convert cimg class into grayscale xy matrix. Helper function for locate_image(). Use grayscale to Speed up and to simplify code.

Description

Convert cimg class into grayscale xy matrix. Helper function for locate_image(). Use grayscale to Speed up and to simplify code.

Usage

image2gray_matrix(img)

Arguments

Value

 An xy dimensional matrix.

Convert array index into xy location in matrix. Helper function for locate_ndl_in_hay().

Description

Convert array index into xy location in matrix. Helper function for locate_ndl_in_hay().

Usage

index2xy(index, nrow)

Arguments

Value

       A numeric pair of xy location.

Examples

nrow <- 4
matrix(1:12, nrow = nrow)
purrr::map(1:12, index2xy, nrow = nrow)

Install command line screenshot for Windows.

Description

Codes are from URL shown below. https://superuser.com/questions/75614/take-a-screen-shot-from-command-line-in-windows#answer-1751844 On Mac screencapture is usually available. On Linux GNOME desktop use gnome-screenshot. If not installed, run ⁠sudo apt install gnome-screenshot⁠.

Usage

install_screenshot(bin_dir = "")

Arguments

Value

   A string of installed directory.

Examples

if(interactive()){

# need only on Win
if(get_os() == "win"){
  bin_dir <- fs::path_package("screenshot")
  # if you want to install another directory
  #   bin_dir <- "SET_YOUR DIRECTORY"
  install_screenshot(bin_dir)
}

}

Helper function for locate_ndl_in_hay().

Description

Helper function for locate_ndl_in_hay().

Usage

is_all_same(ndl_mt, hay_mt, base_xy, tol_val = 0)

Arguments

Value

    A logical.

Locate needle image position on a screenshot image.

Description

Locate needle image position on a screenshot image.

Usage

locate_image(
  needle_image,
  center = TRUE,
  exact = TRUE,
  timeout = 5,
  corner = NULL,
  width = 600,
  height = 300,
  size = NULL,
  scale = NULL,
  bin_dir = "",
  tol = 0
)

Arguments

Value

   A numeric pair of xy location.

Examples

## Not run: 
sc <- screenshot()
if(sc != ""){
  sc_image <- imager::load.image(sc)
  w <- 100
  h <- 80
  pos_x <- 1
  pos_y <- imager::height(sc_image) - h
  needle <- crop_image(sc_image, pos_x, pos_y, w, h)
  (locate_image(needle)) # center location
  pos <- locate_image(needle, center = FALSE)
  found <- crop_image(sc_image, pos[1], pos[2], w, h)
  layout(c(1:3))
  plot(sc_image)
  plot(needle)
  plot(found)
  # usse `coner` to limit searching field
  # `coner` can be used in Windows
  pos <- locate_image(needle, corner = "bottom_left", center = FALSE)
}

## End(Not run)

Locate needle image matrix position in a haystack_image matrix. Helper function for locate_image().

Description

Searches the value that the needle and the haystack have in common and that appears fewest times in the haystack, and uses one of its positions as an anchor. Every candidate position of the needle is then a difference between a position of the value in the haystack and the anchor, so only those candidates have to be compared.

Usage

locate_ndl_in_hay(ndl_mt, hay_mt, exact = TRUE, timeout = 5, tol = 0)

Arguments

Value

    A numeric pair of xy location for needle image.

Examples

haystack_image <- imager::load.example("parrots")
w <- 100
h <- 50
needle_image <- crop_image(haystack_image, 129, 257, w, h)
hay_mt <- image2gray_matrix(haystack_image)
ndl_mt <- image2gray_matrix(needle_image)
(pos <- locate_ndl_in_hay(ndl_mt, hay_mt))

found <- crop_image(haystack_image, pos[1], pos[2], w, h)
layout(c(1:3))
plot(haystack_image)
plot(needle_image)
plot(found)

Reset transparent background of an image

Description

Reset transparent background of an image

Usage

reset_transparent(path)

Arguments

Value

The file path to the processed image.

Examples

## Not run: 
path <- "directory/image.png"
reset_transparent(path)

## End(Not run)

Save an image as a BMP file

Description

Save an image as a BMP file

Usage

save_bmp(image_data, path)

Arguments

Value

Saves the image as a BMP file at the specified path.

Examples

## Not run: 
# Create an image data object
image_data <- matrix(rnorm(100), ncol = 10)
# Save the image as a BMP file
save_bmp(image_data, "image.bmp")

## End(Not run)

Saves an image from the clipboard to a file

Description

This function works only on windows.

Usage

save_clipboard_image(path = "", reset_transparent = TRUE)

Arguments

Value

The path to the saved image file.

Examples

## Not run: 
# Save the image from the clipboard to a file
save_clipboard_image("clipboard_image.png")

## End(Not run)

Take a screenshot.

Description

Need to install screenshot.exe on Win by install_screenshot().

Usage

screenshot(file = "", bin_dir = "", quote = FALSE)

Arguments

Details

The command is always quoted, so that a path with a space (such as "C:/Program Files/R/R-4.5.1/library/screenshot") works.

Value

    A file name of screenshot. When "", screenshot will be saved in a tempral directory.

See Also

   install_screenshot()

Examples

if(interactive()){

sc <- screenshot()
if(sc != ""){
  sc_image <- imager::load.image(sc)
  plot(sc_image)
}

}

Find screenshot exec file.

Description

Find screenshot exec file.

Usage

screenshot_exists(bin_dir = "")

Arguments

Value

A logical.

Examples

screenshot_exists()

Get xy position of a value in a matrix Helper function for locate_ndl_in_hay().

Description

Get xy position of a value in a matrix Helper function for locate_ndl_in_hay().

Usage

xy_pos(mt, val)

Arguments

Value

A numeric pairs of xy location.

Examples

nrow <- 4
mt <- matrix(1:12, nrow = nrow)
xy_pos(mt, 5)