windowcapture - window resize and capture for macOS

Resize a window and take a screen capture of it.

Synopsis

windowcapture [options] [size]

Description

The front window of an application is raised and screen captured into a PNG image file or to the clipboard.

The window can be resized before the capture. Either:

the width is set, and the height left unchanged;
the height is set, and the width is left unchanged;
both the width and height are set; or
the dimensions of the window are left unchanged.

Options

Window options

-a | --application app_name

The name of the application whose window will be captured. Defaults to Safari. The application name is not case sensitive.
-c | --center

Move the window to the center of the screen. This has no effect on the capture, but can make it more obvious which window is being captured.

Capture options

-d | --delay seconds

Number of seconds delay between raising and resizeing the window and when the capture is taken. Useful for interacting with pop-up menus and other on-screen items so they are included in the capture.
-s | --shadow

Include the shadow behind the window in the capture. The image in the PNG file will be larger than the dimensions of the window. By default, the shadow is not included and only the window is captured.

Output options

-o | --output filename

The name of the file the capture will be written to.

Specify "-" as the filename to capture to the clipboard instead of to a file.
-f | --force

Overwrite the output file, if it already exists. Normally, the capture will not proceed if the output file already exists.

General options

-v | --verbose

Output extra information when running.
--version

Display the version information and exits.
-h | --help

Display a short help message and exits.

Arguments

size

Resize the window to the specified size.

This can be specified as: the width only (e.g. 960x) to leave the height unchanged; the height only (e.g. x500) to leave the width unchanged; both width and height (e.g. 1920x1080); or omitted to not change the size of the window at all.

Examples

Capture the front-most Safari window, without changing its size. The capture is saved as a PNG file in the Desktop folder.

./windowcapture.sh

Capture the front-most Safari window, without changing its size. The capture is saved to the clipboard.

./windowcapture.sh -o -

Resize the front-most Safari window to a width of 960 pixels (leaving its height unchanged) and then capture it.

./windowcapture.sh 960x

Resize the front-most FireFox window to 800x600 pixels and then capture it to a file called "foobar.png" in the current directory.

./windowcapture.sh --application firefox  --output foobar.png 800x600

Tip: if the the application name is not known, it can be obtained by using the Activity Monitor application.

Requirements

This is a command line program that only works on an Apple Macintosh, since it is a wrapper for the macOS screencapture program and uses AppleScript to resize the window.

This program has been tested on macOS 11.4 (Big Sur).

Known issues

Does not work with Google Chrome

Workaround: use the program to resize the window, and then manually capture the window: using ⌘-Shift-4, then press the space key and select the window.

Combining command line options does not work

Command line options cannot be combined together. For example, "-sf" does not work and must be specified as "-s -f".

Files

By default, the window captures are saved into the user's Desktop folder with a name that starts with windowcapture_ followed by the date and time in ISO 8601 format. But the file name can be set using the output command line option.

hoylen/windowcapture