Learn how to capture and view screenshots on your Raspberry Pi for project documentation. Use Scrot and ShotWell to do this solely through the command line. Scrot is a command line screen capturing application that's easy to download and use, and Shotwell is a light-weight photo viewing application.
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Step 1: Setup
Connect an external monitor, keyboard, mouse, and power supply to the Pi. Make sure your Raspberry Pi has internet connection through Ethernet or WiFi.
Let the Pi boot and start the graphical user interface by typing
Step 2: Instal Scrot
The installation can be completed on Raspbian using a standard apt-get call
sudo apt-get install scrot
Step 3: Basic Usage
Scrot has many different settings, but you can instantly take a screen shot of the whole image executing the command
Scrot's default name convention will give you a date, time and resolution stamped file like:
You can specify the file name by typing
The image will now be called "example", rather than “2014-10-05-132309_1824x984_scrot.png”. This command will not work if you do not specify a file extension (for example ".png"). Change the output file format by changing the extension (for example ".jpeg", ".gif", etc).
Step 4: Specify File Location
Specify where screenshots are saved with the command
where, for example, "/home/pi/Desktop/" is the file path and "example.png" is the screenshot. Now "example.png" will be saved on the Pi's Desktop. Note that the command
will fail, rather than assigning a default name to the screenshot.
Step 5: Delay a Screen Shot
To delay a screenshot, type
scrot -d 10where 10 is the number of seconds before capturing an image. To display a countdown, add the c option
scrot -cd 10
Step 6: Capture Only Part of the Screen
Capture sections of the screen with the -s option, as can be seen in the image included, with the commands
scrot -s /home/pi/Desktop/example.png
to specify the file path. Then click and drag a box over the area you want to capture.
Capture the current window with the u option
Step 7: Resize a Screenshot
The -t option will create a duplicate image (or thumbnail) that is a smaller version of the primary image. The thumbnail has the same file name as the main image with an addition "-thumb" appended on the end.
For example, this command produces a screen shot and a thumbnail that is 25% smaller.
scrot -t 25 example.png
The resulting files will be example.png and example-thumb.png.
Step 8: Other Scrot Commands
I've reviewed some basic Scrot features, but there are more features that can be enabled with other command line options. These, in addition to commands already reviewed, include
-h Display additional help -v Get the current version -d X Add a delay of X seconds to the capture -c Add a countdown to a delayed capture -s Allow user to specific capture area with the mouse -u Capture the current active window -q X Specify the image quality percentage X (default 75) -t X Create a thumbnail version at a specified percentage size X -e Specify a command to run after the image is capture
Remember you can also mix and match commands.
Step 9: View Screenshots With Shotwell
To view your images, you could open the Pi's File Manager, search for your photo, and double click its icon to view it in NetSurf. However, this is time consuming. Instead, install Shotwell photo viewer to open a screenshot via the terminal with the command
sudo apt-get install shotwell
Navigate to the directory containing the picture you want to open, and open it with the command