Android Things: take a screenshot

Asked 8/1, 2017 at 16:3 Answered 25/2, 2020 at 4:26

How do you take a screenshot via ADB for Android Things? I have tried:

adb shell screencap -p /sdcard/screen.png
adb pull /sdcard/screen.png
adb shell rm /sdcard/screen.png

and

adb shell screencap -p | perl -pe 's/\x0D\x0A/\x0A/g' > screen.png

Impletion answered 8/1, 2017 at 16:3 Comment(5)

have you tried from within Android Studio itself? – Skylab 8/1, 2017 at 19:15

Thanks for the idea- unfortunately it throws an error: "Unexpected error while obtaining screenshot from device: EOF" – Impletion 8/1, 2017 at 19:31

Is this related to your other question? i.e. is this with your non working screen plugged in or not? Did you have a hdmi screen connected? – Alicyclic 8/1, 2017 at 21:50

I have the same issue and it doesn't matter if I'm connected to external monitor or not. The retrieved .png file is 0kB in size and obviously doesn't contain the screen image. – Liddy 9/1, 2017 at 13:18

Check this question: https://mcmap.net/q/1915247/-adb-screenshot-not-found - there is a possible solution using MonkeyRunner – Liddy 9/1, 2017 at 13:24

I couldn't make screepcap work in Android Things Developer Preview. The command results in a 0-size file.

That said, I recommend the following two options: either use the framebuffer or record a video (screenrecord seems to work) and convert it to an image later on by proper tool. I'll consider the first option, so the steps would be:

Pull the framebuffer to the host machine. Note that you need to start adbd as root in order to pass a permission check:
```
adb root
adb pull /dev/graphics/fb0 screenshot
```
Convert the raw binary to image by the tool you prefer. I'm using ffmpeg. The command below might not work for you due to different screen resolution or pixel format. If so, make proper changes.
```
ffmpeg -f rawvideo -pix_fmt rgb565 -s 800x480 -i screenshot screenshot.png
```

Barros answered 22/1, 2017 at 19:35 Comment(3)

Use adb shell dumpsys window | grep mUnres to find out the screen resolution. – Barros 23/1, 2017 at 18:50

@Andriy Omelchenko What was wrong at the first place? Wrong screen resolution? What value of pix_fmt worked for you? – Barros 23/1, 2017 at 19:45

Yes, - wrong screen resolution and -pix_fmt rgb565 works for me too without changes. And You are cool ) Thanx! – Template 24/1, 2017 at 8:49

Seems, because of old limited OpenGL version in Android Things, described by Tatsuhiko Arai here there is no possibility to get screenshot via ADB, but You can record video (e.g. from Android Studio, or via ADB commands) and than grab frame from it, for example via ffmpeg:

ffmpeg -i device-2017-01-23-193539.mp4 -r 1 screen-%04d.png

where device-2017-01-23-193539.mp4 - name of recorded (via Android Studio) file .

Template answered 23/1, 2017 at 18:15 Comment(4)

I noticed they didn't put OpenGL into Android things - quite disappointing – Impletion 24/1, 2017 at 9:43

@Quintin Balsdon "I noticed they didn't put OpenGL into Android things" They did. Namely, it's OpenGL ES-CM 1.0 which can be seen with adb shell dumpsys | grep GLES. – Barros 26/1, 2017 at 0:42

I also doubt it's because of "old limited OpenGL version". I have OpenGL ES-CM 1.1 on my Android 4.2 phone and the screencap works as expected. – Barros 26/1, 2017 at 0:44

@Oink it's strange they didn't support the latest OpenGL the Raspberry Pi - thanks for showing me how to find it! – Impletion 26/1, 2017 at 8:46

I've tried exactly this code with a little bit change like below (but no matter) and it works well. The image is in my platform-tools directory now.

adb shell screencap -p /sdcard/screen.png
adb pull /sdcard/screen.png screen.png
adb shell rm /sdcard/screen.png

Roaster answered 25/2, 2020 at 4:26 Comment(0)

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