Capture a screenshot

Capturing screenshots is done using the ScreenCaptureRequest. This request will check the remote protocol version and will fail if the format is unsupported.

val adapter = RawImageScreenCaptureAdapter()
val image = adb.execute(
    request = ScreenCaptureRequest(adapter),
    serial = "emulator-5554" 
).toBufferedImage()

if (!ImageIO.write(image, "png", File("/tmp/screen.png"))) {
    throw IOException("Failed to find png writer")
}

Image adapter

In order to receive the image you’ll have to transform the framebuffer bytes into something meaningful. There are two options here: RawImageScreenCaptureAdapter and BufferedImageScreenCaptureAdapter. The RawImageScreenCaptureAdapter is a bare minimum to receive the necessary metadata as well as the byte[] that holds the screenshot. The return type of this adapter is RawImage that supports retrieving the pixel value by index using RawImage#getARGB(index: Int). You can also transform the image into Java’s BufferedImage.

However, if you intend to capture a lot of screenshots for a particular device, consider using the BufferedImageScreenCaptureAdapter that will reduce additional allocations of memory when transforming the image.

Please note, that all adapter by default will try to reduce the memory consumption and reuse the internal buffers. If you’re using the same adapter on multiple threads in parallel either set the buffer to null all the time or provide an external buffer that is allocated per thread.