This fork serves as a sample on how to receive Bitmap image from graph for additional postprocessing (google-ai-edge/mediapipe#831).

It works with aar build with https://github.com/Cubbee/mediapipe, you can find instructions on how to build aar there.

Here is the outline on how to receive the bitmap from mediapipe graph:

1. From the mediapipe side, you need to add GpuBufferToImageFrameCalculator to the graph somewhere, for example mediapipe/graphs/hand_tracking/hand_tracking_mobile.pbtxt

node {
   calculator: "GpuBufferToImageFrameCalculator"
   input_stream: "throttled_input_video"
   output_stream: "throttled_input_video_cpu"
 }

2. Add this calculator to needed graph BUILD file mediapipe/graphs/hand_tracking/BUILD

cc_library(
    name = "mobile_calculators",
    deps = [
        "//mediapipe/calculators/core:constant_side_packet_calculator",
        "//mediapipe/calculators/core:flow_limiter_calculator",
        "//mediapipe/graphs/hand_tracking/subgraphs:hand_renderer_gpu",
        "//mediapipe/modules/hand_landmark:hand_landmark_tracking_gpu",
        "//mediapipe/gpu:gpu_buffer_to_image_frame_calculator",
    ],
)

3. Listen to the packet and decode it to bitmap

processor.addPacketCallback(
    "transformed_image_cpu"
) { packet ->
    println("Received image with ts: ${packet.timestamp}")
    val image = AndroidPacketGetter.getBitmapFromRgba(packet)
}

Image is received from the graph and saved to external storage folder mediapipe as an example.

You need to give the app the external storage permission manually through the phone settings.

Don't forget to run adb shell setprop log.tag.MainActivity VERBOSE to enable logging