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[camera_android] Add NV21 as an image stream format flutter#3277 (flu…
…tter#3639) This contains the changes for camera_android from flutter/packages#3277
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228
...mera_android/android/src/main/java/io/flutter/plugins/camera/media/ImageStreamReader.java
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| // Copyright 2013 The Flutter Authors. All rights reserved. | ||
| // Use of this source code is governed by a BSD-style license that can be | ||
| // found in the LICENSE file. | ||
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| package io.flutter.plugins.camera.media; | ||
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| import android.graphics.ImageFormat; | ||
| import android.media.Image; | ||
| import android.media.ImageReader; | ||
| import android.os.Handler; | ||
| import android.os.Looper; | ||
| import android.view.Surface; | ||
| import androidx.annotation.NonNull; | ||
| import androidx.annotation.VisibleForTesting; | ||
| import io.flutter.plugin.common.EventChannel; | ||
| import io.flutter.plugins.camera.types.CameraCaptureProperties; | ||
| import java.nio.ByteBuffer; | ||
| import java.util.ArrayList; | ||
| import java.util.HashMap; | ||
| import java.util.List; | ||
| import java.util.Map; | ||
|
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| // Wraps an ImageReader to allow for testing of the image handler. | ||
| public class ImageStreamReader { | ||
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| /** | ||
| * The image format we are going to send back to dart. Usually it's the same as streamImageFormat | ||
| * but in the case of NV21 we will actually request YUV frames but convert it to NV21 before | ||
| * sending to dart. | ||
| */ | ||
| private final int dartImageFormat; | ||
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| private final ImageReader imageReader; | ||
| private final ImageStreamReaderUtils imageStreamReaderUtils; | ||
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| /** | ||
| * Creates a new instance of the {@link ImageStreamReader}. | ||
| * | ||
| * @param imageReader is the image reader that will receive frames | ||
| * @param imageStreamReaderUtils is an instance of {@link ImageStreamReaderUtils} | ||
| */ | ||
| @VisibleForTesting | ||
| public ImageStreamReader( | ||
| @NonNull ImageReader imageReader, | ||
| int dartImageFormat, | ||
| @NonNull ImageStreamReaderUtils imageStreamReaderUtils) { | ||
| this.imageReader = imageReader; | ||
| this.dartImageFormat = dartImageFormat; | ||
| this.imageStreamReaderUtils = imageStreamReaderUtils; | ||
| } | ||
|
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| /** | ||
| * Creates a new instance of the {@link ImageStreamReader}. | ||
| * | ||
| * @param width is the image width | ||
| * @param height is the image height | ||
| * @param imageFormat is the {@link ImageFormat} that should be returned to dart. | ||
| * @param maxImages is how many images can be acquired at one time, usually 1. | ||
| */ | ||
| public ImageStreamReader(int width, int height, int imageFormat, int maxImages) { | ||
| this.dartImageFormat = imageFormat; | ||
| this.imageReader = | ||
| ImageReader.newInstance(width, height, computeStreamImageFormat(imageFormat), maxImages); | ||
| this.imageStreamReaderUtils = new ImageStreamReaderUtils(); | ||
| } | ||
|
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| /** | ||
| * Returns the image format to stream based on a requested input format. Usually it's the same | ||
| * except when dart is requesting NV21. In that case we stream YUV420 and process it into NV21 | ||
| * before sending the frames over. | ||
| * | ||
| * @param dartImageFormat is the image format dart is requesting. | ||
| * @return the image format that should be streamed from the camera. | ||
| */ | ||
| @VisibleForTesting | ||
| public static int computeStreamImageFormat(int dartImageFormat) { | ||
| if (dartImageFormat == ImageFormat.NV21) { | ||
| return ImageFormat.YUV_420_888; | ||
| } else { | ||
| return dartImageFormat; | ||
| } | ||
| } | ||
|
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| /** | ||
| * Processes a new frame (image) from the image reader and send the frame to Dart. | ||
| * | ||
| * @param image is the image which needs processed as an {@link Image} | ||
| * @param captureProps is the capture props from the camera class as {@link | ||
| * CameraCaptureProperties} | ||
| * @param imageStreamSink is the image stream sink from dart as a dart {@link | ||
| * EventChannel.EventSink} | ||
| */ | ||
| @VisibleForTesting | ||
| public void onImageAvailable( | ||
| @NonNull Image image, | ||
| @NonNull CameraCaptureProperties captureProps, | ||
| @NonNull EventChannel.EventSink imageStreamSink) { | ||
| try { | ||
| Map<String, Object> imageBuffer = new HashMap<>(); | ||
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| // Get plane data ready | ||
| if (dartImageFormat == ImageFormat.NV21) { | ||
| imageBuffer.put("planes", parsePlanesForNv21(image)); | ||
| } else { | ||
| imageBuffer.put("planes", parsePlanesForYuvOrJpeg(image)); | ||
| } | ||
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| imageBuffer.put("width", image.getWidth()); | ||
| imageBuffer.put("height", image.getHeight()); | ||
| imageBuffer.put("format", dartImageFormat); | ||
| imageBuffer.put("lensAperture", captureProps.getLastLensAperture()); | ||
| imageBuffer.put("sensorExposureTime", captureProps.getLastSensorExposureTime()); | ||
| Integer sensorSensitivity = captureProps.getLastSensorSensitivity(); | ||
| imageBuffer.put( | ||
| "sensorSensitivity", sensorSensitivity == null ? null : (double) sensorSensitivity); | ||
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| final Handler handler = new Handler(Looper.getMainLooper()); | ||
| handler.post(() -> imageStreamSink.success(imageBuffer)); | ||
| image.close(); | ||
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| } catch (IllegalStateException e) { | ||
| // Handle "buffer is inaccessible" errors that can happen on some devices from ImageStreamReaderUtils.yuv420ThreePlanesToNV21() | ||
| final Handler handler = new Handler(Looper.getMainLooper()); | ||
| handler.post( | ||
| () -> | ||
| imageStreamSink.error( | ||
| "IllegalStateException", | ||
| "Caught IllegalStateException: " + e.getMessage(), | ||
| null)); | ||
| image.close(); | ||
| } | ||
| } | ||
|
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| /** | ||
| * Given an input image, will return a list of maps suitable to send back to dart where each map | ||
| * describes the image plane. | ||
| * | ||
| * <p>For Yuv / Jpeg, we do no further processing on the frame so we simply send it as-is. | ||
| * | ||
| * @param image - the image to process. | ||
| * @return parsed map describing the image planes to be sent to dart. | ||
| */ | ||
| @NonNull | ||
| public List<Map<String, Object>> parsePlanesForYuvOrJpeg(@NonNull Image image) { | ||
| List<Map<String, Object>> planes = new ArrayList<>(); | ||
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| // For YUV420 and JPEG, just send the data as-is for each plane. | ||
| for (Image.Plane plane : image.getPlanes()) { | ||
| ByteBuffer buffer = plane.getBuffer(); | ||
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| byte[] bytes = new byte[buffer.remaining()]; | ||
| buffer.get(bytes, 0, bytes.length); | ||
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| Map<String, Object> planeBuffer = new HashMap<>(); | ||
| planeBuffer.put("bytesPerRow", plane.getRowStride()); | ||
| planeBuffer.put("bytesPerPixel", plane.getPixelStride()); | ||
| planeBuffer.put("bytes", bytes); | ||
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| planes.add(planeBuffer); | ||
| } | ||
| return planes; | ||
| } | ||
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| /** | ||
| * Given an input image, will return a single-plane NV21 image. Assumes YUV420 as an input type. | ||
| * | ||
| * @param image - the image to process. | ||
| * @return parsed map describing the image planes to be sent to dart. | ||
| */ | ||
| @NonNull | ||
| public List<Map<String, Object>> parsePlanesForNv21(@NonNull Image image) { | ||
| List<Map<String, Object>> planes = new ArrayList<>(); | ||
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| // We will convert the YUV data to NV21 which is a single-plane image | ||
| ByteBuffer bytes = | ||
| imageStreamReaderUtils.yuv420ThreePlanesToNV21( | ||
| image.getPlanes(), image.getWidth(), image.getHeight()); | ||
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| Map<String, Object> planeBuffer = new HashMap<>(); | ||
| planeBuffer.put("bytesPerRow", image.getWidth()); | ||
| planeBuffer.put("bytesPerPixel", 1); | ||
| planeBuffer.put("bytes", bytes.array()); | ||
| planes.add(planeBuffer); | ||
| return planes; | ||
| } | ||
|
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| /** Returns the image reader surface. */ | ||
| @NonNull | ||
| public Surface getSurface() { | ||
| return imageReader.getSurface(); | ||
| } | ||
|
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| /** | ||
| * Subscribes the image stream reader to handle incoming images using onImageAvailable(). | ||
| * | ||
| * @param captureProps is the capture props from the camera class as {@link | ||
| * CameraCaptureProperties} | ||
| * @param imageStreamSink is the image stream sink from dart as {@link EventChannel.EventSink} | ||
| * @param handler is generally the background handler of the camera as {@link Handler} | ||
| */ | ||
| public void subscribeListener( | ||
| @NonNull CameraCaptureProperties captureProps, | ||
| @NonNull EventChannel.EventSink imageStreamSink, | ||
| @NonNull Handler handler) { | ||
| imageReader.setOnImageAvailableListener( | ||
| reader -> { | ||
| Image image = reader.acquireNextImage(); | ||
| if (image == null) return; | ||
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| onImageAvailable(image, captureProps, imageStreamSink); | ||
| }, | ||
| handler); | ||
| } | ||
|
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| /** | ||
| * Removes the listener from the image reader. | ||
| * | ||
| * @param handler is generally the background handler of the camera | ||
| */ | ||
| public void removeListener(@NonNull Handler handler) { | ||
| imageReader.setOnImageAvailableListener(null, handler); | ||
| } | ||
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| /** Closes the image reader. */ | ||
| public void close() { | ||
| imageReader.close(); | ||
| } | ||
| } |
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