25.CameraManager
/**
 * A system service manager for detecting, characterizing, and connecting to
 * {@link CameraDevice CameraDevices}.</p>
 *
 * <p>For more details about communicating with camera devices, read the Camera
 * developer guide or the {@link android.hardware.camera2 camera2}
 * package documentation.</p>
characterizing特征描述；特性刻画
detecting检测
22algorithms算法
specify详细列出 subset子集 request请求reprocess
21.CaptureRequest 
 CaptureRequest  就是 “一次拍摄的指令书”，告诉相机 怎么拍、拍完送到哪，然后交给  CameraCaptureSession  去执行。
An immutable package of settings and outputs needed to capture a single
 * image from the camera device
/**
 * <p>An immutable package of settings and outputs needed to capture a single
 * image from the camera device.</p>
 *
 * <p>Contains the configuration for the capture hardware (sensor, lens, flash),
 * the processing pipeline, the control algorithms, and the output buffers. Also
 * contains the list of target Surfaces to send image data to for this
 * capture.</p>
 *
 * <p>CaptureRequests can be created by using a {@link Builder} instance,
 * obtained by calling {@link CameraDevice#createCaptureRequest}</p>
 *
 * <p>CaptureRequests are given to {@link CameraCaptureSession#capture} or
 * {@link CameraCaptureSession#setRepeatingRequest} to capture images from a camera.</p>
 *
 * <p>Each request can specify a different subset of target Surfaces for the
 * camera to send the captured data to. All the surfaces used in a request must
 * be part of the surface list given to the last call to
 * {@link CameraDevice#createCaptureSession}, when the request is submitted to the
 * session.</p>
 *
 * <p>For example, a request meant for repeating preview might only include the
 * Surface for the preview SurfaceView or SurfaceTexture, while a
 * high-resolution still capture would also include a Surface from a ImageReader
 * configured for high-resolution JPEG images.</p>
 *
 * <p>A reprocess capture request allows a previously-captured image from the camera device to be
 * sent back to the device for further processing. It can be created with
 * {@link CameraDevice#createReprocessCaptureRequest}, and used with a reprocessable capture session
 * created with {@link CameraDevice#createReprocessableCaptureSession}.</p>

19properties属性 20immutable不可变的
18.CameraCharacteristics
The properties describing a CameraDevice.
/**
 * <p>The properties describing a
 * {@link CameraDevice CameraDevice}.</p>
 *
 * <p>These properties are fixed for a given CameraDevice, and can be queried
 * through the {@link CameraManager CameraManager}
 * interface with {@link CameraManager#getCameraCharacteristics}.</p>
 *
 * <p>When obtained by a client that does not hold the CAMERA permission, some metadata values are
 * not included. The list of keys that require the permission is given by
 * {@link #getKeysNeedingPermission}.</p>
 *
 * <p>{@link CameraCharacteristics} objects are immutable.</p>
 *
 * @see CameraDevice
 * @see CameraManager
 */

17.HandlerThread
/** * A {@link Thread} that has a {@link Looper}. * The {@link Looper} can then be used to create {@link Handler}s. * <p> * Note that just like with a regular {@link Thread}, {@link #start()} must still be called
 
cameraManager = (CameraManager) getSystemService(CAMERA_SERVICE);
cameraThread = new HandlerThread("CameraThread");
cameraThread.start();
cameraHandler = new Handler(cameraThread.getLooper());

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10-16
proper合适capabilities能力substantially大量地 slightly稍许cleaner清洁工roughly大约
Licensed under the Apache License, Version 2.0.
  http://www.apache.org/licenses/LICENSE-2.0 
9fine-grain细粒度
8asynchronously
7allocating分配
6pipelines管道
5internal内部
4reprocessable可再处理的可加工，可重用
3desired 渴望的
2previously此前
1.CameraCaptureSession
 * A configured capture session for a {@link CameraDevice}, used for capturing images from the
 * camera or reprocessing images captured from the camera in the same session previously
/**
 * A configured capture session for a {@link CameraDevice}, used for capturing images from the
 * camera or reprocessing images captured from the camera in the same session previously.
 *
 * <p>A CameraCaptureSession is created by providing a set of target output surfaces to
 * {@link CameraDevice#createCaptureSession createCaptureSession}, or by providing an
 * {@link android.hardware.camera2.params.InputConfiguration} and a set of target output surfaces to
 * {@link CameraDevice#createReprocessableCaptureSession createReprocessableCaptureSession} for a
 * reprocessable capture session. Once created, the session is active until a new session is
 * created by the camera device, or the camera device is closed. 
 *
 * <p>All capture sessions can be used for capturing images from the camera but only reprocessable
 * capture sessions can reprocess images captured from the camera in the same session previously.
  
 *
 * <p>Creating a session is an expensive operation and can take several hundred milliseconds, since
 * it requires configuring the camera device's internal pipelines and allocating memory buffers for
 * sending images to the desired targets. Therefore the setup is done asynchronously, and
 * {@link CameraDevice#createCaptureSession createCaptureSession} and
 * {@link CameraDevice#createReprocessableCaptureSession createReprocessableCaptureSession} will
 * send the ready-to-use CameraCaptureSession to the provided listener's
 * {@link CameraCaptureSession.StateCallback#onConfigured onConfigured} callback. If configuration
 * cannot be completed, then the
 * {@link CameraCaptureSession.StateCallback#onConfigureFailed onConfigureFailed} is called, and the
 * session will not become active. 
 * <p>Any capture requests (repeating or non-repeating) submitted before the session is ready will
 * be queued up and will begin capture once the session becomes ready. In case the session cannot be
 * configured and {@link StateCallback#onConfigureFailed onConfigureFailed} is called, all queued
 * capture requests are discarded.