Android -- Camera聚焦流程

@Override public void autoFocus() { //记录当前聚焦开始时间 mFocusStartTime = System.currentTimeMillis(); //设置Camera的回调聚焦  mCameraDevice.autoFocus(mAutoFocusCallback); //设置Camera的状态为Focusing  setCameraState(FOCUSING); }

private void setCameraState(int state) { mCameraState = state; switch (state) { case SNAPSHOT_IN_PROGRESS: case FOCUSING: enableCameraControls(false); break; case IDLE: case PREVIEW_STOPPED: enableCameraControls(true); break; } }

/** * 设置几个button或者view不可点击 * @param enable */ private void enableCameraControls(boolean enable) { if (mIndicatorControlContainer != null) { mIndicatorControlContainer.setEnabled(enable); } if (mModePicker != null) mModePicker.setEnabled(enable); if (mZoomControl != null) mZoomControl.setEnabled(enable); if (mThumbnailView != null) mThumbnailView.setEnabled(enable); }

Override public void setEnabled(boolean enabled) { super.setEnabled(enabled); final int count = getChildCount(); for (int i = 0; i < count; i++) { View v = getChildAt(i); // Zoom buttons and shutter button are controlled by the activity. if (v instanceof AbstractIndicatorButton) { v.setEnabled(enabled); // Show or hide the indicator buttons during recording. if (mCurrentMode == MODE_VIDEO) { v.setVisibility(enabled ? View.VISIBLE : View.INVISIBLE); } } } if (mCameraPicker != null) { mCameraPicker.setEnabled(enabled); if (mCurrentMode == MODE_VIDEO) { mCameraPicker.setVisibility(enabled ? View.VISIBLE : View.INVISIBLE); } } }

private final class AutoFocusCallback implements android.hardware.Camera.AutoFocusCallback { public void onAutoFocus( boolean focused, android.hardware.Camera camera) { //如果是暂停状态，不聚焦 if (mPausing) return; //算出当前到聚焦开始的时间差 mAutoFocusTime = System.currentTimeMillis() - mFocusStartTime; Log.v(TAG, "mAutoFocusTime = " + mAutoFocusTime + "ms"); //设置Camera状态为  setCameraState(IDLE); //调用FocusManager中的AutoFocus  mFocusManager.onAutoFocus(focused); } }

/** * 聚焦 * @param focused */ public void onAutoFocus(boolean focused) { Log.i(TAG, "focus used : " + (System.currentTimeMillis() - focusStart)); //正在进行聚焦，拍照动作必须再聚焦完之后 if (mState == STATE_FOCUSING_SNAP_ON_FINISH) { // 无论聚焦成功还是失败，都会拍照。如果要进行拍照发声，就无需AF发声了 if (focused) { //聚焦成功 mState = STATE_SUCCESS; } else { //聚焦失败 mState = STATE_FAIL; } //更新聚焦框UI&&设置人脸识别UI已经各种状态的设置  updateFocusUI(); //拍照，mState的状态变为STATE_IDLE  capture(); } else if (mState == STATE_FOCUSING) {//如果是聚焦中的状态 //此状态的发生分为两种，half-pressing按压聚焦或者触摸聚焦被触发，这个时候不要发生拍照动作 if (focused) { //聚焦成功 mState = STATE_SUCCESS; //在连续聚焦状态不要发声，聚焦回调会在拍照前完成，所有状态一直为STATE_FOCUSING if (!Parameters.FOCUS_MODE_CONTINUOUS_PICTURE. equals(mFocusMode)) { mListener.playSound(CameraSound.FOCUS_COMPLETE); } } else { //聚焦失败 mState = STATE_FAIL; } //更新聚焦&&人脸UI  updateFocusUI(); // If this is triggered by touch focus, cancel focus after a // while. //如果是触摸聚焦，需要延迟一下取消掉聚焦 if (mFocusArea != null) { mHandler.sendEmptyMessageDelayed(RESET_TOUCH_FOCUS, RESET_TOUCH_FOCUS_DELAY); } } else if (mState == STATE_IDLE) {//空闲 // User has released the focus key before focus completes. // Do nothing.  } }

private class MainHandler extends Handler { @Override public void handleMessage(Message msg) { switch (msg.what) { case RESET_TOUCH_FOCUS: { //取消掉聚焦  cancelAutoFocus(); //开始人脸识别  mListener.startFaceDetection(); break; } } } }

/** * 再重置tap area之前调用mListener.cancelAutofocus，否则，聚焦模式将一直是自动&tap聚焦，并且驱动也不会重置 */ private void cancelAutoFocus() { //放置聚焦框到屏幕中间  resetTouchFocus(); mListener.cancelAutoFocus(); if (mFaceView != null) mFaceView.resume(); mState = STATE_IDLE; updateFocusUI(); mHandler.removeMessages(RESET_TOUCH_FOCUS); }

/** * 触摸，，这里会发生触摸聚焦 * @param e * @return */ public boolean onTouch(MotionEvent e) { //没有初始化或者拍照前的聚焦的状态，直接返回 if (!mInitialized || mState == STATE_FOCUSING_SNAP_ON_FINISH) return false; //让用户可以取消掉之前未消失的触摸聚焦 if ((mFocusArea != null) && (mState == STATE_FOCUSING || mState == STATE_SUCCESS || mState == STATE_FAIL)) { cancelAutoFocus(); } // Initialize variables. int x = Math.round(e.getX()); int y = Math.round(e.getY()); int focusWidth = mFocusIndicatorRotateLayout.getWidth(); int focusHeight = mFocusIndicatorRotateLayout.getHeight(); int previewWidth = mPreviewFrame.getWidth(); int previewHeight = mPreviewFrame.getHeight(); if (mFocusArea == null) { mFocusArea = new ArrayList<Area>(); mFocusArea.add(new Area(new Rect(), 1)); mMeteringArea = new ArrayList<Area>(); mMeteringArea.add(new Area(new Rect(), 1)); } //将坐标转换为驱动的格式。AE面积更大,因为曝光会敏感和容易，或者说曝光不足,如果面积太小了。  calculateTapArea(focusWidth, focusHeight, 1f, x, y, previewWidth, previewHeight, mFocusArea.get(0).rect); calculateTapArea(focusWidth, focusHeight, 1.5f, x, y, previewWidth, previewHeight, mMeteringArea.get(0).rect); // Use margin to set the focus indicator to the touched area. RelativeLayout.LayoutParams p = (RelativeLayout.LayoutParams) mFocusIndicatorRotateLayout.getLayoutParams(); int left = Util.clamp(x - focusWidth / 2, 0, previewWidth - focusWidth); int top = Util.clamp(y - focusHeight / 2, 0, previewHeight - focusHeight); p.setMargins(left, top, 0, 0); // Disable "center" rule because we no longer want to put it in the center. int[] rules = p.getRules(); rules[RelativeLayout.CENTER_IN_PARENT] = 0; mFocusIndicatorRotateLayout.requestLayout(); //停止人脸识别，因为要进行识别聚焦和测量area  mListener.stopFaceDetection(); //设置聚焦区域&测量区域  mListener.setFocusParameters(); //如果支持触摸聚焦&&手指抬起 if (mFocusAreaSupported && (e.getAction() == MotionEvent.ACTION_UP)) { autoFocus(); } else { // Just show the indicator in all other cases.  updateFocusUI(); // Reset the metering area in 3 seconds.  mHandler.removeMessages(RESET_TOUCH_FOCUS); mHandler.sendEmptyMessageDelayed(RESET_TOUCH_FOCUS, RESET_TOUCH_FOCUS_DELAY); } return true; }

doSnap()：空闲状态可以执行拍照 onAutoFocus(boolean focused)：用户再聚焦完成前放掉了聚焦按钮，所以不做任何事。 onPreviewStarted()，onPreviewStopped()：状态都变为空闲 cancelAutoFocus()：取消聚焦，状态变为空闲 updateFocusUI()：如果空闲&有聚焦区域，显示聚焦框框

onShutterUp()：如果是focusmode为自动聚焦，状态为正在聚焦，则取消掉聚焦 doSnap()：如果是正在聚焦状态，将状态改为聚焦完拍照状态 onAutoFocus(boolean focused)：判断focused，为true变为聚焦成功状态，为false变为聚焦失败状态 onTouch(MotionEvent e)：如果正在聚焦&之前有手动聚焦了，则取消掉之前的聚焦 autoFocus()：状态变为聚焦状态 updateFocusUI()：显示聚焦的框框

onShutterUp()：状态不是聚焦完拍照，可以设置FocusParameters onAutoFocus(boolean focused)：判断focused，为true变为聚焦成功状态，为false变为聚焦失败状态，更新聚焦框UI onTouch(MotionEvent e)：直接不继续操作下去 updateFocusUI()：显示聚焦的框框

onShutterDown()：如果是自动聚焦mode，并且不为聚焦成功状态，执行聚焦 onShutterUp()： 如果是自动聚焦mode，并且为聚焦成功状态，执行取消聚焦 doSnap()：拍照 onTouch(MotionEvent e)：让用户可以取消掉之前未消失的触摸聚焦 updateFocusUI()：聚焦框框显示成功

onShutterDown()：如果是自动聚焦mode，并且不为聚焦失败状态，执行聚焦 onShutterUp()： 如果是自动聚焦mode，并且为聚焦失败状态，执行取消聚焦 doSnap()：拍照 onTouch(MotionEvent e)：让用户可以取消掉之前未消失的触摸聚焦 updateFocusUI()：聚焦框框显示失败