Camera2前置摄像头预览旋转

Question

我正在使用camera2并遇到旋转问题。 在某些设备中，切换到前置摄像头时，预览正在旋转180度。 正在为camera2寻找这样的“setDefaultOrientation（）”方法，但无法找到它。

感谢

Answer 1

对于GLSurfaceView，您大概会使用SurfaceTexture将相机预览流映射到GL纹理，然后进行渲染。

纹理中的图像数据不会自动旋转为“直立” - 一方面，操作系统无法知道您将如何渲染纹理。

然而，表面纹理具有getTransformMatrix调用，当连接到camera2 API，会给你必要从相机的定向设备的本地方向（一般人像的电话，景观为平板电脑，但不改变总是）。然后，您必须将原生方向转换为您的应用程序的方向转换为此矩阵，然后应用组合矩阵转换来调整预览图像。

Answer 2

你可以尝试打开你的相机这个代码

我希望这将有助于

public void startPreview() { 
    try { 
     Log.i(TAG, "starting preview: " + started); 

     // .... 
     Camera.CameraInfo camInfo = new Camera.CameraInfo(); 
     Camera.getCameraInfo(cameraIndex, camInfo); 
     int cameraRotationOffset = camInfo.orientation; 
     // ... 

     Camera.Parameters parameters = camera.getParameters(); 
     List<Camera.Size> previewSizes = parameters.getSupportedPreviewSizes(); 
     Camera.Size previewSize = null; 
     float closestRatio = Float.MAX_VALUE; 

     int targetPreviewWidth = isLandscape() ? getWidth() : getHeight(); 
     int targetPreviewHeight = isLandscape() ? getHeight() : getWidth(); 
     float targetRatio = targetPreviewWidth/(float) targetPreviewHeight; 

     Log.v(TAG, "target size: " + targetPreviewWidth + "/" + targetPreviewHeight + " ratio:" + targetRatio); 
     for (Camera.Size candidateSize : previewSizes) { 
      float whRatio = candidateSize.width/(float) candidateSize.height; 
      if (previewSize == null || Math.abs(targetRatio - whRatio) < Math.abs(targetRatio - closestRatio)) { 
       closestRatio = whRatio; 
       previewSize = candidateSize; 
      } 
     } 

     int rotation = getWindowManager().getDefaultDisplay().getRotation(); 
     int degrees = 0; 
     switch (rotation) { 
     case Surface.ROTATION_0: 
      degrees = 0; 
      break; // Natural orientation 
     case Surface.ROTATION_90: 
      degrees = 90; 
      break; // Landscape left 
     case Surface.ROTATION_180: 
      degrees = 180; 
      break;// Upside down 
     case Surface.ROTATION_270: 
      degrees = 270; 
      break;// Landscape right 
     } 
     int displayRotation; 
     if (isFrontFacingCam) { 
      displayRotation = (cameraRotationOffset + degrees) % 360; 
      displayRotation = (360 - displayRotation) % 360; // compensate 
                   // the 
                   // mirror 
     } else { // back-facing 
      displayRotation = (cameraRotationOffset - degrees + 360) % 360; 
     } 

     Log.v(TAG, "rotation cam/phone = displayRotation: " + cameraRotationOffset + "/" + degrees + " = " 
       + displayRotation); 

     this.camera.setDisplayOrientation(displayRotation); 

     int rotate; 
     if (isFrontFacingCam) { 
      rotate = (360 + cameraRotationOffset + degrees) % 360; 
     } else { 
      rotate = (360 + cameraRotationOffset - degrees) % 360; 
     } 

     Log.v(TAG, "screenshot rotation: " + cameraRotationOffset + "/" + degrees + " = " + rotate); 

     Log.v(TAG, "preview size: " + previewSize.width + "/" + previewSize.height); 
     parameters.setPreviewSize(previewSize.width, previewSize.height); 
     parameters.setRotation(rotate); 
     camera.setParameters(parameters); 
     camera.setPreviewDisplay(mHolder); 
     camera.startPreview(); 

     Log.d(TAG, "preview started"); 

     started = true; 
    } catch (IOException e) { 
     Log.d(TAG, "Error setting camera preview: " + e.getMessage()); 
    } 
} 

Answer 3

你可以设置正确的图像旋转CaptureRequest对象，而在CameraCaptureSession.StateCallback拍摄图像使用CameraCharacterisitics

CameraCharacterisitics cameraCharacteristics = cameraManager.getCameraCharacteristics(cameraId); 

这样子。

private CameraCaptureSession.StateCallback sessionStateCallback = new CameraCaptureSession.StateCallback() { 
@Override 
public void onConfigured(@NonNull CameraCaptureSession session) { 
    captureSession = session; 
    try { 
    CaptureRequest.Builder builder = session.getDevice().createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE); 
    builder.addTarget(imageReader.getSurface()); 
    builder.set(CaptureRequest.JPEG_ORIENTATION, cameraCharacteristics.get(CameraCharacteristics.SENSOR_ORIENTATION)); 
    session.capture(builder.build(), null, backgroundHandler); 
    } catch (CameraAccessException e) { 
    Log.d("tag", e.getMessage()); 
    } 
} 

@Override 
public void onConfigureFailed(@NonNull CameraCaptureSession session) { 
} 
};