java - CameraView 中的人像模式

Question

我打算使用 BeyondAR 框架开发一个安卓应用程序。我尝试在屏幕的前半部分使用 CameraView 组件(应用仅在纵向模式下运行)，但是当我将相机旋转 90 度时，图像会拉伸(stretch)并且宽高比错误。有什么帮助吗？

CameraView 类(Beyondar 框架)

public class CameraView extends SurfaceView implements SurfaceHolder.Callback,
    Camera.PictureCallback {

/**
 * 
 * @author Joan Puig Sanz (joanpuigsanz@gmail.com)
 * 
 */
public static interface IPictureCallback {
    /**
     * This method is called when the snapshot of the camera is ready. If
     * there is an error, the image will be null
     * 
     * @param picture
     */
    void onPictureTaken(Bitmap picture);
}

private SurfaceHolder mHolder;
private Camera mCamera;
private IPictureCallback mCameraCallback;
private BitmapFactory.Options mOptions;

private Size mPreviewSize;
private List<Size> mSupportedPreviewSizes;
private List<String> mSupportedFlashModes;

public CameraView(Context context) {
    super(context);
    init(context);
}

public CameraView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    init(context);
}

public CameraView(Context context, AttributeSet attrs) {
    super(context, attrs);
    init(context);
}

private void init(Context context) {
    mHolder = getHolder();
    mHolder.addCallback(this);

    try {
        mCamera = Camera.open();
        //mCamera.setDisplayOrientation(90);


        //Camera.Parameters params = mCamera.getParameters();
        //params.setPreviewSize(427, 1240); 
        //mCamera.setParameters(params);
        setCamera(mCamera);
    } catch (Exception e) {
        Log.e(Constants.TAG, "ERROR: Unable to open the camera", e);
    }

    if (android.os.Build.VERSION.SDK_INT <= 10) {// Android 2.3.x or lower
        mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }
}

public void setCamera(Camera camera) {
    mCamera = camera;
    if (mCamera != null) {
        mSupportedPreviewSizes = mCamera.getParameters().getSupportedPreviewSizes();
        mSupportedFlashModes = mCamera.getParameters().getSupportedFlashModes();
        // Set the camera to Auto Flash mode.
        if (mSupportedFlashModes != null
                && mSupportedFlashModes.contains(Camera.Parameters.FLASH_MODE_AUTO)) {
            Camera.Parameters parameters = mCamera.getParameters();
            parameters.setFlashMode(Camera.Parameters.FLASH_MODE_AUTO);
            //parameters.setPreviewSize(300, 200);
            mCamera.setParameters(parameters);
        }
    }
}

public void setSupportedPreviewSizes(List<Size> supportedPreviewSizes) {
    mSupportedPreviewSizes = supportedPreviewSizes;
}

public Size getPreviewSize() {
    return mPreviewSize;
}

public void surfaceCreated(SurfaceHolder holder) {
    // The Surface has been created, acquire the camera and tell it where
    // to draw.
    try {

        if (mCamera == null) {
            init(getContext());
            if (mCamera == null) {
                return;
            }
        }

        mCamera.setPreviewDisplay(holder);
    } catch (IOException exception) {
        if (mCamera != null) {
            mCamera.release();
        }
        mCamera = null;
        Log.e(Constants.TAG, "CameraView -- ERROR en SurfaceCreated", exception);
    }
}

public void surfaceDestroyed(SurfaceHolder holder) {
    // Surface will be destroyed when we return, so stop the preview.
    // Because the CameraDevice object is not a shared resource, it's very
    // important to release it when the activity is paused.
    if (mCamera == null) {
        return;
    }
    mCamera.stopPreview();
    mCamera.release();
    mCamera = null;
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec);
    final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec);
    setMeasuredDimension(width, height);

    if (mSupportedPreviewSizes != null) {
        mPreviewSize = getOptimalPreviewSize(mSupportedPreviewSizes, width, height);
    }

    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}

private Size getOptimalPreviewSize(List<Size> sizes, int width, int height) {

    Size result = null;

    for (Camera.Size size : sizes) {
        if (size.width <= width && size.height <= height) {
            if (result == null) {
                result = size;
            } else {
                int resultArea = result.width * result.height;
                int newArea = size.width * size.height;

                if (newArea > resultArea) {
                    result = size;
                }
            }
        }
    }

    return result;
}

public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
    if (mCamera == null || getPreviewSize() == null) {
        return;
    }

    Camera.Parameters parameters = mCamera.getParameters();
    Size previewSize = getPreviewSize();
    parameters.setPreviewSize(previewSize.width, previewSize.height);

    mCamera.setParameters(parameters);
    previewCamera();

}

@Override
public void onPictureTaken(byte[] imageData, Camera camera) {
    if (imageData != null && mCameraCallback != null) {
        mCameraCallback.onPictureTaken(StoreByteImage(imageData));
    }
    previewCamera();
}

public void previewCamera() {
    if (mCamera == null){
        return;
    }
    try {
        mCamera.setPreviewDisplay(mHolder);
        mCamera.startPreview();
    } catch (Exception e) {
        Log.d(Constants.TAG, "Cannot start preview.", e);
    }
}

private Bitmap StoreByteImage(byte[] imageData) {

    Bitmap myImage = DebugBitmap.decodeByteArray(imageData, 0, imageData.length, mOptions);

    imageData = null;
    System.gc();

    return myImage;
}

public void tackePicture(IPictureCallback cameraCallback) {
    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inSampleSize = 4;
    tackePicture(cameraCallback, options);
}

public void tackePicture(IPictureCallback cameraCallback, BitmapFactory.Options options) {
    if (mCamera == null) {
        return;
    }
    mCameraCallback = cameraCallback;
    mCamera.takePicture(null, this, this);
    mOptions = options;
}


}

编辑

我的布局 xml 文件

  <LinearLayout
    android:layout_width="match_parent"
    android:layout_height="0dip"
    android:layout_weight="1"
    android:orientation="horizontal"
    android:paddingBottom="@dimen/padding"
    android:paddingLeft="@dimen/padding"
    android:paddingRight="@dimen/padding"
    android:paddingTop="@dimen/padding" >  

    <FrameLayout 
   android:orientation="vertical"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   >
    <com.beyondar.android.opengl.views.BeyondarGLSurfaceView
    android:id="@+id/customGLSurface"
    android:layout_width="match_parent" 
    android:layout_height="match_parent" />    
    <com.beyondar.android.views.CameraView 
    android:id="@+id/camera"
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" />

<TextView  
    android:id="@+id/labelText"
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="Touch an AR Object"
    android:background="#000000"
    android:textColor="#FFFFFF"
    />


    </FrameLayout>
   </LinearLayout

Answer 1

如果您查看 BeyondAR 的示例应用程序，您会发现它有一个类似的问题，即相机的图像被拉伸(stretch)以填满屏幕，因此在横向和纵向中都没有正确的纵横比。这是使用相机预览时的常见问题，因为它会在您首次启动时锁定到特定方向。

为此，您需要将旋转 View 的大小调整为与设备相机相匹配的纵横比。 Here's the official Android guide .

请注意专门称为“设置预览方向”的部分。