Android 相机预览在预览中拉伸(stretch)，而不是在拍照后

Question

我有一个以纵向模式拍照的应用程序，一切正常，只是预览的尺寸与拍照后的图像尺寸不同。预览看起来失真且模糊，但会填满整个屏幕。拍照后，图像清晰，但要么比设备高度短，要么宽度更小(取决于使用的设备)。

下面是一些图像示例和我正在使用的一些代码。

拍照前:

拍照后:

纵向显示的相机预览代码:

protected int getRotationDegrees() {
    android.hardware.Camera.CameraInfo info = new android.hardware.Camera.CameraInfo();
    android.hardware.Camera.getCameraInfo(0, info);
    int rotation = ((WindowManager) mContext
            .getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay()
            .getRotation();
    int degrees = 0;

    switch (rotation) {
        case Surface.ROTATION_0:
            degrees = 0;
            break;
        case Surface.ROTATION_90:
            degrees = 90;
            break;
        case Surface.ROTATION_180:
            degrees = 180;
            break;
        case Surface.ROTATION_270:
            degrees = 270;
            break;
    }

    int result = (info.orientation - degrees + 360) % 360;
    return result;
}

拍照后旋转图像的代码:

Camera.PictureCallback mPictureCallback = new Camera.PictureCallback() {

    @Override
    public void onPictureTaken(byte[] data, Camera camera) {
        Bitmap pictureBitmap = null;

        pictureBitmap = BitmapFactory.decodeByteArray(data, 0, data.length);

        int rotationDegrees = mCameraPreview.getRotationDegrees();
        //mRotation = setCameraDisplayOrientation(MainActivity.this, Camera.CameraInfo.CAMERA_FACING_BACK, mCamera);
        Matrix matrix = new Matrix();
        matrix.postRotate(rotationDegrees);

        //Bitmap scaledBitmap = Bitmap.createScaledBitmap(pictureBitmap ,previewWidth ,previewHeight ,true);
        //Bitmap rotatedBitmap = Bitmap.createBitmap(scaledBitmap , 0, 0, scaledBitmap.getWidth(), scaledBitmap.getHeight(), matrix, true);
        Bitmap rotatedBitmap = Bitmap.createBitmap(pictureBitmap , 0, 0, pictureBitmap.getWidth(), pictureBitmap.getHeight(), matrix, true);

        //rotatedBitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
        ImageView previewImage = (ImageView) findViewById(R.id.preview_image);
        previewImage.setImageBitmap(rotatedBitmap);
        mCameraPreview.setVisibility(View.INVISIBLE);
        mButtonCapture.setVisibility(View.INVISIBLE);
        //flCameraPreview.setVisibility(View.INVISIBLE);
    }
};

有没有人遇到过这个问题？我仍在尝试了解相机 API。提前致谢!

编辑:我用来选择预览和图片尺寸的代码。

private Camera.Size getOptimalSize(List<Camera.Size> sizes, int h, int w) {
    final double ASPECT_TOLERANCE = 0.05;
    double targetRatio = (double) w/h;

    if (sizes == null) {
        return null;
    }

    Camera.Size optimalSize = null;

     double minDiff = Double.MAX_VALUE;

    int targetHeight = h;

    for (Camera.Size size : sizes) {
        double ratio = (double) size.width / size.height;
        if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE) continue;
        if (Math.abs(size.height - targetHeight) < minDiff) {
            optimalSize = size;
            minDiff = Math.abs(size.height - targetHeight);
        }
    }

    if (optimalSize == null) {
        minDiff = Double.MAX_VALUE;
        for (Camera.Size size : sizes) {
            if (Math.abs(size.height - targetHeight) < minDiff) {
                optimalSize = size;
                minDiff = Math.abs(size.height - targetHeight);
            }
        }
    }

    return optimalSize;
}

Answer 1

我找到了这个 comment在另一篇解决了我的问题的帖子中!

它会更改 View 的大小，以便图像在始终尝试填满屏幕时不会被拉伸(stretch)。