Android 使用 Camera2Api 拍照时图像旋转

Question

Does anyone know various rotation angles for mainstream phones. Everytime I take a picture it always rotates it at different angles on different mobile devices.

Answer 1

Most phone cameras are landscape, meaning if you take the photo in portrait, the resulting photos will be rotated 90 degrees. In this case, the camera software should populate the Exif data with the orientation that the photo should be viewed in. Though this is not 100% reliable because it depends on the camera software populating the Exit data

ExifInterface ei = new ExifInterface(photoPath);
int orientation = ei.getAttributeInt(ExifInterface.TAG_ORIENTATION,
                                     ExifInterface.ORIENTATION_UNDEFINED);

Bitmap rotatedBitmap = null;
switch(orientation) {

    case ExifInterface.ORIENTATION_ROTATE_90:
        rotatedBitmap = rotateImage(bitmap, 90);
        break;

    case ExifInterface.ORIENTATION_ROTATE_180:
        rotatedBitmap = rotateImage(bitmap, 180);
        break;

    case ExifInterface.ORIENTATION_ROTATE_270:
        rotatedBitmap = rotateImage(bitmap, 270);
        break;

    case ExifInterface.ORIENTATION_NORMAL:
    default:
        rotatedBitmap = bitmap;
}

Method to rotateimage

public static Bitmap rotateImage(Bitmap source, float angle) {
    Matrix matrix = new Matrix();
    matrix.postRotate(angle);
    return Bitmap.createBitmap(source, 0, 0, source.getWidth(), source.getHeight(),
                               matrix, true);
}