從使用 intent 獲取的 uri 正確旋轉解碼點陣圖

private static final String TAG = "IntentBitmapFetch";
private static final String COLON_SEPARATOR = ":";
private static final String IMAGE = "image";

@Nullable
public Bitmap getBitmap(@NonNull Uri bitmapUri, int maxDimen) {
    InputStream is = context.getContentResolver().openInputStream(bitmapUri);
    Bitmap bitmap = BitmapFactory.decodeStream(is, null, getBitmapOptions(bitmapUri, maxDimen));
    
    int imgRotation = getImageRotationDegrees(bitmapUri);

    int endRotation = (imgRotation < 0) ? -imgRotation : imgRotation;
    endRotation %= 360;
    endRotation = 90 * (endRotation / 90);
    if (endRotation > 0 && bitmap != null) {
        Matrix m = new Matrix();
        m.setRotate(endRotation);
        Bitmap tmp = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), m, true);
        if (tmp != null) {
            bitmap.recycle();
            bitmap = tmp;
        }
    }

    return bitmap;
}

private BitmapFactory.Options getBitmapOptions(Uri uri, int imageMaxDimen){
    BitmapFactory.Options options = new BitmapFactory.Options();
    if (imageMaxDimen > 0) {
        options.inJustDecodeBounds = true;
        decodeImage(null, uri, options);
        options.inSampleSize = calculateScaleFactor(options, imageMaxDimen);
        options.inJustDecodeBounds = false;
        options.inPreferredConfig = Bitmap.Config.RGB_565;
        addInBitmapOptions(options);
    }
}

private int calculateScaleFactor(@NonNull BitmapFactory.Options bitmapOptionsMeasureOnly, int imageMaxDimen) {
    int inSampleSize = 1;
    if (bitmapOptionsMeasureOnly.outHeight > imageMaxDimen || bitmapOptionsMeasureOnly.outWidth > imageMaxDimen) {
        final int halfHeight = bitmapOptionsMeasureOnly.outHeight / 2;
        final int halfWidth = bitmapOptionsMeasureOnly.outWidth / 2;
        while ((halfHeight / inSampleSize) > imageMaxDimen && (halfWidth / inSampleSize) > imageMaxDimen) {
            inSampleSize *= 2;
        }
    }
    return inSampleSize;
}

    public int getImageRotationDegrees(@NonNull Uri imgUri) {
    int photoRotation = ExifInterface.ORIENTATION_UNDEFINED;

    try {
        boolean hasRotation = false;
        //If image comes from the gallery and is not in the folder DCIM (Scheme: content://)
        String[] projection = {MediaStore.Images.ImageColumns.ORIENTATION};
        Cursor cursor = context.getContentResolver().query(imgUri, projection, null, null, null);
        if (cursor != null) {
            if (cursor.getColumnCount() > 0 && cursor.moveToFirst()) {
                photoRotation = cursor.getInt(cursor.getColumnIndex(projection[0]));
                hasRotation = photoRotation != 0;
                Log.d("Cursor orientation: "+ photoRotation);
            }
            cursor.close();
        }

        //If image comes from the camera (Scheme: file://) or is from the folder DCIM (Scheme: content://)
        if (!hasRotation) {
            ExifInterface exif = new ExifInterface(getAbsolutePath(imgUri));
            int exifRotation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION,
                    ExifInterface.ORIENTATION_NORMAL);
            switch (exifRotation) {
                case ExifInterface.ORIENTATION_ROTATE_90: {
                    photoRotation = 90;
                    break;
                }
                case ExifInterface.ORIENTATION_ROTATE_180: {
                    photoRotation = 180;
                    break;
                }
                case ExifInterface.ORIENTATION_ROTATE_270: {
                    photoRotation = 270;
                    break;
                }
            }
            Log.d(TAG, "Exif orientation: "+ photoRotation);
        }
    } catch (IOException e) {
        Log.e(TAG, "Error determining rotation for image"+ imgUri, e);
    }
    return photoRotation;
}

@TargetApi(Build.VERSION_CODES.KITKAT)
private String getAbsolutePath(Uri uri) {
    //Code snippet edited from: http://stackoverflow.com/a/20559418/2235133
    String filePath = uri.getPath();
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT && DocumentsContract.isDocumentUri(context, uri)) {
        // Will return "image:x*"
        String[] wholeID = TextUtils.split(DocumentsContract.getDocumentId(uri), COLON_SEPARATOR);
        // Split at colon, use second item in the array
        String type = wholeID[0];
        if (IMAGE.equalsIgnoreCase(type)) {//If it not type image, it means it comes from a remote location, like Google Photos
            String id = wholeID[1];
            String[] column = {MediaStore.Images.Media.DATA};
            // where id is equal to
            String sel = MediaStore.Images.Media._ID + "=?";
            Cursor cursor = context.getContentResolver().
                    query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
                            column, sel, new String[]{id}, null);
            if (cursor != null) {
                int columnIndex = cursor.getColumnIndex(column[0]);
                if (cursor.moveToFirst()) {
                    filePath = cursor.getString(columnIndex);
                }
                cursor.close();
            }
            Log.d(TAG, "Fetched absolute path for uri" + uri);
        }
    }
    return filePath;
}