Bitmap rotation in Xamarin.Android

Question

How do you rotate Bitmap by 90 degrees in Xamarin.Android? I am using ZXing.Net.Mobile, C#/.NET Barcode Scanning Library and would like to print barcode vertically. Thanks in advance.

Answer 1

Once you have the barcode bitmap:

var barcodeWriter = new ZXing.Mobile.BarcodeWriter
{
    Format = ZXing.BarcodeFormat.CODE_128,
    Options = new ZXing.Common.EncodingOptions
    {
        Width = 300,
        Height = 300
    }
};

var barcode = barcodeWriter.Write("ZXing.Net.Mobile");

You can rotate it with this:

var barcodeRotated = RotateImage(barcode, 90);

Here's the function:

private Bitmap RotateImage(Bitmap src, float degrees)
{
    var matrix = new Matrix();

    matrix.PostRotate(degrees);

    return Bitmap.CreateBitmap(src, 0, 0, src.Width, src.Height, matrix, true);
}

Result:

Hope this helps!