CODEWITHSUNDEEP
c#wpf
Taoufik J
Taoufik J

Reputation: 800

Affecting Streamsource from a bitmap to another not working

Rotating a bitmapImage using UriSource works using the following code 

    private void RotateDocumentImageSourceRight()
    {
        var biOriginal = (BitmapImage)documentImage.Source;
        if (biOriginal == null)
            return;
        var biRotated = new BitmapImage();
        biRotated.BeginInit();
        biRotated.UriSource = biOriginal.UriSource;
        switch (biOriginal.Rotation)
        {
            case Rotation.Rotate0:
                biRotated.Rotation = Rotation.Rotate270;
                break;
            case Rotation.Rotate270:
                biRotated.Rotation = Rotation.Rotate180;
                break;
            case Rotation.Rotate180:
                biRotated.Rotation = Rotation.Rotate90;
                break;
            case Rotation.Rotate90:
                biRotated.Rotation = Rotation.Rotate0;
                break;
            default:
                break;
        }
        biRotated.EndInit();

        documentImage.Source = biRotated;
    }

But when I change the way a bitmapImage is stored to StreamSource it doesn't work and the image disappears 

    private void RotateDocumentImageSourceRight()
    {
        ...same code...
        biRotated.StreamSource= biOriginal.StreamSource;
        ...same code...
    }

Upvotes: 2

Views: 244

Answers (1)

Eli Arbel
Eli Arbel

Reputation: 22739

You can use a TransformedBitmap, which is used by BitmapImage internally when you specify the Rotation property. It will create a new image, but it will be faster (it won't need to read the stream again).

private void RotateDocumentImageSourceRight()
{
    var biOriginal = (BitmapSource)documentImage.Source;
    if (biOriginal == null)
        return;
    var angle = 0.0;
    var biRotated = biOriginal as TransformedBitmap;
    if (biRotated != null)
    {
        biOriginal = biRotated.Source;
        angle = ((RotateTransform)biRotated.Transform).Angle;
    }
    angle -= 90;
    if (angle < 0) angle += 360;
    biRotated = new TransformedBitmap(biOriginal, new RotateTransform(angle));
    documentImage.Source = biRotated;
}

Upvotes: 2

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