How do you save a transformed image?

Question

Windows Store App 8.1.
I have an image that the user has rotated, scaled and clipped etc.  How do you save the transformed image?
There are solutions of the forums but these use the System.Media.Imaging library that isn't available, classes like the TransformedBitmap etc. are not available. 
I'm playing around with this approach but the decoder throws a "The image format is unknown"; 
imageManipulation is UIElement.Image.
Any ideas on how to achieve the saving of a Transformed image in a 4.5.1 8.1 store app?
RenderTargetBitmap rtb = new RenderTargetBitmap();
await rtb.RenderAsync(imageManipulation, (int)imageManipulation.ActualWidth, (int)imageManipulation.ActualHeight);
IBuffer buffer = await rtb.GetPixelsAsync();
using (InMemoryRandomAccessStream ras = new InMemoryRandomAccessStream())
await ras.WriteAsync(buffer);
await ras.FlushAsync();
BitmapDecoder dec = await BitmapDecoder.CreateAsync(BitmapDecoder.BmpDecoderId, ras);
Rob

Answer 1

Hi,
You can use BitmapEncoder to apply transforms such as scaling and cropping, set metadata and properties, and edit pixels while preserving any unedited
data. After transform the data, you can copy the contents from the in-memory stream to the original file’s stream and close all of the streams. That make you can save the encoded image to the file:
memStream.Seek(0);
fileStream.Seek(0);
fileStream.Size = 0;
await RandomAccessStream.CopyAsync(memStream, fileStream);
fileStream.Dispose();
memStream.Dispose();
You can see the link to get more information:
https://msdn.microsoft.com/en-us/library/windows/apps/xaml/jj709937.aspx
Best Wishes!
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