I have this code:
var file = await ImageChooser.GetSelectedImageAsStorageFile();
var sasUri = await Vm.GetBlobSasUri(file.Name);
var blob = await file.UploadToBlob(sasUri);
await Vm.ImageSelected(blob.Uri);
I need to resize the image before uploading to the blob.
But the problem is that the function returns a bitmap, and in my case a copy is not necessary.
Remembering that with UWP (applications for windows 10), you can not use System.Drawing.Image.
You can use this function.
public async Task ResizeImage(byte[] imageData, int reqWidth, int reqHeight, int quality)
{
var memStream = new MemoryStream(imageData);
IRandomAccessStream imageStream = memStream.AsRandomAccessStream();
var decoder = await BitmapDecoder.CreateAsync(imageStream);
if (decoder.PixelHeight > reqHeight || decoder.PixelWidth > reqWidth)
{
using (imageStream)
{
var resizedStream = new InMemoryRandomAccessStream();
BitmapEncoder encoder = await BitmapEncoder.CreateForTranscodingAsync(resizedStream, decoder);
double widthRatio = (double) reqWidth/decoder.PixelWidth;
double heightRatio = (double) reqHeight/decoder.PixelHeight;
double scaleRatio = Math.Min(widthRatio, heightRatio);
if (reqWidth == 0)
scaleRatio = heightRatio;
if (reqHeight == 0)
scaleRatio = widthRatio;
uint aspectHeight = (uint) Math.Floor(decoder.PixelHeight*scaleRatio);
uint aspectWidth = (uint) Math.Floor(decoder.PixelWidth*scaleRatio);
encoder.BitmapTransform.InterpolationMode = BitmapInterpolationMode.Linear;
encoder.BitmapTransform.ScaledHeight = aspectHeight;
encoder.BitmapTransform.ScaledWidth = aspectWidth;
await encoder.FlushAsync();
resizedStream.Seek(0);
var outBuffer = new byte[resizedStream.Size];
await resizedStream.ReadAsync(outBuffer.AsBuffer(), (uint)resizedStream.Size, InputStreamOptions.None);
return outBuffer;
}
}
return imageData;
}
It will use the pixel buffer of the image to generate another buffer, which can be used to create a new image.