public static async Task ResizeImageUniformAsync(StorageFile sourceFile, StorageFile targetFile, int maxWidth = Int32.MaxValue, int maxHeight = Int32.MaxValue)
{
using (var stream = await sourceFile.OpenReadAsync())
{
var decoder = await BitmapDecoder.CreateAsync(stream);
if (IsGifImage(decoder))
{
await sourceFile.CopyAndReplaceAsync(targetFile);
return;
}
maxWidth = Math.Min(maxWidth, (int)decoder.OrientedPixelWidth);
maxHeight = Math.Min(maxHeight, (int)decoder.OrientedPixelHeight);
var imageSize = new Size(decoder.OrientedPixelWidth, decoder.OrientedPixelHeight);
var finalSize = imageSize.ToUniform(new Size(maxWidth, maxHeight));
if (finalSize.Width == decoder.OrientedPixelWidth && finalSize.Height == decoder.OrientedPixelHeight)
{
await sourceFile.CopyAndReplaceAsync(targetFile);
return;
}
await ResizeImageAsync(decoder, targetFile, finalSize);
}
}
private Size GetStretchSize(Size containerSize, Size virtualSize)
{
switch (this.Stretch)
{
case Stretch.Fill:
return new Size(this.ActualWidth, this.ActualHeight);
case Stretch.Uniform:
return virtualSize.ToUniform(containerSize);
case Stretch.UniformToFill:
return virtualSize.ToUniformToFill(containerSize);
default:
return virtualSize;
}
}