Rescale BitmapSource

BitmapSourceExtensions.cs

public static BitmapSource Resize(this BitmapSource source, int resolution)
{
    var scale = resolution / source.DpiX;

    // サイズ変更
    var transformedBitmap = new TransformedBitmap();
    transformedBitmap.BeginInit();
    transformedBitmap.Source = source;
    transformedBitmap.Transform = new ScaleTransform(scale, scale);
    transformedBitmap.EndInit();
    return transformedBitmap;
}