public static void Scale(this InfiniteScrollViewer self, double scale, double centerX, double centerY)
{
var d0 = self.TransformPoint(centerX, centerY);
self.ScaleMatrix.ScaleX = scale;
self.ScaleMatrix.ScaleY = scale;
var d1 = self.TransformPoint(centerX, centerY);
var diff = d1 - d0;
self.TranslateMatrix.X += diff.X * scale;
self.TranslateMatrix.Y += diff.Y * scale;
}
private void update_thumb(Thumb thumb, InfiniteScrollViewer scrollViewer)
{
var rect = NetworkView.ItemsRect.ValidateRect(ActualWidth, ActualHeight).ToOffset(scrollViewer.ViewRectOffset);
var point = scrollViewer.TransformPoint(0, 0);
Canvas.SetLeft(thumb, point.X / (rect.Width / MiniMap.Width));
Canvas.SetTop(thumb, point.Y / (rect.Height / MiniMap.Height));
}