static void scroll_ScrollChanged(object sender, ScrollChangedEventArgs e)
{
try
{
ZoomingScrollViewer scroll = sender as ZoomingScrollViewer;
if (scroll._isRelativeSet)
{
if (e.ExtentWidthChange != 0 || e.ExtentHeightChange != 0)
{
scroll.ScrollToHorizontalOffset(CalculateOffset(e.ExtentWidth, e.ViewportWidth, scroll.ScrollableWidth, scroll.relX));
scroll.ScrollToVerticalOffset(CalculateOffset(e.ExtentHeight, e.ViewportHeight, scroll.ScrollableHeight, scroll.relY));
}
else
{
scroll.relX = (e.HorizontalOffset + 0.5 * e.ViewportWidth) / e.ExtentWidth;
scroll.relY = (e.VerticalOffset + 0.5 * e.ViewportHeight) / e.ExtentHeight;
}
}
else
{
scroll.relX = (e.HorizontalOffset + 0.5 * e.ViewportWidth) / e.ExtentWidth;
scroll.relY = (e.VerticalOffset + 0.5 * e.ViewportHeight) / e.ExtentHeight;
scroll._isRelativeSet = true;
}
scroll.OnScrollChanged();
}
catch { }
}
static void scrollSelectedZoom_ScrollChanged(object sender, ScrollChangedEventArgs e)
{
try
{
ZoomingScrollViewer scroll = sender as ZoomingScrollViewer;
if (e.ExtentWidthChange != 0 || e.ExtentHeightChange != 0)
{
scroll.ScrollToSelectedCenterPoint();
}
scroll.OnScrollChanged();
}
catch { }
}
private static void OnKeepInCenterChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
ZoomingScrollViewer scroll = d as ZoomingScrollViewer;
if (scroll != null)
{
if ((bool)e.NewValue)
{
scroll.ScrollChanged += scroll_ScrollChanged;
scroll.ScrollChanged -= scrollSelectedZoom_ScrollChanged;
scroll._isRelativeSet = false;
}
else
{
scroll.ScrollChanged -= scroll_ScrollChanged;
scroll.ScrollChanged += scrollSelectedZoom_ScrollChanged;
}
}
}
