private void DisplayScroll_MouseMove(object sender, MouseEventArgs e)
{
if (lastDragPoint.HasValue)
{
Point posNow = e.GetPosition(DisplayScroll);
double dX = posNow.X - lastDragPoint.Value.X;
double dY = posNow.Y - lastDragPoint.Value.Y;
lastDragPoint = posNow;
DisplayScroll.ScrollToHorizontalOffset(DisplayScroll.HorizontalOffset - dX);
DisplayScroll.ScrollToVerticalOffset(DisplayScroll.VerticalOffset - dY);
}
}
public void ProcessIndicatorInput(double x)
{
x -= ScrollIndicator.Margin.Left;
x = x / ((ScrollIndicator.Parent as FrameworkElement).ActualWidth - ScrollIndicator.Margin.Left - ScrollIndicator.Margin.Right);
DisplayScroll.ScrollToHorizontalOffset(x * DisplayScroll.ScrollableWidth);
}
private void ScrollViewer_ScrollChanged(object sender, ScrollChangedEventArgs e)
{
#if DEBUG
if (DisplayScroll.CanContentScroll)
{
Console.WriteLine("ScrollChangedEvent just Occurred");
Console.WriteLine("ExtentHeight is now " + e.ExtentHeight);
Console.WriteLine("ExtentWidth is now " + e.ExtentWidth);
Console.WriteLine("ExtentHeightChange was " + e.ExtentHeightChange);
Console.WriteLine("ExtentWidthChange was " + e.ExtentWidthChange);
Console.WriteLine("HorizontalOffset is now " + e.HorizontalOffset);
Console.WriteLine("VerticalOffset is now " + e.VerticalOffset);
Console.WriteLine("HorizontalChange was " + e.HorizontalChange);
Console.WriteLine("VerticalChange was " + e.VerticalChange);
Console.WriteLine("ViewportHeight is now " + e.ViewportHeight);
Console.WriteLine("ViewportWidth is now " + e.ViewportWidth);
Console.WriteLine("ViewportHeightChange was " + e.ViewportHeightChange);
Console.WriteLine("ViewportWidthChange was " + e.ViewportWidthChange);
Console.WriteLine("ActualHeight is now " + DisplayScroll.ActualHeight);
Console.WriteLine("ActualWidth is now " + DisplayScroll.ActualWidth);
Console.WriteLine("--------------------------------------------------------------");
//ActualHeight = ViewportHeight + HorizontalScrollbarHeight
}
#endif
DisplayScroll.UpdateLayout();
if (e.ViewportHeightChange != 0 || e.ViewportWidthChange != 0)
{
_zoomValue = ZoomToFit();
var scale = new ScaleTransform(_zoomValue, _zoomValue);
DisplayImage.LayoutTransform = scale;
DisplayScroll.UpdateLayout();
}
if (e.ExtentHeightChange != 0 || e.ExtentWidthChange != 0)
{
Point?targetBefore = null;
Point?targetNow = null;
if (lastMousePositionOnTarget.HasValue)
{
targetBefore = lastMousePositionOnTarget;
targetNow = Mouse.GetPosition(DisplayImage);
lastMousePositionOnTarget = null;
}
if (targetBefore.HasValue)
{
double dXInTargetPixels = targetNow.Value.X - targetBefore.Value.X;
double dYInTargetPixels = targetNow.Value.Y - targetBefore.Value.Y;
double multiplicatorX = e.ExtentWidth / DisplayImage.ActualWidth;
double multiplicatorY = e.ExtentHeight / DisplayImage.ActualHeight;
double newOffsetX = DisplayScroll.HorizontalOffset - dXInTargetPixels * multiplicatorX;
double newOffsetY = DisplayScroll.VerticalOffset - dYInTargetPixels * multiplicatorY;
if (double.IsNaN(newOffsetX) || double.IsNaN(newOffsetY))
{
return;
}
DisplayScroll.ScrollToHorizontalOffset(newOffsetX);
DisplayScroll.ScrollToVerticalOffset(newOffsetY);
}
}
}
