private void ToolBox_MouseDown(object sender, MouseButtonEventArgs e)
{
Label lb = sender as Label;
switch (lb.Content)
{
case "Move":
this.isMoveMode = !isMoveMode;
break;
case "Zoom in":
if (Zoom <= 2)
{
Zoom += .05;
scaleTransform.ScaleX = Zoom;
scaleTransform.ScaleY = Zoom;
var centerOfViewport = new Point(MainScrollViewer.ViewportWidth / 2, MainScrollViewer.ViewportHeight / 2);
lastCenterPositionOnTarget = MainScrollViewer.TranslatePoint(centerOfViewport, GridWorkspace);
if (!lbZoomOut.IsEnabled)
{
lbZoomOut.IsEnabled = true;
lbZoomOut.Foreground = Brushes.White;
}
}
else
{
lb.IsEnabled = false;
}
break;
case "Zoom out":
if (Zoom > 0.3)
{
Zoom -= .05;
scaleTransform.ScaleX = Zoom;
scaleTransform.ScaleY = Zoom;
var centerOfViewport1 = new Point(MainScrollViewer.ViewportWidth / 2, MainScrollViewer.ViewportHeight / 2);
lastCenterPositionOnTarget = MainScrollViewer.TranslatePoint(centerOfViewport1, GridWorkspace);
}
else
{
lb.IsEnabled = false;
}
break;
}
lbZoomRatio.Content = (Zoom * 100).ToString() + "%";
}
void OnScrollViewerScrollChanged(object sender, ScrollChangedEventArgs e)
{
if (e.ExtentHeightChange != 0 || e.ExtentWidthChange != 0)
{
Point?targetBefore = null;
Point?targetNow = null;
if (!lastMousePositionOnTarget.HasValue)
{
if (lastCenterPositionOnTarget.HasValue)
{
var centerOfViewport = new Point(MainScrollViewer.ViewportWidth / 2, MainScrollViewer.ViewportHeight / 2);
Point centerOfTargetNow = MainScrollViewer.TranslatePoint(centerOfViewport, MainCanvas);
targetBefore = lastCenterPositionOnTarget;
targetNow = centerOfTargetNow;
}
}
else
{
targetBefore = lastMousePositionOnTarget;
targetNow = Mouse.GetPosition(MainCanvas);
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 / MainCanvas.Width;
double multiplicatorY = e.ExtentHeight / MainCanvas.Height;
double newOffsetX = MainScrollViewer.HorizontalOffset - dXInTargetPixels * multiplicatorX;
double newOffsetY = MainScrollViewer.VerticalOffset - dYInTargetPixels * multiplicatorY;
if (double.IsNaN(newOffsetX) || double.IsNaN(newOffsetY))
{
return;
}
MainScrollViewer.ScrollToHorizontalOffset(newOffsetX);
MainScrollViewer.ScrollToVerticalOffset(newOffsetY);
}
}
}
