using System;
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using System.Windows;
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using System.Windows.Controls;
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using System.Windows.Input;
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using System.Windows.Media;
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namespace Bro.Common.ImageCanvas
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{
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/// <summary>
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/// A class that wraps up zooming and panning of it's content.
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/// </summary>
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public class ZoomAndPanViewBox : ContentControl
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{
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#region local fields
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/// <summary>
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/// The control for creating a drag border
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/// </summary>
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private Border _dragBorder;
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/// <summary>
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/// The control for creating a drag border
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/// </summary>
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private Border _sizingBorder;
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/// <summary>
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/// The control for containing a zoom border
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/// </summary>
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private Canvas _viewportCanvas;
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/// <summary>
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/// Specifies the current state of the mouse handling logic.
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/// </summary>
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private MouseHandlingModeEnum _mouseHandlingMode = MouseHandlingModeEnum.None;
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/// <summary>
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/// The point that was clicked relative to the content that is contained within the ZoomAndPanControl.
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/// </summary>
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private Point _origContentMouseDownPoint;
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#endregion
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#region constructor and overrides
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/// <summary>
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/// Static constructor to define metadata for the control (and link it to the style in Generic.xaml).
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/// </summary>
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static ZoomAndPanViewBox()
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{
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DefaultStyleKeyProperty.OverrideMetadata(typeof(ZoomAndPanViewBox), new FrameworkPropertyMetadata(typeof(ZoomAndPanViewBox)));
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}
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public override void OnApplyTemplate()
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{
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base.OnApplyTemplate();
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_dragBorder = Template.FindName("PART_DraggingBorder", this) as Border;
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_sizingBorder = Template.FindName("PART_SizingBorder", this) as Border;
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_viewportCanvas = Template.FindName("PART_Content", this) as Canvas;
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SetBackground(Visual);
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}
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protected override void OnRenderSizeChanged(SizeChangedInfo sizeInfo)
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{
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base.OnRenderSizeChanged(sizeInfo);
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if (ActualWidth > 0 && _viewportCanvas != null)
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{
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_sizingBorder.BorderThickness = _dragBorder.BorderThickness = new Thickness(
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_viewportCanvas.ActualWidth / ActualWidth * BorderThickness.Left,
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_viewportCanvas.ActualWidth / ActualWidth * BorderThickness.Top,
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_viewportCanvas.ActualWidth / ActualWidth * BorderThickness.Right,
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_viewportCanvas.ActualWidth / ActualWidth * BorderThickness.Bottom);
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}
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}
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#endregion
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#region Mouse Event Handlers
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/// <summary>
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/// Event raised on mouse down in the ZoomAndPanControl.
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/// </summary>
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protected override void OnMouseDown(MouseButtonEventArgs e)
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{
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base.OnMouseLeftButtonDown(e);
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GetZoomAndPanControl().SaveZoom();
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_mouseHandlingMode = MouseHandlingModeEnum.Panning;
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_origContentMouseDownPoint = e.GetPosition(_viewportCanvas);
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if ((Keyboard.Modifiers & ModifierKeys.Shift) != 0)
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{
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// Shift + left- or right-down initiates zooming mode.
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_mouseHandlingMode = MouseHandlingModeEnum.DragZooming;
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_dragBorder.Visibility = Visibility.Hidden;
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_sizingBorder.Visibility = Visibility.Visible;
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Canvas.SetLeft(_sizingBorder, _origContentMouseDownPoint.X);
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Canvas.SetTop(_sizingBorder, _origContentMouseDownPoint.Y);
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_sizingBorder.Width = 0;
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_sizingBorder.Height = 0;
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}
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else
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{
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// Just a plain old left-down initiates panning mode.
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_mouseHandlingMode = MouseHandlingModeEnum.Panning;
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}
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if (_mouseHandlingMode != MouseHandlingModeEnum.None)
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{
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// Capture the mouse so that we eventually receive the mouse up event.
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_viewportCanvas.CaptureMouse();
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e.Handled = true;
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}
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}
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/// <summary>
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/// Event raised on mouse up in the ZoomAndPanControl.
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/// </summary>
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protected override void OnMouseUp(MouseButtonEventArgs e)
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{
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base.OnMouseLeftButtonUp(e);
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if (_mouseHandlingMode == MouseHandlingModeEnum.DragZooming)
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{
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var zoomAndPanControl = GetZoomAndPanControl();
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var curContentPoint = e.GetPosition(_viewportCanvas);
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var rect = ViewportHelpers.Clip(curContentPoint, _origContentMouseDownPoint, new Point(0, 0),
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new Point(_viewportCanvas.Width, _viewportCanvas.Height));
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zoomAndPanControl.AnimatedZoomTo(rect);
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_dragBorder.Visibility = Visibility.Visible;
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_sizingBorder.Visibility = Visibility.Hidden;
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}
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_mouseHandlingMode = MouseHandlingModeEnum.None;
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_viewportCanvas.ReleaseMouseCapture();
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e.Handled = true;
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}
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/// <summary>
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/// Event raised on mouse move in the ZoomAndPanControl.
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/// </summary>
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protected override void OnMouseMove(MouseEventArgs e)
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{
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base.OnMouseMove(e);
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if (_mouseHandlingMode == MouseHandlingModeEnum.Panning)
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{
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var curContentPoint = e.GetPosition(_viewportCanvas);
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var rectangleDragVector = curContentPoint - _origContentMouseDownPoint;
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//
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// When in 'dragging rectangles' mode update the position of the rectangle as the user drags it.
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//
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_origContentMouseDownPoint = e.GetPosition(_viewportCanvas).Clamp();
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Canvas.SetLeft(_dragBorder, Canvas.GetLeft(_dragBorder) + rectangleDragVector.X);
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Canvas.SetTop(_dragBorder, Canvas.GetTop(_dragBorder) + rectangleDragVector.Y);
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}
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else if (_mouseHandlingMode == MouseHandlingModeEnum.DragZooming)
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{
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var curContentPoint = e.GetPosition(_viewportCanvas);
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var rect = ViewportHelpers.Clip(curContentPoint, _origContentMouseDownPoint, new Point(0, 0), new Point(_viewportCanvas.Width, _viewportCanvas.Height));
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ViewportHelpers.PositionBorderOnCanvas(_sizingBorder, rect);
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}
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e.Handled = true;
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}
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/// <summary>
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/// Event raised with the double click command
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/// </summary>
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protected override void OnMouseDoubleClick(MouseButtonEventArgs e)
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{
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base.OnMouseDoubleClick(e);
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if ((Keyboard.Modifiers & ModifierKeys.Shift) == 0)
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{
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var zoomAndPanControl = GetZoomAndPanControl();
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zoomAndPanControl.SaveZoom();
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zoomAndPanControl.AnimatedSnapTo(e.GetPosition(_viewportCanvas));
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}
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}
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#endregion
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#region Background--Visual Brush
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/// <summary>
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/// The X coordinate of the content focus, this is the point that we are focusing on when zooming.
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/// </summary>
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public FrameworkElement Visual
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{
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get { return (FrameworkElement)GetValue(VisualProperty); }
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set { SetValue(VisualProperty, value); }
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}
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public static readonly DependencyProperty VisualProperty = DependencyProperty.Register("Visual",
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typeof(FrameworkElement), typeof(ZoomAndPanViewBox), new FrameworkPropertyMetadata(null, OnVisualChanged));
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private static void OnVisualChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
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{
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var c = (ZoomAndPanViewBox)d;
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c.SetBackground(e.NewValue as FrameworkElement);
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}
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private void SetBackground(FrameworkElement frameworkElement)
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{
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frameworkElement = frameworkElement ?? (DataContext as ContentControl)?.Content as FrameworkElement;
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var visualBrush = new VisualBrush
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{
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Visual = frameworkElement,
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ViewboxUnits = BrushMappingMode.RelativeToBoundingBox,
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ViewportUnits = BrushMappingMode.RelativeToBoundingBox,
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TileMode = TileMode.None,
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Stretch = Stretch.Fill
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};
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if (frameworkElement != null) frameworkElement.SizeChanged += (s, e) =>
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{
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_viewportCanvas.Height = frameworkElement.ActualHeight;
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_viewportCanvas.Width = frameworkElement.ActualWidth;
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_viewportCanvas.Background = visualBrush;
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};
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}
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#endregion
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private ZoomAndPanControl GetZoomAndPanControl()
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{
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var zoomAndPanControl = (DataContext as ZoomAndPanControl) ??
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(DataContext as ZoomAndPanScrollViewer)?.ZoomAndPanContent;
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if (zoomAndPanControl == null) throw new NullReferenceException("DataContext is not of type ZoomAndPanControl");
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return zoomAndPanControl;
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}
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}
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}
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