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using System; using System.Windows; using System.Windows.Controls; using System.Windows.Controls.Primitives; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; namespace adorners { public class ResizingAdorner : Adorner { // Resizing adorner uses Thumbs for visual elements. // The Thumbs have built-in mouse input handling. Thumb topLeft, topRight, bottomLeft, bottomRight; // To store and manage the adorner's visual children. VisualCollection visualChildren; // Initialize the ResizingAdorner. public ResizingAdorner(UIElement adornedElement) : base(adornedElement) { // Call a helper method to initialize the Thumbs // with a customized cursors. BuildAdornerCorner(ref topLeft, Cursors.SizeNWSE); BuildAdornerCorner(ref topRight, Cursors.SizeNESW); BuildAdornerCorner(ref bottomLeft, Cursors.SizeNESW); BuildAdornerCorner(ref bottomRight, Cursors.SizeNWSE); // Add handlers for resizing. } // Handler for resizing from the bottom-right. void HandleBottomRight(object sender, DragDeltaEventArgs args) { FrameworkElement adornedElement = this.AdornedElement as FrameworkElement; Thumb hitThumb = sender as Thumb; if (adornedElement == null || hitThumb == null) return; FrameworkElement parentElement = adornedElement.Parent as FrameworkElement; // Ensure that the Width and Height are properly initialized after the resize. EnforceSize(adornedElement); // Change the size by the amount the user drags the mouse, as long as it's larger // than the width or height of an adorner, respectively. adornedElement.Width = Math.Max(adornedElement.Width + args.HorizontalChange, hitThumb.DesiredSize.Width); adornedElement.Height = Math.Max(args.VerticalChange + adornedElement.Height, hitThumb.DesiredSize.Height); } // Handler for resizing from the top-right. void HandleTopRight(object sender, DragDeltaEventArgs args) { FrameworkElement adornedElement = this.AdornedElement as FrameworkElement; Thumb hitThumb = sender as Thumb; if (adornedElement == null || hitThumb == null) return; FrameworkElement parentElement = adornedElement.Parent as FrameworkElement; // Ensure that the Width and Height are properly initialized after the resize. EnforceSize(adornedElement); // Change the size by the amount the user drags the mouse, as long as it's larger // than the width or height of an adorner, respectively. adornedElement.Width = Math.Max(adornedElement.Width + args.HorizontalChange, hitThumb.DesiredSize.Width); //adornedElement.Height = Math.Max(adornedElement.Height - args.VerticalChange, hitThumb.DesiredSize.Height); double height_old = adornedElement.Height; double height_new = Math.Max(adornedElement.Height - args.VerticalChange, hitThumb.DesiredSize.Height); double top_old = Canvas.GetTop(adornedElement); adornedElement.Height = height_new; Canvas.SetTop(adornedElement, top_old - (height_new - height_old)); } // Handler for resizing from the top-left. void HandleTopLeft(object sender, DragDeltaEventArgs args) { FrameworkElement adornedElement = AdornedElement as FrameworkElement; Thumb hitThumb = sender as Thumb; if (adornedElement == null || hitThumb == null) return; // Ensure that the Width and Height are properly initialized after the resize. EnforceSize(adornedElement); // Change the size by the amount the user drags the mouse, as long as it's larger // than the width or height of an adorner, respectively. //adornedElement.Width = Math.Max(adornedElement.Width - args.HorizontalChange, hitThumb.DesiredSize.Width); //adornedElement.Height = Math.Max(adornedElement.Height - args.VerticalChange, hitThumb.DesiredSize.Height); double width_old = adornedElement.Width; double width_new = Math.Max(adornedElement.Width - args.HorizontalChange, hitThumb.DesiredSize.Width); double left_old = Canvas.GetLeft(adornedElement); adornedElement.Width = width_new; Canvas.SetLeft(adornedElement, left_old - (width_new - width_old)); double height_old = adornedElement.Height; double height_new = Math.Max(adornedElement.Height - args.VerticalChange, hitThumb.DesiredSize.Height); double top_old = Canvas.GetTop(adornedElement); adornedElement.Height = height_new; Canvas.SetTop(adornedElement, top_old - (height_new - height_old)); } // Handler for resizing from the bottom-left. void HandleBottomLeft(object sender, DragDeltaEventArgs args) { FrameworkElement adornedElement = AdornedElement as FrameworkElement; Thumb hitThumb = sender as Thumb; if (adornedElement == null || hitThumb == null) return; // Ensure that the Width and Height are properly initialized after the resize. EnforceSize(adornedElement); // Change the size by the amount the user drags the mouse, as long as it's larger // than the width or height of an adorner, respectively. //adornedElement.Width = Math.Max(adornedElement.Width - args.HorizontalChange, hitThumb.DesiredSize.Width); adornedElement.Height = Math.Max(args.VerticalChange + adornedElement.Height, hitThumb.DesiredSize.Height); double width_old = adornedElement.Width; double width_new = Math.Max(adornedElement.Width - args.HorizontalChange, hitThumb.DesiredSize.Width); double left_old = Canvas.GetLeft(adornedElement); adornedElement.Width = width_new; Canvas.SetLeft(adornedElement, left_old - (width_new - width_old)); } // Arrange the Adorners. protected override Size ArrangeOverride(Size finalSize) { // desiredWidth and desiredHeight are the width and height of the element that's being adorned. // These will be used to place the ResizingAdorner at the corners of the adorned element. double desiredWidth = AdornedElement.DesiredSize.Width; double desiredHeight = AdornedElement.DesiredSize.Height; // adornerWidth & adornerHeight are used for placement as well. double adornerWidth = this.DesiredSize.Width; double adornerHeight = this.DesiredSize.Height; topRight.Arrange(new Rect(desiredWidth - adornerWidth / 2, -adornerHeight / 2, adornerWidth, adornerHeight)); bottomLeft.Arrange(new Rect(-adornerWidth / 2, desiredHeight - adornerHeight / 2, adornerWidth, adornerHeight)); bottomRight.Arrange(new Rect(desiredWidth - adornerWidth / 2, desiredHeight - adornerHeight / 2, adornerWidth, adornerHeight)); // Return the final size. return finalSize; } // Helper method to instantiate the corner Thumbs, set the Cursor property, // set some appearance properties, and add the elements to the visual tree. void BuildAdornerCorner(ref Thumb cornerThumb, Cursor customizedCursor) { if (cornerThumb != null) return; // Set some arbitrary visual characteristics. cornerThumb.Cursor = customizedCursor; cornerThumb.Height = cornerThumb.Width = 10; cornerThumb.Opacity = 0.40; visualChildren.Add(cornerThumb); } // This method ensures that the Widths and Heights are initialized. Sizing to content produces // Width and Height values of Double.NaN. Because this Adorner explicitly resizes, the Width and Height // need to be set first. It also sets the maximum size of the adorned element. void EnforceSize(FrameworkElement adornedElement) { if (adornedElement.Width.Equals(Double.NaN)) adornedElement.Width = adornedElement.DesiredSize.Width; if (adornedElement.Height.Equals(Double.NaN)) adornedElement.Height = adornedElement.DesiredSize.Height; FrameworkElement parent = adornedElement.Parent as FrameworkElement; if (parent != null) { adornedElement.MaxHeight = parent.ActualHeight; adornedElement.MaxWidth = parent.ActualWidth; } } // Override the VisualChildrenCount and GetVisualChild properties to interface with // the adorner's visual collection. protected override int VisualChildrenCount { get { return visualChildren.Count; } } protected override Visual GetVisualChild(int index) { return visualChildren[index]; } } }
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