[Last Call] Learn about multicloud storage options and how to improve your company's cloud strategy. Register Now

x
?
Solved

WPF: Thumb DragDelta not Working

Posted on 2010-09-12
2
Medium Priority
?
2,266 Views
Last Modified: 2012-05-10
I wrote a custom adorner for the WPF InkCanvas. It takes over the built-in adorner that InkCanvas provides, and I designed it to do the same things (Select, Resize, Move, etc the adorned elements).

My Thumbs (one on each corner of a Path that has a RectangelGeomoetry locate perfectly when the adorner is added. However, the DragDelta code is not operating correctly. I'll use the TopLeft THumb as the example. As I click on the Thumb and drag it, the Thumb lags about 50-100 pixels behind the mouse point. After I let go, it places correctly, But when I select it again, it bounces back to the TopLeft corner briefly before it starts tracking.

FYI- The Thumbs are in the Adorner layer (they are not children on the InkCanvas).

Here is the code:
// Handler for thumb dragging
    void ThumbPointAdorner_OnDragDelta(object sender, DragDeltaEventArgs args)
    {
      FrameworkElement adornedElement = this.AdornedElement as FrameworkElement;
      Thumb movingThumb = sender as Thumb;

      if (adornedElement == null || movingThumb == null) return;

        {      

            if ((Math.Abs(args.HorizontalChange) > 0) || (Math.Abs(args.VerticalChange) > 0))
            {
                Rect rect = new Rect( (movingThumb as FrameworkElement).DesiredSize);

                rect.Offset(args.HorizontalChange, args.VerticalChange);

                movingThumb.Arrange(rect);
                this.UpdateLayout();
                parentElement.UpdateLayout();

            }
  
        }
    }
   
 // 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;

          Point topLeftPoint = new Point( InkCanvas.GetLeft(_adornedElement),
                                   InkCanvas.GetTop(_adornedElement));
                        
          IDictionary<string, Point> points = Helper.GetFourPoints(adornerHeight,
                                                            adornerWidth, 
                                                            new Point(0,0));

//        TopLeftPoint
//        TopRightPoint
//        BottomLeftPoint
//        BottomRightPoint

      {
            //_thumbs[0].Arrange( new Rect( points["TopLeftPoint"], _thumbs[0].DesiredSize));
            //_thumbs[1].Arrange( new Rect( points["TopRightPoint"], _thumbs[1].DesiredSize));
            //_thumbs[2].Arrange( new Rect( points["BottomLeftPoint"], _thumbs[2].DesiredSize));
            //_thumbs[3].Arrange(new Rect(points["BottomRightPoint"], _thumbs[3].DesiredSize));

          Size outlineSize = new Size(_adornedElement.DesiredSize.Width , _adornedElement.DesiredSize.Height );

          Rect _adornedElementRect = new Rect(outlineSize);
            
            _adornerOutline.Data = new RectangleGeometry(_adornedElementRect);
            _adornerOutline.Arrange(new Rect(outlineSize));

            _thumbs[0].Arrange( new Rect(points["TopLeftPoint"],  finalSize));
            _thumbs[1].Arrange(new Rect(points["TopRightPoint"], finalSize));
            _thumbs[2].Arrange(new Rect(points["BottomLeftPoint"], finalSize));
            _thumbs[3].Arrange(new Rect(points["BottomRightPoint"], finalSize));

      }
      // Return the final size.
      return finalSize;
    }

Open in new window

0
Comment
Question by:cardinalone
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
2 Comments
 
LVL 29

Accepted Solution

by:
Kumaraswamy R earned 2000 total points
ID: 33659614
0
 

Author Closing Comment

by:cardinalone
ID: 33698197
Thanks for the link,. it re-pointed my efforts. I also found a bug in my code that also was part of the solution.
0

Featured Post

VIDEO: THE CONCERTO CLOUD FOR HEALTHCARE

Modern healthcare requires a modern cloud. View this brief video to understand how the Concerto Cloud for Healthcare can help your organization.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This article introduced a TextBox that supports transparent background.   Introduction TextBox is the most widely used control component in GUI design. Most GUI controls do not support transparent background and more or less do not have the…
Entity Framework is a powerful tool to help you interact with the DataBase but still doesn't help much when we have a Stored Procedure that returns more than one resultset. The solution takes some of out-of-the-box thinking; read on!
This course is ideal for IT System Administrators working with VMware vSphere and its associated products in their company infrastructure. This course teaches you how to install and maintain this virtualization technology to store data, prevent vuln…
In this video, Percona Solution Engineer Dimitri Vanoverbeke discusses why you want to use at least three nodes in a database cluster. To discuss how Percona Consulting can help with your design and architecture needs for your database and infras…

656 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question