SnappingEngine and Bounds.Rect.IntersectWith

[Dario Concilio]

Hi to all,

I would avoid ovelap between RadDiagramShapes (all rectangle items).

When I set IsSnapToGridEnabled="False" IsSnapToItemsEnabled="true" and move RadDiagramShapes, SnappingEngine uses snap on myshape aligned to other ractangle.

If I try to user MyMovedShaped.Bounds.Rect.IntersectWith(OtherRectangleShape) returns me ever True.

I'm using this code:

01.private void topRadDiagram_Drag(object sender, DragRoutedEventArgs e)
02.{
03.    var diagram = (RadDiagram)sender;
04.
05.    foreach (var item in e.Items)
06.    {
07.        var currentItem = (RadDiagramShape)item;
08.
09.        var shapeItem = (GruppoPianoDiCarico)currentItem.Tag;
10.
11.        foreach (RadDiagramShape otherItems in diagram.Items)
12.        {
13.            if (otherItems.Tag.GetType() == typeof(GruppoPianoDiCarico))
14.            {
15.                var shapeOther = (GruppoPianoDiCarico)otherItems.Tag;
16.
17.                if (shapeItem != shapeOther)
18.                {
19.                    if (currentItem.Bounds.IntersectsWith(otherItems.Bounds))
20.                    {
21.                        //Da ripristinare le coordinate originarie
22.                        currentItem.Position = new Point(currentItem.Position.X - (e.MousePosition.X - e.StartMousePosition.X),
23.                            currentItem.Position.Y - (e.MousePosition.Y - e.StartMousePosition.Y));
24.                    }
25.                }
26.            }
27.        }
28.    }
29.}

 

[Petar Mladenov]

Hello Dario,

First, keep in mind that the Drag event fires when you release the mouse. If you need event while you still move the mouse before mouse up, you can use DraggingService.Dragging event:

DraggingService dragService = this.diagram.ServiceLocator.GetService<IDraggingService>() as DraggingService;
           if (dragService != null)
           {
               dragService.Dragging += DragService_Dragging;
           }

In your scenario Snap to Grid is disabled but snap to items is enabled. By default SnapX and SnapY properties of RadDiagram are set to 20. This means that if you move one shape closer to other shape (closer than 20 pixels), the snapping engine will move the dragged shape 20 pixels and distance between them will be 0, Bounds will be immediately updated and IntersectsWith will return true (again I am not sure in which moment you test).  I guess in your scenario you move shapes that are closer than 20 px. If this is the case - limit the SnapX, SnapY to 10, 5.

I hope this helps you move forward.


Regards,
Petar Mladenov
Progress Telerik

[Dario Concilio]

I see, but....

The sequence of actions is this:

• I have two shapes (RectangleShape) (ShapeBefore.PNG)
• I try to move first one near other one (ShapeTryToMove.PNG)
• When I release button mouse, my code returns original positions (by Drag event) with di formula (ShapeAfterReleaseMouse.PNG)
• If I change SmapX to 10 and SnapX to 5, it takes not effects

01.private void topRadDiagram_Drag(object sender, DragRoutedEventArgs e)
02.{
03.    var diagram = (RadDiagram)sender;
04.
05.    foreach (var item in e.Items)
06.    {
07.        var currentItem = (RadDiagramShape)item;
08.
09.        var shapeItem = (GruppoPianoDiCarico)currentItem.Tag;
10.
11.        foreach (RadDiagramShape otherItems in diagram.Items)
12.        {
13.            if (otherItems.Tag.GetType() == typeof(GruppoPianoDiCarico))
14.            {
15.                var shapeOther = (GruppoPianoDiCarico)otherItems.Tag;
16.
17.                if (shapeItem != shapeOther)
18.                    if (currentItem.Bounds.IntersectsWith(otherItems.Bounds))
19.                        currentItem.Position = new Point(currentItem.Position.X - (e.MousePosition.X - e.StartMousePosition.X),
20.                            currentItem.Position.Y - (e.MousePosition.Y - e.StartMousePosition.Y));
21.            }
22.        }
23.    }
24.}

[Dario Concilio]

Ok, I added a "Tollerance" of 1 px, do you like it? :-)

1.[....]
2.if (currentItem.Bounds.IntersectsWith(GetRectWithTollerance(otherItems.Bounds)))
3.[....]
4.
5.private Rect GetRectWithTollerance(Rect pBounds)
6.{
7.    return new Rect(pBounds.X + 1, pBounds.Y + 1, pBounds.Width - 2, pBounds.Height - 2);
8.}

[Petar Mladenov]

Hi Dario,

Yes tolerance trick seems a good option. Let us know if you need further assistance on this topic.

Regards,
Petar Mladenov
Progress Telerik