public override void MouseDown(NSEvent evnt)
{
NSPoint point = evnt.LocationInView(this);
int index = this.IndexOfCircleAtPoint(point);
if (index >= 0)
{
this.DragCircleAtIndexWithEvent((uint) index, evnt);
}
}
public void DragCircleAtIndexWithEvent(uint index, NSEvent evnt)
{
Circle circle = this.circles.ObjectAtIndex(index).CastTo<Circle>();
circle.Retain();
this.circles.RemoveObjectAtIndex(index);
this.circles.AddObject(circle);
circle.Release();
this.SetNeedsDisplayInRect(this.BoundsForCircle(circle));
NSEventMask mask = NSEventMask.NSLeftMouseDraggedMask | NSEventMask.NSLeftMouseUpMask;
NSPoint start = evnt.LocationInView(this);
while (true)
{
evnt = this.Window.NextEventMatchingMask(mask);
if (evnt.Type == NSEventType.NSLeftMouseUp)
{
break;
}
this.SetNeedsDisplayInRect(this.BoundsForCircle(circle));
NSPoint center = circle.Center;
NSPoint point = evnt.LocationInView(this);
center.x += point.x - start.x;
center.y += point.y - start.y;
circle.Center = center;
this.SetNeedsDisplayInRect(this.BoundsForCircle(circle));
start = point;
}
}