Allow visual dragging of items

EduNetworkBuilder/IPAddress.cs

@@ -94,6 +94,7 @@ namespace EduNetworkBuilder
             if ((dest.GetIP & _mask) == NetworkAddress)
                 return true;
             return false;
+
         }
 
         public bool Edit(NetworkDevice FromWhat, Form ParentForm, string message="")

EduNetworkBuilder/NetworkBuilder.cs

@@ -40,6 +40,12 @@ namespace EduNetworkBuilder
         private System.Windows.Forms.Timer myTimer = new System.Windows.Forms.Timer();
         public bool NeedsUpdate = false; //Do we do an update next tick
 
+        //For mouse-move / dragging
+        public DateTime LastMoveTime = DateTime.UtcNow;
+        public bool MouseIsDown = false; //For tracking if we are dragging something
+        public Image LastBackgroundImage = null;
+        public Point LastMouseMovePos = new Point(-1, -1);
+
         public BuilderWindow()
         {
             InitializeComponent();
@@ -911,6 +917,9 @@ namespace EduNetworkBuilder
             Point CenteredLocation = myNetwork.clickedPosCentered(e.Location);
             Point ClickLocation = myNetwork.clickedPos(e.Location);
             NetworkDevice ReleasedOn = myNetwork.ItemAtPosition(ClickLocation);
+            MouseIsDown = false;
+            LastBackgroundImage = null;
+            LastMouseMovePos = new Point(-1, -1);
 
             //Do we have something selected that we should add?
             TimeSpan duration;
@@ -1029,10 +1038,45 @@ namespace EduNetworkBuilder
             ClickedLocation = location;
             //See if we have clicked on something
             ItemClickedOn = myNetwork.ItemAtPosition(location);
+            MouseIsDown = true;
+            //Make a duplicate of the old background image.
+            LastBackgroundImage = new Bitmap(pbNetworkView.BackgroundImage);
         }
 
         private void pbNetworkView_MouseMove(object sender, MouseEventArgs e)
         {
+            //Only do this 10 times a second
+            if (DateTime.UtcNow - LastMoveTime < TimeSpan.FromMilliseconds(100)) return;
+
+            if(MouseIsDown && LastBackgroundImage != null && ItemClickedOn != null) //We are trying to drag something
+            {
+                //find where we are
+                Point CenteredLocation = myNetwork.clickedPosCentered(e.Location);
+                Point MouseLocation = myNetwork.clickedPos(e.Location);
+                Size itemsize = new Size(myNetwork.itemsize, myNetwork.itemsize);
+                Rectangle newrec = new Rectangle(CenteredLocation, itemsize);
+ 
+                //erase and Invalidate the old position
+                if(LastMouseMovePos.X >=0 && LastMouseMovePos.Y>= 0)
+                {
+                    Rectangle oldrec = new Rectangle(LastMouseMovePos, itemsize);
+                    Graphics.FromImage(pbNetworkView.BackgroundImage).DrawImage(LastBackgroundImage, oldrec, oldrec,GraphicsUnit.Pixel);
+                    myNetwork.Invalidate(oldrec);
+                }
+
+                //temporarily store old pos
+                Point oldpoint = ItemClickedOn.myLocation();
+                //set it to the new pos
+                ItemClickedOn.ChangeLocation(CenteredLocation);
+                //tell it to draw
+                ItemClickedOn.Print(pbNetworkView.BackgroundImage,false);
+                //invalidate
+                myNetwork.Invalidate(newrec);
+                //return its old pos.
+                ItemClickedOn.ChangeLocation(oldpoint);
+
+             }
+
             Point location = myNetwork.clickedPos(e.Location);
             NetworkDevice MouseOver = myNetwork.ItemAtPosition(location);
             MouseHoverOver = MouseOver;