private static void OnDragging(object sender, PointerRoutedEventArgs e)
#endif
{
var obj = sender as DependencyObject;
if (!GetIsDragging(obj))
{
return;
}
var area = GetAreaFromObject(obj);
var pos = GetPositionInArea(area, e);
double horizontalChange = pos.X - GetOriginalMouseX(obj);
double verticalChange = pos.Y - GetOriginalMouseY(obj);
// Determine whether to use snapping
bool snap = GetIsSnappingPredicate(obj)(obj);
bool individualSnap = false;
// Snap modifier functions to apply to the primary dragged object
SnapModifierFunc snapXMod = null;
SnapModifierFunc snapYMod = null;
// Snap modifier functions to apply to other dragged objects if they snap individually instead of moving
// the same amounts as the primary object.
SnapModifierFunc individualSnapXMod = null;
SnapModifierFunc individualSnapYMod = null;
if (snap)
{
snapXMod = GetXSnapModifier(obj);
snapYMod = GetYSnapModifier(obj);
// If objects snap to grid individually instead of moving the same amount as the primary dragged object,
// use the same snap modifier on each individual object.
individualSnap = GetIsIndividualSnappingPredicate(obj)(obj);
if (individualSnap)
{
individualSnapXMod = snapXMod;
individualSnapYMod = snapYMod;
}
}
if (GetIsTagged(obj))
{
// When the dragged item is a tagged item, we could be dragging a group of objects. If the dragged object is a vertex, it's
// automatically the primary object of the drag. If the dragged object is an edge, prefer the source vertex, but accept the
// target vertex as the primary object of the drag and start with that.
var primaryDragVertex = obj as VertexControl;
if (primaryDragVertex == null)
{
var ec = obj as EdgeControl;
if (ec != null)
{
primaryDragVertex = ec.Source ?? ec.Target;
}
if (primaryDragVertex == null)
{
Debug.WriteLine("OnDragging() -> Tagged and dragged the wrong object?");
return;
}
}
UpdateCoordinates(area, primaryDragVertex, horizontalChange, verticalChange, snapXMod, snapYMod);
if (!individualSnap)
{
// When dragging groups of objects that all move the same amount (not snapping individually, but tracking with
// the movement of the primary dragged object), deterrmine how much offset the primary dragged object experienced
// and use that offset for the rest.
horizontalChange = GraphAreaBase.GetFinalX(primaryDragVertex) - GetOriginalX(primaryDragVertex);
verticalChange = GraphAreaBase.GetFinalY(primaryDragVertex) - GetOriginalY(primaryDragVertex);
}
foreach (var item in area.GetAllVertexControls())
{
if (!ReferenceEquals(item, primaryDragVertex) && GetIsTagged(item))
{
UpdateCoordinates(area, item, horizontalChange, verticalChange, individualSnapXMod, individualSnapYMod);
}
}
}
else
{
UpdateCoordinates(area, obj, horizontalChange, verticalChange, snapXMod, snapYMod);
}
e.Handled = true;
}
private static void UpdateCoordinates(GraphAreaBase area, DependencyObject obj, double horizontalChange, double verticalChange, SnapModifierFunc xSnapModifier, SnapModifierFunc ySnapModifier)
{
if (double.IsNaN(GraphAreaBase.GetX(obj)))
{
GraphAreaBase.SetX(obj, 0, true);
}
if (double.IsNaN(GraphAreaBase.GetY(obj)))
{
GraphAreaBase.SetY(obj, 0, true);
}
//move the object
var x = GetOriginalX(obj) + horizontalChange;
if (xSnapModifier != null)
{
x = xSnapModifier(area, obj, x);
}
GraphAreaBase.SetX(obj, x, true);
var y = GetOriginalY(obj) + verticalChange;
if (ySnapModifier != null)
{
y = ySnapModifier(area, obj, y);
}
GraphAreaBase.SetY(obj, y, true);
if (GetUpdateEdgesOnMove(obj))
{
UpdateVertexEdges(obj as VertexControl);
}
//Debug.WriteLine("({0:##0.00000}, {1:##0.00000})", x, y);
}
public static void SetYSnapModifier(DependencyObject obj, SnapModifierFunc value)
{
obj.SetValue(YSnapModifierProperty, value);
}
