DELPHI AREA Forum

Hello Kambiz,

I have a problem in the Simple Graph Demo:
A Link/Line placed on startpoint X=1 or Y=1 can no longer be reduced by select the endpoint.

Can you help?

I use Version 2.72

I took a look at the bug and found its origin. But it is not easy to fix because needs some major changes on logic behind dragging.

you can fix this problem by modify the code as following:

Code: Select all

procedure TSimpleGraph.PerformDragBy(dX, dY: Integer);
var
  I: Integer;
  Mobility: TObjectSides;
  MinX, MinY: Integer; // by qlg
begin
  if Assigned(DragSource) and ((dX <> 0) or (dY <> 0)) then
  begin
    Mobility := [];
    for I := 0 to DraggingObjects.Count - 1 do
      Mobility := Mobility + DraggingObjects[I].QueryMobility(DragHitTest);
    GraphConstraints.SourceRect := DraggingBounds;
    //------------------ commented by qlg begin
    //if not GraphConstraints.ConfineOffset(dX, dY, Mobility) then
    //  Exit;
    //------------------ commented by qlg end
    BeginUpdate;
    try
      MinX := 0;
      MinY := 0;
      for I := 0 to DraggingObjects.Count - 1 do
      begin
        DraggingObjects[I].OffsetHitTest(DragHitTest, dX, dY);
        MinX := Min(MinX, DraggingObjects[I].BoundsRect.Left); // added by qlg
        MinY := Min(MinY, DraggingObjects[I].BoundsRect.Top);  // added by qlg
      end;

      //------------------by qlg begin
      if (MinX < 0) and (MinY < 0) then
        for I := 0 to Objects.Count - 1 do
          Objects[I].OffsetHitTest(GHT_BODY_MASK, -MinX, -MinY)
      else
      if MinX < 0 then
        for I := 0 to Objects.Count - 1 do
          Objects[I].OffsetHitTest(GHT_BODY_MASK, -MinX, 0)
      else
      if MinY < 0 then
        for I := 0 to Objects.Count - 1 do
          Objects[I].OffsetHitTest(GHT_BODY_MASK, 0, -MinY)
      //------------------by qlg end
    finally
      EndUpdate;
    end;
    Inc(fDragTargetPt.X, dX);
    Inc(fDragTargetPt.Y, dY);
    ScrollInView(fDragTargetPt);
  end;
end;

Not quite true. A rectangle moves down when the line on top applied.

Pity that this did not further elaborated.