Steema Central

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procedure TCustomTree.InternalWheel(IsDown:Boolean);
var tmp : Double;
    tmpFactor : Integer;
begin
  if IsDown then
     tmpFactor:=+1
  else
     tmpFactor:=-1;

  case FWheelNavigation of
    wnSelection     : if IsDown then
                         ProcessKey(TeeTree_DownKey,[]) // navigate one node down
                      else
                         ProcessKey(TeeTree_UpKey,[]);  // navigate one node up

    wnScrollVert    : with View3DOptions do
                        //   VertOffset:=VertOffset+tmpFactor*TreePageScrollQuantity;
                        // Avoid scrolling beyond top and bottom
                        if VertScrollBar.Visible then
                        begin
                           if IsDown then
                             VertOffset:=Max(VertOffset-tmpFactor*TreePageScrollQuantity, -(VertScrollBar.Max - VertScrollBar.PageSize + 1))
                           else
                             VertOffset:=Min(VertOffset-tmpFactor*TreePageScrollQuantity, 0);
                        end;

    wnScrollHoriz   : with View3DOptions do
                           HorizOffset:=HorizOffset+tmpFactor*2;

    wnZoom          : with View3DOptions do
                      begin
                        tmp:=Math.Max(1,0.05*ZoomFloat);
                     // Ensure zooming behaviour of TeeChart 2012:
                     // to top downsize, to bottom enlarge
                     // ZoomFloat:=Max(1,ZoomFloat-tmpFactor*tmp);
                        ZoomFloat:=Max(1,ZoomFloat+tmpFactor*tmp);
                      end;
  end;
end;

Code: Select all

procedure TForm1.FormCreate(Sender: TObject);
begin
  Tree1.WheelNavigation:=wnZoom;

  Chart1.Panning.MouseWheel:=pmwNone;
  Chart1.ZoomWheel:=pmwNormal;

  Chart1.AddSeries(TBarSeries).FillSampleValues();
  Tree1.AddRoot('First node').AddChild('First child');
  Tree1.Shape[0].Expanded:=true;
end;

Code: Select all

procedure TForm1.Button1Click(Sender: TObject);
begin
  Tree1.WheelNavigation := wnScrollVert;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  Tree1.WheelNavigation := wnZoom;
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
  Tree1.WheelNavigation := wnSelection;
end;

procedure TForm1.FormCreate(Sender: TObject);

  procedure Local_InitNode(pxNode : TTreeNodeShape);
  begin
    pxNode.Border.Visible := False;
    pxNode.ImageIndex := tiNone;
  end;

var
  liI    : Integer;
  lxRoot,
  lxNode : TTreeNodeShape;
begin
  Button1.Caption := 'wnScrollVert';
  Button2.Caption := 'wnZoom';
  Button3.Caption := 'wnSelection';

  Tree1.Canvas := TTeeCanvas3D.Create;
  lxRoot := Tree1.AddRoot('Root');
  Local_InitNode(lxRoot);
  for liI := 0 to 100 do
  begin
    lxNode := lxRoot.AddChild(IntToStr(liI+1));
    Local_InitNode(lxNode);
  end;

  lxRoot.Expanded := True;
end;