procedure TForm1.ImageEnView1LayerNotify(Sender: TObject; layer: Integer;
  event: TIELayerEvent);
var
  iRect: TRect;
begin
  { Constrain the position of a magnify layer to the bounds of the bitmap }
  if (event = ielMoving) and (ImageEnView1.Layers[layer].Magnify.Enabled) then
  begin
    if ConstrainMagnifyLayerToBitmap1.Checked then
    begin
      iRect := ImageEnView1.VisibleBitmapRect;
      if ImageEnView1.Layers[layer].PosX + ImageEnView1.Layers[layer].Width > ImageEnView1.Layers[0].Width then
         ImageEnView1.Layers[layer].PosX := ImageEnView1.Layers[0].Width -
            ImageEnView1.Layers[layer].Width;
      if ImageEnView1.Layers[layer].PosX < 0 then
         ImageEnView1.Layers[layer].PosX := 0;
      if ImageEnView1.Layers[layer].PosY + ImageEnView1.Layers[layer].Height > ImageEnView1.Layers[0].Height then
         ImageEnView1.Layers[layer].PosY := ImageEnView1.Layers[0].Height -
            ImageEnView1.Layers[layer].Height;
      if ImageEnView1.Layers[layer].PosY < ImageEnView1.ViewY then
         ImageEnView1.Layers[layer].PosY := ImageEnView1.ViewY;
    end;
  end;
end;

procedure TForm1.ImageEnView1ViewChange(Sender: TObject; Change: Integer);
var
  iRect: TRect;
  ix: Integer;
  iy: Integer;
begin
  { If there is a magnify layer }
  if ImageEnView1.LayersCount > 1 then
    if (ImageEnView1.Layers[1].Magnify.Enabled) then
    begin
      { Get the rect of the visiblebitmap }
      iRect := ImageEnView1.VisibleBitmapRect;
      ix := iRect.Left;
      iy := iRect.Top;
      ImageEnView1.Layers[1].PosX := ix;
      ImageEnView1.Layers[1].PosY := iy;
    end;
end;

procedure TForm1.ImageEnView1ViewChange(Sender: TObject; Change: Integer);
var
  iRect: TRect;
  ix: Integer;
  iy: Integer;
begin
  { If there is a magnify layer }
  if ImageEnView1.LayersCount > 1 then
  if (ImageEnView1.Layers[1].Magnify.Enabled) then
  begin
    { Get the rect of the visiblebitmap }
    iRect := ImageEnView1.VisibleBitmapRect;
    { Set the layers coordinates }
    ix := iRect.TopLeft.X + ImageEnView1.Layers[1].Width;
    iy := iRect.TopLeft.Y + ImageEnView1.Layers[1].Height;
    ImageEnView1.Layers[1].PosX := ix;
    ImageEnView1.Layers[1].PosY := iy;
  end;
end;