procedure CalculateRect(ParentID: TTreemapElementID; ARect: TRect; Layer: Integer;
  CalculateHint: Boolean; MouseX: Integer; MouseY: Integer; var Path: WideString; var FrameRect: TRect;
  var Caption: WideString; var Value: Integer; var ID: TTreemapElementID);
var
  i: Integer;
  ChildCount: Integer;
  StartIndex: Integer;
  EndIndex: Integer;
  Orientation: Boolean;
  CurrentAspect: Single;
  LastAspect: Single;
  CurrentX: Single;
  CurrentY: Single;
  CurrentX1: Single;
  CurrentY1: Single;
  OffsetX: Single;
  OffsetY: Single;
  TotalSum: Integer;
  ScaleValue: Double;
  TempChildCount: Integer;
  AWidth: Integer;
  AHeight: Integer;
  TempWidth: Single;
  TempHeight: Single;
  TempArray: Array of TSortArray;
  j: Integer;
begin
  StartIndex := 0;
  EndIndex := 0;
  CurrentAspect := 999;
  OffsetX := 0.0;
  OffsetY := 0.0;
  AWidth := ARect.BottomRight.X - ARect.TopLeft.X;
  AHeight := ARect.BottomRight.Y - ARect.TopLeft.Y;
  TempWidth := AWidth;
  TempHeight := AHeight;

  // keine Gleitkommazahlberechnungen, daher nich wichtig
  Orientation := DrawingOrientation(TempWidth, TempHeight);
  ComputeSizeArray(ParentID);
  ChildCount := DoGetChildCount(ParentID);
  TotalSum := SumRectangles(ParentID);

  try
    ScaleValue := ((AWidth * AHeight) / TotalSum) / 100
  except
    on EZeroDivide do
      ScaleValue := 0.0;
  end;
  for i := 0 to ChildCount-1 do
  begin
    SortArray[i].SizeTemp := ScaleValue * SortArray[i].Values.ChildValue;
  end;
  while (EndIndex <> ChildCount) do
  begin
    LastAspect := SquarifiedTryLayout(StartIndex, EndIndex, Orientation, TempWidth, TempHeight);
    if ((LastAspect > CurrentAspect) or (LastAspect < 1)) then
    begin
      CurrentX := ARect.TopLeft.X;
      CurrentY := ARect.TopLeft.Y;
      for i:= StartIndex to EndIndex-1 do
      begin
        SortArray[i].X := OffsetX + CurrentX;
        SortArray[i].Y := OffsetY + CurrentY;
        if (Orientation)then
          CurrentY := Single(CurrentY) + Single(SortArray[i].Height)
        else
          CurrentX := Single(CurrentX) + Single(SortArray[i].Width);
      end;//for
      if (Orientation) then
        OffsetX := Single(OffsetX) + Single(SortArray[StartIndex].Width)
      else
        OffsetY := Single(OffsetY) + Single(SortArray[StartIndex].Height);
      TempWidth := AWidth - OffsetX;
      TempHeight := AHeight - OffsetY;
      Orientation := DrawingOrientation(TempWidth, TempHeight);
      StartIndex := EndIndex;
      EndIndex := StartIndex;
      CurrentAspect := 999;
      continue;
    end//if(LastAspect>CurrentAspect)
    else
    begin
      for i:= StartIndex to EndIndex do
      begin
        SortArray[i].Width := SortArray[i].TempWidth;
        SortArray[i].Height := SortArray[i].TempHeight;
      end;//for
      CurrentAspect := LastAspect;
    end;//else
    EndIndex := EndIndex + 1;
  end;//while(EndIndex <> ChildCount)
  CurrentX1 := ARect.TopLeft.X;
  CurrentY1 := ARect.TopLeft.Y;
  for i:= StartIndex to EndIndex-1 do
  begin
    SortArray[i].X := Single(OffsetX) + Single(CurrentX1);
    SortArray[i].Y := Single(OffsetY) + Single(CurrentY1);
    if (Orientation) then
      CurrentY1 := CurrentY1 + SortArray[i].Height
    else
      CurrentX1 := CurrentX1 + SortArray[i].Width;
  end;//for
  if(CalculateHint = False) then
    SquarifiedPaintRect(Layer, ParentID)
  else
  begin
    for i:=0 to ChildCount-1 do
    begin
      ARect.TopLeft := Point(Round(SortArray[i].X), Round(SortArray[i].Y));
      ARect.BottomRight := Point(Round(SortArray[i].Width + SortArray[i].X), Round(SortArray[i].Height + SortArray[i].Y));
      if (CheckMouseMove(MouseX, MouseY, ARect, Path, ParentID, i)) then
      begin
        if ((ComputeArea(ARect) <= MinimumSize) or
          ((ShowLeafs = False) and (SortArray[i].Values.IsFolder = False))) then
        begin
          FrameRect.TopLeft := Point(0,0);
          FrameRect.BottomRight := Point(0,0);
          Value := 0;
        end
        else
        begin
          FrameRect := ARect;
          Caption := SortArray[i].Values.ChildCaption;
          Value := SortArray[i].Values.ChildValue;
          ID := SortArray[i].ChildID;
        end;//else
        exit;
      end;//if(CheckMouseMove)
    end;//for
  end;//if(CalculateHint)
  SetLength(TempArray, Length(SortArray));
  for j := 0 to Length(SortArray) - 1 do
  begin
    TempArray[j] := SortArray[j];
  end;
  for i := 0 to ChildCount-1 do
  begin
    TempChildCount := DoGetChildCount(TempArray[i].ChildID);
    if (TempChildCount >=1) then
    begin
      ARect.TopLeft := Point(Round(TempArray[i].X), Round(TempArray[i].Y));
      ARect.BottomRight := Point(Round(TempArray[i].Width + TempArray[i].X), Round(TempArray[i].Height + TempArray[i].Y));
      if (Parents) then
        AddPadding(ARect);
      DrawOuterRect(ARect, Layer+1, True, 2, SortArray[i].Values.ChildImageIndex, SortArray[i].Values.ChildCaption);
      SquarifiedCalculateRect(TempArray[i].ChildID, ARect, Layer+1, CalculateHint, MouseX, MouseY, Path, FrameRect, Caption,
        Value, ID);
    end;//if(TempChildCount...)
  end;//for
end;

function TCustomTreemapChart.SquarifiedTryLayout(StartIndex: Integer; EndIndex: Integer; Orientation: Boolean; TempWidth: Single;
  TempHeight: Single): Single;
var
  Total: Single;
  Aspect: Single;
  LocalWidth: Single;
  LocalHeight: Single;
  i: Integer;
begin
  Aspect := 0.0;
  Total := SumRectanglesIndex(StartIndex, EndIndex);
  if (Orientation) then
  begin
    try
      LocalWidth := Total / TempHeight * 100;
    except
      on EZeroDivide do
        LocalWidth := 0.0;
    end;
    LocalHeight := TempHeight;
  end//if(Orientation)
  else
  begin
    try
      LocalHeight := Total / TempWidth * 100;
    except
      on EZeroDivide do
        LocalHeight := 0.0;
    end;
    LocalWidth := TempWidth;
  end;//else
  for i:= StartIndex to EndIndex do
  begin
    if (Orientation) then
    begin
      SortArray[i].TempWidth := LocalWidth;
      try
        SortArray[i].TempHeight := Single(LocalHeight) * (Single(SortArray[i].SizeTemp) / Total);
      except
        on EZeroDivide do
          SortArray[i].TempHeight := 0.0;
      end;
    end//if(Orientation)
    else
    begin
      SortArray[i].TempHeight := LocalHeight;
      try
        SortArray[i].TempWidth := Single(LocalWidth) * (Single(SortArray[i].SizeTemp) / Total);
      except
      on EZeroDivide do
        SortArray[i].TempWidth := 0.0;
     end;
    end;//else
    Aspect := AspectRatio(SortArray[i].TempWidth, SortArray[i].TempHeight);
  end;//for
  Result := Aspect;
end;

function TCustomTreemapChart.SumRectanglesIndex(StartIndex: Integer; EndIndex: Integer): Single;
var
  i: Integer;
begin
  Result := 0.0;
  for i:= StartIndex to EndIndex do
  begin
    try
      Result := Single(Result) + Single(SortArray[i].SizeTemp);
    except
      on EAccessViolation do
        Result := 0.0;
    end;//try
  end;//for
end;

class function TCustomTreemapChart.AspectRatio(Width: Single; Height: Single): Single;
begin
  Result := 0.0;
  if ((Width > 0.0) and (Height > 0.0)) then
    Result := Max(Single(Width)/Single(Height), Single(Height)/Single(Width));
end;