DBGrid之进度条显示

https://www.packtpub.com/en-us/product/delphi-cookbook-second-edition-9781785287428/chapter/delphi-basics-1/section/customizing-tdbgrid-ch01lvl1sec11

procedure TForm13.DBGrid1DrawColumnCell(Sender: TObject; const Rect: TRect;  DataCol: Integer; Column: TColumn; State: TGridDrawState);
var  
  LGrid :TDBGrid;
  LText:string;
 LTextWidth:tsize;
begin//=====================================id==================================
   if Column.FieldName.Equals('id') then    begin
      LGrid :=TDBGrid(Sender);

      LGrid.Canvas.Brush.Style := bsSolid;
      LGrid.Canvas.FillRect(Rect);

      LGrid.Canvas.Font.Size := LGrid.Font.Size - 1;
      LGrid.Canvas.Font.Color := clWhite;
      LGrid.Canvas.Brush.Color := clYellow;               //进度 背景颜色
      LGrid.Canvas.RoundRect(Rect.Left, Rect.Top
                                              , Trunc(Rect.Left + Column.Field.AsFloat / 12 * Rect.Width)   //分母
                                              , Rect.Bottom, 2, 2);
      Rect.Inflate(-1, -1);
      LGrid.Canvas.Pen.Style := psClear;
      LGrid.Canvas.Font.Color := clRed;                //   字体颜色
      LGrid.Canvas.Brush.Style := bsClear;

      LText := FormatFloat('##0', Column.Field.AsFloat) + ' %';
      LTextWidth := LGrid.Canvas.TextExtent(LText);
      LGrid.Canvas.TextOut(Rect.Left + (
        (Rect.Width div 2) - (LTextWidth.cx div 2)), Rect.Top + ((Rect.Height div 2) - (LTextWidth.cy div 2)), LText);
    end;
//=================================================================
end;