// TPanel, TImage e TLabel components
// Insert Image into Panel...
private
  BmpH, BmpV : TBitmap;
  OldX, OldY: Integer;
end;
var
 RectSaved : boolean = false;
procedure TFormMain.FormCreate(Sender: TObject);
begin
 PanelImage.DoubleBuffered := true; // This prevents that the image is blinking
 LabelHint.Transparent := true;
 LabelHint.Font.Color := clNave;
end;
procedure TFormMain.FormMouseMove(Sender: TObject; Shift: TShiftState; X,
 Y: Integer);
begin
 Cross(X, Y);
end;
procedure TFormMain.Cross(X, Y: Integer);
begin
 Image.Canvas.Pen.Color := clBlack;
 // Restore last image to erase line
 if RectSaved then
 begin
  Image.Canvas.CopyRect(Rect(OldX - 5, 0, OldX + 5, BmpV.Height),
  BmpV.Canvas, Rect(0,0,BmpV.Width,BmpV.Height));
  Image.Canvas.CopyRect(Rect(0, OldY - 5, BmpH.Width, OldY + 5),
  BmpH.Canvas, Rect(0,0,BmpH.Width,BmpH.Height));
  BmpH.Free;
  BmpV.Free;
 end;
 // Now save the image at new position for each line
 // horizontal line
 BmpH := TBitmap.Create;
 BmpH.Width := Image.Width;
 BmpH.Height := 10;
 BmpH.Canvas.CopyRect(Rect(0,0,BmpH.Width,BmpH.Height),
 Image.Canvas,Rect(0, Y - 5, BmpH.Width, Y + 5));
 // Vertical line
 BmpV := TBitmap.Create;
 BmpV.Width := 10;
 BmpV.Height := Image.Height;
 BmpV.Canvas.CopyRect(Rect(0,0,BmpV.Width,BmpV.Height),
  Image.Canvas,Rect(X - 5, 0, X + 5, BmpV.Height));
 // Now draw the current position
 Image.Canvas.MoveTo(0, Y);
 Image.Canvas.LineTo(Image.Width, Y);
 Image.Canvas.MoveTo(X, 0);
 Image.Canvas.LineTo(X, Image.Height);
 RectSaved := true;
 OldX := X;
 OldY := Y;
 LabelHint.Left := X + 36;
 LabelHint. := Y - 15;
 LabelHint.Caption := '(X:' + IntToStr(X) + ' x Y:' + IntToStr(Y) +')';
end;