private void drawPieces(Canvas canvas) {
    for (int i = 0,n = mWhiteArray.size();i<n;i++){
        Point whitePoint = mWhiteArray.get(i);
        canvas.drawBitmap(mWhitePice,
                (whitePoint.x+(1-ratioPieceOfLineHeught)/2)*mLineHeight,
                (whitePoint.y+(1-ratioPieceOfLineHeught)/2)*mLineHeight,null     );
}
    for (int i = 0,n = mBlackArray.size();i<n;i++){
        Point blackPoint = mBlackArray.get(i);
        canvas.drawBitmap(mBlackPice,
                (blackPoint.x+(1-ratioPieceOfLineHeught)/2)*mLineHeight,
                (blackPoint.y+(1-ratioPieceOfLineHeught)/2)*mLineHeight,null     );
    }

}