android Paint 绘制文字,怎么让文字垂直显示,感激不尽

       left = (int) (mLeft + (i * 2 + 0.5f) * UNIT_WIDTH);
        right = left + UNIT_WIDTH * 2;
        top = mBottom - fontHeight;
        bottom = mBottom;
        mRect.set(left, top, right, bottom);
        int baseLine = (mRect.top + mRect.bottom - fontMetricsInt.top - fontMetricsInt.bottom) / 2;
        mPaint.setColor(Color.BLACK);
        canvas.drawText(bar.bootomText, mRect.centerX(), baseLine, mPaint);


                    需要在哪里有修改,才能让文字竖着排列

用paint测量出一行文字的高度，然后从上往下循环绘制，简单粗暴

这就类似于绘制侧边栏带首字母检索的那一竖字母列表