缩放动画时Canvas.drawText变慢

Question

我根据this演示构建了一个可缩放的可滚动视图。我在每个单元格中都有文字。它工作正常，但当用户缩放时，动画滞后。我找到了罪魁祸首：它是Canvas.drawText，没有它，Rect图纸正在顺利运行。

这是绘图的代码片段，带有一些伪代码：

@Override
protected void onDraw(Canvas canvas) {
    float scale = VISIBLE_NUM_COLUMNS / mCurrentViewport.width();
    float rectWidth = 1.f / mFactor * scale - 1;
    float strokeWidth = scale * 1.f < 1.f ? 0 : scale * 1.f;

    mBorderPaint.setStrokeWidth(strokeWidth);
    mFontPaint.setTextSize(scale * TEXT_SIZE);

    for (int i = first_visible_row; i < all_rows && i <= last_row; ++i) {
        for (int j = first_visiblecolumn; j < all_columns && j <= last_visible_column; ++j) {

            float rectLeft = getDrawX(j);
            float rectTop = getDrawY(i);

            // drawing the rect

            float rectCenterX = rectLeft + rectWidth / 2;
            float rectCenterY = rectTop + rectWidth / 2;

            canvas.drawText(actual_text, rectCenterX, rectCenterY + -(mFontMetricsBuffer.ascent), mFontPaint);
        }

    }
}

...

@Override
public boolean onScale(ScaleGestureDetector scaleGestureDetector) {
    // calculate new viewport
    if (!awakenScrollBars()) {
        ViewCompat.postInvalidateOnAnimation(MyView.this);
    }
}

有没有办法加快文字绘图的速度？