如何制作canvas.drawbitmap的垂直镜像用于绘制应用程序

Question

我创建了一个工作正常的绘图应用程序。现在我想要的是制作绘图路径的垂直镜像。 绘图的代码是

    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    super.onSizeChanged(w, h, oldw, oldh);
    canvasBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
    drawCanvas = new Canvas(canvasBitmap);
}

//draw the view - will be called after touch event
@Override
protected void onDraw(Canvas canvas) {
    canvas.drawBitmap(canvasBitmap, 0, 0, canvasPaint);
    canvas.drawPath(drawPath, drawPaint);




}

//register user touches as drawing action
@Override
public boolean onTouchEvent(MotionEvent event) {
    float touchX = event.getX();
    float touchY = event.getY();
    //respond to down, move and up events
    switch (event.getAction()) {
    case MotionEvent.ACTION_DOWN:
        drawPath.moveTo(touchX, touchY);
        break;
    case MotionEvent.ACTION_MOVE:
        drawPath.lineTo(touchX, touchY);
        break;
    case MotionEvent.ACTION_UP:
        drawPath.lineTo(touchX, touchY);
        drawCanvas.drawPath(drawPath, drawPaint);
        drawPath.reset();
        break;
    default:
        return false;
    }
    //redraw
    invalidate();
    return true;

}

从哪里开始制作路径的垂直镜像。 我搜索了它，我得到了一些关于

的信息

BitmapDrawable flip(BitmapDrawable d){
Matrix m = new Matrix();
m.preScale(-1, 1);
Bitmap src = d.getBitmap();
Bitmap dst = Bitmap.createBitmap(src, 0, 0, src.getWidth(), src.getHeight(),      m, false);
dst.setDensity(DisplayMetrics.DENSITY_DEFAULT);
return new BitmapDrawable(dst); }

我如何在我的应用中使用此代码。 任何帮助将不胜感激。