如何使用Android canvas在固定角度旋转位图？

Question

当我尝试移动线方向删除图标时，我想要旋转Bitmap for Icon删除线，并在顶部修复固定角度。

这是m行上方的删除图标

if (line_cir>1){
        if (touchedline != null){
              canvas.drawBitmap(bitmap1,touchedline.startX+bitmap1.getWidth(),touchedline.startY+bitmap1.getHeight(),null);

        }
    }

这是删除代码的代码

switch (event.getActionMasked()) {
        case MotionEvent.ACTION_DOWN:
            // it's the first pointer, so clear all existing pointers data
            clearCirclePointer();

            xTouch = event.getX(0);
            yTouch = event.getY(0);
            xTouch1 = event.getX(0);
            yTouch1 = event.getY(0);


            startX = event.getX();
            startY = event.getY();

            // check if we've touched inside some circle

            touchedCircle = obtainTouchedCircle(xTouch, yTouch);
            touchedCircle.centerX = xTouch;
            touchedCircle.centerY = yTouch;

            mCirclePointer.put(event.getPointerId(0), touchedCircle);

            touchedline = getTouchedline(xTouch, yTouch, 0);
            touchedline1 = getTouchedline(xTouch-70, yTouch-70, 0);

            //for Remove Line$
            if (line_cir>1) {

                if (touchedline1 != null) {

                    if ((Math.abs(touchedline1.startX+70-xTouch1) < 40) && (Math.abs(touchedline1.startY+70 -yTouch1)< 40)) {
                        lines.remove(touchedline1);
                        line_cir = 0;
                    }
                }
            }

            invalidate();

            handled = true;
            break;

感谢Andvace的帮助