Question

我想在两个纬度点之间绘制一条曲线（Beizer曲线）。目前我指的是this post（代码在javascript中）。

使用三次贝塞尔方程得到曲线点的代码

private void drawElementsOnMap(LatLng init, LatLng end) {

    mMap.addMarker(new MarkerOptions().position(init));
    mMap.addMarker(new MarkerOptions().position(end));

    LatLngBounds.Builder bc = new LatLngBounds.Builder();
    bc.include(init);
    bc.include(end);

    mMap.moveCamera(CameraUpdateFactory.newLatLngBounds(bc.build(), 100));

    PolylineOptions line = new PolylineOptions();
    line.add(init);
    line.add(end);
    mMap.addPolyline(line);

    double distanceBetween = SphericalUtil.computeDistanceBetween(init, end);
    double lineHeadingInit = SphericalUtil.computeHeading(init, end);  
    double lineHeadingEnd = bearing(end, init);*/

    double lineHeading1, lineHeading2;
    if (lineHeadingInit < 0) {
        lineHeading1 = lineHeadingInit + 45;
        lineHeading2 = lineHeadingInit + 135;
    } else {
        lineHeading1 = lineHeadingInit + -45;
        lineHeading2 = lineHeadingInit + -135;
    }

    LatLng pA = SphericalUtil.computeOffset(init, distanceBetween / 2.5, lineHeading1);
    LatLng pB = SphericalUtil.computeOffset(end, distanceBetween / 2.5, lineHeading2);

    // Beizer curves with 4 points
    gmapsCubicBezier(init, end, pA, pB);
}

private void gmapsCubicBezier(LatLng p1, LatLng p2, LatLng pA, LatLng pB) {

    //Polyline options
    PolylineOptions options = new PolylineOptions();

    LatLng curveLatLng = null;
    for (double t = 0.0; t < 1.01; t += 0.01) {
        // P = (1−t)3P1 + 3(1−t)2tP2 +3(1−t)t2P3 + t3P4; for 4 points
        double arcX = (1 - t) * (1 - t) * (1 - t) * p1.latitude
                + 3 * (1 - t) * (1 - t) * t * pA.latitude
                + 3 * (1 - t) * t * t * pB.latitude
                + t * t * t * p2.latitude;
        double arcY = (1 - t) * (1 - t) * (1 - t) * p1.longitude
                + 3 * (1 - t) * (1 - t) * t * pA.longitude
                + 3 * (1 - t) * t * t * pB.longitude
                + t * t * t * p2.longitude;

        curveLatLng = new LatLng(arcX, arcY);
        options.add(curveLatLng);
        //Draw polyline
        mMap.addPolyline(options.width(5).color(Color.DKGRAY).geodesic(false));
    }
    mMap.addMarker(new MarkerOptions().position(curveLatLng));
}

以下图片展示了我尝试的不同测试用例。

案例1：P1 - 孟买，P2 - Chennai