设置上的LatLngBounds Builder中的最大缩放级别 [英] Set a max zoom level on LatLngBounds builder

问题描述

我还没有发现在我寻求答案，也有在这么几个答案，但他们并没有为我工作。

I haven't found an answer in my search, there are a few answers on SO but they didn't work for me.

我有2个标记在地图上，我使用的LatLngBounds建设者为了让相机变焦向右缩放级别，包括他们两人。一切都按预期工作一边一件事，当两个标记都非常接近对方，地图是非常非常缩放和幸福，它没有任何意义，具有缩放的这个水平。

I have 2 markers on the map and I am using LatLngBounds builder in order to let the camera zoom to the right zoom level to include them both. Everything works as expected aside one thing, when the 2 markers are really close to each other, the map is very very zoomed and well, it doesn't make any sense to have this level of zooming.

LatLngBounds.Builder builder = new LatLngBounds.Builder();
builder.include(firstMarker.getPosition());
builder.include(secondMarker.getPosition());
LatLngBounds bounds = builder.build();

CameraUpdate cu = CameraUpdateFactory.newLatLngBounds(bounds, markerPadding);

有没有办法强制一定程度放大，之后，相机将无法放大？这将避免过于放大/缩小地图。基本上我用15.0f缩放水平。如果点太远我想缩放以适应他们。如果点越来越靠近，我不希望缩放级别超越15.0f。

Is there a way to force a certain level of zoom, after which the camera won't zoom ? This would avoid having the map too zoomed in/out. Basically I am using 15.0f as level of zoom. If the points are too far away I want the zoom to fit them both. If points are getting close I don't want the zoom level to go beyond 15.0f.

推荐答案

我也有类似的情况，在这里我想至少有一对角2公里地图。 所以我只是添加两个点的建设者：在第1公里西北原有界限的中心和每秒1公里中心的东南部。如果这些边界内，他们不会改变任何东西。如果它们是原始的边界外，它们增加的边界到一个有意义的大小。

I have a similar case, where I want at least a map diagonal of 2 kilometers. Therefore I just add two additional points to the builder: the first 1 km north-west of the center of the original bounds and the second 1 km south-east of the center. If these are inside the bounds, they do not change anything. If they are outside of the original bounds, they increase the bounds to a meaningful size.

下面是一个完整的code例如：

Here is a full code example:

public LatLngBounds createBoundsWithMinDiagonal(MarkerOptions firstMarker, MarkerOptions secondMarker) {
    LatLngBounds.Builder builder = new LatLngBounds.Builder();
    builder.include(firstMarker.getPosition());
    builder.include(secondMarker.getPosition());

    LatLngBounds tmpBounds = builder.build();
    /** Add 2 points 1000m northEast and southWest of the center.
     * They increase the bounds only, if they are not already larger
     * than this. 
     * 1000m on the diagonal translates into about 709m to each direction. */
    LatLng center = tmpBounds.getCenter();
    LatLng northEast = move(center, 709, 709);
    LatLng southWest = move(center, -709, -709);
    builder.include(southWest);
    builder.include(northEast);
    return builder.build();     
}

private static final double EARTHRADIUS = 6366198;
/**
 * Create a new LatLng which lies toNorth meters north and toEast meters
 * east of startLL
 */
private static LatLng move(LatLng startLL, double toNorth, double toEast) {
    double lonDiff = meterToLongitude(toEast, startLL.latitude);
    double latDiff = meterToLatitude(toNorth);
    return new LatLng(startLL.latitude + latDiff, startLL.longitude
            + lonDiff);
}

private static double meterToLongitude(double meterToEast, double latitude) {
    double latArc = Math.toRadians(latitude);
    double radius = Math.cos(latArc) * EARTHRADIUS;
    double rad = meterToEast / radius;
    return Math.toDegrees(rad);
}


private static double meterToLatitude(double meterToNorth) {
    double rad = meterToNorth / EARTHRADIUS;
    return Math.toDegrees(rad);
}

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