javascript 等效于 gmaps api 3 中的 getBoundsZoomLevel()
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Equivalent of getBoundsZoomLevel() in gmaps api 3
提问by TMS
In API v2, the map object had a handy method getBoundsZoomLevel(). I used it to get the zoom level which fits the bounds best, then manipulated this optimal zoom level somehow and finally set the desired zoom level.
在 API v2 中，地图对象有一个方便的方法getBoundsZoomLevel()。我用它来获得最适合边界的缩放级别，然后以某种方式操纵这个最佳缩放级别，最后设置所需的缩放级别。
I cannot find similar function in API v3. (What a continuous frustrating experience when moving from v2 to v3)
我在API v3 中找不到类似的功能。（从 v2 迁移到 v3 时的持续令人沮丧的体验）
Do I really have to use map.fitBounds(), map.getZoom(), manipulate and setZoom()again? That's really stupid!
我真的必须再次使用map.fitBounds(), map.getZoom(), 操作setZoom()吗？真是太蠢了！
回答by Engineer
Below is a function I have implemented:
下面是我实现的一个功能：
/**
* Returns the zoom level at which the given rectangular region fits in the map view.
* The zoom level is computed for the currently selected map type.
* @param {google.maps.Map} map
* @param {google.maps.LatLngBounds} bounds
* @return {Number} zoom level
**/
function getZoomByBounds( map, bounds ){
var MAX_ZOOM = map.mapTypes.get( map.getMapTypeId() ).maxZoom || 21 ;
var MIN_ZOOM = map.mapTypes.get( map.getMapTypeId() ).minZoom || 0 ;
var ne= map.getProjection().fromLatLngToPoint( bounds.getNorthEast() );
var sw= map.getProjection().fromLatLngToPoint( bounds.getSouthWest() );
var worldCoordWidth = Math.abs(ne.x-sw.x);
var worldCoordHeight = Math.abs(ne.y-sw.y);
//Fit padding in pixels
var FIT_PAD = 40;
for( var zoom = MAX_ZOOM; zoom >= MIN_ZOOM; --zoom ){
if( worldCoordWidth*(1<<zoom)+2*FIT_PAD < $(map.getDiv()).width() &&
worldCoordHeight*(1<<zoom)+2*FIT_PAD < $(map.getDiv()).height() )
return zoom;
}
return 0;
}
