从中心和缩放计算边界(Google Maps API v3) [英] Calculate bounds from center and zoom (Google Maps API v3)
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问题描述
我想我可以临时设置地图中心和缩放,并调用 map.getBounds()
,但我不希望(我需要禁用/重新启用一些事件处理程序)。
有人知道如何在v3中做到这一点吗?
解决方案
这使用了一些mootools,所以你必须编辑用于其他库的代码(应该很容易)。
/ **
*计算边界该地图会以给定的缩放级别显示。
*
* @member google.maps.Map
* @method boundsAt
* @param {数字}缩放缩放级别用于计算。
* @param {google.maps.LatLng} [center]可以设置为指定与当前地图中心不同的中心。
* @param {google.maps.Projection} [projection]可以设置为使用与this.getProjection()返回的投影不同的投影。
* @param {Element} [div]可以设置为指定与this.getDiv()不同的地图视口(仅用于获取尺寸)。
* @return {google.maps.LatLngBounds}计算的范围。
*
* @example
* var bounds = map.boundsAt(5); //和map.boundsAt相同(5,map.getCenter(),map.getProjection(),map.getDiv());
* /
google.maps.Map.prototype.boundsAt = function(zoom,center,projection,div){
var p = projection || this.getProjection();
if(!p)return undefined;
var d = $(div || this.getDiv());
var zf = Math.pow(2,zoom)* 2;
var dw = d.getStyle('width')。toInt()/ zf;
var dh = d.getStyle('height')。toInt()/ zf;
var cpx = p.fromLatLngToPoint(center || this.getCenter());
return new google.maps.LatLngBounds(
p.fromPointToLatLng(new google.maps.Point(cpx.x - dw,cpx.y + dh)),
p.fromPointToLatLng(new google.maps.Point(cpx.x + dw,cpx.y - dh)));
}
I need to calculate the bounds of a map given center and zoom level.
I imagine I could temporarily set map center and zoom and call map.getBounds()
, but I would prefer not to (I would need to disable/re-enable a few event handlers).
Does anybody know how to do this in v3?
解决方案
This uses a bit of mootools, so you'll have to edit the code to use it with other libraries (should be easy enough).
/**
* Calculates the bounds this map would display at a given zoom level.
*
* @member google.maps.Map
* @method boundsAt
* @param {Number} zoom Zoom level to use for calculation.
* @param {google.maps.LatLng} [center] May be set to specify a different center than the current map center.
* @param {google.maps.Projection} [projection] May be set to use a different projection than that returned by this.getProjection().
* @param {Element} [div] May be set to specify a different map viewport than this.getDiv() (only used to get dimensions).
* @return {google.maps.LatLngBounds} the calculated bounds.
*
* @example
* var bounds = map.boundsAt(5); // same as map.boundsAt(5, map.getCenter(), map.getProjection(), map.getDiv());
*/
google.maps.Map.prototype.boundsAt = function (zoom, center, projection, div) {
var p = projection || this.getProjection();
if (!p) return undefined;
var d = $(div || this.getDiv());
var zf = Math.pow(2, zoom) * 2;
var dw = d.getStyle('width').toInt() / zf;
var dh = d.getStyle('height').toInt() / zf;
var cpx = p.fromLatLngToPoint(center || this.getCenter());
return new google.maps.LatLngBounds(
p.fromPointToLatLng(new google.maps.Point(cpx.x - dw, cpx.y + dh)),
p.fromPointToLatLng(new google.maps.Point(cpx.x + dw, cpx.y - dh)));
}
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