我正在编写一个扩展折线功能的Leaflet插件。在我的插件中,我使用SVGPathSegList接口访问路径段。但是根据Chrome DevTools的提示,该接口将在Chrome 48中被删除。我正在寻找另一种访问路径段的方法。
这里是我的示例代码。
(function () {
var __onAdd = L.Polyline.prototype.onAdd,
__onRemove = L.Polyline.prototype.onRemove,
__updatePath = L.Polyline.prototype._updatePath,
__bringToFront = L.Polyline.prototype.bringToFront;
L.Polyline.include({
onAdd: function (map) {
__onAdd.call(this, map);
this._textRedraw();
},
onRemove: function (map) {
__onRemove.call(this, map);
},
bringToFront: function () {
__bringToFront.call(this);
this._textRedraw();
},
_textRedraw: function () {
var textNodes = this._path.parentElement.getElementsByTagName('text'),
tnIndex;
if (textNodes.length > 0) {
for (tnIndex = textNodes.length - 1; tnIndex >= 0; tnIndex -= 1) {
textNodes[tnIndex].parentNode.removeChild(textNodes[tnIndex]);
}
}
if (this.options.measurements) {
this.setText();
}
},
setText: function () {
var path = this._path,
points = this.getLatLngs(),
pathSeg,
prevPathSeg,
center,
angle,
rotation,
textNode;
/*
* If not in SVG mode or Polyline not added to map yet return
* setText will be called by onAdd, using value stored in this._text
*/
if (!L.Browser.svg || typeof this._map === 'undefined') {
return this;
}
for (pathSeg = 0; pathSeg < path.pathSegList.length; pathSeg += 1) {
if (pathSeg > 0) {
prevPathSeg = path.pathSegList[pathSeg - 1];
center = this._calcCenter(
prevPathSeg.x,
prevPathSeg.y,
path.pathSegList[pathSeg].x,
path.pathSegList[pathSeg].y
);
angle = this._calcAngle(
prevPathSeg.x,
prevPathSeg.y,
path.pathSegList[pathSeg].x,
path.pathSegList[pathSeg].y
);
rotation = 'rotate(' + angle + ' ' +
center.x + ',' + center.y + ')';
debugger;
textNode = document
.createElementNS('http://www.w3.org/2000/svg', 'text');
textNode.setAttribute('text-anchor', 'middle');
textNode.setAttribute('x', center.x);
textNode.setAttribute('y', center.y);
textNode.setAttribute('transform', rotation);
textNode.textContent = points[pathSeg - 1]
.distanceTo(points[pathSeg]);
this._path.parentElement.appendChild(textNode);
} else {
continue;
}
}
},
_calcCenter: function (x1, y1, x2, y2) {
return {
x: (x1 + x2) / 2,
y: (y1 + y2) / 2
}
},
_calcAngle: function (x1, y1, x2, y2) {
return Math.atan2(y2 - y1, x2 - x1) * 180 / Math.PI;
},
_updatePath: function () {
__updatePath.call(this);
this._textRedraw();
}
});
})();