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如何在反应传单中制作椭圆?

发布时间:2020-12-15 20:20:15 所属栏目:百科 来源:网络整理
导读:我试图在使用react-leaflet制作的地图上绘制一个椭圆,它内置了对圆形和矩形的支持. 为了达到这个目的,我使用代码在here的(非反应)传单中生成一个椭圆,我在下面修改并粘贴: import * as L from 'leaflet';L.SVG.include ({ _updateEllipse: function (layer)
我试图在使用react-leaflet制作的地图上绘制一个椭圆,它内置了对圆形和矩形的支持.

为了达到这个目的,我使用代码在here的(非反应)传单中生成一个椭圆,我在下面修改并粘贴:

import * as L from 'leaflet';


L.SVG.include ({
    _updateEllipse: function (layer) {
        var // c = layer._point,rx = layer._radiusX,ry = layer._radiusY,phi = layer._tiltDeg,endPoint = layer._endPointParams;

        var d = 'M' + endPoint.x0 + ',' + endPoint.y0 +
            'A' + rx + ',' + ry + ',' + phi + ',' +
            endPoint.largeArc + ',' + endPoint.sweep + ',' +
            endPoint.x1 + ',' + endPoint.y1 + ' z';
        this._setPath(layer,d);
    }
});

L.Canvas.include ({
    _updateEllipse: function (layer) {
        if (layer._empty()) { return; }

        var p = layer._point,ctx = this._ctx,r = layer._radiusX,s = (layer._radiusY || r) / r;

        this._drawnLayers[layer._leaflet_id] = layer;

        ctx.save();

        ctx.translate(p.x,p.y);
        if (layer._tilt !== 0) {
            ctx.rotate( layer._tilt );
        }
        if (s !== 1) {
            ctx.scale(1,s);
        }

        ctx.beginPath();
        ctx.arc(0,r,Math.PI * 2);
        ctx.restore();

        this._fillStroke(ctx,layer);
    },});

L.Ellipse = L.Path.extend({

    options: {
        fill: true,startAngle: 0,endAngle: 359.9
    },initialize: function (latlng,radii,tilt,options) {

        L.setOptions(this,options);
        this._latlng = L.latLng(latlng);

        if (tilt) {
            this._tiltDeg = tilt;
        } else {
            this._tiltDeg = 0;
        }

        if (radii) {
            this._mRadiusX = radii[0];
            this._mRadiusY = radii[1];
        }
    },setRadius: function (radii) {
        this._mRadiusX = radii[0];
        this._mRadiusY = radii[1];
        return this.redraw();
    },getRadius: function () {
        return new L.point(this._mRadiusX,this._mRadiusY);
    },setTilt: function (tilt) {
        this._tiltDeg = tilt;
        return this.redraw();
    },getBounds: function () {
        // TODO respect tilt (bounds are too big)
        var lngRadius = this._getLngRadius(),latRadius = this._getLatRadius(),latlng = this._latlng;

        return new L.LatLngBounds(
            [latlng.lat - latRadius,latlng.lng - lngRadius],[latlng.lat + latRadius,latlng.lng + lngRadius]);
    },// @method setLatLng(latLng: LatLng): this
    // Sets the position of a circle marker to a new location.
    setLatLng: function (latlng) {
        this._latlng = L.latLng(latlng);
        this.redraw();
        return this.fire('move',{latlng: this._latlng});
    },// @method getLatLng(): LatLng
    // Returns the current geographical position of the circle marker
    getLatLng: function () {
        return this._latlng;
    },setStyle: L.Path.prototype.setStyle,_project: function () {
        var lngRadius = this._getLngRadius(),latlng = this._latlng,pointLeft = this._map.latLngToLayerPoint([latlng.lat,latlng.lng - lngRadius]),pointBelow = this._map.latLngToLayerPoint([latlng.lat - latRadius,latlng.lng]);

        this._point = this._map.latLngToLayerPoint(latlng);
        this._radiusX = Math.max(this._point.x - pointLeft.x,1);
        this._radiusY = Math.max(pointBelow.y - this._point.y,1);
        this._tilt = Math.PI * this._tiltDeg / 180;
        this._endPointParams = this._centerPointToEndPoint();
        this._updateBounds();
    },_updateBounds: function () {
        // http://math.stackexchange.com/questions/91132/how-to-get-the-limits-of-rotated-ellipse
        var sin = Math.sin(this._tilt);
        var cos = Math.cos(this._tilt);
        var sinSquare = sin * sin;
        var cosSquare = cos * cos;
        var aSquare = this._radiusX * this._radiusX;
        var bSquare = this._radiusY * this._radiusY;
        var halfWidth = Math.sqrt(aSquare*cosSquare+bSquare*sinSquare);
        var halfHeight = Math.sqrt(aSquare*sinSquare+bSquare*cosSquare);
        var w = this._clickTolerance();
        var p = [halfWidth + w,halfHeight + w];
        this._pxBounds = new L.Bounds(this._point.subtract(p),this._point.add(p));
    },_update: function () {
        if (this._map) {
            this._updatePath();
        }
    },_updatePath: function () {
        this._renderer._updateEllipse(this);
    },_getLatRadius: function () {
        return (this._mRadiusY / 40075017) * 360;
    },_getLngRadius: function () {
        return ((this._mRadiusX / 40075017) * 360) / Math.cos((Math.PI / 180) * this._latlng.lat);
    },_centerPointToEndPoint: function () {
        // Convert between center point parameterization of an ellipse
        // too SVG's end-point and sweep parameters.  This is an
        // adaptation of the perl code found here:
        // http://commons.oreilly.com/wiki/index.php/SVG_Essentials/Paths
        var c = this._point,rx = this._radiusX,ry = this._radiusY,theta2 = (this.options.startAngle + this.options.endAngle) * (Math.PI / 180),theta1 = this.options.startAngle * (Math.PI / 180),delta = this.options.endAngle,phi = this._tiltDeg * (Math.PI / 180);

        // Determine start and end-point coordinates
        var x0 = c.x + Math.cos(phi) * rx * Math.cos(theta1) +
            Math.sin(-phi) * ry * Math.sin(theta1);
        var y0 = c.y + Math.sin(phi) * rx * Math.cos(theta1) +
            Math.cos(phi) * ry * Math.sin(theta1);

        var x1 = c.x + Math.cos(phi) * rx * Math.cos(theta2) +
            Math.sin(-phi) * ry * Math.sin(theta2);
        var y1 = c.y + Math.sin(phi) * rx * Math.cos(theta2) +
            Math.cos(phi) * ry * Math.sin(theta2);

        var largeArc = (delta > 180) ? 1 : 0;
        var sweep = (delta > 0) ? 1 : 0;

        return {'x0': x0,'y0': y0,'tilt': phi,'largeArc': largeArc,'sweep': sweep,'x1': x1,'y1': y1};
    },_empty: function () {
        return this._radiusX && this._radiusY && !this._renderer._bounds.intersects(this._pxBounds);
    },_containsPoint : function (p) {
        // https://stackoverflow.com/questions/7946187/point-and-ellipse-rotated-position-test-algorithm
        var sin = Math.sin(this._tilt);
        var cos = Math.cos(this._tilt);
        var dx = p.x - this._point.x;
        var dy = p.y - this._point.y;
        var sumA = cos * dx + sin * dy;
        var sumB = sin * dx - cos * dy;
        return sumA * sumA / (this._radiusX * this._radiusX)  + sumB * sumB / (this._radiusY * this._radiusY) <= 1;
    }
});

export const lellipse = function (latlng,options) {
    return new L.Ellipse(latlng,options);
};

要创建一个与react-leaflet一起使用的椭圆,我按照Circle in react-leaflet的示例生成以下Ellipse组件:

import PropTypes from 'prop-types'

import { lellipse as LeafletEllipse } from '../l.ellipse';
import Path from './Path'
import children from './propTypes/children'
import latlng from './propTypes/latlng'
import type { LatLng,MapLayerProps,PathOptions } from './types'

type LeafletElement = LeafletEllipse
type Props = {
  center: LatLng,mSemiMajorAxis: number,mSemiMinorAxis: number,degreeTiltFromWest: number,} & MapLayerProps &
  PathOptions &
  Object

export default class Ellipse extends Path<LeafletElement,Props> {
  static propTypes = {
    center: latlng.isRequired,mSemiMajorAxis: PropTypes.number.isRequired,mSemiMinorAxis: PropTypes.number.isRequired,degreeTiltFromWest: PropTypes.number.isRequired,children: children,}

  createLeafletElement(props: Props): LeafletElement {
    const { center,mSemiMajorAxis,mSemiMinorAxis,degreeTiltFromWest,...options } = props
    return new LeafletEllipse(center,[mSemiMajorAxis,mSemiMinorAxis],this.getOptions(options))
  }

  updateLeafletElement(fromProps: Props,toProps: Props) {
    if (toProps.center !== fromProps.center) {
      this.leafletElement.setLatLng(toProps.center);
    }
    if (toProps.degreeTiltFromWest !== fromProps.degreeTiltFromWest) {
      this.leafletElement.setTilt(toProps.degreeTiltFromWest);
    }
    if (toProps.mSemiMinorAxis !== fromProps.mSemiMinorAxis || toProps.mSemiMajorAxis !== fromProps.mSemiMajorAxis) {
      this.leafletElement.setRadius([toProps.mSemiMajorAxis,toProps.mSemiMinorAxis]);
    }

  }
}

代码的问题是它不呈现椭圆并且不会抛出任何错误.有人可以建议如何使用react-leaflet渲染椭圆?谢谢.

解决方法

您的createLeafletElement函数缺少tilt参数.它应该是:

createLeafletElement(props) {
        const { center,...options } = props
        return new LeafletEllipse(center,this.getOptions(options))
    }

请参阅下面的完整文件(在ES6而不是打字稿中,因为我发现它更清晰).

import React,{ PropTypes } from 'react';
import { lellipse as LeafletEllipse } from './l.ellipse';
import { Path } from 'react-leaflet';

export default class Ellipse extends Path {

    static propTypes = {
        center: PropTypes.arrayOf(PropTypes.number).isRequired,degreeTiltFromWest: PropTypes.number.isRequired
    }

    createLeafletElement(props) {
        const { center,this.getOptions(options))
    }

    updateLeafletElement(fromProps,toProps) {
        if (toProps.center !== fromProps.center) {
            this.leafletElement.setLatLng(toProps.center);
        }
        if (toProps.degreeTiltFromWest !== fromProps.degreeTiltFromWest) {
            this.leafletElement.setTilt(toProps.degreeTiltFromWest);
        }
        if (toProps.mSemiMinorAxis !== fromProps.mSemiMinorAxis || toProps.mSemiMajorAxis !== fromProps.mSemiMajorAxis) {
            this.leafletElement.setRadius([toProps.mSemiMajorAxis,toProps.mSemiMinorAxis]);
        }
    }
}

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