Openlayer若干问题汇总二

import {
    Draw as DrawInteraction,
} from 'ol/interaction';
/**
 * 自定义了绘图方法，主要是为了去掉绘图时默认的鼠标样式
 */
export default class Draw extends DrawInteraction {
    constructor(option) {
        super(option);
        // 鼠标移动时的样式
        this.createOrUpdateSketchPoint_=function(){
            return true;
        }
    }
}

let element=this.map.getTargetElement();
element.style.cursor="crosshair";

// 生成地图
var extent = [0, 0, 1024, 968];
var projection = new Projection({
    code: 'draw',
    units: 'pixels',
    extent: extent,
});

let mainmap=new Map({
    target: 's-map',
    view: new View({
        center: [0, 0],
        zoom:  0,
        projection: projection
    }),
});

// 同为火狐浏览器
// windwos上返回的内容为 Array [254,330]
// mac上返回的内容是 Array [568,214]
mainmap.on("postcompose",()=>{
    let xpixel=582;
    let ypixel=303;
    let coor=mainmap.getCoordinateFromPixel([xpixel,ypixel]);
    console.log(coor);
});

// 使用这种方式也不行
var size = map.getSize();
var extent = this.calculateExtent(size);
var coordinate = [
extent[0] + (extent[2]-extent[0]) * pixel[0]/size[0],
extent[1] + (extent[3]-extent[1]) * (size[1]-pixel[1])/size[1]
];

// 获取放置点的x，y坐标
let xpixel=e.clientX/2;
let ypixel=e.clientY/2;

/** 获取屏幕的坐标 */
export function getOffsetX(e){
    var e =e||window.event;
    var srcObj = e.target || e.srcElement;
    if (e.offsetX){
        return e.offsetX;
    }else{
        var rect = srcObj.getBoundingClientRect();
        var clientx = e.clientX;
        return clientx - rect.left;
    }
}

// 获取偏移量
export function getOffsetX(e,map){
    var srcObj=map.getTargetElement();
    var rect = srcObj.getBoundingClientRect();
    var clientx = e.clientX;
    srcObj=null;
    return clientx - rect.left;
}