如何将鼠标滚轮的缩放级别限制为View.resolutions中指定的缩放级别？

Question

我想将鼠标滚轮的缩放级别限制在View.resolutions中指定的级别。

我能做些什么来实现它？

Answer 1

(c) Mike

编辑：如果您只想使用constrainResolution进行鼠标滚轮缩放，那么您应该在创建地图之前覆盖prototype _MouseWheelZoom中的_handleWheelZoom_函数：

import { clamp } from 'ol/math.js';
import { zoomByDelta } from 'ol/interaction/Interaction';
import { MouseWheelZoom } from "ol/interaction";

const mouseWheelZoomContrainResolution = true;

MouseWheelZoom.prototype.handleWheelZoom_ = function (map) {
    var view = map.getView();
    if (view.getAnimating()) {
        view.cancelAnimations();
    }
    var delta = -clamp(this.totalDelta_, -this.maxDelta_ * this.deltaPerZoom_, this.maxDelta_ * this.deltaPerZoom_) / this.deltaPerZoom_;
    if (view.getConstrainResolution() || mouseWheelZoomContrainResolution) {
        // view has a zoom constraint, zoom by 1
        delta = delta ? delta > 0 ? 1 : -1 : 0;
    }
    zoomByDelta(view, delta, this.lastAnchor_, this.duration_);
    this.mode_ = undefined;
    this.totalDelta_ = 0;
    this.lastAnchor_ = null;
    this.startTime_ = undefined;
    this.timeoutId_ = undefined;
};

EDIT2

视图有一个setConstrainResolution方法，因此您可以打开和关闭约束。您可以在手动设置缩放之前将其关闭，如果对分辨率进行了进一步更改，则可以将其重新打开

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