box-client/assets/script/engine/CanvasEx.js

/**
 * 重写Canvas的目的：固定适配方式（宽度适配/高度适配），不可编辑。适配选择的逻辑：
 * 如果宽高比超过2，则选择高度固定适配；否则选择宽度固定适配
 */
// 设计分辨率
let defaultSize = cc.size(1138, 640);
// 宽度、高度固定适配的分界线
let scaleLimit = defaultSize.width / defaultSize.height;
cc.Class({
    editor: {
        menu: 'Engine/CanvasEx'
    },
    extends: cc.Canvas,

    properties: {
        _designResolution: {
            override: true,
            visible: false,
            default: defaultSize
        },
        fitHeight: {
            override: true,
            visible: false,
            get: function () {
                let frameSize = cc.view.getFrameSize();
                return frameSize.width / frameSize.height > scaleLimit;
            },
            set (value) {}
        },
        fitWidth: {
            override: true,
            visible: false,
            get: function () {
                let frameSize = cc.view.getFrameSize();
                return frameSize.width / frameSize.height <= scaleLimit;
            },
            set (value) {}
        }
    }
});