微信小程序代码

example.js

Page({
    data: {
        offsetY: 0,
    },
    onShow(){
        this.get_image_offset();
    },
    get_image_offset(){
        if(this.data.offsetY == 0){
            var that = this;
            var query = wx.createSelectorQuery();
            query.select('.image_show').boundingClientRect(function (rect) {
                if (rect != undefined && rect != null && rect.top != undefined){
                    var top = rect.top
                    console.log(top);
                    // 因页面滚动，有时候 top 可能是负数，比如 -164
                    // 从"标签添加页"进入"写文字页"再回来可能就有这样的问题
                    if (top > 0){
                        that.setData({
                            offsetY: top
                        })
                    }
                }
            }).exec();
        }
    },
    // <image class='image_show' src="x" bind:tap='click_image' mode='widthFix'>
    click_image(e) {
        var p = {
            x: e.detail.x,
            y: e.detail.y,
            show: true,
        }
        if(this.data.offsetY != 0){
            p.y = p.y - this.data.offsetY;
        }
        this.setData(p)
    },
})

https://1c7.me/2019-1-1-wechat-miniapp-customize-navigationbar/