缩放事件侦听器之前的Javascript OpenLayers [英] Javascript OpenLayers before zoom event listener

问题描述

我试图将OpenLayers设置为在缩放开始之前不显示矢量层，并使其在缩放结束后重新出现.我已经像这样建立了变焦端部分:

I am trying to set up OpenLayers to not display the vector layer just before a zoom starts and make it reappear after a zoom ends. I have the zoom ends part already established like this:

map = new OpenLayers.Map('map_element', { eventListeners: { "zoomend": mapEvent}});

function mapEvent(event) {
    if(event.type == "zoomend") {
        hide_vector_layer();
        }
}

但是在文档中开始放大时，我看不到任何类型的事件侦听器.有一个"movestart"，涵盖了移动，平移和缩放.不幸的是，我不能使用"movestart"，因为我不希望该图层在平移过程中消失.您会认为会有一个"zoomstart"，因为会有一个"zoomend".

But I don't see any kind of event listener for the start of a zoom in the documentation. There is a "movestart" which covers moving, panning, and zoom. Unfortunately, I can't use the "movestart" one, because I don't want the layer to disappear during a pan. You would think there would be a "zoomstart", as there is a "zoomend".

之所以尝试这样做，是因为我不喜欢将Google Maps用作基础层时矢量层如何以不同的速率缩放.看起来不对，即使缩放完成后它们落在正确的位置，看起来所有功能也不正确.

The reason I am trying to do this, is because I don't like how the vector layer zooms at a different rate when using Google Maps as a base layer. It looks wrong, looks like all the features are inaccurate, even though they land in the right place after the zoom is complete.

有什么建议吗?

推荐答案

为此，您应该覆盖OpenLayers.Map的moveTo和moveByPx方法，以消除除缩放之外的任何动作的movestart事件触发.

For this purpose you should override moveTo and moveByPx methods of OpenLayers.Map for eliminate movestart event triggering for any actions except zooming.

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