地面透明 [英] Ground Overlay with Transparency

问题描述

我有一个在线地图，其中包含一张地面覆盖的图像，并且希望将图像设为半透明的，以便基础地图能够显示出来.可以向该叠加层添加透明度值吗?

I have an online map that contains a ground-overlay image, and would like to make the image semi-transparent so that the base map will show through. Is it possible to add a transparency value to this overlay?

http://www.tpwd.state. tx.us/fishboat/fish/recreational/lakes/ingulf1c.phtml

以下是地面覆盖层的代码:

var imageBounds = new google.maps.LatLngBounds(
  new google.maps.LatLng(25.71438633861514, -98.33555959121725),
  new google.maps.LatLng(30.40813339247205, -93.57953893270167));


function initialize() {
  var map = new google.maps.Map(document.getElementById("map"), {
    center: new google.maps.LatLng(28.0041,-96.3618),
    zoom: 7,
    mapTypeId: 'roadmap'
  });
  overlay = new google.maps.GroundOverlay(
  '/fishboat/fish/recreational/lakes/images/statemaps/gulfregion.gif',
  imageBounds);
  overlay.setMap(map);

推荐答案

有一个

There is a setOpacity method of the GroundOverlay (works for me with values between 0 and 1.0):

var overlay = null;

function initialize() {
  var map = new google.maps.Map(document.getElementById("map"), {
    center: new google.maps.LatLng(28.0041,-96.3618),
    zoom: 7,
    mapTypeId: 'roadmap'
  });
  overlay = new google.maps.GroundOverlay('http://www.tpwd.state.tx.us/fishboat/fish/recreational/lakes/images/statemaps/gulfregion.gif',
      imageBounds);
  overlay.setMap(map);

}

google.maps.event.addDomListener(window, 'load', initialize);

function setOpacity() {
  var opacityStr = document.getElementById('opacity').value;
  var opacity = parseFloat(opacityStr);
  overlay.setOpacity(opacity);
}

<input type="text" id="opacity" value="0.2"></input>
<input type="button" value="setOpacity" onclick="setOpacity();"></input>

工作示例-

代码段:

var overlay = null;

function initMap() {
  var map = new google.maps.Map(document.getElementById("map"), {
    center: new google.maps.LatLng(28.0041, -96.3618),
    zoom: 7,
    mapTypeId: 'roadmap'
  });

  var imageBounds = new google.maps.LatLngBounds(
    new google.maps.LatLng(25.71438633861514, -98.33555959121725),
    new google.maps.LatLng(30.40813339247205, -93.57953893270167));

  overlay = new google.maps.GroundOverlay(
    'http://www.tpwd.state.tx.us/fishboat/fish/recreational/lakes/images/statemaps/gulfregion.gif',
    imageBounds);
  overlay.setMap(map);
  map.fitBounds(imageBounds);
}

function setOpacity() {
  var opacityStr = document.getElementById('opacity').value;
  var opacity = parseFloat(opacityStr);
  overlay.setOpacity(opacity);
}

html,
body {
  width: 100%;
  height: 100%;
  margin: 0px;
  padding: 0px;
}

#map {
  width: 100%;
  height: 90%;
}

<div id="map"></div>
<input type="text" id="opacity" value="0.2" />
<input type="button" value="setOpacity" onclick="setOpacity();" />

<!-- Replace the value of the key parameter with your own API key. -->
<script async defer src="https://maps.googleapis.com/maps/api/js?key=AIzaSyCkUOdZ5y7hMm0yrcCQoCvLwzdM6M8s5qk&callback=initMap"></script>

这篇关于地面透明的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！