通过滚动事件缩放 in/out 图片

Question

当我在图片上滚动时，我需要缩放 in/out 图片。我只是问你如何检测图片上的滚动 in/out？我正在尝试这个（我在互联网上找到它）：

$('.map').scroll(function(event){
              if(event.originalEvent.wheelDelta /120 > 0) {
                alert('scrolling up !');
              }
             else{
               alert('scrolling down !');
              }
            });

//

 .map

是我图片的class。

它对我不起作用....

Answer 1

Attach mousewheel event as scroll event is sent whenever the element's scroll position changes.

$('#map').on('mousewheel', function(e) {
  e.preventDefault();
  if (e.originalEvent.wheelDelta / 120 > 0) {
    console.log('scrolling up !', 'X: ', e.pageX, 'Y: ', e.pageY);
  } else {
    console.log('scrolling down !', 'X: ', e.pageX, 'Y: ', e.pageY);
  }
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js"></script>
<img src="https://fbcdn-profile-a.akamaihd.net/hprofile-ak-xft1/v/t1.0-1/p200x200/13096358_986500121418450_5109646388299684610_n.jpg?oh=27ee2801d2df5c9426eef38bb8a45509&oe=57DF3F79&__gda__=1474329392_83b88030c94ec8611160c14161311db5" id="map">
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Answer 2

插件有很多，一个是：wheelzoom on GitHub:

window.onload = function() {
  wheelzoom(document.getElementById('map'));
}

<script src="https://cdn.rawgit.com/jackmoore/wheelzoom/master/wheelzoom.js"></script>

<img src="https://fbcdn-profile-a.akamaihd.net/hprofile-ak-xft1/v/t1.0-1/p200x200/13096358_986500121418450_5109646388299684610_n.jpg?oh=27ee2801d2df5c9426eef38bb8a45509&oe=57DF3F79&__gda__=1474329392_83b88030c94ec8611160c14161311db5" id="map">

通过滚动事件缩放 in/out 图片

zoom in/out a picture by scroll event

javascript

jquery

scroll

zooming

uiscrollview