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How do I persist/broadcast the mouse movements of one element into another (with exacting coordinates)? Note that the zoom effect of DIV Bshould work when the generated jQuery .mousemove() is triggered. See code in snippet or this fiddle for further context.

// Code by Magnify JS maintained by thdoan
// http://thdoan.github.io/magnify/
// https://github.com/thdoan

var native_width = 0;
var native_height = 0;

//Now the mousemove function
$(".magnify").mousemove(function(e) {
  //When the user hovers on the image, the script will first calculate
  //the native dimensions if they don't exist. Only after the native dimensions
  //are available, the script will show the zoomed version.
  if (!native_width && !native_height) {
    //This will create a new image object with the same image as that in .small
    //We cannot directly get the dimensions from .small because of the 
    //width specified to 200px in the html. To get the actual dimensions we have
    //created this image object.
    var image_object = new Image();
    image_object.src = $(".small").attr("src");

    //This code is wrapped in the .load function which is important.
    //width and height of the object would return 0 if accessed before 
    //the image gets loaded.
    native_width = image_object.width;
    native_height = image_object.height;
  } else {
    //x/y coordinates of the mouse
    //This is the position of .magnify with respect to the document.
    var magnify_offset = $(this).offset();
    //We will deduct the positions of .magnify from the mouse positions with
    //respect to the document to get the mouse positions with respect to the 
    //container(.magnify)
    var mx = e.pageX - magnify_offset.left;
    var my = e.pageY - magnify_offset.top;

    //Finally the code to fade out the glass if the mouse is outside the container
    if (mx < $(this).width() && my < $(this).height() && mx > 0 && my > 0) {
      $(".large").fadeIn(100);
    } else {
      $(".large").fadeOut(100);
    }
    if ($(".large").is(":visible")) {
      //The background position of .large will be changed according to the position
      //of the mouse over the .small image. So we will get the ratio of the pixel
      //under the mouse pointer with respect to the image and use that to position the 
      //large image inside the magnifying glass
      var rx = Math.round(mx / $(".small").width() * native_width - $(".large").width() / 2) * -1;
      var ry = Math.round(my / $(".small").height() * native_height - $(".large").height() / 2) * -1;
      var bgp = rx + "px " + ry + "px";

      //Time to move the magnifying glass with the mouse
      var px = mx - $(".large").width() / 2;
      var py = my - $(".large").height() / 2;
      //Now the glass moves with the mouse
      //The logic is to deduct half of the glass's width and height from the 
      //mouse coordinates to place it with its center at the mouse coordinates

      //If you hover on the image now, you should see the magnifying glass in action
      $(".large").css({
        left: px,
        top: py,
        backgroundPosition: bgp
      });
    }
  }
});

//http://stackoverflow.com/a/26782439/5076162 - Arun P Johny
$(document).on('mousemove', function(e) {
  var event = $.Event('myevent', {
    pageX: e.pageX,
    pageY: e.pageY
  });
  $(document).trigger(event);
});

$(document).on('myevent', function(e) {
  log(e.pageX + ':' + e.pageY)
});

var log = function(message) {
  var $log = $('#log');
  $log.html(message)
};
/*Some CSS*/

* {
  margin: 0;
  padding: 0;
}
.magnify {
  width: 658px;
  margin: 50px auto;
  position: relative;
}
/*Lets create the magnifying glass*/

.large {
  width: 175px;
  height: 175px;
  position: absolute;
  border-radius: 100%;
  /*Multiple box shadows to achieve the glass effect*/
  box-shadow: 0 0 0 7px rgba(255, 255, 255, 0.85), 0 0 7px 7px rgba(0, 0, 0, 0.25), inset 0 0 40px 2px rgba(0, 0, 0, 0.25);
  /*Lets load up the large image first*/
  background: url('https://s.rrimr.com/SPSSMR/ImageCache/ImageCache.aspx?Project=S1910683&File=B10_COLOR_IMG_FANCY.jpg') no-repeat;
  /*hide the glass by default*/
  display: none;
}
/*To solve overlap bug at the edges during magnification*/

.small {
  display: block;
}
.throwMouse {
  width: 658px;
  height: 208px;
  display: block;
  background-color: #000;
  font-family: arial;
  margin: 0 auto;
  padding: 0;
  color: #FFF;
  vertical-align: middle;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<!-- Lets make a simple image magnifier -->
<div class="throwMouse">
  <h3>
DIV A:
</h3>
  Throw this element's mousemove events INTO the .catchMouse element and have it behave as though the mouse were hovering over it.
</div>
<div class="magnify catchMouse">

  <!-- This is the magnifying glass which will contain the original/large version -->
  <div class="large"></div>

  <!-- This is the small image -->
  <h3>
DIV B:
</h3>
  <img class="small" src="https://s.rrimr.com/SPSSMR/ImageCache/ImageCache.aspx?Project=S1910683&File=B10_COLOR_IMG_FANCY.jpg" width="658" />
</div>
<div id='log'>

</div>
Cœur
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Alexander Dixon
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1 Answers1

1

You can try this

The idea is when the mouse over the .throwMouse div we simulate an a mouseover event on the .magnify div, so we need to adjust the mouse to be 200px down to be on that div

$('.throwMouse').on('mousemove', function(e) {
      var event = $.Event('myevent', {
        pageX: e.pageX,
        pageY: e.pageY + 200
      });
      $(".magnify").trigger(event);

    });

Then we add an event listener for the created event myevent on the .magnify div beside the old event mouseover

$(".magnify").on('mousemove myevent', function(e) { //});

You can check which div is the target of the event by checking event.target

if($(event.target).hasClass('throwMouse')){
 //do something specific for this div
}

// Code by Magnify JS maintained by thdoan
// http://thdoan.github.io/magnify/
// https://github.com/thdoan

var native_width = 0;
var native_height = 0;





//Now the mousemove function
$(".magnify").on('mousemove myevent', function(e) {
  //When the user hovers on the image, the script will first calculate
  //the native dimensions if they don't exist. Only after the native dimensions
  //are available, the script will show the zoomed version.
  if (!native_width && !native_height) {
    //This will create a new image object with the same image as that in .small
    //We cannot directly get the dimensions from .small because of the 
    //width specified to 200px in the html. To get the actual dimensions we have
    //created this image object.
    var image_object = new Image();
    image_object.src = $(".small").attr("src");

    //This code is wrapped in the .load function which is important.
    //width and height of the object would return 0 if accessed before 
    //the image gets loaded.
    native_width = image_object.width;
    native_height = image_object.height;
  } else {
    //x/y coordinates of the mouse
    //This is the position of .magnify with respect to the document.
    var magnify_offset = $(this).offset();
    //We will deduct the positions of .magnify from the mouse positions with
    //respect to the document to get the mouse positions with respect to the 
    //container(.magnify)
    var mx = e.pageX - magnify_offset.left;
    var my = e.pageY - magnify_offset.top;

    //Finally the code to fade out the glass if the mouse is outside the container
    if (mx < $(this).width() && my < $(this).height() && mx > 0 && my > 0) {
      $(".large").fadeIn(100);
    } else {
      $(".large").fadeOut(100);
    }
    if ($(".large").is(":visible")) {
      //The background position of .large will be changed according to the position
      //of the mouse over the .small image. So we will get the ratio of the pixel
      //under the mouse pointer with respect to the image and use that to position the 
      //large image inside the magnifying glass
      var rx = Math.round(mx / $(".small").width() * native_width - $(".large").width() / 2) * -1;
      var ry = Math.round(my / $(".small").height() * native_height - $(".large").height() / 2) * -1;
      var bgp = rx + "px " + ry + "px";

      //Time to move the magnifying glass with the mouse
      var px = mx - $(".large").width() / 2;
      var py = my - $(".large").height() / 2;
      //Now the glass moves with the mouse
      //The logic is to deduct half of the glass's width and height from the 
      //mouse coordinates to place it with its center at the mouse coordinates
      //If the mouse is on the div A make the .large DIV up a 100px.
if($(event.target).hasClass('throwMouse')){
        py -= 100;
      } 
      //If you hover on the image now, you should see the magnifying glass in action
      $(".large").css({
        left: px,
        top: py,
        backgroundPosition: bgp
      });
    }
  }
});

//http://stackoverflow.com/a/26782439/5076162 - Arun P Johny
$('.throwMouse').on('mousemove', function(e) {
  var event = $.Event('myevent', {
    pageX: e.pageX,
    pageY: e.pageY + 200
  });
  $(".magnify").trigger(event);
});

$(document).on('myevent', function(e) {
  log(e.pageX + ':' + e.pageY)
  //$(".magnify").mouse
});

var log = function(message) {
  var $log = $('#log');
  $log.html(message)
};
/*Some CSS*/

* {
  margin: 0;
  padding: 0;
}
.magnify {
  width: 658px;
  margin: 50px auto;
  position: relative;
}
/*Lets create the magnifying glass*/

.large {
  width: 175px;
  height: 175px;
  position: absolute;
  border-radius: 100%;
  /*Multiple box shadows to achieve the glass effect*/
  box-shadow: 0 0 0 7px rgba(255, 255, 255, 0.85), 0 0 7px 7px rgba(0, 0, 0, 0.25), inset 0 0 40px 2px rgba(0, 0, 0, 0.25);
  /*Lets load up the large image first*/
  background: url('https://s.rrimr.com/SPSSMR/ImageCache/ImageCache.aspx?Project=S1910683&File=B10_COLOR_IMG_FANCY.jpg') no-repeat;
  /*hide the glass by default*/
  display: none;
}
/*To solve overlap bug at the edges during magnification*/

.small {
  display: block;
}
.throwMouse {
  width: 658px;
  height: 208px;
  display: block;
  background-color: #000;
  font-family: arial;
  margin: 0 auto;
  padding: 0;
  color: #FFF;
  vertical-align: middle;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<!-- Lets make a simple image magnifier -->
<div class="throwMouse">
  <h3>
DIV A:
</h3>
  Throw this element's mousemove events INTO the .catchMouse element and have it behave as though the mouse were hovering over it.
</div>
<div class="magnify catchMouse">

  <!-- This is the magnifying glass which will contain the original/large version -->
  <div class="large"></div>

  <!-- This is the small image -->
  <h3>
DIV B:
</h3>
  <img class="small" src="https://s.rrimr.com/SPSSMR/ImageCache/ImageCache.aspx?Project=S1910683&File=B10_COLOR_IMG_FANCY.jpg" width="658" />
</div>
<div id='log'>

</div>
Kld
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  • KId this looks good. Could you please give an explanation of exactly what you did here? Also, is there anyway you could "catch" the `.large` element and re-position it to just underneath the mouse (when it is visible only). – Alexander Dixon Jul 08 '16 at 19:44
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    @AlexanderDixon I am a little late, I added some explanation and a solution for your last question. – Kld Jul 08 '16 at 23:41
  • @KId you really understand this jQuery event stuff and have been a great help. The final step, to put it all together, it to Hide div B somewhere off the page flow (perhaps absolute positioning), but keep all the functionality that you've implemented thus far. So like give `DIV B` a negative -9999 margin-left. and then give `pageX` the amount it needs to be over the hidden `DIV B`. – Alexander Dixon Jul 10 '16 at 02:48