I want to implement magnifying glass logic with image in Qualtrics Survey.I tried some code but this is my first time trying this feature.
Replace all occurrences of '$' with 'jQuery' in the JavaScript.
Question html:
<div class="magnify">
<div class="large"></div>
<img class="small" src="http://thecodeplayer.com/uploads/media/iphone.jpg" width="200"/>
</div>
Question JavaScript:
Qualtrics.SurveyEngine.addOnload(function()
{
jQuery(document).ready(function(){
var native_width = 0;
var native_height = 0;
jQuery(".large").css("background","url('" + jQuery(".small").attr("src") + "') no-repeat");
//Now the mousemove function
jQuery(".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 = jQuery(".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 = jQuery(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 < jQuery(this).width() && my < jQuery(this).height() && mx > 0 && my > 0)
{
jQuery(".large").fadeIn(100);
}
else
{
jQuery(".large").fadeOut(100);
}
if(jQuery(".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/jQuery(".small").width()*native_width - jQuery(".large").width()/2)*-1;
var ry = Math.round(my/jQuery(".small").height()*native_height - jQuery(".large").height()/2)*-1;
var bgp = rx + "px " + ry + "px";
//Time to move the magnifying glass with the mouse
var px = mx - jQuery(".large").width()/2;
var py = my - jQuery(".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
jQuery(".large").css({left: px, top: py, backgroundPosition: bgp});
}
}
})
})
});
Look & Feel/Advanced/Add Custom CSS:
/*Some CSS*/
* {margin: 0; padding: 0;}
.magnify {width: 200px; margin: 50px auto; position: relative; cursor: none}
/*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);
/*hide the glass by default*/
display: none;
}
/*To solve overlap bug at the edges during magnification*/
.small { display: block; }