Files
hnsau/assets/js/vanilla-zoom.js
2022-02-03 12:54:19 +11:00

92 lines
3.5 KiB
JavaScript

(function(window){
function define_library() {
var vanillaZoom = {};
vanillaZoom.init = function(el) {
var container = document.querySelector(el);
if(!container) {
console.error('No container element. Please make sure you are using the right markup.');
return;
}
var firstSmallImage = container.querySelector('.small-preview');
var zoomedImage = container.querySelector('.zoomed-image');
if(!zoomedImage) {
console.error('No zoomed image element. Please make sure you are using the right markup.');
return;
}
if(!firstSmallImage) {
console.error('No preview images on page. Please make sure you are using the right markup.');
return;
}
else {
// Set the source of the zoomed image.
zoomedImage.style.backgroundImage = 'url('+ firstSmallImage.src +')';
firstSmallImage.classList.add('active');
}
// Change the selected image to be zoomed when clicking on the previews.
container.addEventListener("click", function (event) {
var elem = event.target;
if (elem.classList.contains("small-preview")) {
var allSmallPreviews = container.querySelectorAll(".small-preview");
allSmallPreviews.forEach(function (preview) {
preview.classList.remove('active');
})
elem.classList.add('active');
var imageSrc = elem.src;
zoomedImage.style.backgroundImage = 'url('+ imageSrc +')';
}
});
// Zoom image on mouse enter.
zoomedImage.addEventListener('mouseenter', function(e) {
this.style.backgroundSize = "250%";
}, false);
// Show different parts of image depending on cursor position.
zoomedImage.addEventListener('mousemove', function(e) {
// getBoundingClientReact gives us various information about the position of the element.
var dimentions = this.getBoundingClientRect();
// Calculate the position of the cursor inside the element (in pixels).
var x = e.clientX - dimentions.left;
var y = e.clientY - dimentions.top;
// Calculate the position of the cursor as a percentage of the total width/height of the element.
var xpercent = Math.round(100 / (dimentions.width / x));
var ypercent = Math.round(100 / (dimentions.height / y));
// Update the background position of the image.
this.style.backgroundPosition = xpercent+'% ' + ypercent+'%';
}, false);
// When leaving the container zoom out the image back to normal size.
zoomedImage.addEventListener('mouseleave', function(e) {
this.style.backgroundSize = "contain";
this.style.backgroundPosition = "left center";
}, false);
}
return vanillaZoom;
}
// Add the vanillaZoom object to global scope.
if(typeof(vanillaZoom) === 'undefined') {
window.vanillaZoom = define_library();
}
else{
console.log("Library already defined.");
}
})(window);