350 lines
7.7 KiB
JavaScript
350 lines
7.7 KiB
JavaScript
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/* global VT */
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window.VT = window.VT || {};
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VT.AppDraggable = function (el, options) {
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var dragThreshold = options.dragThreshold || 5;
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var dropRange = options.dropRange || 50;
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var dropRangeSquared = dropRange * dropRange;
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var originX, originY;
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var clientX, clientY;
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var startTime;
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var dragging = false;
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var clicked = false;
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var data;
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var image;
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var imageSource;
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var imageX, imageY;
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var currentTarget;
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el.addEventListener('touchstart', start);
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el.addEventListener('mousedown', start);
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// maybe prevent click
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el.addEventListener(
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'click',
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function (e) {
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if (dragging || clicked) {
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e.preventDefault();
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e.stopImmediatePropagation();
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}
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},
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true
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);
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function start(e) {
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if (el.classList.contains('_nodrag')) return;
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if (e.type === 'mousedown' && e.button !== 0) return;
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if (e.touches && e.touches.length > 1) return;
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e.preventDefault();
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var p = getPositionHost(e);
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clientX = originX = p.clientX || p.pageX;
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clientY = originY = p.clientY || p.pageY;
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startTime = Date.now();
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startListening();
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}
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function move(e) {
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e.preventDefault();
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var p = getPositionHost(e);
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clientX = p.clientX || p.pageX;
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clientY = p.clientY || p.pageY;
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if (dragging) {
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dispatchDrag();
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dispatchTarget();
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return;
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}
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var deltaX = clientX - originX;
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var deltaY = clientY - originY;
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if (Math.abs(deltaX) < dragThreshold && Math.abs(deltaY) < dragThreshold) {
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return;
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}
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// prevent unintentional dragging on touch devices
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if (e.touches && Date.now() - startTime < 50) {
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stopListening();
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return;
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}
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dragging = true;
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data = {};
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dispatchStart();
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dispatchDrag();
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dispatchTarget();
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dispatchOverContinuously();
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}
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function end(e) {
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e.preventDefault();
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if (!dragging) {
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e.target.click();
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clicked = true;
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}
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stopListening();
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requestAnimationFrame(function () {
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clicked = false;
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if (dragging) {
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dispatchTarget();
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dispatchEnd();
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}
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});
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}
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function startListening() {
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el.addEventListener('touchmove', move);
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el.addEventListener('touchend', end);
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window.addEventListener('mousemove', move);
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window.addEventListener('mouseup', end);
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}
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function stopListening() {
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el.removeEventListener('touchmove', move);
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el.removeEventListener('touchend', end);
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window.removeEventListener('mousemove', move);
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window.removeEventListener('mouseup', end);
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}
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//
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function dispatchStart() {
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setImage(el);
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el.dispatchEvent(
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new CustomEvent('draggableStart', {
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detail: buildDetail(),
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bubbles: true,
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})
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);
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}
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function dispatchDrag() {
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image.dispatchEvent(
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new CustomEvent('draggableDrag', {
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detail: buildDetail(),
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bubbles: true,
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})
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);
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}
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function dispatchTarget() {
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if (!dragging) return;
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var nextTarget = getTarget();
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if (nextTarget === currentTarget) return;
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if (currentTarget) {
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currentTarget.addEventListener('draggableLeave', removeDropClassOnce);
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currentTarget.dispatchEvent(
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new CustomEvent('draggableLeave', {
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detail: buildDetail(),
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bubbles: true,
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})
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);
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}
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if (nextTarget) {
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nextTarget.addEventListener('draggableEnter', addDropClassOnce);
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nextTarget.dispatchEvent(
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new CustomEvent('draggableEnter', {
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detail: buildDetail(),
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bubbles: true,
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})
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);
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}
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currentTarget = nextTarget;
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}
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function dispatchOverContinuously() {
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if (!dragging) return;
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dispatchOver();
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setTimeout(dispatchOver, 50);
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}
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function dispatchOver() {
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if (currentTarget) {
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currentTarget.dispatchEvent(
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new CustomEvent('draggableOver', {
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detail: buildDetail(),
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bubbles: true,
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})
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);
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}
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setTimeout(dispatchOver, 50);
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}
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function dispatchEnd() {
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if (currentTarget) {
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currentTarget.addEventListener('draggableDrop', cleanUpOnce);
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currentTarget.dispatchEvent(
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new CustomEvent('draggableDrop', {
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detail: buildDetail(),
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bubbles: true,
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})
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);
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} else {
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image.dispatchEvent(
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new CustomEvent('draggableCancel', {
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detail: buildDetail(),
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bubbles: true,
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})
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);
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}
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}
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//
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function buildDetail() {
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var detail = {
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el: el,
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data: data,
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image: image,
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imageSource: imageSource,
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originX: originX,
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originY: originY,
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clientX: clientX,
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clientY: clientY,
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imageX: imageX,
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imageY: imageY,
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setImage: function (source) {
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setImage(source);
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detail.image = image;
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},
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};
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return detail;
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}
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function setImage(source) {
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if (imageSource === source) return;
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imageSource = source;
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removeImage();
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image = imageSource.cloneNode(true);
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image.style.position = 'fixed';
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image.style.left = '0';
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image.style.top = '0';
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image.style.width = imageSource.offsetWidth + 'px';
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image.style.height = imageSource.offsetHeight + 'px';
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image.style.margin = '0';
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image.style.zIndex = 9999;
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image.classList.add('-dragging');
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var rect = source.getBoundingClientRect();
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imageX = originX - rect.left;
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imageY = originY - rect.top;
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image.addEventListener('draggableDrag', function (e) {
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var x = e.detail.clientX - e.detail.imageX;
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var y = e.detail.clientY - e.detail.imageY;
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image.style.transition = 'none';
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image.style.transform = 'translate(' + x + 'px, ' + y + 'px)';
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});
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image.addEventListener('draggableCancel', cleanUp);
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document.body.appendChild(image);
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}
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function addDropClassOnce(e) {
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e.target.removeEventListener(e.type, addDropClassOnce);
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e.target.classList.add('-drop');
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}
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function removeDropClassOnce(e) {
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e.target.removeEventListener(e.type, addDropClassOnce);
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e.target.classList.remove('-drop');
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}
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function cleanUpOnce(e) {
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e.target.removeEventListener(e.type, cleanUpOnce);
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cleanUp();
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}
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function cleanUp() {
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if (currentTarget) {
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currentTarget.classList.remove('-drop');
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}
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removeImage();
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data = null;
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image = null;
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imageSource = null;
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currentTarget = null;
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}
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function removeImage() {
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if (image && image.parentNode) {
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image.parentNode.removeChild(image);
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}
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}
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function getTarget() {
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var candidates = [];
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document.querySelectorAll(options.dropSelector).forEach(function (el) {
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var rect = el.getBoundingClientRect();
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var distanceSquared = pointDistanceToRectSquared(clientX, clientY, rect);
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if (distanceSquared > dropRangeSquared) return;
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candidates.push({
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el: el,
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distance2: distanceSquared,
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});
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});
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candidates.sort(function (a, b) {
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if (a.distance2 === 0 && b.distance2 === 0) {
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// in this case, the client position is inside both rectangles
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// if A contains B, B is the correct target and vice versa
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// TODO sort by z-index somehow?
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return a.el.contains(b.el) ? -1 : b.el.contains(a.el) ? 1 : 0;
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}
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// sort by distance, ascending
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return a.distance2 - b.distance2;
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});
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return candidates.length > 0 ? candidates[0].el : null;
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}
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function pointDistanceToRectSquared(x, y, rect) {
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var dx =
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x < rect.left ? x - rect.left : x > rect.right ? x - rect.right : 0;
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var dy =
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y < rect.top ? y - rect.top : y > rect.bottom ? y - rect.bottom : 0;
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return dx * dx + dy * dy;
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}
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function getPositionHost(e) {
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if (e.targetTouches && e.targetTouches.length > 0) {
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return e.targetTouches[0];
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}
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if (e.changedTouches && e.changedTouches.length > 0) {
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return e.changedTouches[0];
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}
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return e;
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}
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};
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