53 lines
1.2 KiB
JavaScript
53 lines
1.2 KiB
JavaScript
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export const findElementPosition = el => {
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let box;
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if (el.getBoundingClientRect && el.parentNode) {
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box = el.getBoundingClientRect();
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}
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if (!box) {
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return {
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left: 0,
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top: 0,
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};
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}
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const docEl = document.documentElement;
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const body = document.body;
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const clientLeft = docEl.clientLeft || body.clientLeft || 0;
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const scrollLeft = window.pageXOffset || body.scrollLeft;
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const left = (box.left + scrollLeft) - clientLeft;
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const clientTop = docEl.clientTop || body.clientTop || 0;
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const scrollTop = window.pageYOffset || body.scrollTop;
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const top = (box.top + scrollTop) - clientTop;
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return {
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left: Math.round(left),
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top: Math.round(top),
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};
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};
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export const getPointerPosition = (el, event) => {
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const position = {};
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const box = findElementPosition(el);
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const boxW = el.offsetWidth;
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const boxH = el.offsetHeight;
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const boxY = box.top;
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const boxX = box.left;
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let pageY = event.pageY;
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let pageX = event.pageX;
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if (event.changedTouches) {
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pageX = event.changedTouches[0].pageX;
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pageY = event.changedTouches[0].pageY;
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}
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position.y = Math.max(0, Math.min(1, (pageY - boxY) / boxH));
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position.x = Math.max(0, Math.min(1, (pageX - boxX) / boxW));
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return position;
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};
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