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import { isSafari, isFirefox } from './BrowserDetector';
import { MonotonicInterpolant } from './MonotonicInterpolant';
const ELEMENT_NODE = 1;
export function getNodeClientOffset(node) {
const el = node.nodeType === ELEMENT_NODE ? node : node.parentElement;
if (!el) {
return null;
}
const { top, left } = el.getBoundingClientRect();
return { x: left, y: top };
}
export function getEventClientOffset(e) {
return {
x: e.clientX,
y: e.clientY,
};
}
function isImageNode(node) {
return (node.nodeName === 'IMG' &&
(isFirefox() || !document.documentElement?.contains(node)));
}
function getDragPreviewSize(isImage, dragPreview, sourceWidth, sourceHeight) {
let dragPreviewWidth = isImage ? dragPreview.width : sourceWidth;
let dragPreviewHeight = isImage ? dragPreview.height : sourceHeight;
// Work around @2x coordinate discrepancies in browsers
if (isSafari() && isImage) {
dragPreviewHeight /= window.devicePixelRatio;
dragPreviewWidth /= window.devicePixelRatio;
}
return { dragPreviewWidth, dragPreviewHeight };
}
export function getDragPreviewOffset(sourceNode, dragPreview, clientOffset, anchorPoint, offsetPoint) {
// The browsers will use the image intrinsic size under different conditions.
// Firefox only cares if it's an image, but WebKit also wants it to be detached.
const isImage = isImageNode(dragPreview);
const dragPreviewNode = isImage ? sourceNode : dragPreview;
const dragPreviewNodeOffsetFromClient = getNodeClientOffset(dragPreviewNode);
const offsetFromDragPreview = {
x: clientOffset.x - dragPreviewNodeOffsetFromClient.x,
y: clientOffset.y - dragPreviewNodeOffsetFromClient.y,
};
const { offsetWidth: sourceWidth, offsetHeight: sourceHeight } = sourceNode;
const { anchorX, anchorY } = anchorPoint;
const { dragPreviewWidth, dragPreviewHeight } = getDragPreviewSize(isImage, dragPreview, sourceWidth, sourceHeight);
const calculateYOffset = () => {
const interpolantY = new MonotonicInterpolant([0, 0.5, 1], [
// Dock to the top
offsetFromDragPreview.y,
// Align at the center
(offsetFromDragPreview.y / sourceHeight) * dragPreviewHeight,
// Dock to the bottom
offsetFromDragPreview.y + dragPreviewHeight - sourceHeight,
]);
let y = interpolantY.interpolate(anchorY);
// Work around Safari 8 positioning bug
if (isSafari() && isImage) {
// We'll have to wait for @3x to see if this is entirely correct
y += (window.devicePixelRatio - 1) * dragPreviewHeight;
}
return y;
};
const calculateXOffset = () => {
// Interpolate coordinates depending on anchor point
// If you know a simpler way to do this, let me know
const interpolantX = new MonotonicInterpolant([0, 0.5, 1], [
// Dock to the left
offsetFromDragPreview.x,
// Align at the center
(offsetFromDragPreview.x / sourceWidth) * dragPreviewWidth,
// Dock to the right
offsetFromDragPreview.x + dragPreviewWidth - sourceWidth,
]);
return interpolantX.interpolate(anchorX);
};
// Force offsets if specified in the options.
const { offsetX, offsetY } = offsetPoint;
const isManualOffsetX = offsetX === 0 || offsetX;
const isManualOffsetY = offsetY === 0 || offsetY;
return {
x: isManualOffsetX ? offsetX : calculateXOffset(),
y: isManualOffsetY ? offsetY : calculateYOffset(),
};
}