@angular/cdk
Version:
Angular Material Component Development Kit
982 lines (981 loc) • 189 kB
JavaScript
/**
* @license
* Copyright Google LLC All Rights Reserved.
*
* Use of this source code is governed by an MIT-style license that can be
* found in the LICENSE file at https://angular.io/license
*/
import { normalizePassiveListenerOptions, _getEventTarget, _getShadowRoot, } from '@angular/cdk/platform';
import { coerceBooleanProperty, coerceElement } from '@angular/cdk/coercion';
import { isFakeMousedownFromScreenReader, isFakeTouchstartFromScreenReader } from '@angular/cdk/a11y';
import { Subscription, Subject } from 'rxjs';
import { combineTransforms, extendStyles, toggleNativeDragInteractions, toggleVisibility, } from './dom/styling';
import { getTransformTransitionDurationInMs } from './dom/transition-duration';
import { getMutableClientRect, adjustClientRect } from './dom/client-rect';
import { ParentPositionTracker } from './dom/parent-position-tracker';
import { deepCloneNode } from './dom/clone-node';
/** Options that can be used to bind a passive event listener. */
const passiveEventListenerOptions = normalizePassiveListenerOptions({ passive: true });
/** Options that can be used to bind an active event listener. */
const activeEventListenerOptions = normalizePassiveListenerOptions({ passive: false });
/**
* Time in milliseconds for which to ignore mouse events, after
* receiving a touch event. Used to avoid doing double work for
* touch devices where the browser fires fake mouse events, in
* addition to touch events.
*/
const MOUSE_EVENT_IGNORE_TIME = 800;
/** Inline styles to be set as `!important` while dragging. */
const dragImportantProperties = new Set([
// Needs to be important, because some `mat-table` sets `position: sticky !important`. See #22781.
'position',
]);
/**
* Reference to a draggable item. Used to manipulate or dispose of the item.
*/
export class DragRef {
/** Whether starting to drag this element is disabled. */
get disabled() {
return this._disabled || !!(this._dropContainer && this._dropContainer.disabled);
}
set disabled(value) {
const newValue = coerceBooleanProperty(value);
if (newValue !== this._disabled) {
this._disabled = newValue;
this._toggleNativeDragInteractions();
this._handles.forEach(handle => toggleNativeDragInteractions(handle, newValue));
}
}
constructor(element, _config, _document, _ngZone, _viewportRuler, _dragDropRegistry) {
this._config = _config;
this._document = _document;
this._ngZone = _ngZone;
this._viewportRuler = _viewportRuler;
this._dragDropRegistry = _dragDropRegistry;
/**
* CSS `transform` applied to the element when it isn't being dragged. We need a
* passive transform in order for the dragged element to retain its new position
* after the user has stopped dragging and because we need to know the relative
* position in case they start dragging again. This corresponds to `element.style.transform`.
*/
this._passiveTransform = { x: 0, y: 0 };
/** CSS `transform` that is applied to the element while it's being dragged. */
this._activeTransform = { x: 0, y: 0 };
/**
* Whether the dragging sequence has been started. Doesn't
* necessarily mean that the element has been moved.
*/
this._hasStartedDragging = false;
/** Emits when the item is being moved. */
this._moveEvents = new Subject();
/** Subscription to pointer movement events. */
this._pointerMoveSubscription = Subscription.EMPTY;
/** Subscription to the event that is dispatched when the user lifts their pointer. */
this._pointerUpSubscription = Subscription.EMPTY;
/** Subscription to the viewport being scrolled. */
this._scrollSubscription = Subscription.EMPTY;
/** Subscription to the viewport being resized. */
this._resizeSubscription = Subscription.EMPTY;
/** Cached reference to the boundary element. */
this._boundaryElement = null;
/** Whether the native dragging interactions have been enabled on the root element. */
this._nativeInteractionsEnabled = true;
/** Elements that can be used to drag the draggable item. */
this._handles = [];
/** Registered handles that are currently disabled. */
this._disabledHandles = new Set();
/** Layout direction of the item. */
this._direction = 'ltr';
/**
* Amount of milliseconds to wait after the user has put their
* pointer down before starting to drag the element.
*/
this.dragStartDelay = 0;
this._disabled = false;
/** Emits as the drag sequence is being prepared. */
this.beforeStarted = new Subject();
/** Emits when the user starts dragging the item. */
this.started = new Subject();
/** Emits when the user has released a drag item, before any animations have started. */
this.released = new Subject();
/** Emits when the user stops dragging an item in the container. */
this.ended = new Subject();
/** Emits when the user has moved the item into a new container. */
this.entered = new Subject();
/** Emits when the user removes the item its container by dragging it into another container. */
this.exited = new Subject();
/** Emits when the user drops the item inside a container. */
this.dropped = new Subject();
/**
* Emits as the user is dragging the item. Use with caution,
* because this event will fire for every pixel that the user has dragged.
*/
this.moved = this._moveEvents;
/** Handler for the `mousedown`/`touchstart` events. */
this._pointerDown = (event) => {
this.beforeStarted.next();
// Delegate the event based on whether it started from a handle or the element itself.
if (this._handles.length) {
const targetHandle = this._getTargetHandle(event);
if (targetHandle && !this._disabledHandles.has(targetHandle) && !this.disabled) {
this._initializeDragSequence(targetHandle, event);
}
}
else if (!this.disabled) {
this._initializeDragSequence(this._rootElement, event);
}
};
/** Handler that is invoked when the user moves their pointer after they've initiated a drag. */
this._pointerMove = (event) => {
const pointerPosition = this._getPointerPositionOnPage(event);
if (!this._hasStartedDragging) {
const distanceX = Math.abs(pointerPosition.x - this._pickupPositionOnPage.x);
const distanceY = Math.abs(pointerPosition.y - this._pickupPositionOnPage.y);
const isOverThreshold = distanceX + distanceY >= this._config.dragStartThreshold;
// Only start dragging after the user has moved more than the minimum distance in either
// direction. Note that this is preferable over doing something like `skip(minimumDistance)`
// in the `pointerMove` subscription, because we're not guaranteed to have one move event
// per pixel of movement (e.g. if the user moves their pointer quickly).
if (isOverThreshold) {
const isDelayElapsed = Date.now() >= this._dragStartTime + this._getDragStartDelay(event);
const container = this._dropContainer;
if (!isDelayElapsed) {
this._endDragSequence(event);
return;
}
// Prevent other drag sequences from starting while something in the container is still
// being dragged. This can happen while we're waiting for the drop animation to finish
// and can cause errors, because some elements might still be moving around.
if (!container || (!container.isDragging() && !container.isReceiving())) {
// Prevent the default action as soon as the dragging sequence is considered as
// "started" since waiting for the next event can allow the device to begin scrolling.
event.preventDefault();
this._hasStartedDragging = true;
this._ngZone.run(() => this._startDragSequence(event));
}
}
return;
}
// We prevent the default action down here so that we know that dragging has started. This is
// important for touch devices where doing this too early can unnecessarily block scrolling,
// if there's a dragging delay.
event.preventDefault();
const constrainedPointerPosition = this._getConstrainedPointerPosition(pointerPosition);
this._hasMoved = true;
this._lastKnownPointerPosition = pointerPosition;
this._updatePointerDirectionDelta(constrainedPointerPosition);
if (this._dropContainer) {
this._updateActiveDropContainer(constrainedPointerPosition, pointerPosition);
}
else {
// If there's a position constraint function, we want the element's top/left to be at the
// specific position on the page. Use the initial position as a reference if that's the case.
const offset = this.constrainPosition ? this._initialClientRect : this._pickupPositionOnPage;
const activeTransform = this._activeTransform;
activeTransform.x = constrainedPointerPosition.x - offset.x + this._passiveTransform.x;
activeTransform.y = constrainedPointerPosition.y - offset.y + this._passiveTransform.y;
this._applyRootElementTransform(activeTransform.x, activeTransform.y);
}
// Since this event gets fired for every pixel while dragging, we only
// want to fire it if the consumer opted into it. Also we have to
// re-enter the zone because we run all of the events on the outside.
if (this._moveEvents.observers.length) {
this._ngZone.run(() => {
this._moveEvents.next({
source: this,
pointerPosition: constrainedPointerPosition,
event,
distance: this._getDragDistance(constrainedPointerPosition),
delta: this._pointerDirectionDelta,
});
});
}
};
/** Handler that is invoked when the user lifts their pointer up, after initiating a drag. */
this._pointerUp = (event) => {
this._endDragSequence(event);
};
/** Handles a native `dragstart` event. */
this._nativeDragStart = (event) => {
if (this._handles.length) {
const targetHandle = this._getTargetHandle(event);
if (targetHandle && !this._disabledHandles.has(targetHandle) && !this.disabled) {
event.preventDefault();
}
}
else if (!this.disabled) {
// Usually this isn't necessary since the we prevent the default action in `pointerDown`,
// but some cases like dragging of links can slip through (see #24403).
event.preventDefault();
}
};
this.withRootElement(element).withParent(_config.parentDragRef || null);
this._parentPositions = new ParentPositionTracker(_document);
_dragDropRegistry.registerDragItem(this);
}
/**
* Returns the element that is being used as a placeholder
* while the current element is being dragged.
*/
getPlaceholderElement() {
return this._placeholder;
}
/** Returns the root draggable element. */
getRootElement() {
return this._rootElement;
}
/**
* Gets the currently-visible element that represents the drag item.
* While dragging this is the placeholder, otherwise it's the root element.
*/
getVisibleElement() {
return this.isDragging() ? this.getPlaceholderElement() : this.getRootElement();
}
/** Registers the handles that can be used to drag the element. */
withHandles(handles) {
this._handles = handles.map(handle => coerceElement(handle));
this._handles.forEach(handle => toggleNativeDragInteractions(handle, this.disabled));
this._toggleNativeDragInteractions();
// Delete any lingering disabled handles that may have been destroyed. Note that we re-create
// the set, rather than iterate over it and filter out the destroyed handles, because while
// the ES spec allows for sets to be modified while they're being iterated over, some polyfills
// use an array internally which may throw an error.
const disabledHandles = new Set();
this._disabledHandles.forEach(handle => {
if (this._handles.indexOf(handle) > -1) {
disabledHandles.add(handle);
}
});
this._disabledHandles = disabledHandles;
return this;
}
/**
* Registers the template that should be used for the drag preview.
* @param template Template that from which to stamp out the preview.
*/
withPreviewTemplate(template) {
this._previewTemplate = template;
return this;
}
/**
* Registers the template that should be used for the drag placeholder.
* @param template Template that from which to stamp out the placeholder.
*/
withPlaceholderTemplate(template) {
this._placeholderTemplate = template;
return this;
}
/**
* Sets an alternate drag root element. The root element is the element that will be moved as
* the user is dragging. Passing an alternate root element is useful when trying to enable
* dragging on an element that you might not have access to.
*/
withRootElement(rootElement) {
const element = coerceElement(rootElement);
if (element !== this._rootElement) {
if (this._rootElement) {
this._removeRootElementListeners(this._rootElement);
}
this._ngZone.runOutsideAngular(() => {
element.addEventListener('mousedown', this._pointerDown, activeEventListenerOptions);
element.addEventListener('touchstart', this._pointerDown, passiveEventListenerOptions);
element.addEventListener('dragstart', this._nativeDragStart, activeEventListenerOptions);
});
this._initialTransform = undefined;
this._rootElement = element;
}
if (typeof SVGElement !== 'undefined' && this._rootElement instanceof SVGElement) {
this._ownerSVGElement = this._rootElement.ownerSVGElement;
}
return this;
}
/**
* Element to which the draggable's position will be constrained.
*/
withBoundaryElement(boundaryElement) {
this._boundaryElement = boundaryElement ? coerceElement(boundaryElement) : null;
this._resizeSubscription.unsubscribe();
if (boundaryElement) {
this._resizeSubscription = this._viewportRuler
.change(10)
.subscribe(() => this._containInsideBoundaryOnResize());
}
return this;
}
/** Sets the parent ref that the ref is nested in. */
withParent(parent) {
this._parentDragRef = parent;
return this;
}
/** Removes the dragging functionality from the DOM element. */
dispose() {
this._removeRootElementListeners(this._rootElement);
// Do this check before removing from the registry since it'll
// stop being considered as dragged once it is removed.
if (this.isDragging()) {
// Since we move out the element to the end of the body while it's being
// dragged, we have to make sure that it's removed if it gets destroyed.
this._rootElement?.remove();
}
this._anchor?.remove();
this._destroyPreview();
this._destroyPlaceholder();
this._dragDropRegistry.removeDragItem(this);
this._removeSubscriptions();
this.beforeStarted.complete();
this.started.complete();
this.released.complete();
this.ended.complete();
this.entered.complete();
this.exited.complete();
this.dropped.complete();
this._moveEvents.complete();
this._handles = [];
this._disabledHandles.clear();
this._dropContainer = undefined;
this._resizeSubscription.unsubscribe();
this._parentPositions.clear();
this._boundaryElement =
this._rootElement =
this._ownerSVGElement =
this._placeholderTemplate =
this._previewTemplate =
this._anchor =
this._parentDragRef =
null;
}
/** Checks whether the element is currently being dragged. */
isDragging() {
return this._hasStartedDragging && this._dragDropRegistry.isDragging(this);
}
/** Resets a standalone drag item to its initial position. */
reset() {
this._rootElement.style.transform = this._initialTransform || '';
this._activeTransform = { x: 0, y: 0 };
this._passiveTransform = { x: 0, y: 0 };
}
/**
* Sets a handle as disabled. While a handle is disabled, it'll capture and interrupt dragging.
* @param handle Handle element that should be disabled.
*/
disableHandle(handle) {
if (!this._disabledHandles.has(handle) && this._handles.indexOf(handle) > -1) {
this._disabledHandles.add(handle);
toggleNativeDragInteractions(handle, true);
}
}
/**
* Enables a handle, if it has been disabled.
* @param handle Handle element to be enabled.
*/
enableHandle(handle) {
if (this._disabledHandles.has(handle)) {
this._disabledHandles.delete(handle);
toggleNativeDragInteractions(handle, this.disabled);
}
}
/** Sets the layout direction of the draggable item. */
withDirection(direction) {
this._direction = direction;
return this;
}
/** Sets the container that the item is part of. */
_withDropContainer(container) {
this._dropContainer = container;
}
/**
* Gets the current position in pixels the draggable outside of a drop container.
*/
getFreeDragPosition() {
const position = this.isDragging() ? this._activeTransform : this._passiveTransform;
return { x: position.x, y: position.y };
}
/**
* Sets the current position in pixels the draggable outside of a drop container.
* @param value New position to be set.
*/
setFreeDragPosition(value) {
this._activeTransform = { x: 0, y: 0 };
this._passiveTransform.x = value.x;
this._passiveTransform.y = value.y;
if (!this._dropContainer) {
this._applyRootElementTransform(value.x, value.y);
}
return this;
}
/**
* Sets the container into which to insert the preview element.
* @param value Container into which to insert the preview.
*/
withPreviewContainer(value) {
this._previewContainer = value;
return this;
}
/** Updates the item's sort order based on the last-known pointer position. */
_sortFromLastPointerPosition() {
const position = this._lastKnownPointerPosition;
if (position && this._dropContainer) {
this._updateActiveDropContainer(this._getConstrainedPointerPosition(position), position);
}
}
/** Unsubscribes from the global subscriptions. */
_removeSubscriptions() {
this._pointerMoveSubscription.unsubscribe();
this._pointerUpSubscription.unsubscribe();
this._scrollSubscription.unsubscribe();
}
/** Destroys the preview element and its ViewRef. */
_destroyPreview() {
this._preview?.remove();
this._previewRef?.destroy();
this._preview = this._previewRef = null;
}
/** Destroys the placeholder element and its ViewRef. */
_destroyPlaceholder() {
this._placeholder?.remove();
this._placeholderRef?.destroy();
this._placeholder = this._placeholderRef = null;
}
/**
* Clears subscriptions and stops the dragging sequence.
* @param event Browser event object that ended the sequence.
*/
_endDragSequence(event) {
// Note that here we use `isDragging` from the service, rather than from `this`.
// The difference is that the one from the service reflects whether a dragging sequence
// has been initiated, whereas the one on `this` includes whether the user has passed
// the minimum dragging threshold.
if (!this._dragDropRegistry.isDragging(this)) {
return;
}
this._removeSubscriptions();
this._dragDropRegistry.stopDragging(this);
this._toggleNativeDragInteractions();
if (this._handles) {
this._rootElement.style.webkitTapHighlightColor =
this._rootElementTapHighlight;
}
if (!this._hasStartedDragging) {
return;
}
this.released.next({ source: this, event });
if (this._dropContainer) {
// Stop scrolling immediately, instead of waiting for the animation to finish.
this._dropContainer._stopScrolling();
this._animatePreviewToPlaceholder().then(() => {
this._cleanupDragArtifacts(event);
this._cleanupCachedDimensions();
this._dragDropRegistry.stopDragging(this);
});
}
else {
// Convert the active transform into a passive one. This means that next time
// the user starts dragging the item, its position will be calculated relatively
// to the new passive transform.
this._passiveTransform.x = this._activeTransform.x;
const pointerPosition = this._getPointerPositionOnPage(event);
this._passiveTransform.y = this._activeTransform.y;
this._ngZone.run(() => {
this.ended.next({
source: this,
distance: this._getDragDistance(pointerPosition),
dropPoint: pointerPosition,
event,
});
});
this._cleanupCachedDimensions();
this._dragDropRegistry.stopDragging(this);
}
}
/** Starts the dragging sequence. */
_startDragSequence(event) {
if (isTouchEvent(event)) {
this._lastTouchEventTime = Date.now();
}
this._toggleNativeDragInteractions();
const dropContainer = this._dropContainer;
if (dropContainer) {
const element = this._rootElement;
const parent = element.parentNode;
const placeholder = (this._placeholder = this._createPlaceholderElement());
const anchor = (this._anchor = this._anchor || this._document.createComment(''));
// Needs to happen before the root element is moved.
const shadowRoot = this._getShadowRoot();
// Insert an anchor node so that we can restore the element's position in the DOM.
parent.insertBefore(anchor, element);
// There's no risk of transforms stacking when inside a drop container so
// we can keep the initial transform up to date any time dragging starts.
this._initialTransform = element.style.transform || '';
// Create the preview after the initial transform has
// been cached, because it can be affected by the transform.
this._preview = this._createPreviewElement();
// We move the element out at the end of the body and we make it hidden, because keeping it in
// place will throw off the consumer's `:last-child` selectors. We can't remove the element
// from the DOM completely, because iOS will stop firing all subsequent events in the chain.
toggleVisibility(element, false, dragImportantProperties);
this._document.body.appendChild(parent.replaceChild(placeholder, element));
this._getPreviewInsertionPoint(parent, shadowRoot).appendChild(this._preview);
this.started.next({ source: this, event }); // Emit before notifying the container.
dropContainer.start();
this._initialContainer = dropContainer;
this._initialIndex = dropContainer.getItemIndex(this);
}
else {
this.started.next({ source: this, event });
this._initialContainer = this._initialIndex = undefined;
}
// Important to run after we've called `start` on the parent container
// so that it has had time to resolve its scrollable parents.
this._parentPositions.cache(dropContainer ? dropContainer.getScrollableParents() : []);
}
/**
* Sets up the different variables and subscriptions
* that will be necessary for the dragging sequence.
* @param referenceElement Element that started the drag sequence.
* @param event Browser event object that started the sequence.
*/
_initializeDragSequence(referenceElement, event) {
// Stop propagation if the item is inside another
// draggable so we don't start multiple drag sequences.
if (this._parentDragRef) {
event.stopPropagation();
}
const isDragging = this.isDragging();
const isTouchSequence = isTouchEvent(event);
const isAuxiliaryMouseButton = !isTouchSequence && event.button !== 0;
const rootElement = this._rootElement;
const target = _getEventTarget(event);
const isSyntheticEvent = !isTouchSequence &&
this._lastTouchEventTime &&
this._lastTouchEventTime + MOUSE_EVENT_IGNORE_TIME > Date.now();
const isFakeEvent = isTouchSequence
? isFakeTouchstartFromScreenReader(event)
: isFakeMousedownFromScreenReader(event);
// If the event started from an element with the native HTML drag&drop, it'll interfere
// with our own dragging (e.g. `img` tags do it by default). Prevent the default action
// to stop it from happening. Note that preventing on `dragstart` also seems to work, but
// it's flaky and it fails if the user drags it away quickly. Also note that we only want
// to do this for `mousedown` since doing the same for `touchstart` will stop any `click`
// events from firing on touch devices.
if (target && target.draggable && event.type === 'mousedown') {
event.preventDefault();
}
// Abort if the user is already dragging or is using a mouse button other than the primary one.
if (isDragging || isAuxiliaryMouseButton || isSyntheticEvent || isFakeEvent) {
return;
}
// If we've got handles, we need to disable the tap highlight on the entire root element,
// otherwise iOS will still add it, even though all the drag interactions on the handle
// are disabled.
if (this._handles.length) {
const rootStyles = rootElement.style;
this._rootElementTapHighlight = rootStyles.webkitTapHighlightColor || '';
rootStyles.webkitTapHighlightColor = 'transparent';
}
this._hasStartedDragging = this._hasMoved = false;
// Avoid multiple subscriptions and memory leaks when multi touch
// (isDragging check above isn't enough because of possible temporal and/or dimensional delays)
this._removeSubscriptions();
this._initialClientRect = this._rootElement.getBoundingClientRect();
this._pointerMoveSubscription = this._dragDropRegistry.pointerMove.subscribe(this._pointerMove);
this._pointerUpSubscription = this._dragDropRegistry.pointerUp.subscribe(this._pointerUp);
this._scrollSubscription = this._dragDropRegistry
.scrolled(this._getShadowRoot())
.subscribe(scrollEvent => this._updateOnScroll(scrollEvent));
if (this._boundaryElement) {
this._boundaryRect = getMutableClientRect(this._boundaryElement);
}
// If we have a custom preview we can't know ahead of time how large it'll be so we position
// it next to the cursor. The exception is when the consumer has opted into making the preview
// the same size as the root element, in which case we do know the size.
const previewTemplate = this._previewTemplate;
this._pickupPositionInElement =
previewTemplate && previewTemplate.template && !previewTemplate.matchSize
? { x: 0, y: 0 }
: this._getPointerPositionInElement(this._initialClientRect, referenceElement, event);
const pointerPosition = (this._pickupPositionOnPage =
this._lastKnownPointerPosition =
this._getPointerPositionOnPage(event));
this._pointerDirectionDelta = { x: 0, y: 0 };
this._pointerPositionAtLastDirectionChange = { x: pointerPosition.x, y: pointerPosition.y };
this._dragStartTime = Date.now();
this._dragDropRegistry.startDragging(this, event);
}
/** Cleans up the DOM artifacts that were added to facilitate the element being dragged. */
_cleanupDragArtifacts(event) {
// Restore the element's visibility and insert it at its old position in the DOM.
// It's important that we maintain the position, because moving the element around in the DOM
// can throw off `NgFor` which does smart diffing and re-creates elements only when necessary,
// while moving the existing elements in all other cases.
toggleVisibility(this._rootElement, true, dragImportantProperties);
this._anchor.parentNode.replaceChild(this._rootElement, this._anchor);
this._destroyPreview();
this._destroyPlaceholder();
this._initialClientRect =
this._boundaryRect =
this._previewRect =
this._initialTransform =
undefined;
// Re-enter the NgZone since we bound `document` events on the outside.
this._ngZone.run(() => {
const container = this._dropContainer;
const currentIndex = container.getItemIndex(this);
const pointerPosition = this._getPointerPositionOnPage(event);
const distance = this._getDragDistance(pointerPosition);
const isPointerOverContainer = container._isOverContainer(pointerPosition.x, pointerPosition.y);
this.ended.next({ source: this, distance, dropPoint: pointerPosition, event });
this.dropped.next({
item: this,
currentIndex,
previousIndex: this._initialIndex,
container: container,
previousContainer: this._initialContainer,
isPointerOverContainer,
distance,
dropPoint: pointerPosition,
event,
});
container.drop(this, currentIndex, this._initialIndex, this._initialContainer, isPointerOverContainer, distance, pointerPosition, event);
this._dropContainer = this._initialContainer;
});
}
/**
* Updates the item's position in its drop container, or moves it
* into a new one, depending on its current drag position.
*/
_updateActiveDropContainer({ x, y }, { x: rawX, y: rawY }) {
// Drop container that draggable has been moved into.
let newContainer = this._initialContainer._getSiblingContainerFromPosition(this, x, y);
// If we couldn't find a new container to move the item into, and the item has left its
// initial container, check whether the it's over the initial container. This handles the
// case where two containers are connected one way and the user tries to undo dragging an
// item into a new container.
if (!newContainer &&
this._dropContainer !== this._initialContainer &&
this._initialContainer._isOverContainer(x, y)) {
newContainer = this._initialContainer;
}
if (newContainer && newContainer !== this._dropContainer) {
this._ngZone.run(() => {
// Notify the old container that the item has left.
this.exited.next({ item: this, container: this._dropContainer });
this._dropContainer.exit(this);
// Notify the new container that the item has entered.
this._dropContainer = newContainer;
this._dropContainer.enter(this, x, y, newContainer === this._initialContainer &&
// If we're re-entering the initial container and sorting is disabled,
// put item the into its starting index to begin with.
newContainer.sortingDisabled
? this._initialIndex
: undefined);
this.entered.next({
item: this,
container: newContainer,
currentIndex: newContainer.getItemIndex(this),
});
});
}
// Dragging may have been interrupted as a result of the events above.
if (this.isDragging()) {
this._dropContainer._startScrollingIfNecessary(rawX, rawY);
this._dropContainer._sortItem(this, x, y, this._pointerDirectionDelta);
if (this.constrainPosition) {
this._applyPreviewTransform(x, y);
}
else {
this._applyPreviewTransform(x - this._pickupPositionInElement.x, y - this._pickupPositionInElement.y);
}
}
}
/**
* Creates the element that will be rendered next to the user's pointer
* and will be used as a preview of the element that is being dragged.
*/
_createPreviewElement() {
const previewConfig = this._previewTemplate;
const previewClass = this.previewClass;
const previewTemplate = previewConfig ? previewConfig.template : null;
let preview;
if (previewTemplate && previewConfig) {
// Measure the element before we've inserted the preview
// since the insertion could throw off the measurement.
const rootRect = previewConfig.matchSize ? this._initialClientRect : null;
const viewRef = previewConfig.viewContainer.createEmbeddedView(previewTemplate, previewConfig.context);
viewRef.detectChanges();
preview = getRootNode(viewRef, this._document);
this._previewRef = viewRef;
if (previewConfig.matchSize) {
matchElementSize(preview, rootRect);
}
else {
preview.style.transform = getTransform(this._pickupPositionOnPage.x, this._pickupPositionOnPage.y);
}
}
else {
preview = deepCloneNode(this._rootElement);
matchElementSize(preview, this._initialClientRect);
if (this._initialTransform) {
preview.style.transform = this._initialTransform;
}
}
extendStyles(preview.style, {
// It's important that we disable the pointer events on the preview, because
// it can throw off the `document.elementFromPoint` calls in the `CdkDropList`.
'pointer-events': 'none',
// We have to reset the margin, because it can throw off positioning relative to the viewport.
'margin': '0',
'position': 'fixed',
'top': '0',
'left': '0',
'z-index': `${this._config.zIndex || 1000}`,
}, dragImportantProperties);
toggleNativeDragInteractions(preview, false);
preview.classList.add('cdk-drag-preview');
preview.setAttribute('dir', this._direction);
if (previewClass) {
if (Array.isArray(previewClass)) {
previewClass.forEach(className => preview.classList.add(className));
}
else {
preview.classList.add(previewClass);
}
}
return preview;
}
/**
* Animates the preview element from its current position to the location of the drop placeholder.
* @returns Promise that resolves when the animation completes.
*/
_animatePreviewToPlaceholder() {
// If the user hasn't moved yet, the transitionend event won't fire.
if (!this._hasMoved) {
return Promise.resolve();
}
const placeholderRect = this._placeholder.getBoundingClientRect();
// Apply the class that adds a transition to the preview.
this._preview.classList.add('cdk-drag-animating');
// Move the preview to the placeholder position.
this._applyPreviewTransform(placeholderRect.left, placeholderRect.top);
// If the element doesn't have a `transition`, the `transitionend` event won't fire. Since
// we need to trigger a style recalculation in order for the `cdk-drag-animating` class to
// apply its style, we take advantage of the available info to figure out whether we need to
// bind the event in the first place.
const duration = getTransformTransitionDurationInMs(this._preview);
if (duration === 0) {
return Promise.resolve();
}
return this._ngZone.runOutsideAngular(() => {
return new Promise(resolve => {
const handler = ((event) => {
if (!event ||
(_getEventTarget(event) === this._preview && event.propertyName === 'transform')) {
this._preview?.removeEventListener('transitionend', handler);
resolve();
clearTimeout(timeout);
}
});
// If a transition is short enough, the browser might not fire the `transitionend` event.
// Since we know how long it's supposed to take, add a timeout with a 50% buffer that'll
// fire if the transition hasn't completed when it was supposed to.
const timeout = setTimeout(handler, duration * 1.5);
this._preview.addEventListener('transitionend', handler);
});
});
}
/** Creates an element that will be shown instead of the current element while dragging. */
_createPlaceholderElement() {
const placeholderConfig = this._placeholderTemplate;
const placeholderTemplate = placeholderConfig ? placeholderConfig.template : null;
let placeholder;
if (placeholderTemplate) {
this._placeholderRef = placeholderConfig.viewContainer.createEmbeddedView(placeholderTemplate, placeholderConfig.context);
this._placeholderRef.detectChanges();
placeholder = getRootNode(this._placeholderRef, this._document);
}
else {
placeholder = deepCloneNode(this._rootElement);
}
// Stop pointer events on the preview so the user can't
// interact with it while the preview is animating.
placeholder.style.pointerEvents = 'none';
placeholder.classList.add('cdk-drag-placeholder');
return placeholder;
}
/**
* Figures out the coordinates at which an element was picked up.
* @param referenceElement Element that initiated the dragging.
* @param event Event that initiated the dragging.
*/
_getPointerPositionInElement(elementRect, referenceElement, event) {
const handleElement = referenceElement === this._rootElement ? null : referenceElement;
const referenceRect = handleElement ? handleElement.getBoundingClientRect() : elementRect;
const point = isTouchEvent(event) ? event.targetTouches[0] : event;
const scrollPosition = this._getViewportScrollPosition();
const x = point.pageX - referenceRect.left - scrollPosition.left;
const y = point.pageY - referenceRect.top - scrollPosition.top;
return {
x: referenceRect.left - elementRect.left + x,
y: referenceRect.top - elementRect.top + y,
};
}
/** Determines the point of the page that was touched by the user. */
_getPointerPositionOnPage(event) {
const scrollPosition = this._getViewportScrollPosition();
const point = isTouchEvent(event)
? // `touches` will be empty for start/end events so we have to fall back to `changedTouches`.
// Also note that on real devices we're guaranteed for either `touches` or `changedTouches`
// to have a value, but Firefox in device emulation mode has a bug where both can be empty
// for `touchstart` and `touchend` so we fall back to a dummy object in order to avoid
// throwing an error. The value returned here will be incorrect, but since this only
// breaks inside a developer tool and the value is only used for secondary information,
// we can get away with it. See https://bugzilla.mozilla.org/show_bug.cgi?id=1615824.
event.touches[0] || event.changedTouches[0] || { pageX: 0, pageY: 0 }
: event;
const x = point.pageX - scrollPosition.left;
const y = point.pageY - scrollPosition.top;
// if dragging SVG element, try to convert from the screen coordinate system to the SVG
// coordinate system
if (this._ownerSVGElement) {
const svgMatrix = this._ownerSVGElement.getScreenCTM();
if (svgMatrix) {
const svgPoint = this._ownerSVGElement.createSVGPoint();
svgPoint.x = x;
svgPoint.y = y;
return svgPoint.matrixTransform(svgMatrix.inverse());
}
}
return { x, y };
}
/** Gets the pointer position on the page, accounting for any position constraints. */
_getConstrainedPointerPosition(point) {
const dropContainerLock = this._dropContainer ? this._dropContainer.lockAxis : null;
let { x, y } = this.constrainPosition
? this.constrainPosition(point, this, this._initialClientRect, this._pickupPositionInElement)
: point;
if (this.lockAxis === 'x' || dropContainerLock === 'x') {
y = this._pickupPositionOnPage.y;
}
else if (this.lockAxis === 'y' || dropContainerLock === 'y') {
x = this._pickupPositionOnPage.x;
}
if (this._boundaryRect) {
const { x: pickupX, y: pickupY } = this._pickupPositionInElement;
const boundaryRect = this._boundaryRect;
const { width: previewWidth, height: previewHeight } = this._getPreviewRect();
const minY = boundaryRect.top + pickupY;
const maxY = boundaryRect.bottom - (previewHeight - pickupY);
const minX = boundaryRect.left + pickupX;
const maxX = boundaryRect.right - (previewWidth - pickupX);
x = clamp(x, minX, maxX);
y = clamp(y, minY, maxY);
}
return { x, y };
}
/** Updates the current drag delta, based on the user's current pointer position on the page. */
_updatePointerDirectionDelta(pointerPositionOnPage) {
const { x, y } = pointerPositionOnPage;
const delta = this._pointerDirectionDelta;
const positionSinceLastChange = this._pointerPositionAtLastDirectionChange;
// Amount of pixels the user has dragged since the last time the direction changed.
const changeX = Math.abs(x - positionSinceLastChange.x);
const changeY = Math.abs(y - positionSinceLastChange.y);
// Because we handle pointer events on a per-pixel basis, we don't want the delta
// to change for every pixel, otherwise anything that depends on it can look erratic.
// To make the delta more consistent, we track how much the user has moved since the last
// delta change and we only update it after it has reached a certain threshold.
if (changeX > this._config.pointerDirectionChangeThreshold) {
delta.x = x > positionSinceLastChange.x ? 1 : -1;
positionSinceLastChange.x = x;
}
if (changeY > this._config.pointerDirectionChangeThreshold) {
delta.y = y > positionSinceLastChange.y ? 1 : -1;
positionSinceLastChange.y = y;
}
return delta;
}
/** Toggles the native drag interactions, based on how many handles are registered. */
_toggleNativeDragInteractions() {
if (!this._rootElement || !this._handles) {
return;
}
const shouldEnable = this._handles.length > 0 || !this.isDragging();
if (shouldEnable !== this._nativeInteractionsEnabled) {
this._nativeInteractionsEnabled = shouldEnable;
toggleNativeDragInteractions(this._rootElement, shouldEnable);
}
}
/** Removes the manually-added event listeners from the root element. */
_removeRootElementListeners(element) {
element.removeEventListener('mousedown', this._pointerDown, activeEventListenerOptions);
element.removeEventListener('touchstart', this._pointerDown, passiveEventListenerOptions);
element.removeEventListener('dragstart', this._nativeDragStart, activeEventListenerOptions);
}
/**
* Applies a `transform` to the root element, taking into account any existing transforms on it.
* @param x New transform value along the X axis.
* @param y New transform value along the Y axis.
*/
_applyRootElementTransform(x, y) {
const transform = getTransform(x, y);
const styles = this._rootElement.style;
// Cache the previous transform amount only after the first drag sequence, because
// we don't want our own transforms to stack on top of each other.
// Should be excluded none because none + translate3d(x, y, x) is invalid css
if (this._initialTransform == null) {
this._initialTransform =
styles.transform && styles.transform != 'none' ? styles.transform : '';
}
// Preserve the previous `transform` value, if there was one. Note that we apply our own
// transform before the user's, because things like rotation can affect which direction
// the element will be translated towards.
styles.transform = combineTransforms(transform, this._initialTransform);
}
/**
* Applies a `transform` to the preview, taking into account any existing transforms on it.
* @param x New transform value along the X axis.
* @param y New transform value along the Y axis.
*/
_applyPreviewTransform(x, y) {
// Only apply the initial transform if the preview is a clone of the original element, otherwise
// it could be completely different and the transform might not make sense anymore.
const initialTransform = this._previewTemplate?.template ? undefined : this._initialTransform;
const transform = getTransform(x, y);
this._preview.style.transform = combineTransforms(transform, initialTransform);
}
/**
* Gets the distance that the user has dragged during the current drag sequence.
* @param currentPosition Current position of the user's pointer.
*/
_getDragDistance(currentPosition) {
const pickupPosition = this._pickupPositionOnPage;
if (pickupPosition) {
return { x: currentPosition.x - pickupPosition.x, y: currentPosition.y - pickupPosition.y };
}
return { x: 0, y: 0 };
}
/** Cleans up any cached element dimensions that we don't need after dragging has stopped. */
_cleanupCachedDimensions() {
this._boundaryRect = this._previewRect = undefined;
this._parentPositions.clear();
}
/**
* Checks whether the element is still inside its boundary after the viewport has been resized.
* If not, the position is adjusted so that the element fits again.
*/
_containInsideBoundaryOnResize() {
let { x, y } = this._passiveTransform;
if ((x === 0 && y === 0) || this.isDragging() || !this._boundaryElement) {
return;
}
// Note: don't use `_clientRectAtStart` here, because we want the latest position.
const elementRect = this._rootElement.getBoundingClientRect();
const boundaryRect = this._boundaryElement.getBoundingClientRect();
// It's possible that the element got hidden away after dragging (e.g. by switching to a
// different tab). Don't do anything in this case so we don't clear the user's position.
if ((boundaryRect.width === 0 && boundaryRect.height === 0) ||
(elementRect.width === 0 && elementRect.height === 0)) {
return;
}
const leftOverflow = boundaryRect.left - elementRect.left;
const rightOverflow = elementRect.right - boundaryRect.right;
const topOverflow = boundaryRect.top - elementRect.top;