зеркало из https://github.com/mozilla/gecko-dev.git
141 строка
4.3 KiB
JavaScript
141 строка
4.3 KiB
JavaScript
#ifdef 0
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this file,
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* You can obtain one at http://mozilla.org/MPL/2.0/. */
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#endif
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/**
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* This singleton implements site dragging functionality.
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*/
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let gDrag = {
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/**
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* The site offset to the drag start point.
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*/
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_offsetX: null,
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_offsetY: null,
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/**
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* The site that is dragged.
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*/
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_draggedSite: null,
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get draggedSite() this._draggedSite,
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/**
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* The cell width/height at the point the drag started.
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*/
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_cellWidth: null,
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_cellHeight: null,
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get cellWidth() this._cellWidth,
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get cellHeight() this._cellHeight,
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/**
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* Start a new drag operation.
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* @param aSite The site that's being dragged.
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* @param aEvent The 'dragstart' event.
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*/
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start: function Drag_start(aSite, aEvent) {
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this._draggedSite = aSite;
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// Prevent moz-transform for left, top.
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aSite.node.setAttribute("dragged", "true");
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// Make sure the dragged site is floating above the grid.
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aSite.node.setAttribute("ontop", "true");
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this._setDragData(aSite, aEvent);
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// Store the cursor offset.
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let node = aSite.node;
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let rect = node.getBoundingClientRect();
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this._offsetX = aEvent.clientX - rect.left;
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this._offsetY = aEvent.clientY - rect.top;
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// Store the cell dimensions.
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let cellNode = aSite.cell.node;
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this._cellWidth = cellNode.offsetWidth;
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this._cellHeight = cellNode.offsetHeight;
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gTransformation.freezeSitePosition(aSite);
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},
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/**
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* Handles the 'drag' event.
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* @param aSite The site that's being dragged.
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* @param aEvent The 'drag' event.
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*/
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drag: function Drag_drag(aSite, aEvent) {
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// Get the viewport size.
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let {clientWidth, clientHeight} = document.documentElement;
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// We'll want a padding of 5px.
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let border = 5;
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// Enforce minimum constraints to keep the drag image inside the window.
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let left = Math.max(scrollX + aEvent.clientX - this._offsetX, border);
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let top = Math.max(scrollY + aEvent.clientY - this._offsetY, border);
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// Enforce maximum constraints to keep the drag image inside the window.
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left = Math.min(left, scrollX + clientWidth - this.cellWidth - border);
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top = Math.min(top, scrollY + clientHeight - this.cellHeight - border);
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// Update the drag image's position.
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gTransformation.setSitePosition(aSite, {left: left, top: top});
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},
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/**
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* Ends the current drag operation.
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* @param aSite The site that's being dragged.
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* @param aEvent The 'dragend' event.
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*/
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end: function Drag_end(aSite, aEvent) {
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aSite.node.removeAttribute("dragged");
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// Slide the dragged site back into its cell (may be the old or the new cell).
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gTransformation.slideSiteTo(aSite, aSite.cell, {
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unfreeze: true,
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callback: function () aSite.node.removeAttribute("ontop")
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});
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this._draggedSite = null;
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},
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/**
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* Checks whether we're responsible for a given drag event.
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* @param aEvent The drag event to check.
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* @return Whether we should handle this drag and drop operation.
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*/
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isValid: function Drag_isValid(aEvent) {
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let dt = aEvent.dataTransfer;
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return dt && dt.types.contains("text/x-moz-url");
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},
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/**
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* Initializes the drag data for the current drag operation.
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* @param aSite The site that's being dragged.
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* @param aEvent The 'dragstart' event.
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*/
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_setDragData: function Drag_setDragData(aSite, aEvent) {
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let {url, title} = aSite;
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let dt = aEvent.dataTransfer;
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dt.mozCursor = "default";
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dt.effectAllowed = "move";
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dt.setData("text/plain", url);
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dt.setData("text/uri-list", url);
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dt.setData("text/x-moz-url", url + "\n" + title);
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dt.setData("text/html", "<a href=\"" + url + "\">" + url + "</a>");
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// Create and use an empty drag element. We don't want to use the default
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// drag image with its default opacity.
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let dragElement = document.createElementNS(HTML_NAMESPACE, "div");
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dragElement.classList.add("drag-element");
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let body = document.getElementById("body");
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body.appendChild(dragElement);
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dt.setDragImage(dragElement, 0, 0);
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// After the 'dragstart' event has been processed we can remove the
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// temporary drag element from the DOM.
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setTimeout(function () body.removeChild(dragElement), 0);
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}
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};
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