gecko-dev/browser/components/customizableui/DragPositionManager.jsm
Till Schneidereit 5dec54d943 Bug 1101817 - Part 1: Remove usages of WeakMap.prototype.clear from Gecko. r=yzen,mak,yoric,gijs,jlongster
--HG--
extra : rebase_source : ef9f83be96af75ee25f8e9fb90ce2b84ab3689bd
2016-01-04 13:06:50 +01:00

423 lines
16 KiB
JavaScript

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
"use strict";
Components.utils.import("resource:///modules/CustomizableUI.jsm");
var gManagers = new WeakMap();
const kPaletteId = "customization-palette";
const kPlaceholderClass = "panel-customization-placeholder";
this.EXPORTED_SYMBOLS = ["DragPositionManager"];
function AreaPositionManager(aContainer) {
// Caching the direction and bounds of the container for quick access later:
let window = aContainer.ownerDocument.defaultView;
this._dir = window.getComputedStyle(aContainer).direction;
let containerRect = aContainer.getBoundingClientRect();
this._containerInfo = {
left: containerRect.left,
right: containerRect.right,
top: containerRect.top,
width: containerRect.width
};
this._inPanel = aContainer.id == CustomizableUI.AREA_PANEL;
this._horizontalDistance = null;
this.update(aContainer);
}
AreaPositionManager.prototype = {
_nodePositionStore: null,
_wideCache: null,
update: function(aContainer) {
let window = aContainer.ownerDocument.defaultView;
this._nodePositionStore = new WeakMap();
this._wideCache = new Set();
let last = null;
let singleItemHeight;
for (let child of aContainer.children) {
if (child.hidden) {
continue;
}
let isNodeWide = this._checkIfWide(child);
if (isNodeWide) {
this._wideCache.add(child.id);
}
let coordinates = this._lazyStoreGet(child);
// We keep a baseline horizontal distance between non-wide nodes around
// for use when we can't compare with previous/next nodes
if (!this._horizontalDistance && last && !isNodeWide) {
this._horizontalDistance = coordinates.left - last.left;
}
// We also keep the basic height of non-wide items for use below:
if (!isNodeWide && !singleItemHeight) {
singleItemHeight = coordinates.height;
}
last = !isNodeWide ? coordinates : null;
}
if (this._inPanel) {
this._heightToWidthFactor = CustomizableUI.PANEL_COLUMN_COUNT;
} else {
this._heightToWidthFactor = this._containerInfo.width / singleItemHeight;
}
},
/**
* Find the closest node in the container given the coordinates.
* "Closest" is defined in a somewhat strange manner: we prefer nodes
* which are in the same row over nodes that are in a different row.
* In order to implement this, we use a weighted cartesian distance
* where dy is more heavily weighted by a factor corresponding to the
* ratio between the container's width and the height of its elements.
*/
find: function(aContainer, aX, aY, aDraggedItemId) {
let closest = null;
let minCartesian = Number.MAX_VALUE;
let containerX = this._containerInfo.left;
let containerY = this._containerInfo.top;
for (let node of aContainer.children) {
let coordinates = this._lazyStoreGet(node);
let offsetX = coordinates.x - containerX;
let offsetY = coordinates.y - containerY;
let hDiff = offsetX - aX;
let vDiff = offsetY - aY;
// For wide widgets, we're always going to be further from the center
// horizontally. Compensate:
if (this.isWide(node)) {
hDiff /= CustomizableUI.PANEL_COLUMN_COUNT;
}
// Then compensate for the height/width ratio so that we prefer items
// which are in the same row:
hDiff /= this._heightToWidthFactor;
let cartesianDiff = hDiff * hDiff + vDiff * vDiff;
if (cartesianDiff < minCartesian) {
minCartesian = cartesianDiff;
closest = node;
}
}
// Now correct this node based on what we're dragging
if (closest) {
let doc = aContainer.ownerDocument;
let draggedItem = doc.getElementById(aDraggedItemId);
// If dragging a wide item, always pick the first item in a row:
if (this._inPanel && draggedItem &&
draggedItem.classList.contains(CustomizableUI.WIDE_PANEL_CLASS)) {
return this._firstInRow(closest);
}
let targetBounds = this._lazyStoreGet(closest);
let farSide = this._dir == "ltr" ? "right" : "left";
let outsideX = targetBounds[farSide];
// Check if we're closer to the next target than to this one:
// Only move if we're not targeting a node in a different row:
if (aY > targetBounds.top && aY < targetBounds.bottom) {
if ((this._dir == "ltr" && aX > outsideX) ||
(this._dir == "rtl" && aX < outsideX)) {
return closest.nextSibling || aContainer;
}
}
}
return closest;
},
/**
* "Insert" a "placeholder" by shifting the subsequent children out of the
* way. We go through all the children, and shift them based on the position
* they would have if we had inserted something before aBefore. We use CSS
* transforms for this, which are CSS transitioned.
*/
insertPlaceholder: function(aContainer, aBefore, aWide, aSize, aIsFromThisArea) {
let isShifted = false;
let shiftDown = aWide;
for (let child of aContainer.children) {
// Don't need to shift hidden nodes:
if (child.getAttribute("hidden") == "true") {
continue;
}
// If this is the node before which we're inserting, start shifting
// everything that comes after. One exception is inserting at the end
// of the menupanel, in which case we do not shift the placeholders:
if (child == aBefore && !child.classList.contains(kPlaceholderClass)) {
isShifted = true;
// If the node before which we're inserting is wide, we should
// shift everything one row down:
if (!shiftDown && this.isWide(child)) {
shiftDown = true;
}
}
// If we're moving items before a wide node that were already there,
// it's possible it's not necessary to shift nodes
// including & after the wide node.
if (this.__undoShift) {
isShifted = false;
}
if (isShifted) {
// Conversely, if we're adding something before a wide node, for
// simplicity's sake we move everything including the wide node down:
if (this.__moveDown) {
shiftDown = true;
}
if (aIsFromThisArea && !this._lastPlaceholderInsertion) {
child.setAttribute("notransition", "true");
}
// Determine the CSS transform based on the next node:
child.style.transform = this._getNextPos(child, shiftDown, aSize);
} else {
// If we're not shifting this node, reset the transform
child.style.transform = "";
}
}
if (aContainer.lastChild && aIsFromThisArea &&
!this._lastPlaceholderInsertion) {
// Flush layout:
aContainer.lastChild.getBoundingClientRect();
// then remove all the [notransition]
for (let child of aContainer.children) {
child.removeAttribute("notransition");
}
}
delete this.__moveDown;
delete this.__undoShift;
this._lastPlaceholderInsertion = aBefore;
},
isWide: function(aNode) {
return this._wideCache.has(aNode.id);
},
_checkIfWide: function(aNode) {
return this._inPanel && aNode && aNode.firstChild &&
aNode.firstChild.classList.contains(CustomizableUI.WIDE_PANEL_CLASS);
},
/**
* Reset all the transforms in this container, optionally without
* transitioning them.
* @param aContainer the container in which to reset transforms
* @param aNoTransition if truthy, adds a notransition attribute to the node
* while resetting the transform.
*/
clearPlaceholders: function(aContainer, aNoTransition) {
for (let child of aContainer.children) {
if (aNoTransition) {
child.setAttribute("notransition", true);
}
child.style.transform = "";
if (aNoTransition) {
// Need to force a reflow otherwise this won't work.
child.getBoundingClientRect();
child.removeAttribute("notransition");
}
}
// We snapped back, so we can assume there's no more
// "last" placeholder insertion point to keep track of.
if (aNoTransition) {
this._lastPlaceholderInsertion = null;
}
},
_getNextPos: function(aNode, aShiftDown, aSize) {
// Shifting down is easy:
if (this._inPanel && aShiftDown) {
return "translate(0, " + aSize.height + "px)";
}
return this._diffWithNext(aNode, aSize);
},
_diffWithNext: function(aNode, aSize) {
let xDiff;
let yDiff = null;
let nodeBounds = this._lazyStoreGet(aNode);
let side = this._dir == "ltr" ? "left" : "right";
let next = this._getVisibleSiblingForDirection(aNode, "next");
// First we determine the transform along the x axis.
// Usually, there will be a next node to base this on:
if (next) {
let otherBounds = this._lazyStoreGet(next);
xDiff = otherBounds[side] - nodeBounds[side];
// If the next node is a wide item in the panel, check if we could maybe
// just move further out in the same row, without snapping to the next
// one. This happens, for example, if moving an item that's before a wide
// node within its own row of items. There will be space to drop this
// item within the row, and the rest of the items do not need to shift.
if (this.isWide(next)) {
let otherXDiff = this._moveNextBasedOnPrevious(aNode, nodeBounds,
this._firstInRow(aNode));
// If this has the same sign as our original shift, we're still
// snapping to the start of the row. In this case, we should move
// everything after us a row down, so as not to display two nodes on
// top of each other:
// (we would be able to get away with checking for equality instead of
// equal signs here, but one of these is based on the x coordinate of
// the first item in row N and one on that for row N - 1, so this is
// safer, as their margins might differ)
if ((otherXDiff < 0) == (xDiff < 0)) {
this.__moveDown = true;
} else {
// Otherwise, we succeeded and can move further out. This also means
// we can stop shifting the rest of the content:
xDiff = otherXDiff;
this.__undoShift = true;
}
} else {
// We set this explicitly because otherwise some strange difference
// between the height and the actual difference between line creeps in
// and messes with alignments
yDiff = otherBounds.top - nodeBounds.top;
}
} else {
// We don't have a sibling whose position we can use. First, let's see
// if we're also the first item (which complicates things):
let firstNode = this._firstInRow(aNode);
if (aNode == firstNode) {
// Maybe we stored the horizontal distance between non-wide nodes,
// if not, we'll use the width of the incoming node as a proxy:
xDiff = this._horizontalDistance || aSize.width;
} else {
// If not, we should be able to get the distance to the previous node
// and use the inverse, unless there's no room for another node (ie we
// are the last node and there's no room for another one)
xDiff = this._moveNextBasedOnPrevious(aNode, nodeBounds, firstNode);
}
}
// If we've not determined the vertical difference yet, check it here
if (yDiff === null) {
// If the next node is behind rather than in front, we must have moved
// vertically:
if ((xDiff > 0 && this._dir == "rtl") || (xDiff < 0 && this._dir == "ltr")) {
yDiff = aSize.height;
} else {
// Otherwise, we haven't
yDiff = 0;
}
}
return "translate(" + xDiff + "px, " + yDiff + "px)";
},
/**
* Helper function to find the transform a node if there isn't a next node
* to base that on.
* @param aNode the node to transform
* @param aNodeBounds the bounding rect info of this node
* @param aFirstNodeInRow the first node in aNode's row
*/
_moveNextBasedOnPrevious: function(aNode, aNodeBounds, aFirstNodeInRow) {
let next = this._getVisibleSiblingForDirection(aNode, "previous");
let otherBounds = this._lazyStoreGet(next);
let side = this._dir == "ltr" ? "left" : "right";
let xDiff = aNodeBounds[side] - otherBounds[side];
// If, however, this means we move outside the container's box
// (i.e. the row in which this item is placed is full)
// we should move it to align with the first item in the next row instead
let bound = this._containerInfo[this._dir == "ltr" ? "right" : "left"];
if ((this._dir == "ltr" && xDiff + aNodeBounds.right > bound) ||
(this._dir == "rtl" && xDiff + aNodeBounds.left < bound)) {
xDiff = this._lazyStoreGet(aFirstNodeInRow)[side] - aNodeBounds[side];
}
return xDiff;
},
/**
* Get position details from our cache. If the node is not yet cached, get its position
* information and cache it now.
* @param aNode the node whose position info we want
* @return the position info
*/
_lazyStoreGet: function(aNode) {
let rect = this._nodePositionStore.get(aNode);
if (!rect) {
// getBoundingClientRect() returns a DOMRect that is live, meaning that
// as the element moves around, the rects values change. We don't want
// that - we want a snapshot of what the rect values are right at this
// moment, and nothing else. So we have to clone the values.
let clientRect = aNode.getBoundingClientRect();
rect = {
left: clientRect.left,
right: clientRect.right,
width: clientRect.width,
height: clientRect.height,
top: clientRect.top,
bottom: clientRect.bottom,
};
rect.x = rect.left + rect.width / 2;
rect.y = rect.top + rect.height / 2;
Object.freeze(rect);
this._nodePositionStore.set(aNode, rect);
}
return rect;
},
_firstInRow: function(aNode) {
// XXXmconley: I'm not entirely sure why we need to take the floor of these
// values - it looks like, periodically, we're getting fractional pixels back
//from lazyStoreGet. I've filed bug 994247 to investigate.
let bound = Math.floor(this._lazyStoreGet(aNode).top);
let rv = aNode;
let prev;
while (rv && (prev = this._getVisibleSiblingForDirection(rv, "previous"))) {
if (Math.floor(this._lazyStoreGet(prev).bottom) <= bound) {
return rv;
}
rv = prev;
}
return rv;
},
_getVisibleSiblingForDirection: function(aNode, aDirection) {
let rv = aNode;
do {
rv = rv[aDirection + "Sibling"];
} while (rv && rv.getAttribute("hidden") == "true")
return rv;
}
}
var DragPositionManager = {
start: function(aWindow) {
let areas = CustomizableUI.areas.filter((area) => CustomizableUI.getAreaType(area) != "toolbar");
areas = areas.map((area) => CustomizableUI.getCustomizeTargetForArea(area, aWindow));
areas.push(aWindow.document.getElementById(kPaletteId));
for (let areaNode of areas) {
let positionManager = gManagers.get(areaNode);
if (positionManager) {
positionManager.update(areaNode);
} else {
gManagers.set(areaNode, new AreaPositionManager(areaNode));
}
}
},
add: function(aWindow, aArea, aContainer) {
if (CustomizableUI.getAreaType(aArea) != "toolbar") {
return;
}
gManagers.set(aContainer, new AreaPositionManager(aContainer));
},
remove: function(aWindow, aArea, aContainer) {
if (CustomizableUI.getAreaType(aArea) != "toolbar") {
return;
}
gManagers.delete(aContainer);
},
stop: function() {
gManagers = new WeakMap();
},
getManagerForArea: function(aArea) {
return gManagers.get(aArea);
}
};
Object.freeze(DragPositionManager);