gristlabs_grist-core/app/client/components/Layout.ts

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/**
* This module provides the ability to render and edit hierarchical layouts of boxes. Each box may
* contain a list of other boxes, and horizontally- and vertically-arranged lists alternating with
* the depth in the hierarchy.
*
* Layout
* Layout is a tree of LayoutBoxes (HBoxes and VBoxes). It consists of HBoxes and VBoxes in
* alternating levels. The leaves of the tree are LeafBoxes, and those are the only items that
* may be moved around, with the structure of Boxes above them changing to accommodate.
*
* LayoutBox
* A LayoutBox is a node in the Layout tree. LayoutBoxes should typically have nothing visual
* about them (e.g. no borders) except their dimensions: they serve purely for layout purposes.
*
* A LayoutBox may be an HBox or a VBox. An HBox may contain multiple VBoxes arranged in a row.
* A VBox may contain multiple HBoxes one under the other. Either kind of LayoutBox may contain
* a single LeafBox instead of child LayoutBoxes. No LayoutBox may be empty, and no LayoutBox
* may contain a single LayoutBox as a child: it must contain either multiple LayoutBox
* children, or a single LeafBox.
*
* LeafBox
* A LeafBox is the container for user content, i.e. what needs to be laid out, for example
* form elements. LeafBoxes are what the user can drag around to other location in the layout.
* All the LeafBoxes in a Layout together fill the entire Layout rectangle. If some parts of
* the layout are to be empty, they should still contain an empty LeafBox.
*
* There is no separate JS class for LeafBoxes, they are simply LayoutBoxes with .layout_leaf
* class and set leafId and leafContent member observables.
*
* Floater
* A Floater is a rectangle that floats over the layout with the mouse pointer while the user is
* dragging a LeafBox. It contains the content of the LeafBox being dragged, so that the user
* can see what is being repositioned.
*
* DropOverlay
* An DropOverlay is a visual aid to the user to indicate area over the current LeafBox where a
* drop may be attempted. It also computes the "affinity": which border of the current LeafBox
* the user is trying to target as the insertion point.
*
* DropTargeter
* DropTargeter displays a set of rectangles, each of which represents a particular allowed
* insertion point for the element being dragged. E.g. dragging an element to the right side of
* a LeafBox would display a drop target for each LayoutBox up the tree that allows a sibling
* to be inserted on the right.
*
* Saving Changes
* --------------
* We don't attempt to save granular changes to the layout, for each drag operation, because
* for the user, it's better to finish editing the layout, and only save the end result. Also,
* it's not so easy (the structure changes many times while dragging, and a single drag
* operation results in a non-trivial diff of the 'before' and 'after' layouts). So instead, we
* just have a way to serialize the layout to and from a JSON blob.
*/
import dom, {detachNode, findAncestor} from 'app/client/lib/dom';
import koArray, {isKoArray, KoArray} from 'app/client/lib/koArray';
import {cssClass, domData, foreach, scope, style, toggleClass} from 'app/client/lib/koDom';
import {Disposable} from 'app/client/lib/dispose';
import assert from 'assert';
import {Events as BackboneEvents} from 'backbone';
import * as ko from 'knockout';
import {computed, isObservable, observable, utils} from 'knockout';
import {identity, isEqual, last, uniqueId} from 'underscore';
export interface ContentBox {
leafId: ko.Observable<any>;
leafContent: ko.Observable<Element|null>;
dom: HTMLElement|null;
}
export interface BoxSpec {
leaf?: string|number;
size?: number;
children?: BoxSpec[];
collapsed?: BoxSpec[];
}
/**
* A LayoutBox is the node in the hierarchy of boxes comprising the layout. This class is used for
* rendering as well as for the code editor. Since it may be rendered many times on a page, it's
* important for it to be efficient.
* @param {Layout} layout: The Layout object that manages this LayoutBox.
*/
export class LayoutBox extends Disposable implements ContentBox {
public layout: Layout;
public dom: HTMLElement | null = null;
public leafId: ko.Observable<any>; // probably number for section id
public parentBox: ko.Observable<LayoutBox|null>;
public childBoxes: KoArray<LayoutBox>;
public leafContent: ko.Observable<Element|null>;
public uniqueId: string;
public isVBox: ko.Computed<boolean>;
public isHBox: ko.Computed<boolean>;
public isLeaf: ko.Computed<boolean>;
public isMaximized: ko.Computed<boolean>;
public isHidden: ko.Computed<boolean>;
public flexSize: ko.Observable<number>;
private _parentBeingDisposed: boolean;
public create(layout: Layout) {
this.layout = layout;
this.parentBox = observable(null as any);
this.childBoxes = koArray();
this.leafId = observable(null);
this.leafContent = observable(null as any);
this.uniqueId = uniqueId("lb"); // For logging and debugging.
this.isVBox = this.autoDispose(computed(() => {
return this.parentBox() ? !this.parentBox()!.isVBox() : true;
}, this));
this.isHBox = this.autoDispose(computed(() => { return !this.isVBox(); }));
this.isLeaf = this.autoDispose(computed(() => { return this.leafId() !== null; },
this));
this.isMaximized = this.autoDispose(ko.pureComputed(() => {
const leafId = this.layout?.maximizedLeaf();
if (!leafId) { return false; }
if (leafId === this.leafId()) { return true; }
return this.childBoxes.all().some(function(child) { return child.isMaximized(); });
}, this));
this.isHidden = this.autoDispose(ko.pureComputed(() => {
// If there isn't any maximized box, then no box is hidden.
const maximized = this.layout?.maximizedLeaf();
if (!maximized) { return false; }
return !this.isMaximized();
}, this));
// flexSize represents flexWidth for VBoxes and flexHeight for HBoxes.
// Undesirable transition effects are likely when <1, so we set average value
// to 100 so that reduction below 1 is rare.
this.flexSize = observable(100);
this.dom = null;
// This is an optimization to avoid the wasted cost of removeFromParent during disposal.
this._parentBeingDisposed = false;
this.autoDisposeCallback(() => {
if (!this._parentBeingDisposed) {
this.removeFromParent();
}
this.childBoxes.peek().forEach(function(child) {
child._parentBeingDisposed = true;
child.dispose();
});
});
}
public getDom() {
return this.dom || (this.dom = this.autoDispose(this.buildDom()));
}
public maximize() {
if (this.layout.maximizedLeaf.peek() !== this.leafId.peek()) {
this.layout.maximizedLeaf(this.leafId());
} else {
this.layout.maximizedLeaf(null);
}
}
public buildDom() {
const self = this;
const wrap = this.layout.needDynamic ? identity : makeStatic;
return dom('div.layout_box',
toggleClass('layout_leaf', wrap(this.isLeaf)),
toggleClass('layout_hidden', this.isHidden),
toggleClass(this.layout.leafId, wrap(this.isLeaf)),
cssClass(wrap(function() { return self.isVBox() ? "layout_vbox" : "layout_hbox"; })),
cssClass(wrap(function() {
return (self.layout.fillWindow ? 'layout_fill_window' :
(self.isLastChild() ? 'layout_last_child' : null));
})),
style('--flex-grow', wrap(function() {
return (self.isVBox() || (self.isHBox() && self.layout.fillWindow)) ? self.flexSize() : '';
})),
domData('layoutBox', this),
foreach(wrap(this.childBoxes), function(layoutBox: LayoutBox) {
return layoutBox.getDom();
}),
scope(wrap(this.leafContent), function(leafContent: any) {
return leafContent;
})
);
}
/**
* Moves the leaf id and content from another layoutBox, unsetting them in the source one.
*/
public takeLeafFrom(sourceLayoutBox: ContentBox) {
this.leafId(sourceLayoutBox.leafId.peek());
// Note that we detach the node, so that the old box doesn't destroy its DOM.
this.leafContent(detachNode(sourceLayoutBox.leafContent.peek()));
sourceLayoutBox.leafId(null);
sourceLayoutBox.leafContent(null);
}
public setChildren(children: LayoutBox[]) {
children.forEach((child) => child.parentBox(this));
this.childBoxes.assign(children);
}
public isFirstChild() {
return this.parentBox() ? this.parentBox()!.childBoxes.peek()[0] === this : true;
}
public isLastChild() {
// Use .all() rather than .peek() because it's used in kd.toggleClass('layout_last_child'), and
// we want it to automatically stay correct when childBoxes array changes.
return this.parentBox() ? last(this.parentBox()!.childBoxes.all()) === this : true;
}
public isDomDetached() {
return !(this.dom && this.dom.parentNode);
}
public getSiblingBox(isAfter: boolean) {
if (!this.parentBox()) {
return null;
}
const siblings = this.parentBox()!.childBoxes.peek();
let index = siblings.indexOf(this);
if (index < 0) {
return null;
}
index += (isAfter ? 1 : -1);
return (index < 0 || index >= siblings.length ? null : siblings[index]);
}
public _addChild(childBox: LayoutBox, isAfter: boolean, optNextSibling?: LayoutBox) {
assert(childBox.parentBox() === null, "LayoutBox._addChild: child already has parentBox set");
let index;
if (optNextSibling) {
index = this.childBoxes.peek().indexOf(optNextSibling) + (isAfter ? 1 : 0);
} else {
index = isAfter ? this.childBoxes.peekLength : 0;
}
childBox.parentBox(this);
this.childBoxes.splice(index, 0, childBox);
}
public addSibling(childBox: LayoutBox, isAfter: boolean) {
childBox.removeFromParent();
const parentBox = this.parentBox();
if (parentBox) {
// Normally, we just add a sibling as requested.
parentBox._addChild(childBox, isAfter, this);
} else {
// If adding a sibling to the root node (another VBox), we need to create a new root and push
// things down two levels (HBox and VBox), and add the sibling to the lower VBox.
if (this.childBoxes.peekLength === 1) {
// Except when the root has a single child, in which case there is already a good place to
// add the new node two levels lower. And we should not create another level because the
// root is the only place that can have a single child.
const lowerBox = this.childBoxes.peek()[0];
assert(!lowerBox.isLeaf(), 'LayoutBox.addSibling: should not have leaf as a single child');
lowerBox._addChild(childBox, isAfter);
} else {
// Create a new root, and add the sibling two levels lower.
const vbox = LayoutBox.create(this.layout);
const hbox = LayoutBox.create(this.layout);
// We don't need removeFromParent here because this only runs when there is no parent.
vbox._addChild(hbox, false);
hbox._addChild(this, false);
hbox._addChild(childBox, isAfter);
this.layout.setRoot(vbox);
}
}
this.layout.trigger('layoutChanged');
}
public addChild(childBox: LayoutBox, isAfter: boolean) {
childBox.removeFromParent();
if (this.isLeaf()) {
// Move the leaf data into a new child, then add the requested childBox.
const newBox = LayoutBox.create(this.layout);
newBox.takeLeafFrom(this);
this._addChild(newBox, false);
}
this._addChild(childBox, isAfter);
this.layout.trigger('layoutChanged');
}
public toString(): string {
return this.isDisposed() ? this.uniqueId + "[disposed]" : (this.uniqueId +
(this.isHBox() ? "H" : "V") +
(this.isLeaf() ? "(" + this.leafId() + ")" :
"[" + this.childBoxes.peek().map(function(b) { return b.toString(); }).join(",") + "]")
);
}
public _removeChildBox(childBox: LayoutBox) {
//console.log("_removeChildBox %s from %s", childBox.toString(), this.toString());
let index = this.childBoxes.peek().indexOf(childBox);
childBox.parentBox(null);
if (index >= 0) {
this.childBoxes.splice(index, 1);
this.rescaleFlexSizes();
}
if (this.childBoxes.peekLength === 1) {
// If we now have a single child, then something needs to collapse.
const lowerBox = this.childBoxes.peek()[0];
const parentBox = this.parentBox();
if (lowerBox.isLeaf()) {
// Move the leaf data into ourselves, and remove the lower box.
this.takeLeafFrom(lowerBox);
lowerBox.dispose();
} else if (parentBox) {
// Move grandchildren into our place within our parent, and collapse two levels.
// (Unless we are the root, in which case it's OK for us to have a single non-leaf child.)
index = parentBox.childBoxes.peek().indexOf(this);
assert(index >= 0, 'LayoutBox._removeChildBox: box not found in parent');
const grandchildBoxes = lowerBox.childBoxes.peek();
grandchildBoxes.forEach(function(box) { box.parentBox(parentBox); });
parentBox.childBoxes.arraySplice(index, 0, grandchildBoxes);
lowerBox.childBoxes.splice(0, lowerBox.childBoxes.peekLength);
this.removeFromParent();
lowerBox.dispose();
this.dispose();
}
}
}
/**
* Helper to detach a box from its parent without disposing it. If you no longer plan to reattach
* the box, you should probably call box.dispose().
*/
public removeFromParent() {
if (this.parentBox()) {
this.parentBox()!._removeChildBox(this);
this.layout.trigger('layoutChanged');
}
}
/**
* Adjust flexSize values of the children so that they add up to at least 1.
* Otherwise, Firefox will not stretch them to the full size of the container.
*/
public rescaleFlexSizes() {
// Just scale so that the smallest value is 1.
const children = this.childBoxes.peek();
const minSize = Math.min.apply(null, children.map(function(b) { return b.flexSize(); }));
if (minSize < 1) {
children.forEach(function(b) {
b.flexSize(b.flexSize() / minSize);
});
}
}
}
/**
* This helper turns a value, observable, or function (as accepted by koDom functions) into a
* plain value. It's used to build a static piece of DOM without subscribing to any of the
* observables, to avoid the performance cost of subscribing/unsubscribing.
*/
function makeStatic(valueOrFunc: any) {
if (isObservable(valueOrFunc) || isKoArray(valueOrFunc)) {
return valueOrFunc.peek();
} else if (typeof valueOrFunc === 'function') {
return valueOrFunc();
} else {
return valueOrFunc;
}
}
//----------------------------------------------------------------------
/**
* @event layoutChanged: Triggered on changes to the structure of the layout.
* @event layoutResized: Triggered on non-structural changes that may affect the size of rootElem.
*/
export class Layout extends Disposable {
/**
* You can also find the nearest containing LayoutBox without having the Layout object itself by
* using Layout.Layout.getContainingBox. The Layout object is then accessible as box.layout.
*/
public static getContainingBox(elem: Element|null, optContainer: any) {
const boxElem = findAncestor(elem, optContainer, '.layout_box');
return boxElem ? utils.domData.get(boxElem, 'layoutBox') : null;
}
public listenTo: BackboneEvents["listenTo"]; // set by Backbone
public trigger: BackboneEvents["trigger"]; // set by Backbone
public stopListening: BackboneEvents["stopListening"]; // set by Backbone
public maximizedLeaf: ko.Observable<string|null>;
public rootBox: ko.Observable<LayoutBox|null>;
public createLeafFunc: (id: string) => HTMLElement;
public fillWindow: boolean;
public needDynamic: boolean;
public rootElem: HTMLElement;
public leafId: string;
private _leafIdMap: Map<any, LayoutBox>|null;
public create(boxSpec: BoxSpec, createLeafFunc: (id: string) => HTMLElement, optFillWindow: boolean) {
this.maximizedLeaf = observable(null as (string|null));
this.rootBox = observable(null as any);
this.createLeafFunc = createLeafFunc;
this._leafIdMap = null;
this.fillWindow = optFillWindow || false;
this.needDynamic = false;
this.rootElem = this.autoDispose(this.buildDom());
// Generates a unique id class so boxes can only be placed next to other boxes in this layout.
this.leafId = uniqueId('layout_leaf_');
this.buildLayout(boxSpec || {});
// Invalidate the _leafIdMap when the layout is adjusted.
this.listenTo(this, 'layoutChanged', () => { this._leafIdMap = null; });
this.autoDisposeCallback(() => {
if (this.rootBox()) {
this.rootBox()!.dispose();
}
});
}
/**
* Finds and returns the leaf layout box containing the content for the given leafId.
*/
public getLeafBox(leafId: string|number) {
return this.getLeafIdMap().get(leafId);
}
/**
* Returns the list of all leafIds present in this layout.
*/
public getAllLeafIds() {
return Array.from(this.getLeafIdMap().keys());
}
public setRoot(layoutBox: LayoutBox) {
this.rootBox(layoutBox);
}
public buildDom() {
return dom('div.layout_root',
domData('layoutModel', this),
toggleClass('layout_fill_window', this.fillWindow),
toggleClass('layout_box_maximized', this.maximizedLeaf),
scope(this.rootBox, (rootBox: LayoutBox) => {
return rootBox ? rootBox.getDom() : null;
})
);
}
/**
* Calls cb on each box in the layout recursively.
*/
public forEachBox(cb: (box: LayoutBox) => void, optContext?: any) {
if (!this.rootBox.peek()) {
return;
}
function iter(box: any) {
cb.call(optContext, box);
box.childBoxes.peek().forEach(iter);
}
iter(this.rootBox.peek());
}
public buildLayoutBox(boxSpec: BoxSpec) {
// Note that this is hot code: it runs when rendering a layout for each record, not only for the
// layout editor.
const box = LayoutBox.create(this);
if (boxSpec.size) {
box.flexSize(boxSpec.size);
}
if (boxSpec.leaf) {
box.leafId(boxSpec.leaf);
box.leafContent(this.createLeafFunc(box.leafId()!));
} else if (boxSpec.children) {
box.setChildren(boxSpec.children.map(this.buildLayoutBox, this));
}
return box;
}
public buildLayout(boxSpec: BoxSpec, needDynamic = false) {
if (needDynamic === this.needDynamic &&
this.rootBox() &&
isEqual(boxSpec, this.getLayoutSpec())) {
// Nothing has changed, and we already have a layout. No need to rebuild.
return;
}
this.needDynamic = needDynamic;
const oldRootBox = this.rootBox();
this.rootBox(this.buildLayoutBox(boxSpec));
this.trigger('layoutChanged');
if (oldRootBox) {
oldRootBox.dispose();
}
}
public _getBoxSpec(layoutBox: LayoutBox) {
const spec: BoxSpec = {};
if (layoutBox.isDisposed()) {
return spec;
}
if (layoutBox.flexSize() && layoutBox.flexSize() !== 100) {
spec.size = layoutBox.flexSize();
}
if (layoutBox.isLeaf()) {
spec.leaf = layoutBox.leafId();
} else {
spec.children = layoutBox.childBoxes.peek().map(this._getBoxSpec, this);
}
return spec;
}
public getLayoutSpec() {
const rootBox = this.rootBox();
return rootBox ? this._getBoxSpec(rootBox) : {};
}
/**
* Returns a Map object mapping leafId to its LayoutBox. This gets invalidated on layoutAdjust
* events, and rebuilt on next request.
*/
public getLeafIdMap() {
if (!this._leafIdMap) {
this._leafIdMap = new Map<number|string, LayoutBox>();
this.forEachBox((box) => {
const leafId = box.leafId.peek();
if (leafId !== null) {
this._leafIdMap!.set(leafId, box);
}
}, this);
}
return this._leafIdMap;
}
/**
* Returns a LayoutBox object containing the given DOM element, or null if not found.
*/
public getContainingBox(elem: Element|null) {
return Layout.getContainingBox(elem, this.rootElem);
}
}
Object.assign(Layout.prototype, BackboneEvents);