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Copy pathvariation_tree.ts
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437 lines (377 loc) · 12.6 KB
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// Copyright 2018 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
import {Nullable} from './base'
import {getElement, pixelRatio} from './util'
import {View} from './view'
// Spacing between nodes in the tree.
const SPACE = 19;
// Padding from the edge of the canvas.
const PAD = 11;
// Radius of the nodes.
const RADIUS = 5;
interface Position {
parent: Nullable<Position>;
children: Position[];
}
class Node {
isMainline: boolean;
children: Node[] = [];
constructor(public parent: Nullable<Node>, public position: Position,
public x: number, public y: number) {
if (parent == null) {
// Root node.
this.isMainline = true;
} else {
this.isMainline = parent.isMainline && parent.children.length == 0;
parent.children.push(this);
}
}
}
interface LayoutResult {
maxDepth: number;
rootNode: Node;
}
type ClickListener = (position: Position) => void;
type HoverListener = (position: Nullable<Position>) => void;
class VariationTree extends View {
private rootNode: Nullable<Node> = null;
private ctx: CanvasRenderingContext2D;
private hoveredNode: Nullable<Node> = null;
private activeNode: Nullable<Node> = null;
private clickListeners: ClickListener[] = [];
private hoverListeners: HoverListener[] = [];
// Size of the canvas (ignoring the device's pixel ratio).
private width = 0;
private height = 0;
// Maximum x and y coordinate of tree nodes.
private maxX = 0;
private maxY = 0;
// Scroll offset for rendering the tree.
private scrollX = 0;
private scrollY = 0;
// It's 2018 and MouseEvent.movementX and MouseEvent.movementY is still not
// supported by all browsers, so we must calculate the movement deltas
// ourselves... *sigh*
private mouseX = 0;
private mouseY = 0;
constructor(parent: HTMLElement | string) {
super();
if (typeof(parent) == 'string') {
parent = getElement(parent);
}
let canvas = document.createElement('canvas');
this.ctx = canvas.getContext('2d') as CanvasRenderingContext2D;
parent.appendChild(canvas);
this.resizeCanvas();
parent.addEventListener('mousemove', (e) => {
let oldNode = this.hoveredNode;
this.hoveredNode = this.hitTest(e.offsetX, e.offsetY);
if (this.hoveredNode != oldNode) {
if (this.hoveredNode != null) {
canvas.classList.add('pointer');
} else {
canvas.classList.remove('pointer');
}
for (let listener of this.hoverListeners) {
listener(this.hoveredNode ? this.hoveredNode.position : null);
}
}
});
parent.addEventListener('mousedown', (e) => {
this.mouseX = e.screenX;
this.mouseY = e.screenY;
let moveHandler = (e: MouseEvent) => {
this.scrollX += this.mouseX - e.screenX;
this.scrollY += this.mouseY - e.screenY;
this.scrollX = Math.min(this.scrollX, this.maxX + PAD - this.width);
this.scrollY = Math.min(this.scrollY, this.maxY + PAD - this.height);
this.scrollX = Math.max(this.scrollX, 0);
this.scrollY = Math.max(this.scrollY, 0);
this.mouseX = e.screenX;
this.mouseY = e.screenY;
this.draw();
e.preventDefault();
return false;
};
let upHandler = (e: MouseEvent) => {
window.removeEventListener('mousemove', moveHandler);
window.removeEventListener('mouseup', upHandler);
};
window.addEventListener('mousemove', moveHandler);
window.addEventListener('mouseup', upHandler);
});
parent.addEventListener('click', (e) => {
if (this.hoveredNode != null) {
for (let listener of this.clickListeners) {
listener(this.hoveredNode.position);
}
}
});
window.addEventListener('resize', () => {
this.resizeCanvas();
this.scrollIntoView();
this.draw();
});
}
newGame() {
this.rootNode = null;
this.activeNode = null;
this.layout();
this.scrollIntoView();
this.draw();
}
setRoot(position: Position) {
if (this.rootNode != null){
throw new Error('Already have a root note, you should call newGame first');
}
this.rootNode = new Node(null, position, PAD, PAD);
this.activeNode = this.rootNode;
}
setActive(position: Position) {
if (this.activeNode != null && this.activeNode.position != position) {
this.activeNode = this.lookupNode(position);
this.scrollIntoView();
this.draw();
}
}
addChild(parentPosition: Position, childPosition: Position) {
if (this.rootNode == null) {
throw new Error('Must start a game before attempting to add children');
}
// Add a new child node to the parent if necessary, or reuse the existing
// node.
let parentNode = this.lookupNode(parentPosition);
let childNode: Nullable<Node> = null;
for (let child of parentNode.children) {
if (child.position == childPosition) {
childNode = child;
break;
}
}
if (childNode == null) {
let x = parentNode.x + SPACE;
let y = parentNode.y + SPACE * parentNode.children.length;
childNode = new Node(parentNode, childPosition, x, y);
this.layout();
}
}
onClick(cb: ClickListener) {
this.clickListeners.push(cb);
}
onHover(cb: HoverListener) {
this.hoverListeners.push(cb);
}
private lookupNode(position: Position) {
let impl = (node: Node): Nullable<Node> => {
if (node.position == position) {
return node;
}
for (let child of node.children) {
let node = impl(child);
if (node != null) {
return node;
}
}
return null;
}
let node = this.rootNode != null ? impl(this.rootNode) : null;
if (node == null) {
throw new Error('Couldn\'t find node');
}
return node;
}
private hitTest(x: number, y: number) {
if (this.rootNode == null) {
return null;
}
x += this.scrollX;
y += this.scrollY;
let threshold = 0.4 * SPACE;
let traverse = (node: Node): Nullable<Node> => {
let dx = x - node.x;
let dy = y - node.y;
if (dx * dx + dy * dy < threshold * threshold) {
return node;
}
for (let child of node.children) {
let result = traverse(child);
if (result != null) {
return result;
}
}
return null;
};
return traverse(this.rootNode);
}
// TODO(tommadams): Don't draw parts of the tree that are out of view.
drawImpl() {
let ctx = this.ctx;
ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height);
if (this.rootNode == null) {
return;
}
let pr = pixelRatio();
ctx.save();
ctx.translate(0.5 - pr * this.scrollX, 0.5 - pr * this.scrollY);
ctx.lineWidth = pr;
// Recursively draw the edges in the tree.
let drawEdges = (node: Node, drawMainline: boolean) => {
if (node.children.length == 0) {
return;
}
// Draw edges from parent to all children.
// The first child's edge is horizontal.
// The remaining childrens' edges slope at 45 degrees.
for (let child of node.children) {
let y = child.y;
if (child != node.children[0]) {
y -= SPACE;
}
if (drawMainline == child.isMainline) {
ctx.moveTo(pr * node.x, pr * y);
ctx.lineTo(pr * child.x, pr * child.y);
}
drawEdges(child, drawMainline);
}
// If a node has two or more children, draw a vertical line to
// connect the tops of all of the sloping edges.
if (node.children.length > 1 && !drawMainline) {
let lastChild = node.children[node.children.length - 1];
if (lastChild.y - SPACE > node.y) {
ctx.moveTo(pr * node.x, pr * node.y);
ctx.lineTo(pr * node.x, pr * (lastChild.y - SPACE));
}
}
};
for (let style of ['#fff', '#888']) {
ctx.beginPath();
ctx.strokeStyle = style;
drawEdges(this.rootNode, style == '#fff');
ctx.stroke();
}
// Draw the active node in red.
let r = RADIUS * pr;
if (this.activeNode != null) {
ctx.fillStyle = '#800';
ctx.strokeStyle = '#ff0';
ctx.beginPath();
ctx.arc(pr * this.activeNode.x, pr * this.activeNode.y, r, 0,
2 * Math.PI);
ctx.fill();
ctx.stroke();
}
// Draw the root node in gray.
ctx.strokeStyle = '#888';
if (this.activeNode != this.rootNode) {
ctx.fillStyle = '#666';
ctx.beginPath();
ctx.arc(pr * this.rootNode.x, pr * this.rootNode.y, r, 0, 2 * Math.PI);
ctx.fill();
ctx.stroke();
}
// Recursively draw the non-root nodes.
// To avoid repeatedly changing the fill style between black and white,
// we draw in two passes: first all the black nodes, then all the white
// ones.
let drawNodes = (node: Node, draw: boolean) => {
if (draw && node != this.rootNode && node != this.activeNode) {
ctx.moveTo(pr * node.x + r, pr * node.y);
ctx.arc(pr * node.x, pr * node.y, r, 0, 2 * Math.PI);
}
for (let child of node.children) {
drawNodes(child, !draw);
}
};
for (let style of ['#000', '#fff']) {
ctx.fillStyle = style;
ctx.beginPath();
drawNodes(this.rootNode, style != '#000');
ctx.fill();
ctx.stroke();
}
ctx.restore();
}
private scrollIntoView() {
if (this.activeNode == null) {
return;
}
if (this.activeNode.x - this.scrollX > this.width - PAD) {
this.scrollX = this.activeNode.x - this.width + PAD;
} else if (this.activeNode.x - this.scrollX < PAD) {
this.scrollX = this.activeNode.x - PAD;
}
if (this.activeNode.y - this.scrollY > this.height - PAD) {
this.scrollY = this.activeNode.y - this.height + PAD;
} else if (this.activeNode.y - this.scrollY < PAD) {
this.scrollY = this.activeNode.y - PAD;
}
}
private layout() {
this.maxX = 0;
this.maxY = 0;
if (this.rootNode == null) {
return;
}
// Bottom-most node at each depth in the tree.
let bottomNode: Node[] = [this.rootNode];
// We want to lay the nodes in the tree out such that the main line of each
// node (the chain of first children of all descendants) is a horizontal
// line. We do this by incrementally building a new tree of layout data in
// traversal order of the game tree, satisfying the following constraints at
// each step:
// 1) A newly inserted node's y coordinate is greater than all other nodes
// at the same depth. This is enforced pre-traversal.
// 2) A newly inserted node's y coordinate is greater or equal to the y
// coordinate of its first child. This is enforced post-traversal.
let traverse = (node: Node, depth: number) => {
// Tell the compiler that node.parent is guaranteed to be non-null.
let parent = node.parent as Node;
// Satisfy constraint 1. In order to make the layout less cramped, we
// actually check both the current depth and the next depth.
node.y = parent.y;
for (let i = 0; i < 2 && depth + i < bottomNode.length; ++i) {
node.y = Math.max(node.y, bottomNode[depth + i].y + SPACE);
}
bottomNode[depth] = node;
for (let child of node.children) {
traverse(child, depth + 1);
}
// Satisfy constraint 2.
if (node == parent.children[0]) {
parent.y = Math.max(parent.y, node.y);
}
this.maxX = Math.max(this.maxX, node.x);
this.maxY = Math.max(this.maxY, node.y);
};
// Traverse the root node's children: the root node doesn't need laying
// out and this guarantees that all traversed nodes have parents.
for (let child of this.rootNode.children) {
traverse(child, 1);
}
}
private resizeCanvas() {
let pr = pixelRatio();
let canvas = this.ctx.canvas;
let parent = canvas.parentElement as HTMLElement;
this.width = parent.offsetWidth;
this.height = parent.offsetHeight;
canvas.width = pr * this.width;
canvas.height = pr * this.height;
canvas.style.width = `${this.width}px`;
canvas.style.height = `${this.height}px`;
}
}
export {
VariationTree,
}