Typicalc/frontend/src/mathjax-proof-tree.ts
2021-02-27 21:28:17 +01:00

233 lines
11 KiB
TypeScript

import {MathjaxAdapter} from "./mathjax-adapter";
declare let window: {
svgPanZoomFun: (svg: SVGElement, options: { fit: boolean }) => void;
}
// these attributes and functions are supported by major browsers, but TS does not know about them
declare global {
interface SVGElement {
viewBox: SVGAnimatedRect;
}
interface SVGGraphicsElement {
getTransformToElement: (other: SVGGraphicsElement) => SVGMatrix;
}
interface SVGTransformList {
[index: number]: SVGTransform;
}
}
interface ProofTreeServer {
setStepCount: (count: number) => void;
}
class MathjaxProofTree extends MathjaxAdapter {
private steps: [SVGElement, SVGElement[]][] = [];
private $server: ProofTreeServer | undefined;
protected showStep(n: number): void {
for (let current = 0; current < this.steps.length; current++) {
this.steps[current][0].style.display = "none";
for (const node of this.steps[current][1]) {
node.style.display = "none";
}
}
for (let current = 0; current < this.steps.length && current <= n; current++) {
this.steps[current][0].style.display = "";
for (const node of this.steps[current][1]) {
node.style.display = "";
}
}
}
protected calculateSteps(): void {
const semanticsMatch = (semantics: string) => semantics.indexOf("bspr_inference:") >= 0;
const inferenceRuleSelector = 'g[semantics="bspr_inferenceRule:down"]';
const labelSelector = 'g[semantics="bspr_prooflabel:left"]';
const stepSelector = 'g[typicalc="step"]';
// space between inference premises
const padding = 300;
if (this.shadowRoot !== null) {
console.time('stepCalculation');
const root = this.shadowRoot;
// first, enumerate all of the steps
let stepIdx = 0;
for (const a of root.querySelectorAll<SVGElement>("g[semantics]")) {
let semantics = a.getAttribute("semantics")!;
if (semanticsMatch(semantics)) {
a.setAttribute("typicalc", "step");
a.setAttribute("id", "step" + stepIdx);
stepIdx++;
}
}
// then create the steps
let steps: [SVGElement, SVGElement[]][] = [];
stepIdx = 0;
for (const a of root.querySelectorAll<SVGElement>("g[semantics]")) {
let semantics = a.getAttribute("semantics")!;
if (semanticsMatch(semantics)) {
const id = "step" + stepIdx;
const idSelector = `#${id} `;
stepIdx++;
// find the next one/two steps above this one
const aboveStep1 = a.querySelector<SVGElement>(idSelector + stepSelector);
let above = [];
if (aboveStep1 != null) {
const parent = aboveStep1.parentElement!.parentElement!;
parent.setAttribute("id", "typicalc-selector");
for (const node of parent.querySelectorAll<SVGElement>('#typicalc-selector > g > ' + stepSelector)) {
above.push(node);
}
parent.removeAttribute("id");
}
const rule = a.querySelector(idSelector + inferenceRuleSelector);
if (rule !== null) {
let i = 0;
for (const node of rule.children) {
if (i !== 1) {
above.push(node as SVGElement);
}
i += 1;
}
}
const label = a.querySelector<SVGElement>(idSelector + labelSelector);
if (label) {
above.push(label);
}
if (stepIdx === 1) {
// initial step should not show premises
steps.push([a, []]);
}
steps.push([a, above]);
}
}
// MathJax layout of bussproofs is sometimes wrong:
// https://github.com/mathjax/MathJax/issues/2270
// https://github.com/mathjax/MathJax/issues/2626
// we fix it in two phases:
// 1. fix overlapping by iterating over "rows" in the SVG created by MathJax
// in each row, the elements are arranged to not overlap
// 2. place inference conclusions under the center of their line
const svg = root.querySelector<SVGElement>("svg")!;
svg.viewBox.baseVal.width = Math.min(100000, svg.viewBox.baseVal.width);
const nodeIterator = [...svg.querySelectorAll<SVGGraphicsElement>("g[data-mml-node='mtr']," + inferenceRuleSelector)];
console.log(`working with ${nodeIterator.length} nodes`);
// start layout fixes in the innermost part of the SVG
nodeIterator.reverse();
for (const row of nodeIterator) {
const semantics = row.getAttribute("semantics");
if (semantics === "bspr_inferenceRule:down") {
const conclusion = row.children[1].querySelector<SVGGraphicsElement>('g[data-mml-node="mstyle"]')!;
const conclusionBox = conclusion.getBBox();
const line = row.children[2] as SVGGraphicsElement;
const bbox = line.getBBox();
const offset2 = line.getTransformToElement(conclusion);
let dx = bbox.width / 2 + offset2.e - conclusionBox.width / 2;
dx += Number(line.getAttribute("x1"));
let table = row.parentNode as SVGGraphicsElement;
let prevNode;
let magicNumber = 0;
while (table.getAttribute("semantics") !== "bspr_inferenceRule:down") {
prevNode = table;
table = table.parentNode as SVGGraphicsElement;
if (table.getAttribute("data-mml-node") === "mtr" && table.childNodes.length === 3) {
for (let i = 0; i < table.childNodes.length; i++) {
if (table.childNodes[i] === prevNode) {
magicNumber = i;
}
}
}
if (table === svg) {
break;
}
}
conclusion.transform.baseVal[0].matrix.e += dx;
if (magicNumber !== 0) {
continue;
}
if (table === svg) {
break; // last step
}
const lineBelow = table.children[2] as SVGGraphicsElement;
let lineStart = 0;
if (lineBelow) {
const offset1 = lineBelow.getTransformToElement(conclusion);
lineStart = -offset1.e;
const x1 = Number(lineBelow.getAttribute("x1"));
const x2 = Number(lineBelow.getAttribute("x2"));
lineBelow.setAttribute("x1", String(x1 + lineStart));
lineBelow.setAttribute("x2", String(x2 + lineStart));
}
const label = table.parentElement!.children[1] as SVGGraphicsElement;
if (label && label.transform) {
label.transform.baseVal[0].matrix.e += lineStart;
}
} else {
let left = null;
let i = 0;
for (const rawNode of row.children) {
const node = rawNode as SVGGraphicsElement;
if (i === 1 || i === 3) {
i += 1;
continue; // spacing node
}
const bbox = node.getBBox();
const mat = node.transform.baseVal[0];
if (mat) {
bbox.x += mat.matrix.e;
}
// move box, and add padding between inference steps
if (left == null) {
// first box
left = bbox.x + bbox.width;
} else {
// this box has some elements left of it
// -> move to free space after other elements
mat.matrix.e -= bbox.x - left - padding;
left = bbox.x + mat.matrix.e + bbox.width;
}
if (i == 2) {
let parentNode = node.parentNode! as SVGGraphicsElement;
while (parentNode.getAttribute("semantics") !== "bspr_inferenceRule:down") {
parentNode = parentNode.parentNode! as SVGGraphicsElement;
}
parentNode = parentNode.children[2] as SVGGraphicsElement;
const rule = node.querySelector<SVGGraphicsElement>(inferenceRuleSelector);
if (rule) {
// this selector should be checked again when updating MathJax
const term = rule.children[1].children[0].children[0].children[1].children[0] as SVGGraphicsElement;
let w = -parentNode.getTransformToElement(term).e;
w += term.getBBox().width;
w += padding;
parentNode.setAttribute("x2", w.toString());
}
}
i += 1;
}
}
}
const conclusion0 = svg.querySelector<SVGElement>(inferenceRuleSelector)!.children[1].children[0].children[0].children[1] as SVGGraphicsElement;
const conclusionWidth = conclusion0.getBBox().width;
const svgWidth = svg.viewBox.baseVal.width;
const offset = (svg.children[1] as SVGGraphicsElement).getTransformToElement(conclusion0);
(svg.children[1] as SVGGraphicsElement).transform.baseVal[0].matrix.e += offset.e + svgWidth / 2 - conclusionWidth / 2;
console.timeEnd('stepCalculation');
if (nodeIterator.length >= 3) {
// should not be used on empty SVGs
window.svgPanZoomFun(svg, { fit: false });
}
this.steps = steps;
this.showStep(0);
this.$server!.setStepCount(steps.length);
}
}
}
customElements.define('tc-proof-tree', MathjaxProofTree);