From 763597c62203a49ed0cc08dfc3562d1ef5871f68 Mon Sep 17 00:00:00 2001
From: fk128 <fkanavati@gmail.com>
Date: Tue, 27 Aug 2024 11:53:17 +0100
Subject: [PATCH] Enable preview for empheq env

---
 src/parse/find.ts          | 4 ++--
 src/preview/hover/utils.ts | 4 ++++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/parse/find.ts b/src/parse/find.ts
index e1b8c3044..002771459 100644
--- a/src/parse/find.ts
+++ b/src/parse/find.ts
@@ -3,7 +3,7 @@ import { escapeRegExp, stripCommentsAndVerbatim } from '../utils/utils'
 import type { TeXMathEnv } from '../types'
 
 const ENV_NAMES = [
-    'align', 'align\\*', 'alignat', 'alignat\\*', 'aligned', 'alignedat', 'array', 'Bmatrix', 'bmatrix', 'cases', 'CD', 'eqnarray', 'eqnarray\\*', 'equation', 'equation\\*', 'flalign', 'flalign\\*', 'gather', 'gather\\*', 'gathered', 'matrix', 'multline', 'multline\\*', 'pmatrix', 'smallmatrix', 'split', 'subarray', 'Vmatrix', 'vmatrix'
+    'align', 'align\\*', 'alignat', 'alignat\\*', 'aligned', 'alignedat', 'array', 'Bmatrix', 'bmatrix', 'cases', 'CD', 'eqnarray', 'eqnarray\\*', 'equation', 'equation\\*', 'flalign', 'flalign\\*', 'gather', 'gather\\*', 'gathered', 'matrix', 'multline', 'multline\\*', 'pmatrix', 'smallmatrix', 'split', 'subarray', 'Vmatrix', 'vmatrix', 'empheq'
 ]
 
 export function findTeX(document: vscode.TextDocument, position: vscode.Position): TeXMathEnv | undefined {
@@ -106,7 +106,7 @@ function getFirstRememberedSubstring(s: string, pat: RegExp): string {
 }
 
 const MATH_ENV_NAMES = [
-    'align', 'align\\*', 'alignat', 'alignat\\*', 'eqnarray', 'eqnarray\\*', 'equation', 'equation\\*', 'flalign', 'flalign\\*', 'gather', 'gather\\*', 'multline', 'multline\\*'
+    'align', 'align\\*', 'alignat', 'alignat\\*', 'eqnarray', 'eqnarray\\*', 'equation', 'equation\\*', 'flalign', 'flalign\\*', 'gather', 'gather\\*', 'multline', 'multline\\*', 'empheq'
 ]
 
 export function findMath(document: vscode.TextDocument, position: vscode.Position): TeXMathEnv | undefined {
diff --git a/src/preview/hover/utils.ts b/src/preview/hover/utils.ts
index c451b0a06..fc9a3ab59 100644
--- a/src/preview/hover/utils.ts
+++ b/src/preview/hover/utils.ts
@@ -15,6 +15,10 @@ export function mathjaxify(tex: string, envname: string, opt = { stripLabel: tru
     if (envname.match(/^(aligned|alignedat|array|Bmatrix|bmatrix|cases|CD|gathered|matrix|pmatrix|smallmatrix|split|subarray|Vmatrix|vmatrix)$/)) {
         s = '\\begin{equation}' + s + '\\end{equation}'
     }
+    if (envname == 'empheq') {
+        const empheqPat = /\\begin\{empheq\}\[.*?\]\{(\w+)\}/g;
+        s = s.replace(empheqPat, '\\begin{empheq}[]{$1}');
+    }
     return s
 }