Fix LaTeX pane MathJax rendering

panel/models/mathjax.py

@@ -1,23 +1,10 @@
 """
 Defines a custom MathJax bokeh model to render text using MathJax.
 """
-from bokeh.models import Markup
+from bokeh.models import Div
 
 
-class MathJax(Markup):
+class MathJax(Div):
     """
     A bokeh model that renders text using MathJax.
     """
-
-    __javascript__ = [
-        "https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.5/MathJax.js?config=TeX-MML-AM_CHTML"
-    ]
-
-    __js_skip__ = {'MathJax': __javascript__}
-
-    __js_require__ = {
-        'paths': {
-            'mathjax': "//cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.5/MathJax.js?config=TeX-AMS_HTML"
-        },
-        'shim': {'mathjax': {'exports': "MathJax"}}
-    }

panel/models/mathjax.ts

@@ -14,7 +14,21 @@ export class MathJaxView extends PanelMarkupView {
 
   override render(): void {
     super.render()
-    this.container.innerHTML = this.has_math_disabled() ? this.model.text : this.process_tex(this.model.text)
+    const text = this.model.text
+    const tex_parts = this.provider.MathJax.find_tex(text)
+    const processed_text: string[] = []
+
+    let last_index: number | undefined = 0
+    for (const part of tex_parts) {
+      processed_text.push(text.slice(last_index, part.start.n))
+      processed_text.push(this.provider.MathJax.tex2svg(part.math, {display: part.display}).outerHTML)
+      last_index = part.end.n
+    }
+    if (last_index! < text.length) {
+      processed_text.push(text.slice(last_index))
+    }
+
+    this.container.innerHTML = processed_text.join("")
   }
 }
 

panel/pane/equation.py

@@ -4,7 +4,6 @@
 """
 from __future__ import annotations
 
-import re
 import sys
 
 from typing import (
@@ -24,15 +23,6 @@
     from bokeh.model import Model
 
 
-def is_sympy_expr(obj: Any) -> bool:
-    """Test for sympy.Expr types without usually needing to import sympy"""
-    if 'sympy' in sys.modules and 'sympy' in str(type(obj).__class__):
-        import sympy  # type: ignore
-        if isinstance(obj, sympy.Expr):
-            return True
-    return False
-
-
 class LaTeX(ModelPane):
     r"""
     The `LaTeX` pane allows rendering LaTeX equations. It uses either
@@ -71,27 +61,21 @@ class LaTeX(ModelPane):
 
     @classmethod
     def applies(cls, obj: Any) -> float | bool | None:
-        if is_sympy_expr(obj) or hasattr(obj, '_repr_latex_'):
+        if hasattr(obj, '_repr_latex_'):
             return 0.05
         elif isinstance(obj, str):
             return None
         else:
             return False
 
-    def _process_param_change(self, params) -> dict[str, Any]:
-        if self.renderer == "mathjax":
-            # Replace $$math$$ with \[math\] and $math$ with \(math\)
-            msg = re.sub(r"(\$\$)(.*?)(\$\$)", r"\[\2\]", params["object"])
-            params["object"] = re.sub(r"(\$)(.*?)(\$)", r"\(\2\)", msg)
-        return super()._process_param_change(params)
-
     def _get_model_type(self, root: Model, comm: Comm | None) -> type[Model]:
         module = self.renderer
         if module is None:
             if 'panel.models.mathjax' in sys.modules and 'panel.models.katex' not in sys.modules:
                 module = 'mathjax'
             else:
                 module = 'katex'
+            self.renderer = module
         model = 'KaTeX' if module == 'katex' else 'MathJax'
         return lazy_load(f'panel.models.{module}', model, isinstance(comm, JupyterComm), root)
 
@@ -110,7 +94,6 @@ def _transform_object(self, obj: Any) -> dict[str, Any]:
             obj = ''
         elif hasattr(obj, '_repr_latex_'):
             obj = obj._repr_latex_()
-        elif is_sympy_expr(obj):
-            import sympy
-            obj = r'$'+sympy.latex(obj)+'$'
+        if self.renderer == 'mathjax' and obj.startswith('$') and not obj.startswith('$$'):
+            obj = f'${obj}$'
         return dict(object=obj)

panel/tests/pane/test_equation.py

@@ -24,7 +24,7 @@ def test_latex_mathjax_pane(document, comm):
     assert pane._models[model.ref['id']][0] is model
     assert type(model).__name__ == 'MathJax'
     # assert model.text == r"$\frac{p^3}{q}$"
-    assert model.text == r"\(\frac{p^3}{q}\)"
+    assert model.text == r"$$\frac{p^3}{q}$$"
 
     # Cleanup
     pane._cleanup(model)

panel/tests/ui/pane/test_equation.py

@@ -0,0 +1,24 @@
+import pytest
+
+pytest.importorskip("playwright")
+
+from playwright.sync_api import expect
+
+from panel.pane import LaTeX
+from panel.tests.util import serve_component
+
+pytestmark = pytest.mark.ui
+
+def test_latex_mathjax_renderer(page):
+    ltx = LaTeX('$1+1$', renderer='mathjax')
+
+    serve_component(page, ltx)
+
+    expect(page.locator('mjx-container')).to_have_count(1)
+
+def test_latex_katex_renderer(page):
+    ltx = LaTeX('$1+1$', renderer='katex')
+
+    serve_component(page, ltx)
+
+    expect(page.locator('.katex-html')).to_have_count(1)