fix: add preprocess

app/services/converter.py

@@ -217,6 +217,9 @@ class Converter:
         This is a separate method due to the performance overhead of OMML conversion,
         which requires creating a temporary DOCX file.
 
+        The formula is preprocessed using the same logic as export_to_file to ensure
+        proper conversion.
+
         Args:
             latex_formula: Pure LaTeX formula (without delimiters like $ or $$).
 
@@ -230,7 +233,37 @@ class Converter:
         if not latex_formula or not latex_formula.strip():
             raise ValueError("LaTeX formula cannot be empty")
 
-        return self._latex_to_omml(latex_formula.strip())
+        # Preprocess formula using the same preprocessing as export
+        preprocessed = self._preprocess_formula_for_omml(latex_formula.strip())
+        
+        return self._latex_to_omml(preprocessed)
+
+    def _preprocess_formula_for_omml(self, latex_formula: str) -> str:
+        """Preprocess LaTeX formula for OMML conversion.
+
+        Applies the same preprocessing steps as preprocess_for_export to ensure
+        consistency. This fixes common issues that cause Pandoc OMML conversion to fail.
+
+        Args:
+            latex_formula: Pure LaTeX formula.
+
+        Returns:
+            Preprocessed LaTeX formula.
+        """
+        # Use the same preprocessing methods as export
+        # 1. Convert matrix environments
+        latex_formula = self._convert_matrix_environments(latex_formula)
+        
+        # 2. Fix array column specifiers (remove spaces)
+        latex_formula = self._fix_array_column_specifiers(latex_formula)
+        
+        # 3. Fix brace spacing
+        latex_formula = self._fix_brace_spacing(latex_formula)
+        
+        # 4. Convert special environments (cases, aligned)
+        latex_formula = self._convert_special_environments(latex_formula)
+        
+        return latex_formula
 
     def _extract_latex_formula(self, text: str) -> str:
         """Extract LaTeX formula from text by removing delimiters.