async parsing + tex caching

Plugins/ZShell/Llm/mathtext.hpp

@@ -7,6 +7,8 @@
 #include <QUrl>
 #include <QtQml>
 
+#include <memory>
+
 #include <jkqtmathtext/jkqtmathtext.h>
 
 namespace ZShell::llm {
@@ -14,7 +16,9 @@ namespace ZShell::llm {
 // QML wrapper around JKQTMathText (JKQtPlotter's LaTeX renderer).
 //
 // Parses a display-math string and renders it into a transparent
-// QImage at the given device pixel ratio. QML displays the image
+// QImage at the given device pixel ratio, off the GUI thread (with a
+// process-wide cache keyed on the full render state, so re-opening a
+// chat does not re-render the same equations). QML displays the image
 // (scaling it to the bubble width when needed) and falls back to the
 // raw LaTeX when parsing fails.
 class LlmMathText : public QObject {
@@ -57,7 +61,9 @@ class LlmMathText : public QObject {
 	private:
 	void reRender();
 
-	JKQTMathText m_renderer;
+	// Shared so an in-flight worker render keeps the renderer alive if
+	// this object (and its QML item) is destroyed mid-render.
+	std::shared_ptr<JKQTMathText> m_renderer;
 	QString m_latex;
 	QColor m_color;
 	double m_fontPointSize = 12.0;
@@ -67,6 +73,10 @@ class LlmMathText : public QObject {
 	qreal m_width = 0;
 	qreal m_height = 0;
 	bool m_ok = false;
+	// Bumps on every reRender; a delivery carrying an older id was
+	// superseded and is dropped.
+	int m_requestId = 0;
+	bool m_inFlight = false;
 };
 
 } // namespace ZShell::llm