Overhaul (no)limits support

- Add limits support to InsetMathScript
- Add limits support to InsetMathClass
- Fix bug where limits changing is disabled in inline math

Now the MathData objects remember whether they are in diaply mode.

Fixes bug #12045.

src/mathed/InsetMath.h

@@ -209,8 +209,8 @@ public:
 
 	/// Whether the inset allows \(no)limits
 	bool allowsLimitsChange() const { return mathClass() == MC_OP; }
-	/// The default limits value
-	virtual Limits defaultLimits() const { return NO_LIMITS; }
+	/// The default limits value depending on whether display mode is on
+	virtual Limits defaultLimits(bool /* display */) const { return NO_LIMITS; }
 	/// whether the inset has limit-like sub/superscript
 	virtual Limits limits() const { return AUTO_LIMITS; }
 	/// sets types of sub/superscripts

src/mathed/InsetMathClass.cpp

@@ -28,6 +28,15 @@ Inset * InsetMathClass::clone() const
 }
 
 
+Limits InsetMathClass::defaultLimits(bool display) const
+{
+	if (allowsLimitsChange() && display)
+		return LIMITS;
+	else
+		return NO_LIMITS;
+}
+
+
 void InsetMathClass::metrics(MetricsInfo & mi, Dimension & dim) const
 {
 	cell(0).metrics(mi, dim);
@@ -40,6 +49,13 @@ void InsetMathClass::draw(PainterInfo & pi, int x, int y) const
 }
 
 
+void InsetMathClass::write(WriteStream & os) const
+{
+	InsetMathNest::write(os);
+	writeLimits(os);
+}
+
+
 docstring InsetMathClass::name() const
 {
 	return class_to_string(math_class_);

src/mathed/InsetMathClass.h

@@ -30,11 +30,19 @@ public:
 	docstring name() const override;
 	///
 	MathClass mathClass() const override { return math_class_; }
+	/// The default limits value in \c display style
+	Limits defaultLimits(bool display) const override;
+	/// whether the inset has limit-like sub/superscript
+	Limits limits() const override { return limits_; }
+	/// sets types of sub/superscripts
+	void limits(Limits lim) override { limits_ = lim; }
 	///
 	void metrics(MetricsInfo & mi, Dimension & dim) const override;
 	///
 	void draw(PainterInfo & pi, int x, int y) const override;
 	///
+	void write(WriteStream & os) const override;
+	///
 	void infoize(odocstream & os) const override;
 	///
 	InsetCode lyxCode() const override { return MATH_CLASS_CODE; }
@@ -47,6 +55,8 @@ private:
 	Inset * clone() const override;
 	///
 	MathClass math_class_;
+	///
+	Limits limits_ = AUTO_LIMITS;
 };
 
 

src/mathed/InsetMathDecoration.cpp

@@ -64,6 +64,15 @@ MathClass InsetMathDecoration::mathClass() const
 }
 
 
+Limits InsetMathDecoration::defaultLimits(bool display) const
+{
+	if (allowsLimitsChange() && display)
+		return LIMITS;
+	else
+		return NO_LIMITS;
+}
+
+
 bool InsetMathDecoration::protect() const
 {
 	return

src/mathed/InsetMathDecoration.h

@@ -39,8 +39,8 @@ public:
 	void infoize(odocstream & os) const override;
 	///
 	MathClass mathClass() const override;
-	/// The default limits value
-	Limits defaultLimits() const override { return allowsLimitsChange() ? LIMITS : NO_LIMITS; }
+	/// The default limits value in \c display style
+	Limits defaultLimits(bool display) const override;
 	/// whether the inset has limit-like sub/superscript
 	Limits limits() const override { return limits_; }
 	/// sets types of sub/superscripts

src/mathed/InsetMathMacro.cpp

@@ -398,14 +398,14 @@ bool InsetMathMacro::allowsLimitsChange() const
 }
 
 
-Limits InsetMathMacro::defaultLimits() const
+Limits InsetMathMacro::defaultLimits(bool display) const
 {
 	if (d->expanded_.empty())
 		return NO_LIMITS;
 	// Guess from the expanded macro
 	InsetMath const * in = d->expanded_.back().nucleus();
 	Limits const lim = in->limits() == AUTO_LIMITS
-		? in->defaultLimits() : in->limits();
+		? in->defaultLimits(display) : in->limits();
 	LATTEST(lim != AUTO_LIMITS);
 	return lim;
 }

src/mathed/InsetMathMacro.h

@@ -45,7 +45,7 @@ public:
 	/// Whether the inset allows \(no)limits
 	bool allowsLimitsChange() const;
 	/// The default limits value
-	Limits defaultLimits() const override;
+	Limits defaultLimits(bool display) const override;
 	/// whether the inset has limit-like sub/superscript
 	Limits limits() const override;
 	/// sets types of sub/superscripts

src/mathed/InsetMathNest.cpp

@@ -1299,10 +1299,12 @@ void InsetMathNest::doDispatch(Cursor & cur, FuncRequest & cmd)
 				in->limits(NO_LIMITS);
 			else
 				in->limits(AUTO_LIMITS);
-		} else if (in->limits() == AUTO_LIMITS)
-			in->limits(in->defaultLimits() == LIMITS ? NO_LIMITS : LIMITS);
-		else
+		} else if (in->limits() != AUTO_LIMITS)
 			in->limits(AUTO_LIMITS);
+		else if (in->defaultLimits(cur.cell().displayStyle()) == LIMITS)
+			in->limits(NO_LIMITS);
+		else
+			in->limits(LIMITS);
 		return;
 	}
 

src/mathed/InsetMathScript.cpp

@@ -253,6 +253,23 @@ int InsetMathScript::nker(BufferView const * bv) const
 }
 
 
+Limits InsetMathScript::limits() const
+{
+	if (nuc().empty())
+		return AUTO_LIMITS;
+	else
+		// only the limits status of the last element counts
+		return nuc().back()->limits();
+}
+
+
+void InsetMathScript::limits(Limits lim)
+{
+	if (!nuc().empty())
+		nuc().back()->limits(lim);
+}
+
+
 MathClass InsetMathScript::mathClass() const
 {
 	// FIXME: this is a hack, since the class will not be correct if
@@ -370,13 +387,12 @@ void InsetMathScript::drawT(TextPainter & pain, int x, int y) const
 
 bool InsetMathScript::hasLimits(FontInfo const & font) const
 {
-	if (font.style() != DISPLAY_STYLE)
-		return false;
 	if (nuc().empty())
 		return false;
 
 	Limits const lim = nuc().back()->limits() == AUTO_LIMITS
-		? nuc().back()->defaultLimits() : nuc().back()->limits();
+		? nuc().back()->defaultLimits(font.style() == DISPLAY_STYLE)
+		: nuc().back()->limits();
 	LASSERT(lim != AUTO_LIMITS, return false);
 	return lim == LIMITS;
 }

src/mathed/InsetMathScript.h

@@ -32,6 +32,10 @@ public:
 	InsetMathScript(Buffer * buf, MathAtom const & at, bool up);
 	///
 	mode_type currentMode() const override { return MATH_MODE; }
+	/// whether the inset has limit-like sub/superscript
+	Limits limits() const override;
+	/// sets types of sub/superscripts
+	void limits(Limits lim) override;
 	///
 	MathClass mathClass() const override;
 	///

src/mathed/InsetMathSymbol.cpp

@@ -58,10 +58,12 @@ docstring InsetMathSymbol::name() const
 
 
 /// The default limits value
-Limits InsetMathSymbol::defaultLimits() const
+Limits InsetMathSymbol::defaultLimits(bool display) const
 {
-	return (allowsLimitsChange() && sym_->extra != "func")
-			? LIMITS : NO_LIMITS;
+	if (allowsLimitsChange() && sym_->extra != "func" && display)
+		return LIMITS;
+	else
+		return NO_LIMITS;
 }
 
 

src/mathed/InsetMathSymbol.h

@@ -42,7 +42,7 @@ public:
 	///
 	bool isOrdAlpha() const;
 	/// The default limits value
-	Limits defaultLimits() const override;
+	Limits defaultLimits(bool display) const override;
 	/// whether the inset has limit-like sub/superscript
 	Limits limits() const override { return limits_; }
 	/// sets types of sub/superscripts

src/mathed/MathData.cpp

@@ -224,6 +224,7 @@ bool MathData::addToMathRow(MathRow & mrow, MetricsInfo & mi) const
 {
 	bool has_contents = false;
 	BufferView * bv = mi.base.bv;
+	display_style_ = mi.base.font.style() == DISPLAY_STYLE;
 	MathData * ar = const_cast<MathData*>(this);
 	ar->updateMacros(&bv->cursor(), mi.macrocontext,
 	                 InternalUpdate, mi.base.macro_nesting);

src/mathed/MathData.h

@@ -146,6 +146,8 @@ public:
 	MathClass mathClass() const;
 	/// math class of last interesting element
 	MathClass lastMathClass() const;
+	/// is the cell in display style
+	bool displayStyle() const { return display_style_; }
 
 	/// access to cached x coordinate of last drawing
 	int xo(BufferView const & bv) const;
@@ -192,6 +194,8 @@ protected:
 	mutable int mindes_ = 0;
 	mutable int slevel_ = 0;
 	mutable int sshift_ = 0;
+	/// cached value for display style
+	mutable bool display_style_ = false;
 	Buffer * buffer_ = nullptr;
 
 private: