Remove a conversion to_utf8() inside FontSetChanger

This requires to change many docstrings into std::strings. The logic behind that
is that they represent a fixed set of math fonts, and therefore “string” means
here “poor man's enum” rather than text (this is consistent with MetricsBase).

Profiling of scrolling inside a document over macro-instensive areas:

Before the patch:
  44,1% BufferView::updateMetrics()
   -> 34,8% InsetMathHull::metrics()
     -> 9,8% FontSetChanger::FontSetChanger()
  28,4% BufferView::draw()

After the patch:
  35,3% BufferView::updateMetrics()
   -> 27,2% InsetMathHull::metrics
     -> 0,4% FontSetChanger::FontSetChanger()
  47,5% BufferView::draw()

FontSetChanger::FontSetChanger() is made 41x less expensive (with reference
BV::draw()) just by removing this conversion. The remaining 0,4% could be
squished by replacing the strings with a proper enum, but this is premature. Of
course, this only treats the symptoms: there is no good reason that this
function is called 45500 times over the time of 40 repaints.

src/MetricsInfo.cpp

@@ -66,15 +66,15 @@ MetricsBase::MetricsBase(BufferView * b, FontInfo f, int w)
 }
 
 
-Changer MetricsBase::changeFontSet(docstring const & name, bool cond)
+Changer MetricsBase::changeFontSet(string const & name, bool cond)
 {
 	RefChanger<MetricsBase> rc = make_save(*this);
 	if (!cond)
 		rc->keep();
 	else {
 		ColorCode oldcolor = font.color();
-		docstring const oldname = from_ascii(fontname);
+		string const oldname = fontname;
-		fontname = to_utf8(name);
+		fontname = name;
 		font = sane_font;
 		augmentFont(font, name);
 		font.setSize(rc->old.font.size());
@@ -87,12 +87,6 @@ Changer MetricsBase::changeFontSet(docstring const & name, bool cond)
 }
 
 
-Changer MetricsBase::changeFontSet(char const * name, bool cond)
-{
-	return changeFontSet(from_ascii(name), cond);
-}
-
-
 /////////////////////////////////////////////////////////////////////////
 //
 // MetricsInfo

src/MetricsInfo.h

@@ -68,8 +68,7 @@ public:
 	int textwidth;
 
 	/// Temporarily change a full font.
-	Changer changeFontSet(docstring const & font, bool cond = true);
+	Changer changeFontSet(std::string const & font, bool cond = true);
-	Changer changeFontSet(char const * font, bool cond = true);
 	/// Temporarily change the font size and the math style.
 	Changer changeStyle(Styles style, bool cond = true);
 	// Temporarily change to the style suitable for use in fractions

src/mathed/InsetMathBrace.cpp

@@ -50,7 +50,7 @@ void InsetMathBrace::metrics(MetricsInfo & mi, Dimension & dim) const
 	Dimension dim0;
 	cell(0).metrics(mi, dim0);
 	FontInfo font = mi.base.font;
-	augmentFont(font, from_ascii("mathnormal"));
+	augmentFont(font, "mathnormal");
 	Dimension t = theFontMetrics(font).dimension('{');
 	dim.asc = max(dim0.asc, t.asc);
 	dim.des = max(dim0.des, t.des);
@@ -62,7 +62,7 @@ void InsetMathBrace::metrics(MetricsInfo & mi, Dimension & dim) const
 void InsetMathBrace::draw(PainterInfo & pi, int x, int y) const
 {
 	FontInfo font = pi.base.font;
-	augmentFont(font, from_ascii("mathnormal"));
+	augmentFont(font, "mathnormal");
 	font.setShape(UP_SHAPE);
 	font.setColor(Color_latex);
 	Dimension t = theFontMetrics(font).dimension('{');

src/mathed/InsetMathDecoration.cpp

@@ -106,7 +106,7 @@ InsetMath::mode_type InsetMathDecoration::currentMode() const
 void InsetMathDecoration::metrics(MetricsInfo & mi, Dimension & dim) const
 {
 	bool really_change_font = currentMode() == TEXT_MODE
-				&& isMathFont(from_ascii(mi.base.fontname));
+				&& isMathFont(mi.base.fontname);
 	Changer dummy = mi.base.changeFontSet("textnormal", really_change_font);
 
 	cell(0).metrics(mi, dim);
@@ -129,7 +129,7 @@ void InsetMathDecoration::metrics(MetricsInfo & mi, Dimension & dim) const
 void InsetMathDecoration::draw(PainterInfo & pi, int x, int y) const
 {
 	bool really_change_font = currentMode() == TEXT_MODE
-				&& isMathFont(from_ascii(pi.base.fontname));
+		                      && isMathFont(pi.base.fontname);
 	Changer dummy = pi.base.changeFontSet("textnormal", really_change_font);
 
 	cell(0).draw(pi, x + 1, y);

src/mathed/InsetMathEnsureMath.cpp

@@ -38,7 +38,7 @@ Inset * InsetMathEnsureMath::clone() const
 
 void InsetMathEnsureMath::metrics(MetricsInfo & mi, Dimension & dim) const
 {
-	bool really_change_font = isTextFont(from_ascii(mi.base.fontname));
+	bool really_change_font = isTextFont(mi.base.fontname);
 	Changer dummy = mi.base.changeFontSet("mathnormal", really_change_font);
 	cell(0).metrics(mi, dim);
 	metricsMarkers(dim);
@@ -47,7 +47,7 @@ void InsetMathEnsureMath::metrics(MetricsInfo & mi, Dimension & dim) const
 
 void InsetMathEnsureMath::draw(PainterInfo & pi, int x, int y) const
 {
-	bool really_change_font = isTextFont(from_ascii(pi.base.fontname));
+	bool really_change_font = isTextFont(pi.base.fontname);
 	Changer dummy = pi.base.changeFontSet("mathnormal", really_change_font);
 	cell(0).draw(pi, x, y);
 	drawMarkers(pi, x, y);

src/mathed/InsetMathFont.cpp

@@ -19,6 +19,7 @@
 #include "MetricsInfo.h"
 
 #include "support/gettext.h"
+#include "support/lassert.h"
 #include "support/lstrings.h"
 
 #include <ostream>
@@ -38,6 +39,13 @@ Inset * InsetMathFont::clone() const
 }
 
 
+std::string InsetMathFont::font() const
+{
+	LASSERT(isAscii(key_->name), return "mathnormal");
+	return to_ascii(key_->name);
+}
+
+
 InsetMath::mode_type InsetMathFont::currentMode() const
 {
 	if (key_->extra == "mathmode")
@@ -58,7 +66,7 @@ bool InsetMathFont::lockedMode() const
 
 void InsetMathFont::metrics(MetricsInfo & mi, Dimension & dim) const
 {
-	Changer dummy = mi.base.changeFontSet(key_->name);
+	Changer dummy = mi.base.changeFontSet(font());
 	cell(0).metrics(mi, dim);
 	metricsMarkers(dim);
 }
@@ -66,7 +74,7 @@ void InsetMathFont::metrics(MetricsInfo & mi, Dimension & dim) const
 
 void InsetMathFont::draw(PainterInfo & pi, int x, int y) const
 {
-	Changer dummy = pi.base.changeFontSet(key_->name);
+	Changer dummy = pi.base.changeFontSet(font());
 	cell(0).draw(pi, x + 1, y);
 	drawMarkers(pi, x, y);
 	setPosCache(pi, x, y);
@@ -96,19 +104,20 @@ docstring InsetMathFont::name() const
 void InsetMathFont::validate(LaTeXFeatures & features) const
 {
 	InsetMathNest::validate(features);
+	std::string fontname = font();
 	if (features.runparams().isLaTeX()) {
 		// Make sure amssymb is put in preamble if Blackboard Bold or
 		// Fraktur used:
-		if (key_->name == "mathfrak" || key_->name == "mathbb")
+		if (fontname == "mathfrak" || fontname == "mathbb")
 			features.require("amssymb");
-		if (key_->name == "text" || key_->name == "textnormal"
+		if (fontname == "text" || fontname == "textnormal"
-				|| (key_->name.length() == 6 && key_->name.substr(0, 4) == "text"))
+		    || (fontname.length() == 6 && fontname.substr(0, 4) == "text"))
 			features.require("amstext");
-		if (key_->name == "mathscr")
+		if (fontname == "mathscr")
 			features.require("mathrsfs");
-		if (key_->name == "textipa")
+		if (fontname == "textipa")
 			features.require("tipa");
-		if (key_->name == "ce" || key_->name == "cf")
+		if (fontname == "ce" || fontname == "cf")
 			features.require("mhchem");
 	} else if (features.runparams().math_flavor == OutputParams::MathAsHTML) {
 		features.addCSSSnippet(

src/mathed/InsetMathFont.h

@@ -57,6 +57,8 @@ public:
 	InsetCode lyxCode() const { return MATH_FONT_CODE; }
 
 private:
+	std::string font() const;
+	///
 	virtual Inset * clone() const;
 	/// the font to be used on screen
 	latexkeys const * key_;

src/mathed/InsetMathFontOld.cpp

@@ -19,6 +19,7 @@
 #include "MetricsInfo.h"
 
 #include "support/gettext.h"
+#include "support/lassert.h"
 #include "support/lstrings.h"
 
 #include <ostream>
@@ -34,6 +35,13 @@ InsetMathFontOld::InsetMathFontOld(Buffer * buf, latexkeys const * key)
 }
 
 
+std::string InsetMathFontOld::font() const
+{
+	LASSERT(isAscii(key_->name), return "mathnormal");
+	return to_ascii(key_->name);
+}
+
+
 Inset * InsetMathFontOld::clone() const
 {
 	return new InsetMathFontOld(*this);
@@ -42,16 +50,16 @@ Inset * InsetMathFontOld::clone() const
 
 void InsetMathFontOld::metrics(MetricsInfo & mi, Dimension & dim) const
 {
-	current_mode_ = isTextFont(from_ascii(mi.base.fontname))
+	current_mode_ = isTextFont(mi.base.fontname)
 				? TEXT_MODE : MATH_MODE;
 
-	docstring const font = current_mode_ == MATH_MODE
+	std::string const fontname = current_mode_ == MATH_MODE
-				? "math" + key_->name : "text" + key_->name;
+		? "math" + font() : "text" + font();// I doubt that this still works
 
 	// When \cal is used in text mode, the font is not changed
-	bool really_change_font = font != "textcal";
+	bool really_change_font = fontname != "textcal";
 
-	Changer dummy = mi.base.changeFontSet(font, really_change_font);
+	Changer dummy = mi.base.changeFontSet(fontname, really_change_font);
 	cell(0).metrics(mi, dim);
 	metricsMarkers(dim);
 }
@@ -59,16 +67,16 @@ void InsetMathFontOld::metrics(MetricsInfo & mi, Dimension & dim) const
 
 void InsetMathFontOld::draw(PainterInfo & pi, int x, int y) const
 {
-	current_mode_ = isTextFont(from_ascii(pi.base.fontname))
+	current_mode_ = isTextFont(pi.base.fontname)
 				? TEXT_MODE : MATH_MODE;
 
-	docstring const font = current_mode_ == MATH_MODE
+	std::string const fontname = current_mode_ == MATH_MODE
-				? "math" + key_->name : "text" + key_->name;
+		? "math" + font() : "text" + font();// I doubt that this still works
 
 	// When \cal is used in text mode, the font is not changed
-	bool really_change_font = font != "textcal";
+	bool really_change_font = fontname != "textcal";
 
-	Changer dummy = pi.base.changeFontSet(font, really_change_font);
+	Changer dummy = pi.base.changeFontSet(fontname, really_change_font);
 	cell(0).draw(pi, x + 1, y);
 	drawMarkers(pi, x, y);
 }

src/mathed/InsetMathFontOld.h

@@ -49,6 +49,8 @@ public:
 	InsetCode lyxCode() const { return MATH_FONTOLD_CODE; }
 
 private:
+	std::string font() const;
+	///
 	virtual Inset * clone() const;
 	/// the font to be used on screen
 	latexkeys const * key_;

src/mathed/InsetMathHull.cpp

@@ -426,15 +426,15 @@ int InsetMathHull::defaultColSpace(col_type col)
 }
 
 
-docstring InsetMathHull::standardFont() const
+string InsetMathHull::standardFont() const
 {
 	switch (type_) {
 	case hullRegexp:
-		return from_ascii("texttt");
+		return "texttt";
 	case hullNone:
-		return from_ascii("lyxnochange");
+		return "lyxnochange";
 	default:
-		return from_ascii("mathnormal");
+		return "mathnormal";
 	}
 }
 
@@ -501,7 +501,7 @@ void InsetMathHull::metrics(MetricsInfo & mi, Dimension & dim) const
 	}
 
 	if (numberedType()) {
-		Changer dummy = mi.base.changeFontSet(from_ascii("mathbf"));
+		Changer dummy = mi.base.changeFontSet("mathbf");
 		int l = 0;
 		for (row_type row = 0; row < nrows(); ++row)
 			l = max(l, mathed_string_width(mi.base.font, nicelabel(row)));
@@ -592,7 +592,7 @@ void InsetMathHull::draw(PainterInfo & pi, int x, int y) const
 		int const xx = x + colinfo_.back().offset_ + colinfo_.back().width_ + 20;
 		for (row_type row = 0; row < nrows(); ++row) {
 			int const yy = y + rowinfo_[row].offset_;
-			Changer dummy = pi.base.changeFontSet(from_ascii("mathrm"));
+			Changer dummy = pi.base.changeFontSet("mathrm");
 			docstring const nl = nicelabel(row);
 			pi.draw(xx, yy, nl);
 		}

src/mathed/InsetMathHull.h

@@ -235,7 +235,7 @@ private:
 	/// change number of columns, split or combine columns if necessary.
 	void changeCols(col_type);
 	///
-	docstring standardFont() const;
+	std::string standardFont() const;
 	///
 	ColorCode standardColor() const;
 	/// consistency check

src/mathed/InsetMathSymbol.cpp

@@ -69,7 +69,7 @@ void InsetMathSymbol::metrics(MetricsInfo & mi, Dimension & dim) const
 					 sym_->extra == "mathalpha" &&
 					 mi.base.fontname == "mathit";
 	std::string const font = italic_upcase_greek ? "cmm" : sym_->inset;
-	Changer dummy = mi.base.changeFontSet(from_ascii(font));
+	Changer dummy = mi.base.changeFontSet(font);
 	mathed_string_dim(mi.base.font, sym_->draw, dim);
 	docstring::const_reverse_iterator rit = sym_->draw.rbegin();
 	kerning_ = mathed_char_kerning(mi.base.font, *rit);
@@ -118,7 +118,7 @@ void InsetMathSymbol::draw(PainterInfo & pi, int x, int y) const
 	//else
 	//	x += support::iround(0.0833 * em);
 
-	Changer dummy = pi.base.changeFontSet(from_ascii(font));
+	Changer dummy = pi.base.changeFontSet(font);
 	pi.draw(x, y - h_, sym_->draw);
 }
 

src/mathed/MathData.cpp

@@ -285,7 +285,7 @@ void MathData::metrics(MetricsInfo & mi, Dimension & dim) const
 			continue;
 
 		FontInfo font = mi.base.font;
-		augmentFont(font, from_ascii("mathnormal"));
+		augmentFont(font, "mathnormal");
 		dim.wid += mathed_string_width(font, completion);
 	}
 	// Cache the dimension.
@@ -334,7 +334,7 @@ void MathData::draw(PainterInfo & pi, int x, int y) const
 		if (completion.length() == 0)
 			continue;
 		FontInfo f = pi.base.font;
-		augmentFont(f, from_ascii("mathnormal"));
+		augmentFont(f, "mathnormal");
 
 		// draw the unique and the non-unique completion part
 		// Note: this is not time-critical as it is

src/mathed/MathFactory.cpp

@@ -92,7 +92,7 @@ bool isMathFontAvailable(string & name)
 		return false;
 
 	FontInfo f;
-	augmentFont(f, from_ascii(name));
+	augmentFont(f, name);
 
 	// Do we have the font proper?
 	if (theFontLoader().available(f))
@@ -233,7 +233,7 @@ void initSymbols()
 		docstring help;
 		is >> tmp.name >> help;
 		tmp.inset = to_ascii(help);
-		if (isFontName(help))
+		if (isFontName(tmp.inset))
 			is >> charid >> fallbackid >> tmp.extra >> tmp.xmlname;
 		else
 			is >> tmp.extra;
@@ -253,7 +253,7 @@ void initSymbols()
 			continue;
 		}
 
-		if (isFontName(from_ascii(tmp.inset))) {
+		if (isFontName(tmp.inset)) {
 			// tmp.inset _is_ the fontname here.
 			// create fallbacks if necessary
 

src/mathed/MathMacro.cpp

@@ -433,7 +433,7 @@ void MathMacro::metrics(MetricsInfo & mi, Dimension & dim) const
 		if (lyxrc.macro_edit_style == LyXRC::MACRO_EDIT_INLINE_BOX
 		    && d->editing_[mi.base.bv]) {
 			FontInfo font = mi.base.font;
-			augmentFont(font, from_ascii("lyxtex"));
+			augmentFont(font, "lyxtex");
 			Dimension namedim;
 			mathed_string_dim(font, name(), namedim);
 #if 0
@@ -622,7 +622,7 @@ void MathMacro::draw(PainterInfo & pi, int x, int y) const
 		if (drawBox && d->editing_[pi.base.bv]) {
 			// draw header and rectangle around
 			FontInfo font = pi.base.font;
-			augmentFont(font, from_ascii("lyxtex"));
+			augmentFont(font, "lyxtex");
 			font.setSize(FONT_SIZE_TINY);
 			font.setColor(Color_mathmacrolabel);
 			Dimension namedim;

src/mathed/MathMacroTemplate.cpp

@@ -543,7 +543,7 @@ void MathMacroTemplate::createLook(int args) const
 
 void MathMacroTemplate::metrics(MetricsInfo & mi, Dimension & dim) const
 {
-	Changer dummy1 = mi.base.changeFontSet(from_ascii("mathnormal"));
+	Changer dummy1 = mi.base.changeFontSet("mathnormal");
 	Changer dummy2 = mi.base.changeStyle(LM_ST_TEXT);
 
 	// valid macro?
@@ -587,7 +587,7 @@ void MathMacroTemplate::draw(PainterInfo & pi, int x, int y) const
 {
 	// FIXME: Calling Changer on the same object repeatedly is inefficient.
 	Changer dummy0 = pi.base.font.changeColor(Color_math);
-	Changer dummy1 = pi.base.changeFontSet(from_ascii("mathnormal"));
+	Changer dummy1 = pi.base.changeFontSet("mathnormal");
 	Changer dummy2 = pi.base.changeStyle(LM_ST_TEXT);
 
 	setPosCache(pi, x, y);

src/mathed/MathSupport.cpp

@@ -659,7 +659,7 @@ void mathed_draw_deco(PainterInfo & pi, int x, int y, int w, int h,
 void metricsStrRedBlack(MetricsInfo & mi, Dimension & dim, docstring const & str)
 {
 	FontInfo font = mi.base.font;
-	augmentFont(font, from_ascii("mathnormal"));
+	augmentFont(font, "mathnormal");
 	mathed_string_dim(font, str, dim);
 }
 
@@ -667,7 +667,7 @@ void metricsStrRedBlack(MetricsInfo & mi, Dimension & dim, docstring const & str
 void drawStrRed(PainterInfo & pi, int x, int y, docstring const & str)
 {
 	FontInfo f = pi.base.font;
-	augmentFont(f, from_ascii("mathnormal"));
+	augmentFont(f, "mathnormal");
 	f.setColor(Color_latex);
 	pi.pain.text(x, y, str, f);
 }
@@ -676,7 +676,7 @@ void drawStrRed(PainterInfo & pi, int x, int y, docstring const & str)
 void drawStrBlack(PainterInfo & pi, int x, int y, docstring const & str)
 {
 	FontInfo f = pi.base.font;
-	augmentFont(f, from_ascii("mathnormal"));
+	augmentFont(f, "mathnormal");
 	f.setColor(Color_foreground);
 	pi.pain.text(x, y, str, f);
 }
@@ -806,11 +806,10 @@ fontinfo fontinfos[] = {
 };
 
 
-fontinfo * lookupFont(docstring const & name0)
+fontinfo * lookupFont(string const & name)
 {
 	//lyxerr << "searching font '" << name << "'" << endl;
 	int const n = sizeof(fontinfos) / sizeof(fontinfo);
-	string name = to_utf8(name0);
 	for (int i = 0; i < n; ++i)
 		if (fontinfos[i].cmd_ == name) {
 			//lyxerr << "found '" << i << "'" << endl;
@@ -820,7 +819,7 @@ fontinfo * lookupFont(docstring const & name0)
 }
 
 
-fontinfo * searchFont(docstring const & name)
+fontinfo * searchFont(string const & name)
 {
 	fontinfo * f = lookupFont(name);
 	return f ? f : fontinfos;
@@ -829,27 +828,27 @@ fontinfo * searchFont(docstring const & name)
 }
 
 
-bool isFontName(docstring const & name)
+bool isFontName(string const & name)
 {
 	return lookupFont(name);
 }
 
 
-bool isMathFont(docstring const & name)
+bool isMathFont(string const & name)
 {
 	fontinfo * f = lookupFont(name);
 	return f && f->color_ == Color_math;
 }
 
 
-bool isTextFont(docstring const & name)
+bool isTextFont(string const & name)
 {
 	fontinfo * f = lookupFont(name);
 	return f && f->color_ == Color_foreground;
 }
 
 
-FontInfo getFont(docstring const & name)
+FontInfo getFont(string const & name)
 {
 	FontInfo font;
 	augmentFont(font, name);
@@ -857,7 +856,7 @@ FontInfo getFont(docstring const & name)
 }
 
 
-void fakeFont(docstring const & orig, docstring const & fake)
+void fakeFont(string const & orig, string const & fake)
 {
 	fontinfo * forig = searchFont(orig);
 	fontinfo * ffake = searchFont(fake);
@@ -867,22 +866,22 @@ void fakeFont(docstring const & orig, docstring const & fake)
 		forig->shape_  = ffake->shape_;
 		forig->color_  = ffake->color_;
 	} else {
-		lyxerr << "Can't fake font '" << to_utf8(orig) << "' with '"
+		lyxerr << "Can't fake font '" << orig << "' with '"
-		       << to_utf8(fake) << "'" << endl;
+		       << fake << "'" << endl;
 	}
 }
 
 
-void augmentFont(FontInfo & font, docstring const & name)
+void augmentFont(FontInfo & font, string const & name)
 {
 	static bool initialized = false;
 	if (!initialized) {
 		initialized = true;
 		// fake fonts if necessary
-		if (!theFontLoader().available(getFont(from_ascii("mathfrak"))))
+		if (!theFontLoader().available(getFont("mathfrak")))
-			fakeFont(from_ascii("mathfrak"), from_ascii("lyxfakefrak"));
+			fakeFont("mathfrak", "lyxfakefrak");
-		if (!theFontLoader().available(getFont(from_ascii("mathcal"))))
+		if (!theFontLoader().available(getFont("mathcal")))
-			fakeFont(from_ascii("mathcal"), from_ascii("lyxfakecal"));
+			fakeFont("mathcal", "lyxfakecal");
 	}
 	fontinfo * info = searchFont(name);
 	if (info->family_ != inh_family)

src/mathed/MathSupport.h

@@ -55,13 +55,13 @@ void drawStrBlack(PainterInfo & pi, int x, int y, docstring const & s);
 
 void math_font_max_dim(FontInfo const &, int & asc, int & desc);
 
-void augmentFont(FontInfo & f, docstring const & cmd);
+void augmentFont(FontInfo & f, std::string const & cmd);
 
-bool isFontName(docstring const & name);
+bool isFontName(std::string const & name);
 
-bool isMathFont(docstring const & name);
+bool isMathFont(std::string const & name);
 
-bool isTextFont(docstring const & name);
+bool isTextFont(std::string const & name);
 
 bool isAlphaSymbol(MathAtom const & at);