Re-implement text justification

* GuiFontMetrics::pos2x, x2pos: add support for inter-word spacing.
* GuiPainter::text: idem

* Row::Element::countSeparators:
  Row::countSeparators: new methods that count spaces in strings.
  Row::setSeparatorExtraWidth: new method (code lifted from TextMetrics.cpp).

* TextMetrics::computeRowMetrics: rely on the above methods.

* RowPainter::paintMispelledMarked: pass only a Row::Element object reference
  RowPainter::paintStringAndSel: idem; do not rely on values returned by
      Painter::text (trailing spaces do not honor wordspacing value).

src/Row.cpp

@@ -36,6 +36,15 @@ namespace lyx {
 using support::rtrim;
 using frontend::FontMetrics;
 
+
+int Row::Element::countSeparators() const
+{
+	if (type != STRING)
+		return 0;
+	return count(str.begin(), str.end(), ' ');
+}
+
+
 double Row::Element::pos2x(pos_type const i) const
 {
 	// This can happen with inline completion when clicking on the
@@ -54,7 +63,7 @@ double Row::Element::pos2x(pos_type const i) const
 		w = rtl ? full_width() : 0;
 	else {
 		FontMetrics const & fm = theFontMetrics(font);
-		w = fm.pos2x(str, i - pos, font.isVisibleRightToLeft());
+		w = fm.pos2x(str, i - pos, font.isVisibleRightToLeft(), extra);
 	}
 
 	return w;
@@ -70,7 +79,7 @@ pos_type Row::Element::x2pos(int &x) const
 	switch (type) {
 	case STRING: {
 		FontMetrics const & fm = theFontMetrics(font);
-		i = fm.x2pos(str, x, rtl);
+		i = fm.x2pos(str, x, rtl, extra);
 		break;
 	}
 	case VIRTUAL:
@@ -257,6 +266,26 @@ ostream & operator<<(ostream & os, Row const & row)
 }
 
 
+int Row::countSeparators() const
+{
+	int n = 0;
+	const_iterator const end = elements_.end();
+	for (const_iterator cit = elements_.begin() ; cit != end ; ++cit)
+		n += cit->countSeparators();
+	return n;
+}
+
+
+void Row::setSeparatorExtraWidth(double w)
+{
+	separator = w;
+	iterator const end = elements_.end();
+	for (iterator it = elements_.begin() ; it != end ; ++it)
+		if (it->type == Row::STRING)
+			it->extra = w;
+}
+
+
 bool Row::sameString(Font const & f, Change const & ch) const
 {
 	if (elements_.empty())

src/Row.h

@@ -76,7 +76,10 @@ public:
 			  extra(0), font(f), change(ch), final(false) {}
 
 		// Return total width of element, including separator overhead
-		double full_width() const { return dim.wid + extra; };
+		double full_width() const { return dim.wid + extra * countSeparators(); };
+		// Return the number of separator in the element (only STRING type)
+		int countSeparators() const;
+
 		/** Return position in pixels (from the left) of position
 		 * \param i in the row element.
 		 */
@@ -174,6 +177,11 @@ public:
 	///
 	int descent() const { return dim_.des; }
 
+	// Return the number of separators in the row
+	int countSeparators() const;
+	// Set the extra spacing for every separator in STRING elements
+	void setSeparatorExtraWidth(double w);
+
 	///
 	void add(pos_type pos, Inset const * ins, Dimension const & dim,
 		 Font const & f, Change const & ch);

src/RowPainter.cpp

@@ -186,14 +186,12 @@ void RowPainter::paintForeignMark(double orig_x, Language const * lang, int desc
 
 
 void RowPainter::paintMisspelledMark(double const orig_x,
-                                     docstring const & str, Font const & font,
+                                     Row::Element const & e) const
-                                     pos_type const start_pos,
-                                     bool const changed) const
 {
 	// if changed the misspelled marker gets placed slightly lower than normal
 	// to avoid drawing at the same vertical offset
 	int const y = yo_ + solid_line_offset_ + solid_line_thickness_
-		+ (changed ? solid_line_thickness_ + 1 : 0)
+		+ (e.change.changed() ? solid_line_thickness_ + 1 : 0)
 		+ dotted_line_offset_;
 
 	//FIXME: this could be computed only once, it is probably not costly.
@@ -210,8 +208,8 @@ void RowPainter::paintMisspelledMark(double const orig_x,
 			--cpos;
 	}
 
-	pos_type pos = start_pos;
+	pos_type pos = e.pos;
-	while (pos < start_pos + pos_type(str.length())) {
+	while (pos < e.pos + pos_type(e.str.length())) {
 		if (!par_.isMisspelled(pos)) {
 			++pos;
 			continue;
@@ -226,12 +224,12 @@ void RowPainter::paintMisspelledMark(double const orig_x,
 			continue;
 		}
 
-		FontMetrics const & fm = theFontMetrics(font);
+		FontMetrics const & fm = theFontMetrics(e.font);
-		int x1 = fm.pos2x(str, range.first - start_pos,
+		int x1 = fm.pos2x(e.str, range.first - e.pos,
-		                  font.isVisibleRightToLeft());
+		                  e.font.isVisibleRightToLeft(), e.extra);
-		int x2 = fm.pos2x(str, min(range.last - start_pos + 1,
+		int x2 = fm.pos2x(e.str, min(range.last - e.pos + 1,
-		                           pos_type(str.length())),
+									 pos_type(e.str.length())),
-		                  font.isVisibleRightToLeft());
+									 e.font.isVisibleRightToLeft(), e.extra);
 		if (x1 > x2)
 			swap(x1, x2);
 
@@ -243,32 +241,31 @@ void RowPainter::paintMisspelledMark(double const orig_x,
 }
 
 
-void RowPainter::paintStringAndSel(docstring const & str, Font const & font,
+void RowPainter::paintStringAndSel(Row::Element const & e)
-                                 Change const & change,
-                                 pos_type start_pos, pos_type end_pos)
 {
 	// at least part of text selected?
-	bool const some_sel = (end_pos >= row_.sel_beg && start_pos < row_.sel_end)
+	bool const some_sel = (e.endpos >= row_.sel_beg && e.pos < row_.sel_end)
 		|| pi_.selected;
 	// all the text selected?
-	bool const all_sel = (start_pos >= row_.sel_beg && end_pos < row_.sel_end)
+	bool const all_sel = (e.pos >= row_.sel_beg && e.endpos < row_.sel_end)
 		|| pi_.selected;
 
 	if (all_sel) {
-		Font copy = font;
+		Font copy = e.font;
 		copy.fontInfo().setPaintColor(Color_selectiontext);
-		x_ += pi_.pain.text(int(x_), yo_, str, copy);
+		pi_.pain.text(int(x_), yo_, e.str, copy, e.extra);
-	} else if (change.changed()) {
+	} else if (e.change.changed()) {
-		Font copy = font;
+		Font copy = e.font;
-		copy.fontInfo().setPaintColor(change.color());
+		copy.fontInfo().setPaintColor(e.change.color());
-		x_ += pi_.pain.text(int(x_), yo_, str, copy);
+		pi_.pain.text(int(x_), yo_, e.str, copy, e.extra);
 	} else if (!some_sel) {
-		x_ += pi_.pain.text(int(x_), yo_, str, font);
+		pi_.pain.text(int(x_), yo_, e.str, e.font, e.extra);
 	} else {
-		x_ += pi_.pain.text(int(x_), yo_, str, font, Color_selectiontext,
+		pi_.pain.text(int(x_), yo_, e.str, e.font, Color_selectiontext,
-				    max(row_.sel_beg, start_pos) - start_pos,
+				    max(row_.sel_beg, e.pos) - e.pos,
-				    min(row_.sel_end, end_pos) - start_pos);
+                        min(row_.sel_end, e.endpos) - e.pos, e.extra);
 	}
+	x_ += e.full_width();
 }
 
 
@@ -639,12 +636,12 @@ void RowPainter::paintText()
 		switch (e.type) {
 		case Row::STRING:
 		case Row::VIRTUAL:
-			paintStringAndSel(e.str, e.font, e.change, e.pos, e.endpos);
+			paintStringAndSel(e);
 
 			// Paint the spelling mark if needed.
 			if (lyxrc.spellcheck_continuously && pi_.do_spellcheck
 				&& par_.isMisspelled(e.pos)) {
-				paintMisspelledMark(orig_x, e.str, e.font, e.pos, e.change.changed());
+				paintMisspelledMark(orig_x, e);
 			}
 			break;
 		case Row::INSET: {

src/RowPainter.h

@@ -15,6 +15,7 @@
 #define ROWPAINTER_H
 
 #include "Changes.h"
+#include "Row.h"
 
 #include "support/types.h"
 
@@ -29,7 +30,6 @@ class PainterInfo;
 class Paragraph;
 class ParagraphList;
 class ParagraphMetrics;
-class Row;
 class Text;
 class TextMetrics;
 
@@ -60,12 +60,8 @@ public:
 private:
 	void paintSeparator(double width, Font const & font);
 	void paintForeignMark(double orig_x, Language const * lang, int desc = 0) const;
-	void paintStringAndSel(docstring const & str, Font const & font,
+	void paintStringAndSel(Row::Element const & e);
-                         Change const & change,
+	void paintMisspelledMark(double orig_x, Row::Element const & e) const;
-                         pos_type start_pos, pos_type end_pos);
-	void paintMisspelledMark(double orig_x,
-	                         docstring const & str, Font const & font,
-	                         pos_type pos, bool changed) const;
 	void paintChange(double orig_x , Font const & font, Change const & change) const;
 	int paintAppendixStart(int y) const;
 	void paintInset(Inset const * inset, Font const & font,

src/TextMetrics.cpp

@@ -58,28 +58,6 @@ using frontend::FontMetrics;
 
 namespace {
 
-int numberOfSeparators(Row const & row)
-{
-	int n = 0;
-	Row::const_iterator cit = row.begin();
-	Row::const_iterator const end = row.end();
-	for ( ; cit != end ; ++cit)
-		if (cit->type == Row::SEPARATOR)
-			++n;
-	return n;
-}
-
-
-void setSeparatorWidth(Row & row, double w)
-{
-	row.separator = w;
-	Row::iterator it = row.begin();
-	Row::iterator const end = row.end();
-	for ( ; it != end ; ++it)
-		if (it->type == Row::SEPARATOR)
-			it->extra = w;
-}
-
 
 int numberOfLabelHfills(Paragraph const & par, Row const & row)
 {
@@ -603,13 +581,13 @@ void TextMetrics::computeRowMetrics(pit_type const pit,
 		// set x how you need it
 		switch (getAlign(par, row.pos())) {
 		case LYX_ALIGN_BLOCK: {
-			int const ns = numberOfSeparators(row);
+			int const ns = row.countSeparators();
 			/** If we have separators, and this row has
 			 * not be broken abruptly by a display inset
 			 * or newline, then stretch it */
 			if (ns && !row.right_boundary()
 			    && row.endpos() != par.size()) {
-				setSeparatorWidth(row, double(w) / ns);
+				row.setSeparatorExtraWidth(double(w) / ns);
 				row.dimension().wid = width;
 			} else if (text_->isRTL(par)) {
 				row.dimension().wid = width;

src/frontends/FontMetrics.h

@@ -84,15 +84,19 @@ public:
 	 * return the x offset of a position in the string. The
 	 * direction of the string is forced, and the returned value
 	 * is from the left edge of the word, not from the start of the string.
+	 * \param rtl is true for right-to-left layout
+	 * \param ws is the amount of extra inter-word space applied text justication.
 	 */
-	virtual int pos2x(docstring const & s, int pos, bool rtl) const = 0;
+	virtual int pos2x(docstring const & s, int pos, bool rtl, double ws) const = 0;
 	/**
 	 * return the position in the string for a given x offset. The
 	 * direction of the string is forced, and the returned value
 	 * is from the left edge of the word, not from the start of the string.
 	 * the offset x is updated to match the closest position in the string.
+	 * \param rtl is true for right-to-left layout
+	 * \param ws is the amount of extra inter-word space applied text justication.
 	 */
-	virtual int x2pos(docstring const & s, int & x, bool rtl) const = 0;
+	virtual int x2pos(docstring const & s, int & x, bool rtl, double ws) const = 0;
 	/**
 	 * Break string at width at most x.
 	 * \return true if successful

src/frontends/Painter.h

@@ -120,13 +120,15 @@ public:
 	 * text direction is given by \c rtl.
 	 * \return the width of the drawn text.
 	 */
-	virtual int text(int x, int y, docstring const & str, FontInfo const & f, bool rtl = false) = 0;
+	virtual int text(int x, int y, docstring const & str, FontInfo const & f,
+                     bool rtl = false, double wordspacing = 0.0) = 0;
 
 	/** draw a string at position x, y (y is the baseline). The
 	 * text direction is enforced by the \c Font.
 	 * \return the width of the drawn text.
 	 */
-	virtual int text(int x, int y, docstring const & str, Font const & f) = 0;
+	virtual int text(int x, int y, docstring const & str, Font const & f,
+                     double wordspacing = 0.0) = 0;
 
 	/** draw a string at position x, y (y is the baseline), but
 	 * make sure that the part between \c from and \c to is in
@@ -134,7 +136,8 @@ public:
 	 * \return the width of the drawn text.
 	 */
 	virtual int text(int x, int y, docstring const & str, Font const & f,
-			 Color other, size_type from, size_type to) = 0;
+                     Color other, size_type from, size_type to,
+                     double const wordspacing) = 0;
 
 	void setDrawingEnabled(bool drawing_enabled)
 	{ drawing_enabled_ = drawing_enabled; }

src/frontends/qt4/GuiFontMetrics.cpp

@@ -150,10 +150,11 @@ int GuiFontMetrics::signedWidth(docstring const & s) const
 }
 
 namespace {
-void setTextLayout(QTextLayout & tl, docstring const & s, QFont const & font,
+void setTextLayout(QTextLayout & tl, docstring const & s, QFont font,
-			     bool const rtl)
+                   bool const rtl, double const wordspacing)
 {
 	tl.setText(toqstr(s));
+	font.setWordSpacing(wordspacing);
 	tl.setFont(font);
 	// Note that both setFlags and the enums are undocumented
 	tl.setFlags(rtl ? Qt::TextForceRightToLeft : Qt::TextForceLeftToRight);
@@ -164,18 +165,22 @@ void setTextLayout(QTextLayout & tl, docstring const & s, QFont const & font,
 }
 
 
-int GuiFontMetrics::pos2x(docstring const & s, int const pos, bool const rtl) const
+int GuiFontMetrics::pos2x(docstring const & s, int const pos, bool const rtl,
+                          double const wordspacing) const
 {
 	QTextLayout tl;
-	setTextLayout(tl, s, font_, rtl);
+	QFont copy = font_;
+	copy.setWordSpacing(wordspacing);
+	setTextLayout(tl, s, font_, rtl, wordspacing);
 	return static_cast<int>(tl.lineForTextPosition(pos).cursorToX(pos));
 }
 
 
-int GuiFontMetrics::x2pos(docstring const & s, int & x, bool const rtl) const
+int GuiFontMetrics::x2pos(docstring const & s, int & x, bool const rtl,
+                          double const wordspacing) const
 {
 	QTextLayout tl;
-	setTextLayout(tl, s, font_, rtl);
+	setTextLayout(tl, s, font_, rtl, wordspacing);
 	int pos = tl.lineForTextPosition(0).xToCursor(x);
 	// correct x value to the actual cursor position.
 	x = static_cast<int>(tl.lineForTextPosition(0).cursorToX(pos));

src/frontends/qt4/GuiFontMetrics.h

@@ -43,8 +43,8 @@ public:
 	virtual int rbearing(char_type c) const;
 	virtual int width(docstring const & s) const;
 	virtual int signedWidth(docstring const & s) const;
-	virtual int pos2x(docstring const & s, int pos, bool rtl) const;
+	virtual int pos2x(docstring const & s, int pos, bool rtl, double ws) const;
-	virtual int x2pos(docstring const & s, int & x, bool rtl) const;
+	virtual int x2pos(docstring const & s, int & x, bool rtl, double ws) const;
 	virtual bool breakAt(docstring & s, int & x, bool rtl, bool force) const;
 	virtual Dimension const dimension(char_type c) const;
 

src/frontends/qt4/GuiPainter.cpp

@@ -290,7 +290,8 @@ int GuiPainter::text(int x, int y, char_type c, FontInfo const & f)
 
 
 int GuiPainter::text(int x, int y, docstring const & s,
-		     FontInfo const & f, bool const rtl)
+                     FontInfo const & f, bool const rtl,
+                     double const wordspacing)
 {
 	//LYXERR0("text: x=" << x << ", s=" << s);
 	if (s.empty())
@@ -316,7 +317,8 @@ int GuiPainter::text(int x, int y, docstring const & s,
 		str = ' ' + str;
 #endif
 
-	QFont const & ff = getFont(f);
+	QFont ff = getFont(f);
+	ff.setWordSpacing(wordspacing);
 	GuiFontMetrics const & fm = getFontMetrics(f);
 
 	// Here we use the font width cache instead of
@@ -418,14 +420,16 @@ int GuiPainter::text(int x, int y, docstring const & s,
 }
 
 
-int GuiPainter::text(int x, int y, docstring const & str, Font const & f)
+int GuiPainter::text(int x, int y, docstring const & str, Font const & f,
+                     double const wordspacing)
 {
-	return text(x, y, str, f.fontInfo(), f.isVisibleRightToLeft());
+	return text(x, y, str, f.fontInfo(), f.isVisibleRightToLeft(), wordspacing);
 }
 
 
 int GuiPainter::text(int x, int y, docstring const & str, Font const & f,
-		     Color other, size_type from, size_type to)
+                     Color other, size_type const from, size_type const to,
+                     double const wordspacing)
 {
 	GuiFontMetrics const & fm = getFontMetrics(f.fontInfo());
 	FontInfo fi = f.fontInfo();
@@ -434,8 +438,8 @@ int GuiPainter::text(int x, int y, docstring const & str, Font const & f,
 	// dimensions
 	int const ascent = fm.maxAscent();
 	int const height = fm.maxAscent() + fm.maxDescent();
-	int xmin = fm.pos2x(str, from, rtl);
+	int xmin = fm.pos2x(str, from, rtl, wordspacing);
-	int xmax = fm.pos2x(str, to, rtl);
+	int xmax = fm.pos2x(str, to, rtl, wordspacing);
 	if (xmin > xmax)
 		swap(xmin, xmax);
 
@@ -444,7 +448,7 @@ int GuiPainter::text(int x, int y, docstring const & str, Font const & f,
 	fi.setPaintColor(other);
 	QRegion const clip(x + xmin, y - ascent, xmax - xmin, height);
 	setClipRegion(clip);
-	int const textwidth = text(x, y, str, fi, rtl);
+	int const textwidth = text(x, y, str, fi, rtl, wordspacing);
 
 	// Then the part in normal color
 	// Note that in Qt5, it is not possible to use Qt::UniteClip,
@@ -452,7 +456,7 @@ int GuiPainter::text(int x, int y, docstring const & str, Font const & f,
 	fi.setPaintColor(orig);
 	QRegion region(viewport());
 	setClipRegion(region - clip);
-	text(x, y, str, fi, rtl);
+	text(x, y, str, fi, rtl, wordspacing);
 	setClipping(false);
 
 	return textwidth;

src/frontends/qt4/GuiPainter.h

@@ -91,13 +91,15 @@ public:
 	 * text direction is given by \c rtl.
 	 * \return the width of the drawn text.
 	 */
-	virtual int text(int x, int y, docstring const & str, FontInfo const & f, bool rtl = false);
+	virtual int text(int x, int y, docstring const & str, FontInfo const & f,
+                     bool rtl = false, double wordspacing = 0.0);
 
 	/** draw a string at position x, y (y is the baseline). The
 	 * text direction is enforced by the \c Font.
 	 * \return the width of the drawn text.
 	 */
-	virtual int text(int x, int y, docstring const & str, Font const & f);
+	virtual int text(int x, int y, docstring const & str, Font const & f,
+                     double wordspacing = 0.0);
 
 	/** draw a string at position x, y (y is the baseline), but
 	 * make sure that the part between \c from and \c to is in
@@ -105,7 +107,8 @@ public:
 	 * \return the width of the drawn text.
 	 */
 	virtual int text(int x, int y, docstring const & str, Font const & f,
-			 Color other, size_type from, size_type to);
+                     Color other, size_type from, size_type to,
+                     double const wordspacing);
 
 	/// draw a char at position x, y (y is the baseline)
 	virtual int text(int x, int y, char_type c, FontInfo const & f);