Revert optimization where several words are drawn at the same time

This can only be done where splitting of string is identical in row breaking and display. It will be possible to reintroduce this when row painting uses the tokenized row information.

00README_STR_METRICS_BRANCH

@@ -39,10 +39,6 @@ What is done:
 
 * Draw also RtL text string-wise. This speeds-up drawing.
 
-* Do not cut strings at separators in RowPainter when text is not
-  justified. This speeds-up painting by reducing the number of strings
-  to draw.
-
 * Do not cut strings at selection boundary in RowPainter. This avoids
   ligature/kerning breaking in latin text, and bad rendering problems
   in Arabic.

src/TextMetrics.cpp

@@ -565,7 +565,7 @@ void TextMetrics::computeRowMetrics(pit_type const pit,
 
 	Paragraph const & par = text_->getPar(pit);
 
-	double w = width - row.right_margin - row.width();
+	double const w = width - row.right_margin - row.width();
 	// FIXME: put back this assertion when the crash on new doc is solved.
 	//LASSERT(w >= 0, /**/);
 
@@ -607,9 +607,7 @@ void TextMetrics::computeRowMetrics(pit_type const pit,
 	} else if (int(row.width()) < max_width_) {
 		// is it block, flushleft or flushright?
 		// set x how you need it
-		int const align = getAlign(par, row.pos());
-
-		switch (align) {
+		switch (getAlign(par, row.pos())) {
 		case LYX_ALIGN_BLOCK: {
 			int const ns = numberOfSeparators(row);
 			/** If we have separators, and this row has
@@ -650,12 +648,12 @@ void TextMetrics::computeRowMetrics(pit_type const pit,
 	}
 #endif
 
+	// Finally,  handle hfill insets
 	pos_type const endpos = row.endpos();
 	pos_type body_pos = par.beginOfBody();
 	if (body_pos > 0
 	    && (body_pos > endpos || !par.isLineSeparator(body_pos - 1)))
 		body_pos = 0;
-
 	ParagraphMetrics & pm = par_metrics_[pit];
 	Row::iterator cit = row.begin();
 	Row::iterator const cend = row.end();
@@ -798,8 +796,7 @@ void TextMetrics::breakRow(Row & row, int const right_margin, pit_type const pit
 	int const width = max_width_ - right_margin;
 	pos_type const body_pos = par.beginOfBody();
 	row.clear();
-	row.x = leftMargin(max_width_, pit, pos);
-	row.dimension().wid = row.x;
+	row.dimension().wid = leftMargin(max_width_, pit, pos);
 	row.right_margin = right_margin;
 
 	if (pos >= end || row.width() > width) {

src/frontends/qt4/GuiPainter.cpp

@@ -273,14 +273,14 @@ void GuiPainter::image(int x, int y, int w, int h, graphics::Image const & i)
 
 int GuiPainter::text(int x, int y, char_type c, FontInfo const & f)
 {
-	docstring s(1, c);
-	return text(x, y, s, f);
+	return text(x, y, docstring(1, c), f);
 }
 
 
 int GuiPainter::text(int x, int y, docstring const & s,
 		FontInfo const & f)
 {
+	//LYXERR0("text: x=" << x << ", s=" << s);
 	if (s.empty())
 		return 0;
 

src/rowpainter.cpp

@@ -186,16 +186,15 @@ void RowPainter::paintChars(pos_type & vpos, Font const & font)
 	}
 	str.push_back(c);
 
-	pos_type const end = row_.endpos();
 	FontSpan const font_span = par_.fontSpan(pos);
 	// Track-change status.
 	Change const & change_running = par_.lookupChange(pos);
-
 	// spelling correct?
 	bool const spell_state =
 		lyxrc.spellcheck_continuously && par_.isMisspelled(pos);
 
 	// collect as much similar chars as we can
+	pos_type const end = row_.endpos();
 	for (++vpos ; vpos < end ; ++vpos) {
 		pos = bidi_.vis2log(vpos);
 
@@ -218,11 +217,7 @@ void RowPainter::paintChars(pos_type & vpos, Font const & font)
 		if (c == '\t')
 			break;
 
-		// When row_.separator == 0, it is possible to print a
-		// string longer than a word in one fell swoop.
-		// Therefore there is no need to break at spaces.
-		if (!isPrintableNonspace(c)
-		    && (c != ' ' || row_.separator > 0))
+		if (!isPrintableNonspace(c))
 			break;
 
 		// FIXME: Why only round brackets and why the difference to
@@ -707,6 +702,7 @@ void RowPainter::paintOnlyInsets()
 
 void RowPainter::paintText()
 {
+	//LYXERR0("-------------------------------------------------------");
 	pos_type const end = row_.endpos();
 	// Spaces at logical line breaks in bidi text must be skipped during
 	// painting. However, they may appear visually in the middle