Show nbsps as a degree symbol to differeniate from normal spaces

When using QTextOption::ShowTabsAndSpaces then spaces and nbsps
would appear the same. So since using the degree symbol to
illustrate nbsps is an accepted standard, we use that and spaces
are illustrated as before.

[ChangeLog][QtGui] Display non-breaking spaces as a degree symbol
when QTextOption::ShowTabsAndSpaces is used.

Task-number: QTBUG-57479
Change-Id: I20c72c9e1640457c034b87587a8975cb73228803
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>

4 files changed, 9 insertions, 6 deletions

diff --git a/src/gui/text/qtextengine.cpp b/src/gui/text/qtextengine.cpp
index 9169ed8da1..2d1f0fa823 100644
--- a/src/gui/text/qtextengine.cpp
+++ b/src/gui/text/qtextengine.cpp
@@ -2064,7 +2064,7 @@ void QTextEngine::itemize() const
         case QChar::Space:
         case QChar::Nbsp:
             if (option.flags() & QTextOption::ShowTabsAndSpaces) {
-                analysis->flags = QScriptAnalysis::Space;
+                analysis->flags = (*uc == QChar::Space) ? QScriptAnalysis::Space : QScriptAnalysis::Nbsp;
                 analysis->bidiLevel = bidi.baseLevel;
                 break;
             }
diff --git a/src/gui/text/qtextengine_p.h b/src/gui/text/qtextengine_p.h
index 42061deff5..e9187ea605 100644
--- a/src/gui/text/qtextengine_p.h
+++ b/src/gui/text/qtextengine_p.h
@@ -143,9 +143,10 @@ struct Q_AUTOTEST_EXPORT QScriptAnalysis
         LineOrParagraphSeparator = 4,
         Space = 5,
         SpaceTabOrObject = Space,
-        Tab = 6,
+        Nbsp = 6,
+        Tab = 7,
         TabOrObject = Tab,
-        Object = 7
+        Object = 8
     };
     enum BidiFlags {
         BidiBN = 1,
diff --git a/src/gui/text/qtextlayout.cpp b/src/gui/text/qtextlayout.cpp
index cd1990dfb9..860d1e8c7c 100644
--- a/src/gui/text/qtextlayout.cpp
+++ b/src/gui/text/qtextlayout.cpp
@@ -2610,12 +2610,13 @@ void QTextLine::draw(QPainter *p, const QPointF &pos, const QTextLayout::FormatR
             QPainterPrivate::get(p)->drawTextItem(pos, gf, eng);
         }
 
-        if (si.analysis.flags == QScriptAnalysis::Space
+        if ((si.analysis.flags == QScriptAnalysis::Space
+             || si.analysis.flags == QScriptAnalysis::Nbsp)
             && (eng->option.flags() & QTextOption::ShowTabsAndSpaces)) {
             QBrush c = format.foreground();
             if (c.style() != Qt::NoBrush)
                 p->setPen(c.color());
-            QChar visualSpace((ushort)0xb7);
+            QChar visualSpace(si.analysis.flags == QScriptAnalysis::Space ? (ushort)0xb7 : (ushort)0xb0);
             p->drawText(QPointF(iterator.x.toReal(), itemBaseLine.toReal()), visualSpace);
             p->setPen(pen);
         }
diff --git a/src/gui/text/qtextoption.cpp b/src/gui/text/qtextoption.cpp
index a3fa0e7351..2c2c05567f 100644
--- a/src/gui/text/qtextoption.cpp
+++ b/src/gui/text/qtextoption.cpp
@@ -307,7 +307,8 @@ QList<QTextOption::Tab> QTextOption::tabs() const
   \value IncludeTrailingSpaces When this option is set, QTextLine::naturalTextWidth() and naturalTextRect() will
                                return a value that includes the width of trailing spaces in the text; otherwise
                                this width is excluded.
-  \value ShowTabsAndSpaces Visualize spaces with little dots, and tabs with little arrows.
+  \value ShowTabsAndSpaces Visualize spaces with little dots, and tabs with little arrows. Non-breaking spaces are
+            shown differently to breaking spaces.
   \value ShowLineAndParagraphSeparators Visualize line and paragraph separators with appropriate symbol characters.
   \value ShowDocumentTerminator Visualize the end of the document with a section sign. This enum value was added
             in Qt 5.7.