Fix horizontal centered text drawing without word wrap

In this case we can't use line width to align the text, we have to
use the rectangle width given in QPainter::drawText for alignment
instead.

Reviewed-by: Eskil
(cherry picked from commit b92a31da01ee50fed4b10282e79f812167faf659)

4 files changed, 30 insertions, 23 deletions

diff --git a/src/gui/painting/qpainter.cpp b/src/gui/painting/qpainter.cpp
index 14fb772..64ef549 100644
--- a/src/gui/painting/qpainter.cpp
+++ b/src/gui/painting/qpainter.cpp
@@ -8149,10 +8149,6 @@ start_lengthVariant:
     engine.option.setTextDirection(layout_direction);
     if (tf & Qt::AlignJustify)
         engine.option.setAlignment(Qt::AlignJustify);
-    else if (tf & Qt::AlignRight)
-        engine.option.setAlignment(Qt::AlignRight);
-    else if (tf & Qt::AlignHCenter)
-        engine.option.setAlignment(Qt::AlignHCenter);
     else
         engine.option.setAlignment(Qt::AlignLeft); // do not do alignment twice
 
@@ -8248,7 +8244,18 @@ start_lengthVariant:
 
         for (int i = 0; i < textLayout.lineCount(); i++) {
             QTextLine line = textLayout.lineAt(i);
-            line.draw(painter, QPointF(r.x(), r.y() + yoff));
+
+            qreal advance = line.horizontalAdvance();
+            xoff = 0;
+            if (tf & Qt::AlignRight) {
+                QTextEngine *eng = textLayout.engine();
+                xoff = r.width() - advance -
+                    eng->leadingSpaceWidth(eng->lines[line.lineNumber()]).toReal();
+            }
+            else if (tf & Qt::AlignHCenter)
+                xoff = (r.width() - advance) / 2;
+
+            line.draw(painter, QPointF(r.x() + xoff, r.y() + yoff));
         }
 
         if (restore) {
diff --git a/src/gui/text/qtextengine.cpp b/src/gui/text/qtextengine.cpp
index a63fdbf..6aa333c 100644
--- a/src/gui/text/qtextengine.cpp
+++ b/src/gui/text/qtextengine.cpp
@@ -2725,6 +2725,22 @@ void QTextEngine::resolveAdditionalFormats() const
     specialData->resolvedFormatIndices = indices;
 }
 
+QFixed QTextEngine::leadingSpaceWidth(const QScriptLine &line)
+{
+    if (!line.hasTrailingSpaces
+        || (option.flags() & QTextOption::IncludeTrailingSpaces)
+        || !isRightToLeft())
+        return QFixed();
+
+    int pos = line.length;
+    const HB_CharAttributes *attributes = this->attributes();
+    if (!attributes)
+        return QFixed();
+    while (pos > 0 && attributes[line.from + pos - 1].whiteSpace)
+        --pos;
+    return width(line.from + pos, line.length - pos);
+}
+
 QStackTextEngine::QStackTextEngine(const QString &string, const QFont &f)
     : QTextEngine(string, f),
       _layoutData(string, _memory, MemSize)
diff --git a/src/gui/text/qtextengine_p.h b/src/gui/text/qtextengine_p.h
index 50d1ff8..366c5c3 100644
--- a/src/gui/text/qtextengine_p.h
+++ b/src/gui/text/qtextengine_p.h
@@ -609,6 +609,7 @@ public:
     QString elidedText(Qt::TextElideMode mode, const QFixed &width, int flags = 0) const;
 
     void shapeLine(const QScriptLine &line);
+    QFixed leadingSpaceWidth(const QScriptLine &line);
 
 private:
     void setBoundary(int strPos) const;
diff --git a/src/gui/text/qtextlayout.cpp b/src/gui/text/qtextlayout.cpp
index 8eff7d2..afe6949 100644
--- a/src/gui/text/qtextlayout.cpp
+++ b/src/gui/text/qtextlayout.cpp
@@ -66,23 +66,6 @@ QT_BEGIN_NAMESPACE
 #define SuppressText 0x5012
 #define SuppressBackground 0x513
 
-static inline QFixed leadingSpaceWidth(QTextEngine *eng, const QScriptLine &line)
-{
-    if (!line.hasTrailingSpaces
-        || (eng->option.flags() & QTextOption::IncludeTrailingSpaces)
-        || !(eng->option.alignment() & Qt::AlignRight)
-        || !eng->isRightToLeft())
-        return QFixed();
-
-    int pos = line.length;
-    const HB_CharAttributes *attributes = eng->attributes();
-    if (!attributes)
-        return QFixed();
-    while (pos > 0 && attributes[line.from + pos - 1].whiteSpace)
-        --pos;
-    return eng->width(line.from + pos, line.length - pos);
-}
-
 static QFixed alignLine(QTextEngine *eng, const QScriptLine &line)
 {
     QFixed x = 0;
@@ -93,7 +76,7 @@ static QFixed alignLine(QTextEngine *eng, const QScriptLine &line)
         if (align & Qt::AlignJustify && eng->isRightToLeft())
             align = Qt::AlignRight;
         if (align & Qt::AlignRight)
-            x = line.width - (line.textAdvance + leadingSpaceWidth(eng, line));
+            x = line.width - (line.textAdvance + eng->leadingSpaceWidth(line));
         else if (align & Qt::AlignHCenter)
             x = (line.width - line.textAdvance)/2;
     }