Revert hacks in text rendering code path

There are a lot of hacks here and there in Qt trying to align the
text in a correct way which caused regressions to appear once
the default coordinate system changed. We need to remove these
hacks to get a more consistent and maintainable base. This also
fixes the regression introduced by changing the aliased coordinate
system.

Task-number: QTBUG-27667

Change-Id: I620db2ca23b7ff6c912f3a51e86e7e36bbef81f0
Reviewed-by: Samuel Rødal <samuel.rodal@digia.com>

2 files changed, 13 insertions, 4 deletions

diff --git a/src/gui/text/qtextengine.cpp b/src/gui/text/qtextengine.cpp
index 38fe2f8140..025d4289aa 100644
--- a/src/gui/text/qtextengine.cpp
+++ b/src/gui/text/qtextengine.cpp
@@ -3060,8 +3060,7 @@ void QTextEngine::drawItemDecorationList(QPainter *painter, const ItemDecoration
 
     foreach (const ItemDecoration &decoration, decorationList) {
         painter->setPen(decoration.pen);
-        QLineF line(decoration.x1, decoration.y, decoration.x2, decoration.y);
-        painter->drawLine(line);
+        painter->drawLine(QLineF(decoration.x1, decoration.y, decoration.x2, decoration.y));
     }
 }
 
@@ -3069,13 +3068,23 @@ void QTextEngine::drawDecorations(QPainter *painter)
 {
     QPen oldPen = painter->pen();
 
+    bool wasCompatiblePainting = painter->renderHints()
+            & QPainter::Qt4CompatiblePainting;
+
+    if (wasCompatiblePainting)
+        painter->setRenderHint(QPainter::Qt4CompatiblePainting, false);
+
     adjustUnderlines();
     drawItemDecorationList(painter, underlineList);
     drawItemDecorationList(painter, strikeOutList);
     drawItemDecorationList(painter, overlineList);
 
-    painter->setPen(oldPen);
     clearDecorations();
+
+    if (wasCompatiblePainting)
+        painter->setRenderHint(QPainter::Qt4CompatiblePainting);
+
+    painter->setPen(oldPen);
 }
 
 void QTextEngine::clearDecorations()
diff --git a/src/gui/text/qtextengine_p.h b/src/gui/text/qtextengine_p.h
index 82467229eb..aff5e1cb7f 100644
--- a/src/gui/text/qtextengine_p.h
+++ b/src/gui/text/qtextengine_p.h
@@ -390,7 +390,7 @@ struct Q_AUTOTEST_EXPORT QScriptLine
     mutable uint gridfitted : 1;
     uint hasTrailingSpaces : 1;
     uint leadingIncluded : 1;
-    QFixed height() const { return (ascent + descent).ceil()
+    QFixed height() const { return ascent + descent
                             + (leadingIncluded?  qMax(QFixed(),leading) : QFixed()); }
     QFixed base() const { return ascent
                           + (leadingIncluded ? qMax(QFixed(),leading) : QFixed()); }