QTextDocument: add setLayoutEnabled()

This allows to set up everything first - without paying for layouting
at every step - and only then trigger layouting.

Same performance behavior as setTextWidth(0), but this is a more
explicit/readable API.

Change-Id: I044dbd8b1301b1c97a92f9a29ccde2baf27a7665
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

1 files changed, 18 insertions, 0 deletions

diff --git a/tests/benchmarks/widgets/graphicsview/qgraphicsitem/tst_qgraphicsitem.cpp b/tests/benchmarks/widgets/graphicsview/qgraphicsitem/tst_qgraphicsitem.cpp
index 536d366b63..b8684610a8 100644
--- a/tests/benchmarks/widgets/graphicsview/qgraphicsitem/tst_qgraphicsitem.cpp
+++ b/tests/benchmarks/widgets/graphicsview/qgraphicsitem/tst_qgraphicsitem.cpp
@@ -35,6 +35,7 @@ private slots:
     void translate();
     void createTextItem();
     void createTextItemZeroWidth();
+    void createTextItemNoLayouting();
 };
 
 tst_QGraphicsItem::tst_QGraphicsItem()
@@ -235,5 +236,22 @@ void tst_QGraphicsItem::createTextItemZeroWidth()
     }
 }
 
+void tst_QGraphicsItem::createTextItemNoLayouting()
+{
+    // Ensure QFontDatabase loaded the font beforehand
+    QFontInfo(qApp->font()).family();
+    const QString text = "This is some text";
+    QBENCHMARK {
+        QGraphicsTextItem item;
+        item.document()->setLayoutEnabled(false);
+        // Prepare everything
+        item.setPlainText(text);
+        QTextOption option = item.document()->defaultTextOption();
+        option.setAlignment(Qt::AlignHCenter);
+        item.document()->setDefaultTextOption(option);
+        // And (in a real app) enable layouting here
+    }
+}
+
 QTEST_MAIN(tst_QGraphicsItem)
 #include "tst_qgraphicsitem.moc"