Fix whatsThis breakage when using custom style sheet font

When setting a large font using style sheets, the whats this
popup size calculation would be incorrect resulting in
half visible lables. By calling ensurePolished before showing the
label, we ensure that this will be properly handled.

We also added a new test case for whatsThis in tst_qtooltip

Task-number: QTBUG-2416
Reviewed-by: ogoffart

2 files changed, 23 insertions, 1 deletions

diff --git a/src/gui/kernel/qwhatsthis.cpp b/src/gui/kernel/qwhatsthis.cpp
index 5e5e56f..0da3a9b 100644
--- a/src/gui/kernel/qwhatsthis.cpp
+++ b/src/gui/kernel/qwhatsthis.cpp
@@ -194,9 +194,9 @@ QWhatsThat::QWhatsThat(const QString& txt, QWidget* parent, QWidget *showTextFor
 #ifndef QT_NO_CURSOR
     setCursor(Qt::ArrowCursor);
 #endif
-
     QRect r;
     doc = 0;
+    ensurePolished(); // Ensures style sheet font before size calc
     if (Qt::mightBeRichText(text)) {
         doc = new QTextDocument();
         doc->setUndoRedoEnabled(false);
diff --git a/tests/auto/qtooltip/tst_qtooltip.cpp b/tests/auto/qtooltip/tst_qtooltip.cpp
index 283effa..fc76069 100644
--- a/tests/auto/qtooltip/tst_qtooltip.cpp
+++ b/tests/auto/qtooltip/tst_qtooltip.cpp
@@ -66,6 +66,7 @@ private slots:
     // task-specific tests below me
     void task183679_data();
     void task183679();
+    void whatsThis();
     void setPalette();
 };
 
@@ -131,6 +132,27 @@ void tst_QToolTip::task183679()
     QCOMPARE(QToolTip::isVisible(), visible);
 }
 
+#include <QWhatsThis>
+
+void tst_QToolTip::whatsThis()
+{
+    qApp->setStyleSheet( "QWidget { font-size: 72px; }" );
+    QWhatsThis::showText(QPoint(0,0), "THis is text");
+    QTest::qWait(400);	
+    QWidget *whatsthis = 0;
+    foreach (QWidget *widget, QApplication::topLevelWidgets()) {
+        if (widget->inherits("QWhatsThat")) {
+            whatsthis = widget;
+            break;
+        }
+    }
+    QVERIFY(whatsthis);
+    QVERIFY(whatsthis->isVisible());
+    QVERIFY(whatsthis->height() > 100); // Test QTBUG-2416
+    qApp->setStyleSheet("");
+}
+
+
 void tst_QToolTip::setPalette()
 {
     //the previous test may still have a tooltip pending for deletion