Make sure propagated font in QGraphicsWidget can be set on a QPainter

In QWidget and QGraphicsWidget, propagating fonts blank out the resolve
mask, mainly to help in determining inheritance. This means that when
the font is set on a QPainter with device and therefore resolved against
the device font, none of the attributes in the font will take presedence
and the font will essentially just be ignored. For QWidgets this has not
been a problem due to the fact that the painter is opened on the widget,
getting the propagated font as its device font. For QGraphicsWidget,
however, the QPainter is opened on the viewport and the viewport's font
will therefore override the propagated font when it's passed into
setFont(). To fix this, we need the font returned by
QGraphicsWidget::font() to contain the resolve mask of the inherited
parts of its font as well. This is done last minute to avoid messing
up the rules of inheritance in the QGraphicsWidget tree (problem arises
e.g. in hierarchy A -> B -> C and a font is set on B which should override
the font C has previously inherited from A.)

Task-number: QTBUG-13188
Reviewed-by: Lars

3 files changed, 200 insertions, 2 deletions

diff --git a/src/gui/graphicsview/qgraphicswidget.cpp b/src/gui/graphicsview/qgraphicswidget.cpp
index 0fabd18..1bfe266 100644
--- a/src/gui/graphicsview/qgraphicswidget.cpp
+++ b/src/gui/graphicsview/qgraphicswidget.cpp
@@ -937,7 +937,9 @@ void QGraphicsWidget::setStyle(QStyle *style)
 QFont QGraphicsWidget::font() const
 {
     Q_D(const QGraphicsWidget);
-    return d->font;
+    QFont fnt = d->font;
+    fnt.resolve(fnt.resolve() | d->inheritedFontResolveMask);
+    return fnt;
 }
 void QGraphicsWidget::setFont(const QFont &font)
 {
diff --git a/src/gui/graphicsview/qgraphicswidget_p.cpp b/src/gui/graphicsview/qgraphicswidget_p.cpp
index f7850ca..3466733 100644
--- a/src/gui/graphicsview/qgraphicswidget_p.cpp
+++ b/src/gui/graphicsview/qgraphicswidget_p.cpp
@@ -254,7 +254,10 @@ void QGraphicsWidgetPrivate::setFont_helper(const QFont &font)
 
 void QGraphicsWidgetPrivate::resolveFont(uint inheritedMask)
 {
+    Q_Q(QGraphicsWidget);
     inheritedFontResolveMask = inheritedMask;
+    if (QGraphicsWidget *p = q->parentWidget())
+        inheritedFontResolveMask |= p->d_func()->inheritedFontResolveMask;
     QFont naturalFont = naturalWidgetFont();
     QFont resolvedFont = font.resolve(naturalFont);
     updateFont(resolvedFont);
diff --git a/tests/auto/qgraphicswidget/tst_qgraphicswidget.cpp b/tests/auto/qgraphicswidget/tst_qgraphicswidget.cpp
index e5628d1..ddc4f73 100644
--- a/tests/auto/qgraphicswidget/tst_qgraphicswidget.cpp
+++ b/tests/auto/qgraphicswidget/tst_qgraphicswidget.cpp
@@ -172,6 +172,12 @@ private slots:
     void itemChangeEvents();
     void itemSendGeometryPosChangesDeactivated();
 
+    void fontPropagatesResolveToChildren();
+    void fontPropagatesResolveToGrandChildren();
+    void fontPropagatesResolveInParentChange();
+    void fontPropagatesResolveViaNonWidget();
+    void fontPropagatesResolveFromScene();
+
     // Task fixes
     void task236127_bspTreeIndexFails();
     void task243004_setStyleCrash();
@@ -622,6 +628,192 @@ void tst_QGraphicsWidget::font()
     QCOMPARE(widget.font().family(), font.family());
 }
 
+void tst_QGraphicsWidget::fontPropagatesResolveToChildren()
+{
+    QGraphicsWidget *root = new QGraphicsWidget();
+    QGraphicsWidget *child1 = new QGraphicsWidget(root);
+
+    QGraphicsScene scene;
+    scene.addItem(root);
+
+    QFont font;
+    font.setItalic(true);
+    root->setFont(font);
+
+    QGraphicsWidget *child2 = new QGraphicsWidget(root);
+    QGraphicsWidget *child3 = new QGraphicsWidget();
+    child3->setParentItem(root);
+
+    QGraphicsView view;
+    view.setScene(&scene);
+    view.show();
+    QTest::qWaitForWindowShown(&view);
+
+    QCOMPARE(font.resolve(), uint(QFont::StyleResolved));
+    QCOMPARE(root->font().resolve(), uint(QFont::StyleResolved));
+    QCOMPARE(child1->font().resolve(), uint(QFont::StyleResolved));
+    QCOMPARE(child2->font().resolve(), uint(QFont::StyleResolved));
+    QCOMPARE(child3->font().resolve(), uint(QFont::StyleResolved));
+}
+
+void tst_QGraphicsWidget::fontPropagatesResolveToGrandChildren()
+{
+    QGraphicsWidget *root = new QGraphicsWidget();
+    QGraphicsWidget *child1 = new QGraphicsWidget(root);
+    QGraphicsWidget *grandChild1 = new QGraphicsWidget(child1);
+
+    QGraphicsScene scene;
+    scene.addItem(root);
+
+    QFont font;
+    font.setItalic(true);
+    root->setFont(font);
+
+    QGraphicsWidget *child2 = new QGraphicsWidget(root);
+    QGraphicsWidget *grandChild2 = new QGraphicsWidget(child2);
+    QGraphicsWidget *grandChild3 = new QGraphicsWidget(child2);
+
+    QGraphicsWidget *child3 = new QGraphicsWidget();
+    QGraphicsWidget *grandChild4 = new QGraphicsWidget(child3);
+    QGraphicsWidget *grandChild5 = new QGraphicsWidget(child3);
+    child3->setParentItem(root);
+    grandChild5->setParentItem(child3);
+
+    QGraphicsView view;
+    view.setScene(&scene);
+    view.show();
+    QTest::qWaitForWindowShown(&view);
+
+    QCOMPARE(font.resolve(), uint(QFont::StyleResolved));
+    QCOMPARE(grandChild1->font().resolve(), uint(QFont::StyleResolved));
+    QCOMPARE(grandChild2->font().resolve(), uint(QFont::StyleResolved));
+    QCOMPARE(grandChild3->font().resolve(), uint(QFont::StyleResolved));
+    QCOMPARE(grandChild4->font().resolve(), uint(QFont::StyleResolved));
+    QCOMPARE(grandChild5->font().resolve(), uint(QFont::StyleResolved));
+}
+
+void tst_QGraphicsWidget::fontPropagatesResolveViaNonWidget()
+{
+    QGraphicsWidget *root = new QGraphicsWidget();
+    QGraphicsPixmapItem *child1 = new QGraphicsPixmapItem(root);
+    QGraphicsWidget *grandChild1 = new QGraphicsWidget(child1);
+
+    QGraphicsScene scene;
+    scene.addItem(root);
+
+    QFont font;
+    font.setItalic(true);
+    root->setFont(font);
+
+    QGraphicsPixmapItem *child2 = new QGraphicsPixmapItem(root);
+    QGraphicsWidget *grandChild2 = new QGraphicsWidget(child2);
+    QGraphicsWidget *grandChild3 = new QGraphicsWidget(child2);
+
+    QGraphicsPixmapItem *child3 = new QGraphicsPixmapItem();
+    QGraphicsWidget *grandChild4 = new QGraphicsWidget(child3);
+    QGraphicsWidget *grandChild5 = new QGraphicsWidget(child3);
+    child3->setParentItem(root);
+    grandChild5->setParentItem(child3);
+
+    QGraphicsView view;
+    view.setScene(&scene);
+    view.show();
+    QTest::qWaitForWindowShown(&view);
+
+    QCOMPARE(font.resolve(), uint(QFont::StyleResolved));
+    QCOMPARE(grandChild1->font().resolve(), uint(QFont::StyleResolved));
+    QCOMPARE(grandChild2->font().resolve(), uint(QFont::StyleResolved));
+    QCOMPARE(grandChild3->font().resolve(), uint(QFont::StyleResolved));
+    QCOMPARE(grandChild4->font().resolve(), uint(QFont::StyleResolved));
+    QCOMPARE(grandChild5->font().resolve(), uint(QFont::StyleResolved));
+}
+
+void tst_QGraphicsWidget::fontPropagatesResolveFromScene()
+{
+    QGraphicsWidget *root = new QGraphicsWidget();
+    QGraphicsWidget *child1 = new QGraphicsWidget(root);
+    QGraphicsWidget *grandChild1 = new QGraphicsWidget(child1);
+
+    QGraphicsScene scene;
+    scene.addItem(root);
+
+    QFont font;
+    font.setItalic(true);
+    scene.setFont(font);
+
+    QGraphicsWidget *child2 = new QGraphicsWidget(root);
+    QGraphicsWidget *grandChild2 = new QGraphicsWidget(child2);
+    QGraphicsWidget *grandChild3 = new QGraphicsWidget(child2);
+
+    QGraphicsWidget *child3 = new QGraphicsWidget();
+    QGraphicsWidget *grandChild4 = new QGraphicsWidget(child3);
+    QGraphicsWidget *grandChild5 = new QGraphicsWidget(child3);
+    child3->setParentItem(root);
+    grandChild5->setParentItem(child3);
+
+    QGraphicsView view;
+    view.setScene(&scene);
+    view.show();
+    QTest::qWaitForWindowShown(&view);
+
+    QCOMPARE(font.resolve(), uint(QFont::StyleResolved));
+    QCOMPARE(root->font().resolve(), uint(QFont::StyleResolved));
+    QCOMPARE(child1->font().resolve(), uint(QFont::StyleResolved));
+    QCOMPARE(child2->font().resolve(), uint(QFont::StyleResolved));
+    QCOMPARE(child3->font().resolve(), uint(QFont::StyleResolved));
+    QCOMPARE(grandChild1->font().resolve(), uint(QFont::StyleResolved));
+    QCOMPARE(grandChild2->font().resolve(), uint(QFont::StyleResolved));
+    QCOMPARE(grandChild3->font().resolve(), uint(QFont::StyleResolved));
+    QCOMPARE(grandChild4->font().resolve(), uint(QFont::StyleResolved));
+    QCOMPARE(grandChild5->font().resolve(), uint(QFont::StyleResolved));
+}
+
+void tst_QGraphicsWidget::fontPropagatesResolveInParentChange()
+{
+    QGraphicsWidget *root = new QGraphicsWidget();
+
+    QGraphicsWidget *child1 = new QGraphicsWidget(root);
+    QGraphicsWidget *grandChild1 = new QGraphicsWidget(child1);
+
+    QGraphicsWidget *child2 = new QGraphicsWidget(root);
+    QGraphicsWidget *grandChild2 = new QGraphicsWidget(child2);
+
+    QGraphicsScene scene;
+    scene.addItem(root);
+
+    QFont italicFont;
+    italicFont.setItalic(true);
+    child1->setFont(italicFont);
+
+    QFont boldFont;
+    boldFont.setBold(true);
+    child2->setFont(boldFont);
+
+    QVERIFY(grandChild1->font().italic());
+    QVERIFY(!grandChild1->font().bold());
+    QVERIFY(!grandChild2->font().italic());
+    QVERIFY(grandChild2->font().bold());
+
+    QCOMPARE(grandChild1->font().resolve(), uint(QFont::StyleResolved));
+    QCOMPARE(grandChild2->font().resolve(), uint(QFont::WeightResolved));
+
+    grandChild2->setParentItem(child1);
+
+    QGraphicsView view;
+    view.setScene(&scene);
+    view.show();
+    QTest::qWaitForWindowShown(&view);
+
+    QVERIFY(grandChild1->font().italic());
+    QVERIFY(!grandChild1->font().bold());
+    QVERIFY(grandChild2->font().italic());
+    QVERIFY(!grandChild2->font().bold());
+
+    QCOMPARE(grandChild1->font().resolve(), uint(QFont::StyleResolved));
+    QCOMPARE(grandChild2->font().resolve(), uint(QFont::StyleResolved));
+
+}
+
 void tst_QGraphicsWidget::fontPropagation()
 {
     QGraphicsWidget *root = new QGraphicsWidget;
@@ -728,11 +920,12 @@ void tst_QGraphicsWidget::fontPropagationWidgetItemWidget()
     widget->setFont(font);
 
     QCOMPARE(widget2->font().pointSize(), 43);
-    QCOMPARE(widget2->font().resolve(), QFont().resolve());
+    QCOMPARE(widget2->font().resolve(), uint(QFont::SizeResolved));
 
     widget->setFont(QFont());
 
     QCOMPARE(widget2->font().pointSize(), qApp->font().pointSize());
+    QCOMPARE(widget2->font().resolve(), QFont().resolve());
 }
 
 void tst_QGraphicsWidget::fontPropagationSceneChange()