QFrame: introduce initStyleOption (and use it)

For some reason lost in time QFrame was missing that method. Of course
that led to duplicated code and to subtle sizing miscalculations.

Task-number: QTBUG-29330
Change-Id: I81163f5def6661e01cb2ecc49c1169449a3e3758
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>

3 files changed, 129 insertions, 31 deletions

diff --git a/src/widgets/widgets/qframe.cpp b/src/widgets/widgets/qframe.cpp
index 57cd51396c..b914a80f1d 100644
--- a/src/widgets/widgets/qframe.cpp
+++ b/src/widgets/widgets/qframe.cpp
@@ -202,6 +202,49 @@ QFrame::QFrame(QFramePrivate &dd, QWidget* parent, Qt::WindowFlags f)
     d->init();
 }
 
+/*!
+    \since 5.5
+
+    Initializes \a option with the values from this QFrame. This method is
+    useful for subclasses when they need a QStyleOptionFrame but don't want to
+    fill in all the information themselves.
+
+    \sa QStyleOption::initFrom()
+*/
+void QFrame::initStyleOption(QStyleOptionFrame *option) const
+{
+    if (!option)
+        return;
+
+    Q_D(const QFrame);
+    option->initFrom(this);
+
+    int frameShape  = d->frameStyle & QFrame::Shape_Mask;
+    int frameShadow = d->frameStyle & QFrame::Shadow_Mask;
+    option->frameShape = Shape(int(option->frameShape) | frameShape);
+    option->rect = frameRect();
+    switch (frameShape) {
+        case QFrame::Box:
+        case QFrame::HLine:
+        case QFrame::VLine:
+        case QFrame::StyledPanel:
+        case QFrame::Panel:
+            option->lineWidth = d->lineWidth;
+            option->midLineWidth = d->midLineWidth;
+            break;
+        default:
+            // most frame styles do not handle customized line and midline widths
+            // (see updateFrameWidth()).
+            option->lineWidth = d->frameWidth;
+            break;
+    }
+
+    if (frameShadow == Sunken)
+        option->state |= QStyle::State_Sunken;
+    else if (frameShadow == Raised)
+        option->state |= QStyle::State_Raised;
+}
+
 
 /*!
   Destroys the frame.
@@ -362,10 +405,7 @@ void QFramePrivate::updateStyledFrameWidths()
 {
     Q_Q(const QFrame);
     QStyleOptionFrame opt;
-    opt.initFrom(q);
-    opt.lineWidth = lineWidth;
-    opt.midLineWidth = midLineWidth;
-    opt.frameShape = QFrame::Shape(frameStyle & QFrame::Shape_Mask);
+    q->initStyleOption(&opt);
 
     QRect cr = q->style()->subElementRect(QStyle::SE_ShapedFrameContents, &opt, q);
     leftFrameWidth = cr.left() - opt.rect.left();
@@ -472,34 +512,8 @@ void QFrame::paintEvent(QPaintEvent *)
  */
 void QFrame::drawFrame(QPainter *p)
 {
-    Q_D(QFrame);
     QStyleOptionFrame opt;
-    opt.init(this);
-    int frameShape  = d->frameStyle & QFrame::Shape_Mask;
-    int frameShadow = d->frameStyle & QFrame::Shadow_Mask;
-    opt.frameShape = Shape(int(opt.frameShape) | frameShape);
-    opt.rect = frameRect();
-    switch (frameShape) {
-        case QFrame::Box:
-        case QFrame::HLine:
-        case QFrame::VLine:
-        case QFrame::StyledPanel:
-        case QFrame::Panel:
-            opt.lineWidth = d->lineWidth;
-            opt.midLineWidth = d->midLineWidth;
-            break;
-        default:
-            // most frame styles do not handle customized line and midline widths
-            // (see updateFrameWidth()).
-            opt.lineWidth = d->frameWidth;
-            break;
-    }
-
-    if (frameShadow == Sunken)
-        opt.state |= QStyle::State_Sunken;
-    else if (frameShadow == Raised)
-        opt.state |= QStyle::State_Raised;
-
+    initStyleOption(&opt);
     style()->drawControl(QStyle::CE_ShapedFrame, &opt, p, this);
 }
 
diff --git a/src/widgets/widgets/qframe.h b/src/widgets/widgets/qframe.h
index ff04d70afc..70dd138ad1 100644
--- a/src/widgets/widgets/qframe.h
+++ b/src/widgets/widgets/qframe.h
@@ -40,6 +40,7 @@ QT_BEGIN_NAMESPACE
 
 
 class QFramePrivate;
+class QStyleOptionFrame;
 
 class Q_WIDGETS_EXPORT QFrame : public QWidget
 {
@@ -107,6 +108,7 @@ protected:
 
 protected:
     QFrame(QFramePrivate &dd, QWidget* parent = 0, Qt::WindowFlags f = 0);
+    void initStyleOption(QStyleOptionFrame *option) const;
 
 private:
     Q_DISABLE_COPY(QFrame)
diff --git a/tests/auto/widgets/widgets/qframe/tst_qframe.cpp b/tests/auto/widgets/widgets/qframe/tst_qframe.cpp
index fdd7f0afda..a94ea2ed68 100644
--- a/tests/auto/widgets/widgets/qframe/tst_qframe.cpp
+++ b/tests/auto/widgets/widgets/qframe/tst_qframe.cpp
@@ -34,12 +34,15 @@
 
 #include <QTest>
 #include <QFrame>
+#include <QStyleOptionFrame>
 
 class tst_QFrame : public QObject
 {
     Q_OBJECT
 private slots:
     void testDefaults();
+    void testInitStyleOption_data();
+    void testInitStyleOption();
 };
 
 Q_DECLARE_METATYPE(QFrame::Shape)
@@ -55,6 +58,85 @@ void tst_QFrame::testDefaults()
     QCOMPARE(frame.frameStyle(), int(QFrame::Box));
 }
 
+class Frame : public QFrame
+{
+public:
+    using QFrame::initStyleOption;
+};
+
+void tst_QFrame::testInitStyleOption_data()
+{
+    QTest::addColumn<QString>("basename");
+    QTest::addColumn<int>("lineWidth");
+    QTest::addColumn<int>("midLineWidth");
+    QTest::addColumn<QFrame::Shape>("shape");
+    QTest::addColumn<QFrame::Shadow>("shadow");
+
+    for (int lineWidth = 0; lineWidth < 3; ++lineWidth) {
+        for (int midLineWidth = 0; midLineWidth < 3; ++midLineWidth) {
+            QTest::newRow(qPrintable(QStringLiteral("box_noshadow_%1_%2").arg(lineWidth).arg(midLineWidth)))
+                    << "box_noshadow" << lineWidth << midLineWidth << QFrame::Box << (QFrame::Shadow)0;
+            QTest::newRow(qPrintable(QStringLiteral("box_plain_%1_%2").arg(lineWidth).arg(midLineWidth)))
+                    << "box_plain" << lineWidth << midLineWidth << QFrame::Box << QFrame::Plain;
+            QTest::newRow(qPrintable(QStringLiteral("box_raised_%1_%2").arg(lineWidth).arg(midLineWidth)))
+                    << "box_raised" << lineWidth << midLineWidth << QFrame::Box << QFrame::Raised;
+            QTest::newRow(qPrintable(QStringLiteral("box_sunken_%1_%2").arg(lineWidth).arg(midLineWidth)))
+                    << "box_sunken" << lineWidth << midLineWidth << QFrame::Box << QFrame::Sunken;
+
+            QTest::newRow(qPrintable(QStringLiteral("winpanel_noshadow_%1_%2").arg(lineWidth).arg(midLineWidth)))
+                    << "winpanel_noshadow" << lineWidth << midLineWidth << QFrame::WinPanel << (QFrame::Shadow)0;
+            QTest::newRow(qPrintable(QStringLiteral("winpanel_plain_%1_%2").arg(lineWidth).arg(midLineWidth)))
+                    << "winpanel_plain" << lineWidth << midLineWidth << QFrame::WinPanel << QFrame::Plain;
+            QTest::newRow(qPrintable(QStringLiteral("winpanel_raised_%1_%2").arg(lineWidth).arg(midLineWidth)))
+                    << "winpanel_raised" << lineWidth << midLineWidth << QFrame::WinPanel << QFrame::Raised;
+            QTest::newRow(qPrintable(QStringLiteral("winpanel_sunken_%1_%2").arg(lineWidth).arg(midLineWidth)))
+                    << "winpanel_sunken" << lineWidth << midLineWidth << QFrame::WinPanel << QFrame::Sunken;
+        }
+    }
+}
+
+void tst_QFrame::testInitStyleOption()
+{
+    QFETCH(QString, basename);
+    QFETCH(int, lineWidth);
+    QFETCH(int, midLineWidth);
+    QFETCH(QFrame::Shape, shape);
+    QFETCH(QFrame::Shadow, shadow);
+
+    Frame frame;
+    frame.setFrameStyle(shape | shadow);
+    frame.setLineWidth(lineWidth);
+    frame.setMidLineWidth(midLineWidth);
+    frame.resize(16, 16);
+
+    QStyleOptionFrame styleOption;
+    frame.initStyleOption(&styleOption);
+
+    switch (shape) {
+    case QFrame::Box:
+    case QFrame::Panel:
+    case QFrame::StyledPanel:
+    case QFrame::HLine:
+    case QFrame::VLine:
+        QCOMPARE(styleOption.lineWidth, lineWidth);
+        QCOMPARE(styleOption.midLineWidth, midLineWidth);
+        break;
+
+    case QFrame::NoFrame:
+    case QFrame::WinPanel:
+        QCOMPARE(styleOption.lineWidth, frame.frameWidth());
+        QCOMPARE(styleOption.midLineWidth, 0);
+        break;
+    }
+
+    QCOMPARE(styleOption.features, QStyleOptionFrame::None);
+    QCOMPARE(styleOption.frameShape, shape);
+    if (shadow == QFrame::Sunken)
+        QVERIFY(styleOption.state & QStyle::State_Sunken);
+    else if (shadow == QFrame::Raised)
+        QVERIFY(styleOption.state & QStyle::State_Raised);
+}
+
 QTEST_MAIN(tst_QFrame)
 
 #include "tst_qframe.moc"