Teach Rectangle's gradient property to accept QGradient::Preset

Change-Id: Id640b596c1d8d52221f2f2be8807d6e245971bdc
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

8 files changed, 136 insertions, 28 deletions

diff --git a/src/quick/doc/snippets/qml/rectangle/rectangle-gradient.qml b/src/quick/doc/snippets/qml/rectangle/rectangle-gradient.qml
index 031bee960d..e52a0ce0ef 100644
--- a/src/quick/doc/snippets/qml/rectangle/rectangle-gradient.qml
+++ b/src/quick/doc/snippets/qml/rectangle/rectangle-gradient.qml
@@ -80,5 +80,17 @@ Rectangle {
     }
 }
 //! [rectangles]
+
+//! [presets]
+Rectangle {
+    y: 0; width: 80; height: 80
+    gradient: Gradient.NightFade
+}
+
+Rectangle {
+    y: 0; width: 80; height: 80
+    gradient: "NightFade"
+}
+//! [presets]
 }
 }
diff --git a/src/quick/items/qquickrectangle.cpp b/src/quick/items/qquickrectangle.cpp
index ab8203d0a8..5e217dcd0c 100644
--- a/src/quick/items/qquickrectangle.cpp
+++ b/src/quick/items/qquickrectangle.cpp
@@ -40,9 +40,13 @@
 #include "qquickrectangle_p.h"
 #include "qquickrectangle_p_p.h"
 
+#include <QtQml/qqmlinfo.h>
+
 #include <QtQuick/private/qsgcontext_p.h>
 #include <private/qsgadaptationlayer_p.h>
 
+#include <private/qqmlmetatype_p.h>
+
 #include <QtGui/qpixmapcache.h>
 #include <QtCore/qmath.h>
 #include <QtCore/qmetaobject.h>
@@ -393,7 +397,7 @@ QQuickPen *QQuickRectangle::border()
 }
 
 /*!
-    \qmlproperty Gradient QtQuick::Rectangle::gradient
+    \qmlproperty any QtQuick::Rectangle::gradient
 
     The gradient to use to fill the rectangle.
 
@@ -407,37 +411,66 @@ QQuickPen *QQuickRectangle::border()
     \snippet qml/rectangle/rectangle-gradient.qml rectangles
     \clearfloat
 
+    The property also accepts gradient presets from QGradient::Preset. Note however
+    that due to Rectangle only supporting simple vertical or horizontal gradients,
+    any preset with an unsupported angle will revert to the closest representation.
+
+    \snippet qml/rectangle/rectangle-gradient.qml presets
+    \clearfloat
+
     If both a gradient and a color are specified, the gradient will be used.
 
     \sa Gradient, color
 */
-QQuickGradient *QQuickRectangle::gradient() const
+QJSValue QQuickRectangle::gradient() const
 {
     Q_D(const QQuickRectangle);
     return d->gradient;
 }
 
-void QQuickRectangle::setGradient(QQuickGradient *gradient)
+void QQuickRectangle::setGradient(const QJSValue &gradient)
 {
     Q_D(QQuickRectangle);
-    if (d->gradient == gradient)
+    if (d->gradient.equals(gradient))
         return;
-    static int updatedSignalIdx = -1;
-    if (updatedSignalIdx < 0)
-        updatedSignalIdx = QMetaMethod::fromSignal(&QQuickGradient::updated).methodIndex();
+
+    static int updatedSignalIdx = QMetaMethod::fromSignal(&QQuickGradient::updated).methodIndex();
     if (d->doUpdateSlotIdx < 0)
         d->doUpdateSlotIdx = QQuickRectangle::staticMetaObject.indexOfSlot("doUpdate()");
-    if (d->gradient)
-        QMetaObject::disconnect(d->gradient, updatedSignalIdx, this, d->doUpdateSlotIdx);
-    d->gradient = gradient;
-    if (d->gradient)
-        QMetaObject::connect(d->gradient, updatedSignalIdx, this, d->doUpdateSlotIdx);
+
+    if (auto oldGradient = qobject_cast<QQuickGradient*>(d->gradient.toQObject()))
+        QMetaObject::disconnect(oldGradient, updatedSignalIdx, this, d->doUpdateSlotIdx);
+
+    if (gradient.isQObject()) {
+        if (auto newGradient = qobject_cast<QQuickGradient*>(gradient.toQObject())) {
+            d->gradient = gradient;
+            QMetaObject::connect(newGradient, updatedSignalIdx, this, d->doUpdateSlotIdx);
+        } else {
+            qmlWarning(this) << "Can't assign "
+                << QQmlMetaType::prettyTypeName(gradient.toQObject()) << " to gradient property";
+            d->gradient = QJSValue();
+        }
+    } else if (gradient.isNumber() || gradient.isString()) {
+        QGradient preset(gradient.toVariant().value<QGradient::Preset>());
+        if (preset.type() != QGradient::NoGradient) {
+            d->gradient = gradient;
+        } else {
+            qmlWarning(this) << "No such gradient preset '" << gradient.toString() << "'";
+            d->gradient = QJSValue();
+        }
+    } else if (gradient.isNull() || gradient.isUndefined()) {
+        d->gradient = gradient;
+    } else {
+        qmlWarning(this) << "Unknown gradient type. Expected int, string, or Gradient";
+        d->gradient = QJSValue();
+    }
+
     update();
 }
 
 void QQuickRectangle::resetGradient()
 {
-    setGradient(nullptr);
+    setGradient(QJSValue());
 }
 
 /*!
@@ -534,9 +567,31 @@ QSGNode *QQuickRectangle::updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData
 
     QGradientStops stops;
     bool vertical = true;
-    if (d->gradient) {
-        stops = d->gradient->gradientStops();
-        vertical = d->gradient->orientation() == QQuickGradient::Vertical;
+    if (d->gradient.isQObject()) {
+        auto gradient = qobject_cast<QQuickGradient*>(d->gradient.toQObject());
+        Q_ASSERT(gradient);
+        stops = gradient->gradientStops();
+        vertical = gradient->orientation() == QQuickGradient::Vertical;
+    } else if (d->gradient.isNumber() || d->gradient.isString()) {
+        QGradient preset(d->gradient.toVariant().value<QGradient::Preset>());
+        if (preset.type() == QGradient::LinearGradient) {
+            auto linearGradient = static_cast<QLinearGradient&>(preset);
+            const QPointF start = linearGradient.start();
+            const QPointF end = linearGradient.finalStop();
+            vertical = qAbs(start.y() - end.y()) >= qAbs(start.x() - end.x());
+            stops = linearGradient.stops();
+            if ((vertical && start.y() > end.y()) || (!vertical && start.x() > end.x())) {
+                // QSGInternalRectangleNode doesn't support stops in the wrong order,
+                // so we need to manually reverse them here.
+                QGradientStops reverseStops;
+                for (auto it = stops.rbegin(); it != stops.rend(); ++it) {
+                    auto stop = *it;
+                    stop.first = 1 - stop.first;
+                    reverseStops.append(stop);
+                }
+                stops = reverseStops;
+            }
+        }
     }
     rectangle->setGradientStops(stops);
     rectangle->setGradientVertical(vertical);
diff --git a/src/quick/items/qquickrectangle_p.h b/src/quick/items/qquickrectangle_p.h
index ddafaafb28..d56a03d22d 100644
--- a/src/quick/items/qquickrectangle_p.h
+++ b/src/quick/items/qquickrectangle_p.h
@@ -122,6 +122,7 @@ class Q_QUICK_PRIVATE_EXPORT QQuickGradient : public QObject
     Q_PROPERTY(Orientation orientation READ orientation WRITE setOrientation NOTIFY orientationChanged REVISION 12)
     Q_CLASSINFO("DefaultProperty", "stops")
 
+    Q_ENUMS(QGradient::Preset)
 public:
     QQuickGradient(QObject *parent=nullptr);
     ~QQuickGradient() override;
@@ -157,7 +158,7 @@ class Q_QUICK_PRIVATE_EXPORT QQuickRectangle : public QQuickItem
     Q_OBJECT
 
     Q_PROPERTY(QColor color READ color WRITE setColor NOTIFY colorChanged)
-    Q_PROPERTY(QQuickGradient *gradient READ gradient WRITE setGradient RESET resetGradient)
+    Q_PROPERTY(QJSValue gradient READ gradient WRITE setGradient RESET resetGradient)
     Q_PROPERTY(QQuickPen * border READ border CONSTANT)
     Q_PROPERTY(qreal radius READ radius WRITE setRadius NOTIFY radiusChanged)
 public:
@@ -168,8 +169,8 @@ public:
 
     QQuickPen *border();
 
-    QQuickGradient *gradient() const;
-    void setGradient(QQuickGradient *gradient);
+    QJSValue gradient() const;
+    void setGradient(const QJSValue &gradient);
     void resetGradient();
 
     qreal radius() const;
diff --git a/src/quick/items/qquickrectangle_p_p.h b/src/quick/items/qquickrectangle_p_p.h
index 3c1aaf7661..c7c5293f9b 100644
--- a/src/quick/items/qquickrectangle_p_p.h
+++ b/src/quick/items/qquickrectangle_p_p.h
@@ -73,7 +73,7 @@ public:
     }
 
     QColor color;
-    QQuickGradient *gradient;
+    QJSValue gradient;
     QQuickPen *pen;
     qreal radius;
     static int doUpdateSlotIdx;
diff --git a/tests/auto/quick/qquickdesignersupport/data/test.qml b/tests/auto/quick/qquickdesignersupport/data/test.qml
index 1d43cb3b7e..6c89f15257 100644
--- a/tests/auto/quick/qquickdesignersupport/data/test.qml
+++ b/tests/auto/quick/qquickdesignersupport/data/test.qml
@@ -1,4 +1,4 @@
-import QtQuick 2.0
+import QtQuick 2.11
 
 Rectangle {
     objectName: "rootItem"
@@ -13,7 +13,7 @@ Rectangle {
 
     Rectangle {
         objectName: "rectangleItem"
-        gradient: Gradient {
+        containmentMask: Item {
 
         }
     }
diff --git a/tests/auto/quick/qquickdesignersupport/tst_qquickdesignersupport.cpp b/tests/auto/quick/qquickdesignersupport/tst_qquickdesignersupport.cpp
index 96a11e16e9..3e0765552a 100644
--- a/tests/auto/quick/qquickdesignersupport/tst_qquickdesignersupport.cpp
+++ b/tests/auto/quick/qquickdesignersupport/tst_qquickdesignersupport.cpp
@@ -209,15 +209,15 @@ void tst_qquickdesignersupport::objectProperties()
 
 
     //Read gradient property as QObject
-    int propertyIndex = rectangleItem->metaObject()->indexOfProperty("gradient");
+    int propertyIndex = rectangleItem->metaObject()->indexOfProperty("containmentMask");
     QVERIFY(propertyIndex > 0);
     QMetaProperty metaProperty = rectangleItem->metaObject()->property(propertyIndex);
     QVERIFY(metaProperty.isValid());
 
     QVERIFY(QQuickDesignerSupportProperties::isPropertyQObject(metaProperty));
 
-    QObject*gradient = QQuickDesignerSupportProperties::readQObjectProperty(metaProperty, rectangleItem);
-    QVERIFY(gradient);
+    QObject *containmentItem = QQuickDesignerSupportProperties::readQObjectProperty(metaProperty, rectangleItem);
+    QVERIFY(containmentItem);
 
 
     //The width property is not a QObject
@@ -450,7 +450,7 @@ void tst_qquickdesignersupport::testNotifyPropertyChangeCallBack()
 
     QQuickDesignerSupportMetaInfo::registerNotifyPropertyChangeCallBack(notifyPropertyChangeCallBackPointer);
 
-    rectangle->setProperty("gradient", QVariant::fromValue<QQuickGradient *>(gradient));
+    rectangle->setProperty("gradient", QVariant::fromValue<QJSValue>(view->engine()->newQObject(gradient)));
 
     QVERIFY(s_object);
     QCOMPARE(s_object, rootItem);
diff --git a/tests/auto/quick/qquickrectangle/data/gradient-preset.qml b/tests/auto/quick/qquickrectangle/data/gradient-preset.qml
new file mode 100644
index 0000000000..b740bdd610
--- /dev/null
+++ b/tests/auto/quick/qquickrectangle/data/gradient-preset.qml
@@ -0,0 +1,16 @@
+import QtQuick 2.0
+
+Item {
+    Rectangle {
+        objectName: "enum"
+        gradient: Gradient.NightFade
+    }
+    Rectangle {
+        objectName: "string"
+        gradient: "NightFade"
+    }
+    Rectangle {
+        objectName: "invalid"
+        gradient: -1
+    }
+}
diff --git a/tests/auto/quick/qquickrectangle/tst_qquickrectangle.cpp b/tests/auto/quick/qquickrectangle/tst_qquickrectangle.cpp
index 2aaad867bf..f6ca999cf5 100644
--- a/tests/auto/quick/qquickrectangle/tst_qquickrectangle.cpp
+++ b/tests/auto/quick/qquickrectangle/tst_qquickrectangle.cpp
@@ -49,6 +49,7 @@ private slots:
     void gradient_border();
     void gradient_separate();
     void gradient_multiple();
+    void gradient_preset();
     void antialiasing();
 
 private:
@@ -84,7 +85,7 @@ void tst_qquickrectangle::gradient()
     QQuickRectangle *rect = qobject_cast<QQuickRectangle*>(component.create());
     QVERIFY(rect);
 
-    QQuickGradient *grad = rect->gradient();
+    QQuickGradient *grad = qobject_cast<QQuickGradient *>(rect->gradient().toQObject());
     QVERIFY(grad);
 
     QQmlListProperty<QQuickGradientStop> stops = grad->stops();
@@ -103,7 +104,7 @@ void tst_qquickrectangle::gradient()
 
     QMetaObject::invokeMethod(rect, "resetGradient");
 
-    grad = rect->gradient();
+    grad = qobject_cast<QQuickGradient *>(rect->gradient().toQObject());
     QVERIFY(!grad);
 
     delete rect;
@@ -174,6 +175,29 @@ void tst_qquickrectangle::gradient_multiple()
     QVERIFY(secondIsDirty);
 }
 
+void tst_qquickrectangle::gradient_preset()
+{
+    QQuickView view;
+    view.setSource(testFileUrl("gradient-preset.qml"));
+    view.show();
+
+    QVERIFY(QTest::qWaitForWindowExposed(&view));
+
+    QQuickRectangle *enumRect = view.rootObject()->findChild<QQuickRectangle *>("enum");
+    QVERIFY(enumRect);
+    QVERIFY(enumRect->gradient().isNumber());
+    QCOMPARE(enumRect->gradient().toUInt(), QGradient::NightFade);
+
+    QQuickRectangle *stringRect = view.rootObject()->findChild<QQuickRectangle *>("string");
+    QVERIFY(stringRect);
+    QVERIFY(stringRect->gradient().isString());
+    QCOMPARE(stringRect->gradient().toString(), QLatin1String("NightFade"));
+
+    QQuickRectangle *invalidRect = view.rootObject()->findChild<QQuickRectangle *>("invalid");
+    QVERIFY(invalidRect);
+    QVERIFY(invalidRect->gradient().isUndefined());
+}
+
 void tst_qquickrectangle::antialiasing()
 {
     QQmlComponent component(&engine);