Add X axis rotation property to PathArc

It is a standard feature of elliptical arc. While perhaps deemed too
advanced for PathView purposes, rendering the path using PathItem must
offer the ability to specify a non-zero X axis rotation for the
ellipses of which the arc is a section of.

Change-Id: I53f01713b7e0e97c40f22d75d46f75a140830683
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

5 files changed, 97 insertions, 2 deletions

diff --git a/src/quick/doc/images/declarative-arcrotation.png b/src/quick/doc/images/declarative-arcrotation.png
new file mode 100644
index 0000000000..03f009bc12
--- /dev/null
+++ b/src/quick/doc/images/declarative-arcrotation.png
diff --git a/src/quick/doc/snippets/qml/path/arcrotation.qml b/src/quick/doc/snippets/qml/path/arcrotation.qml
new file mode 100644
index 0000000000..c73d67ff17
--- /dev/null
+++ b/src/quick/doc/snippets/qml/path/arcrotation.qml
@@ -0,0 +1,52 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the documentation of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** You may use this file under the terms of the BSD license as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.9
+//![0]
+Path {
+    startX: 50; startY: 100
+
+    PathArc {
+        x: 150; y: 100
+        radiusX: 50; radiusY: 20
+        xAxisRotation: 45
+    }
+}
+//![0]
diff --git a/src/quick/items/qquickitemsmodule.cpp b/src/quick/items/qquickitemsmodule.cpp
index b0d7f7f8a3..9c70daab1f 100644
--- a/src/quick/items/qquickitemsmodule.cpp
+++ b/src/quick/items/qquickitemsmodule.cpp
@@ -373,6 +373,7 @@ static void qt_quickitems_defineModule(const char *uri, int major, int minor)
     qmlRegisterType<QQuickMouseArea, 9>(uri, 2, 9, "MouseArea");
 
 #if QT_CONFIG(quick_path)
+    qmlRegisterType<QQuickPathArc, 2>(uri, 2, 9, "PathArc");
     qmlRegisterType<QQuickPathMove>(uri, 2, 9, "PathMove");
     qmlRegisterType<QQuickPathItem>(uri, 2, 9, "PathItem");
     qmlRegisterType<QQuickPathGradientStop>(uri, 2, 9, "PathGradientStop");
diff --git a/src/quick/util/qquickpath.cpp b/src/quick/util/qquickpath.cpp
index a6fa21d696..228056fdb5 100644
--- a/src/quick/util/qquickpath.cpp
+++ b/src/quick/util/qquickpath.cpp
@@ -1799,6 +1799,42 @@ void QQuickPathArc::setDirection(ArcDirection direction)
     emit changed();
 }
 
+/*!
+    \qmlproperty real QtQuick::PathArc::xAxisRotation
+
+    Defines the rotation of the arc, in degrees. The default value is 0.
+
+    An arc is a section of circles or ellipses. Given the radius and the start
+    and end points, there are two ellipses that connect the points. This
+    property defines the rotation of the X axis of these ellipses.
+
+    \note The value is only useful when the x and y radius differ, meaning the
+    arc is a section of ellipses.
+
+    The following QML demonstrates how different radius values can be used to change
+    the shape of the arc:
+    \table
+    \row
+    \li \image declarative-arcrotation.png
+    \li \snippet qml/path/arcrotation.qml 0
+    \endtable
+*/
+
+qreal QQuickPathArc::xAxisRotation() const
+{
+    return _xAxisRotation;
+}
+
+void QQuickPathArc::setXAxisRotation(qreal rotation)
+{
+    if (_xAxisRotation == rotation)
+        return;
+
+    _xAxisRotation = rotation;
+    emit xAxisRotationChanged();
+    emit changed();
+}
+
 void QQuickPathArc::addToPath(QPainterPath &path, const QQuickPathData &data)
 {
     const QPointF &startPoint = path.currentPosition();
@@ -1806,7 +1842,7 @@ void QQuickPathArc::addToPath(QPainterPath &path, const QQuickPathData &data)
     QQuickSvgParser::pathArc(path,
             _radiusX,
             _radiusY,
-            0,  //xAxisRotation
+            _xAxisRotation,
             _useLargeArc,
             _direction == Clockwise ? 1 : 0,
             endPoint.x(),
diff --git a/src/quick/util/qquickpath_p.h b/src/quick/util/qquickpath_p.h
index 283283f377..4bcefb032e 100644
--- a/src/quick/util/qquickpath_p.h
+++ b/src/quick/util/qquickpath_p.h
@@ -290,10 +290,11 @@ class Q_QUICK_PRIVATE_EXPORT QQuickPathArc : public QQuickCurve
     Q_PROPERTY(qreal radiusY READ radiusY WRITE setRadiusY NOTIFY radiusYChanged)
     Q_PROPERTY(bool useLargeArc READ useLargeArc WRITE setUseLargeArc NOTIFY useLargeArcChanged)
     Q_PROPERTY(ArcDirection direction READ direction WRITE setDirection NOTIFY directionChanged)
+    Q_PROPERTY(qreal xAxisRotation READ xAxisRotation WRITE setXAxisRotation NOTIFY xAxisRotationChanged REVISION 2)
 
 public:
     QQuickPathArc(QObject *parent=0)
-        : QQuickCurve(parent), _radiusX(0), _radiusY(0), _useLargeArc(false), _direction(Clockwise) {}
+        : QQuickCurve(parent), _radiusX(0), _radiusY(0), _useLargeArc(false), _direction(Clockwise), _xAxisRotation(0) {}
 
     enum ArcDirection { Clockwise, Counterclockwise };
     Q_ENUM(ArcDirection)
@@ -310,6 +311,9 @@ public:
     ArcDirection direction() const;
     void setDirection(ArcDirection direction);
 
+    qreal xAxisRotation() const;
+    void setXAxisRotation(qreal rotation);
+
     void addToPath(QPainterPath &path, const QQuickPathData &) override;
 
 Q_SIGNALS:
@@ -317,12 +321,14 @@ Q_SIGNALS:
     void radiusYChanged();
     void useLargeArcChanged();
     void directionChanged();
+    Q_REVISION(2) void xAxisRotationChanged();
 
 private:
     qreal _radiusX;
     qreal _radiusY;
     bool _useLargeArc;
     ArcDirection _direction;
+    qreal _xAxisRotation;
 };
 
 class Q_QUICK_PRIVATE_EXPORT QQuickPathSvg : public QQuickCurve