Add accessibility to qml

This consists of two parts:
An attached property for QML items and a plugin for the accessibility framework.

The attached property simply takes care of some properties (name, role)
that are needed in order to expose semantics of the application to
assistive tools.

The plugin exposes the hierarchy of QML items to the
accessibility framework.

Change-Id: I32f5603d0d9549b01b3645b205b710b9801762f7
Reviewed-by: Jan-Arve Sæther <jan-arve.saether@nokia.com>

10 files changed, 343 insertions, 1 deletions

diff --git a/src/quick/items/items.pri b/src/quick/items/items.pri
index 28a32fcc48..f02c769c3a 100644
--- a/src/quick/items/items.pri
+++ b/src/quick/items/items.pri
@@ -1,10 +1,11 @@
 HEADERS += \
     $$PWD/qquickevents_p_p.h \
-    $$PWD/qquickitemchangelistener_p.h \
     $$PWD/qquickanchors_p.h \
     $$PWD/qquickanchors_p_p.h \
+    $$PWD/qquickaccessibleattached_p.h \
     $$PWD/qquickitem.h \
     $$PWD/qquickitem_p.h \
+    $$PWD/qquickitemchangelistener_p.h \
     $$PWD/qquickrectangle_p.h \
     $$PWD/qquickrectangle_p_p.h \
     $$PWD/qquickcanvas.h \
@@ -116,6 +117,7 @@ SOURCES += \
     $$PWD/qquickspriteengine.cpp \
     $$PWD/qquicksprite.cpp \
     $$PWD/qquickspriteimage.cpp \
+    $$PWD/qquickaccessibleattached.cpp \
     $$PWD/qquickdrag.cpp \
     $$PWD/qquickdroparea.cpp \
     $$PWD/qquickmultipointtoucharea.cpp \
diff --git a/src/quick/items/qquickaccessibleattached.cpp b/src/quick/items/qquickaccessibleattached.cpp
new file mode 100644
index 0000000000..4fa3b87bf0
--- /dev/null
+++ b/src/quick/items/qquickaccessibleattached.cpp
@@ -0,0 +1,132 @@
+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtDeclarative module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this
+** file. Please review the following information to ensure the GNU Lesser
+** General Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qquickaccessibleattached_p.h"
+
+#ifndef QT_NO_ACCESSIBILITY
+
+#include "private/qquickitem_p.h"
+
+QT_BEGIN_NAMESPACE
+
+/*!
+    \qmlclass Accessible QQuickAccessibleAttached
+    \inqmlmodule QtQuick 2
+    \ingroup qml-basic-interaction-elements
+    \brief Attached property to enable accessibility of QML items.
+
+    Items the user interacts with or that give information to the user
+    need to expose their information in a semantic way.
+    Then assistive tools can make use of that information to enable
+    users to interact with the application in various ways.
+
+    This enables Qt Quick applications to be used with screen-readers for example.
+
+    The most important properties to set are \l name and \l role.
+
+    \sa Accessibility
+*/
+
+/*!
+    \qmlproperty string QtQuick2::Accessible::name
+
+    This property sets an accessible name.
+    For a button for example, this should have a binding to its text.
+    In general this property should be set to a simple and concise
+    but human readable name. Do not include the type of control
+    you want to represent but just the name.
+*/
+
+/*!
+    \qmlproperty string QtQuick2::Accessible::description
+
+    This property sets an accessible description.
+    Similar to the name it describes the item. The description
+    can be a little more verbose and tell what the item does,
+    for example the functionallity of the button it describes.
+*/
+
+/*!
+    \qmlproperty enumeration QtQuick2::Accessible::role
+
+    This flags sets the semantic type of the widget.
+    A button for example would have "Button" as type.
+    The value must be one of \l QAccessible::Role .
+    Example:
+    \qml
+    Item {
+        id: myButton
+        Text {
+            id: label
+            // ...
+        }
+        Accessible.name: label.text
+        Accessible.role: Accessible.Button
+    }
+    \endqml
+*/
+
+QQuickAccessibleAttached::QQuickAccessibleAttached(QObject *parent)
+    : QObject(parent)
+{
+    Q_ASSERT(parent);
+    QQuickItem *item = qobject_cast<QQuickItem*>(parent);
+    if (!item)
+        return;
+
+    // Enable accessibility for items with accessible content. This also
+    // enables accessibility for the ancestors of souch items.
+    item->d_func()->setAccessibleFlagAndListener();
+    QAccessible::updateAccessibility(item, 0, QAccessible::ObjectCreated);
+}
+
+QQuickAccessibleAttached::~QQuickAccessibleAttached()
+{
+}
+
+QQuickAccessibleAttached *QQuickAccessibleAttached::qmlAttachedProperties(QObject *obj)
+{
+    return new QQuickAccessibleAttached(obj);
+}
+
+QT_END_NAMESPACE
+
+#endif
diff --git a/src/quick/items/qquickaccessibleattached_p.h b/src/quick/items/qquickaccessibleattached_p.h
new file mode 100644
index 0000000000..184dc2116d
--- /dev/null
+++ b/src/quick/items/qquickaccessibleattached_p.h
@@ -0,0 +1,153 @@
+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtDeclarative module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this
+** file. Please review the following information to ensure the GNU Lesser
+** General Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QQUICKACCESSIBLEATTACHED_H
+#define QQUICKACCESSIBLEATTACHED_H
+
+#include <QtQuick/qquickitem.h>
+
+#include <QtCore/qobject.h>
+#include <QtCore/qstring.h>
+
+#ifndef QT_NO_ACCESSIBILITY
+
+#include <QtGui/qaccessible.h>
+#include <private/qtquickglobal_p.h>
+
+QT_BEGIN_HEADER
+
+QT_BEGIN_NAMESPACE
+
+QT_MODULE(Declarative)
+
+class Q_QUICK_PRIVATE_EXPORT QQuickAccessibleAttached : public QObject
+{
+    Q_OBJECT
+    Q_PROPERTY(QAccessible::Role role READ role WRITE setRole NOTIFY roleChanged)
+    Q_PROPERTY(QString name READ name WRITE setName NOTIFY nameChanged)
+    Q_PROPERTY(QString description READ description WRITE setDescription NOTIFY descriptionChanged)
+
+public:
+    Q_ENUMS(QAccessible::Role QAccessible::Event QAccessible::State)
+
+    QQuickAccessibleAttached(QObject *parent);
+    ~QQuickAccessibleAttached();
+
+    QAccessible::Role role() const { return m_role; }
+    void setRole(QAccessible::Role role)
+    {
+        if (role != m_role) {
+            m_role = role;
+            emit roleChanged();
+            // There is no way to signify role changes at the moment.
+            // QAccessible::updateAccessibility(parent(), 0, QAccessible::);
+        }
+    }
+    QString name() const { return m_name; }
+    void setName(const QString &name) {
+        if (name != m_name) {
+            m_name = name;
+            emit nameChanged();
+            QAccessible::updateAccessibility(parent(), 0, QAccessible::NameChanged);
+        }
+    }
+
+    QString description() const { return m_description; }
+    void setDescription(const QString &description)
+    {
+        if (m_description != description) {
+            m_description = description;
+            emit descriptionChanged();
+            QAccessible::updateAccessibility(parent(), 0, QAccessible::DescriptionChanged);
+        }
+    }
+
+    // Factory function
+    static QQuickAccessibleAttached *qmlAttachedProperties(QObject *obj);
+
+    // Property getter
+    static QObject *attachedProperties(const QObject *obj)
+    {
+        return qmlAttachedPropertiesObject<QQuickAccessibleAttached>(obj, false);
+    }
+
+    static QVariant property(const QObject *object, const char *propertyName)
+    {
+        if (QObject *attachedObject = QQuickAccessibleAttached::attachedProperties(object))
+            return attachedObject->property(propertyName);
+        return QVariant();
+    }
+
+    static bool setProperty(QObject *object, const char *propertyName, const QVariant &value)
+    {
+        QObject *obj = qmlAttachedPropertiesObject<QQuickAccessibleAttached>(object, true);
+        if (!obj) {
+            qWarning("cannot set property Accessible.%s of QObject %s", propertyName, object->metaObject()->className());
+            return false;
+        }
+        return obj->setProperty(propertyName, value);
+    }
+
+
+Q_SIGNALS:
+    void roleChanged();
+    void nameChanged();
+    void descriptionChanged();
+private:
+    QAccessible::Role m_role;
+    QString m_name;
+    QString m_description;
+
+public:
+    using QObject::property;
+};
+
+
+QT_END_NAMESPACE
+
+QML_DECLARE_TYPE(QQuickAccessibleAttached)
+QML_DECLARE_TYPEINFO(QQuickAccessibleAttached, QML_HAS_ATTACHED_PROPERTIES)
+
+QT_END_HEADER
+
+#endif // QT_NO_ACCESSIBILITY
+
+#endif
diff --git a/src/quick/items/qquickcanvas.cpp b/src/quick/items/qquickcanvas.cpp
index c827bfbb52..eab6292f22 100644
--- a/src/quick/items/qquickcanvas.cpp
+++ b/src/quick/items/qquickcanvas.cpp
@@ -116,6 +116,10 @@ private:
     bool m_eventSent;
 };
 
+QAccessibleInterface *QQuickCanvas::accessibleRoot() const
+{
+    return QAccessible::queryAccessibleInterface(const_cast<QQuickCanvas*>(this));
+}
 
 
 /*
diff --git a/src/quick/items/qquickcanvas.h b/src/quick/items/qquickcanvas.h
index d38ed97028..de82e8386e 100644
--- a/src/quick/items/qquickcanvas.h
+++ b/src/quick/items/qquickcanvas.h
@@ -97,6 +97,8 @@ public:
 
     QDeclarativeIncubationController *incubationController() const;
 
+    virtual QAccessibleInterface *accessibleRoot() const;
+
     // Scene graph specific functions
     QSGTexture *createTextureFromImage(const QImage &image) const;
     QSGTexture *createTextureFromId(uint id, const QSize &size, CreateTextureOptions options = CreateTextureOption(0)) const;
diff --git a/src/quick/items/qquickitem.cpp b/src/quick/items/qquickitem.cpp
index c95ae1a9c3..e9dc737e8a 100644
--- a/src/quick/items/qquickitem.cpp
+++ b/src/quick/items/qquickitem.cpp
@@ -66,6 +66,7 @@
 #include <private/qlistmodelinterface_p.h>
 #include <private/qquickitem_p.h>
 #include <private/qdeclarativeaccessors_p.h>
+#include <QtQuick/private/qquickaccessibleattached_p.h>
 
 #include <float.h>
 
@@ -1603,6 +1604,22 @@ void QQuickItemPrivate::setLayoutMirror(bool mirror)
     }
 }
 
+void QQuickItemPrivate::setAccessibleFlagAndListener()
+{
+    Q_Q(QQuickItem);
+    QQuickItem *item = q;
+    while (item) {
+        if (item->d_func()->isAccessible)
+            break; // already set - grandparents should have the flag set as well.
+
+        if (item->canvas() && item->canvas()->rootItem() == item)
+            break; // don't add a listener to the canvas root item
+
+        item->d_func()->isAccessible = true;
+        item = item->d_func()->parentItem;
+    }
+}
+
 /*!
     \class QQuickItem
     \brief The QQuickItem class provides the most basic of all visual items in QML.
@@ -1804,6 +1821,7 @@ QQuickItem::~QQuickItem()
         if (change.types & QQuickItemPrivate::Destroyed)
             change.listener->itemDestroyed(this);
     }
+
     d->changeListeners.clear();
     delete d->_anchorLines; d->_anchorLines = 0;
     delete d->_anchors; d->_anchors = 0;
@@ -1913,6 +1931,10 @@ void QQuickItem::setParentItem(QQuickItem *parentItem)
     d->itemChange(ItemParentHasChanged, d->parentItem);
 
     d->parentNotifier.notify();
+    if (d->isAccessible && d->parentItem) {
+        d->parentItem->d_func()->setAccessibleFlagAndListener();
+    }
+
     emit parentChanged(d->parentItem);
 }
 
@@ -2251,6 +2273,7 @@ QQuickItemPrivate::QQuickItemPrivate()
   inheritedLayoutMirror(false), effectiveLayoutMirror(false), isMirrorImplicit(true),
   inheritMirrorFromParent(false), inheritMirrorFromItem(false), childrenDoNotOverlap(false),
   staticSubtreeGeometry(false),
+  isAccessible(false),
 
   canvas(0), parentItem(0), sortedChildItems(&childItems),
 
@@ -2886,6 +2909,11 @@ void QQuickItem::updatePolish()
 {
 }
 
+void QQuickItem::sendAccessibilityUpdate()
+{
+    Q_D(QQuickItem);
+}
+
 void QQuickItemPrivate::removeItemChangeListener(QQuickItemChangeListener *listener, ChangeTypes types)
 {
     ChangeListener change(listener, types);
@@ -2931,6 +2959,7 @@ void QQuickItem::inputMethodEvent(QInputMethodEvent *event)
 
 void QQuickItem::focusInEvent(QFocusEvent *)
 {
+    QAccessible::updateAccessibility(this, 0, QAccessible::Focus);
 }
 
 void QQuickItem::focusOutEvent(QFocusEvent *)
@@ -3895,6 +3924,9 @@ void QQuickItemPrivate::setEffectiveVisibleRecur(bool newEffectiveVisible)
             change.listener->itemVisibilityChanged(q);
     }
 
+    if (isAccessible)
+        QAccessible::updateAccessibility(q, 0, effectiveVisible ? QAccessible::ObjectShow : QAccessible::ObjectHide );
+
     emit q->visibleChanged();
 }
 
diff --git a/src/quick/items/qquickitem.h b/src/quick/items/qquickitem.h
index ffc1017105..763fc59ac4 100644
--- a/src/quick/items/qquickitem.h
+++ b/src/quick/items/qquickitem.h
@@ -51,6 +51,7 @@
 #include <QtCore/QList>
 #include <QtGui/qevent.h>
 #include <QtGui/qfont.h>
+#include <QtGui/qaccessible.h>
 
 QT_BEGIN_HEADER
 
@@ -393,6 +394,9 @@ protected:
     virtual QSGNode *updatePaintNode(QSGNode *, UpdatePaintNodeData *);
     virtual void updatePolish();
 
+protected Q_SLOTS:
+    void sendAccessibilityUpdate();
+
 protected:
     QQuickItem(QQuickItemPrivate &dd, QQuickItem *parent = 0);
 
@@ -400,6 +404,8 @@ private:
     friend class QQuickCanvas;
     friend class QQuickCanvasPrivate;
     friend class QSGRenderer;
+    friend class QAccessibleQuickItem;
+    friend class QQuickAccessibleAttached;
     Q_DISABLE_COPY(QQuickItem)
     Q_DECLARE_PRIVATE(QQuickItem)
 };
diff --git a/src/quick/items/qquickitem_p.h b/src/quick/items/qquickitem_p.h
index 6ed4a694a7..1a23ab1732 100644
--- a/src/quick/items/qquickitem_p.h
+++ b/src/quick/items/qquickitem_p.h
@@ -280,6 +280,7 @@ public:
     bool inheritMirrorFromItem:1;
     bool childrenDoNotOverlap:1;
     bool staticSubtreeGeometry:1;
+    bool isAccessible:1;
 
     QQuickCanvas *canvas;
     QSGContext *sceneGraphContext() const { Q_ASSERT(canvas); return static_cast<QQuickCanvasPrivate *>(QObjectPrivate::get(canvas))->context; }
@@ -337,6 +338,8 @@ public:
     Qt::MouseButtons acceptedMouseButtons;
     Qt::InputMethodHints imHints;
 
+    void setAccessibleFlagAndListener();
+
     QPointF transformOriginPoint;
 
     virtual qreal getImplicitWidth() const;
diff --git a/src/quick/items/qquickitemsmodule.cpp b/src/quick/items/qquickitemsmodule.cpp
index 69b9caf940..b5eb611e78 100644
--- a/src/quick/items/qquickitemsmodule.cpp
+++ b/src/quick/items/qquickitemsmodule.cpp
@@ -82,6 +82,7 @@
 #include "qquickdroparea_p.h"
 #include "qquickmultipointtoucharea_p.h"
 #include <private/qdeclarativemetatype_p.h>
+#include <QtQuick/private/qquickaccessibleattached_p.h>
 
 static QDeclarativePrivate::AutoParentResult qquickitem_autoParent(QObject *obj, QObject *parent)
 {
@@ -215,6 +216,10 @@ static void qt_quickitems_defineModule(const char *uri, int major, int minor)
     qmlRegisterType<QQuickMultiPointTouchArea>("QtQuick", 2, 0, "MultiPointTouchArea");
     qmlRegisterType<QQuickTouchPoint>("QtQuick", 2, 0, "TouchPoint");
     qmlRegisterType<QQuickGrabGestureEvent>();
+
+#ifndef QT_NO_ACCESSIBILITY
+    qmlRegisterUncreatableType<QQuickAccessibleAttached>("QtQuick", 2, 0, "Accessible",QQuickAccessibleAttached::tr("Accessible is only available via attached properties"));
+#endif
 }
 
 void QQuickItemsModule::defineModule()
diff --git a/src/quick/items/qquicktext.cpp b/src/quick/items/qquicktext.cpp
index 2a6be05851..5072bf1a58 100644
--- a/src/quick/items/qquicktext.cpp
+++ b/src/quick/items/qquicktext.cpp
@@ -1920,6 +1920,9 @@ void QQuickText::componentComplete()
     QQuickItem::componentComplete();
     if (d->updateOnComponentComplete)
         d->updateLayout();
+
+    // Enable accessibility for text items.
+    d->setAccessibleFlagAndListener();
 }