3 files changed, 102 insertions, 3 deletions

diff --git a/src/webengine/api/qquickwebengineview.cpp b/src/webengine/api/qquickwebengineview.cpp
index 4cfff0102..b7d9a2d7c 100644
--- a/src/webengine/api/qquickwebengineview.cpp
+++ b/src/webengine/api/qquickwebengineview.cpp
@@ -45,6 +45,7 @@
 #include "web_contents_adapter.h"
 #include "render_widget_host_view_qt_delegate_quick.h"
 
+#include <QScreen>
 #include <QUrl>
 
 QT_BEGIN_NAMESPACE
@@ -52,15 +53,40 @@ QT_BEGIN_NAMESPACE
 QQuickWebEngineViewPrivate::QQuickWebEngineViewPrivate()
     : adapter(new WebContentsAdapter(qApp->property("QQuickWebEngineView_DisableHardwareAcceleration").toBool() ? SoftwareRenderingMode : HardwareAccelerationMode))
     , e(new QQuickWebEngineViewExperimental(this))
+    , v(new QQuickWebEngineViewport(this))
     , loadProgress(0)
     , inspectable(false)
+    , devicePixelRatio(QGuiApplication::primaryScreen()->devicePixelRatio())
+    , m_dpiScale(1.0)
 {
+    // The gold standard for mobile web content is 160 dpi, and the devicePixelRatio expected
+    // is the (possibly quantized) ratio of device dpi to 160 dpi.
+    // However GUI toolkits on non-iOS platforms may be using different criteria than relative
+    // DPI (depending on the history of that platform), dictating the choice of
+    // QScreen::devicePixelRatio().
+    // Where applicable (i.e. non-iOS mobile platforms), override QScreen::devicePixelRatio
+    // and instead use a reasonable default value for viewport.devicePixelRatio to avoid every
+    // app having to use this experimental API.
+    QString platform = qApp->platformName().toLower();
+    if (platform == QStringLiteral("qnx")) {
+        qreal webPixelRatio = QGuiApplication::primaryScreen()->physicalDotsPerInch() / 160;
+
+        // Quantize devicePixelRatio to increments of 1 to allow JS and media queries to select
+        // 1x, 2x, 3x etc assets that fit an integral number of pixels.
+        setDevicePixelRatio(qMax(1, qRound(webPixelRatio)));
+    }
+
     adapter->initialize(this);
 }
 
 QQuickWebEngineViewExperimental *QQuickWebEngineViewPrivate::experimental() const
 {
-    return e;
+    return e.data();
+}
+
+QQuickWebEngineViewport *QQuickWebEngineViewPrivate::viewport() const
+{
+    return v.data();
 }
 
 RenderWidgetHostViewQtDelegate *QQuickWebEngineViewPrivate::CreateRenderWidgetHostViewQtDelegate(RenderWidgetHostViewQtDelegateClient *client, RenderingMode mode)
@@ -112,6 +138,11 @@ QRectF QQuickWebEngineViewPrivate::viewportRect() const
     return QRectF(q->x(), q->y(), q->width(), q->height());
 }
 
+qreal QQuickWebEngineViewPrivate::dpiScale() const
+{
+    return m_dpiScale;
+}
+
 void QQuickWebEngineViewPrivate::loadFinished(bool success)
 {
     Q_Q(QQuickWebEngineView);
@@ -137,6 +168,13 @@ void QQuickWebEngineViewPrivate::close()
     Q_UNREACHABLE();
 }
 
+void QQuickWebEngineViewPrivate::setDevicePixelRatio(qreal devicePixelRatio)
+{
+    this->devicePixelRatio = devicePixelRatio;
+    QScreen *screen = window ? window->screen() : QGuiApplication::primaryScreen();
+    m_dpiScale = devicePixelRatio / screen->devicePixelRatio();
+}
+
 QQuickWebEngineView::QQuickWebEngineView(QQuickItem *parent)
     : QQuickItem(*(new QQuickWebEngineViewPrivate), parent)
 {
@@ -253,4 +291,33 @@ QQuickWebEngineViewExperimental::QQuickWebEngineViewExperimental(QQuickWebEngine
 {
 }
 
+QQuickWebEngineViewport *QQuickWebEngineViewExperimental::viewport() const
+{
+    Q_D(const QQuickWebEngineView);
+    return d->viewport();
+}
+
+QQuickWebEngineViewport::QQuickWebEngineViewport(QQuickWebEngineViewPrivate *viewPrivate)
+    : d_ptr(viewPrivate)
+{
+}
+
+qreal QQuickWebEngineViewport::devicePixelRatio() const
+{
+    Q_D(const QQuickWebEngineView);
+    return d->devicePixelRatio;
+}
+
+void QQuickWebEngineViewport::setDevicePixelRatio(qreal devicePixelRatio)
+{
+    Q_D(QQuickWebEngineView);
+    // Valid range is [1, inf)
+    devicePixelRatio = qMax(1.0, devicePixelRatio);
+    if (d->devicePixelRatio == devicePixelRatio)
+        return;
+    d->setDevicePixelRatio(devicePixelRatio);
+    d->adapter->dpiScaleChanged();
+    Q_EMIT devicePixelRatioChanged();
+}
+
 QT_END_NAMESPACE
diff --git a/src/webengine/api/qquickwebengineview_p_p.h b/src/webengine/api/qquickwebengineview_p_p.h
index e7c87ce1d..b356b8881 100644
--- a/src/webengine/api/qquickwebengineview_p_p.h
+++ b/src/webengine/api/qquickwebengineview_p_p.h
@@ -45,7 +45,7 @@
 #include "qquickwebengineview_p.h"
 #include "web_contents_adapter_client.h"
 
-#include <QSharedData>
+#include <QScopedPointer>
 #include <QtQuick/private/qquickitem_p.h>
 
 class WebContentsAdapter;
@@ -53,9 +53,29 @@ class WebContentsAdapter;
 QT_BEGIN_NAMESPACE
 class QQuickWebEngineView;
 
+class Q_WEBENGINE_PRIVATE_EXPORT QQuickWebEngineViewport : public QObject {
+    Q_OBJECT
+    Q_PROPERTY(qreal devicePixelRatio READ devicePixelRatio WRITE setDevicePixelRatio NOTIFY devicePixelRatioChanged)
+public:
+    QQuickWebEngineViewport(QQuickWebEngineViewPrivate *viewPrivate);
+
+    qreal devicePixelRatio() const;
+    void setDevicePixelRatio(qreal);
+
+Q_SIGNALS:
+    void devicePixelRatioChanged();
+
+private:
+    QQuickWebEngineViewPrivate *d_ptr;
+
+    Q_DECLARE_PRIVATE(QQuickWebEngineView)
+};
+
 class Q_WEBENGINE_PRIVATE_EXPORT QQuickWebEngineViewExperimental : public QObject {
     Q_OBJECT
+    Q_PROPERTY(QQuickWebEngineViewport *viewport READ viewport)
 public:
+    QQuickWebEngineViewport *viewport() const;
 
 private:
     QQuickWebEngineViewExperimental(QQuickWebEngineViewPrivate* viewPrivate);
@@ -73,6 +93,7 @@ public:
     QQuickWebEngineViewPrivate();
 
     QQuickWebEngineViewExperimental *experimental() const;
+    QQuickWebEngineViewport *viewport() const;
 
     virtual RenderWidgetHostViewQtDelegate* CreateRenderWidgetHostViewQtDelegate(RenderWidgetHostViewQtDelegateClient *client, RenderingMode) Q_DECL_OVERRIDE;
     virtual void titleChanged(const QString&) Q_DECL_OVERRIDE;
@@ -81,6 +102,7 @@ public:
     virtual void loadingStateChanged() Q_DECL_OVERRIDE;
     virtual void loadProgressChanged(int progress) Q_DECL_OVERRIDE;
     virtual QRectF viewportRect() const Q_DECL_OVERRIDE;
+    virtual qreal dpiScale() const Q_DECL_OVERRIDE;
     virtual void loadFinished(bool success) Q_DECL_OVERRIDE;
     virtual void focusContainer() Q_DECL_OVERRIDE;
     virtual void adoptNewWindow(WebContentsAdapter *newWebContents, WindowOpenDisposition disposition, const QRect &) Q_DECL_OVERRIDE;
@@ -88,15 +110,23 @@ public:
     virtual bool contextMenuRequested(const WebEngineContextMenuData &) Q_DECL_OVERRIDE { return false;}
     virtual bool javascriptDialog(JavascriptDialogType type, const QString &message, const QString &defaultValue = QString(), QString *result = 0) Q_DECL_OVERRIDE { return false; }
 
+    void setDevicePixelRatio(qreal);
+
     QExplicitlySharedDataPointer<WebContentsAdapter> adapter;
-    QQuickWebEngineViewExperimental *e;
+    QScopedPointer<QQuickWebEngineViewExperimental> e;
+    QScopedPointer<QQuickWebEngineViewport> v;
     QUrl icon;
     int loadProgress;
     bool inspectable;
+    qreal devicePixelRatio;
+
+private:
+    qreal m_dpiScale;
 };
 
 QT_END_NAMESPACE
 
 QML_DECLARE_TYPE(QQuickWebEngineViewExperimental)
+QML_DECLARE_TYPE(QQuickWebEngineViewport)
 
 #endif // QQUICKWEBENGINEVIEW_P_P_H
diff --git a/src/webengine/plugin/experimental/plugin.cpp b/src/webengine/plugin/experimental/plugin.cpp
index 08d482508..6107147cf 100644
--- a/src/webengine/plugin/experimental/plugin.cpp
+++ b/src/webengine/plugin/experimental/plugin.cpp
@@ -69,6 +69,8 @@ public:
         qmlRegisterExtendedType<QQuickWebEngineView, QQuickWebEngineViewExperimentalExtension>(uri, 1, 0, "WebEngineView");
         qmlRegisterUncreatableType<QQuickWebEngineViewExperimental>(uri, 1, 0, "WebEngineViewExperimental",
             QObject::tr("Cannot create a separate instance of WebEngineViewExperimental"));
+        qmlRegisterUncreatableType<QQuickWebEngineViewport>(uri, 1, 0, "WebEngineViewport",
+            QObject::tr("Cannot create a separate instance of WebEngineViewport"));
     }
 };