iOS: Retina display support.

Scale the OpenGL paint device size and physical dpi
by the device pixel ratio.

Change-Id: I8b576f23129aafc47371795151c548663e94ad52
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@digia.com>

src/gui/opengl/qopenglpaintdevice.cpp

@@ -116,6 +116,7 @@ public:
 
     qreal dpmx;
     qreal dpmy;
+    qreal devicePixelRatio;
 
     bool flipped;
 
@@ -178,6 +179,7 @@ QOpenGLPaintDevicePrivate::QOpenGLPaintDevicePrivate(const QSize &sz)
     , ctx(QOpenGLContext::currentContext())
     , dpmx(qt_defaultDpiX() * 100. / 2.54)
     , dpmy(qt_defaultDpiY() * 100. / 2.54)
+    , devicePixelRatio(1.0)
     , flipped(false)
     , engine(0)
 {
@@ -248,6 +250,14 @@ void QOpenGLPaintDevice::setSize(const QSize &size)
     d_ptr->size = size;
 }
 
+/*!
+    Sets the device pixel ratio for the paint device to \a devicePixelRatio.
+*/
+void QOpenGLPaintDevice::setDevicePixelRatio(qreal devicePixelRatio)
+{
+    d_ptr->devicePixelRatio = devicePixelRatio;
+}
+
 /*!
     \reimp
 */
@@ -272,9 +282,9 @@ int QOpenGLPaintDevice::metric(QPaintDevice::PaintDeviceMetric metric) const
     case PdmDpiY:
         return qRound(d_ptr->dpmy * 0.0254);
     case PdmPhysicalDpiX:
-        return qRound(d_ptr->dpmx * 0.0254);
+        return qRound(d_ptr->dpmx * 0.0254 * d_ptr->devicePixelRatio);
     case PdmPhysicalDpiY:
-        return qRound(d_ptr->dpmy * 0.0254);
+        return qRound(d_ptr->dpmy * 0.0254 * d_ptr->devicePixelRatio);
     default:
         qWarning("QOpenGLPaintDevice::metric() - metric %d not known", metric);
         return 0;

src/gui/opengl/qopenglpaintdevice.h

@@ -68,6 +68,7 @@ public:
     QOpenGLContext *context() const;
     QSize size() const;
     void setSize(const QSize &size);
+    void setDevicePixelRatio(qreal devicePixelRatio);
 
     qreal dotsPerMeterX() const;
     qreal dotsPerMeterY() const;

src/plugins/platforms/ios/qiosbackingstore.mm

@@ -71,12 +71,18 @@ void QIOSBackingStore::beginPaint(const QRegion &)
     m_context->makeCurrent(window());
 
     static_cast<QOpenGLPaintDevice *>(paintDevice())->setSize(window()->size());
+    QIOSWindow *iosWindow = static_cast<QIOSWindow *>(window()->handle());
+    static_cast<QOpenGLPaintDevice *>(paintDevice())->setSize(window()->size() * iosWindow->devicePixelRatio());
 }
 
 QPaintDevice *QIOSBackingStore::paintDevice()
 {
-    if (!m_device)
-        m_device = new QOpenGLPaintDevice;
+    if (!m_device) {
+        QIOSWindow *iosWindow = static_cast<QIOSWindow *>(window()->handle());
+        QOpenGLPaintDevice *openGLDevice = new QOpenGLPaintDevice(window()->size() * iosWindow->devicePixelRatio());
+        openGLDevice->setDevicePixelRatio(iosWindow->devicePixelRatio());
+        m_device = openGLDevice;
+    }
 
     return m_device;
 }

src/plugins/platforms/ios/qioswindow.h

@@ -90,6 +90,7 @@ public:
 
     GLuint framebufferObject(const QIOSContext &context) const;
     GLuint colorRenderbuffer(const QIOSContext &context) const;
+    qreal devicePixelRatio() const;
 
     EAGLView *nativeView() const { return m_view; }
 
@@ -104,6 +105,7 @@ private:
         GLint renderbufferWidth;
         GLint renderbufferHeight;
     } m_glData;
+    qreal m_devicePixelRatio;
 };
 
 QT_END_NAMESPACE

src/plugins/platforms/ios/qioswindow.mm

@@ -126,8 +126,7 @@ static QRect fromCGRect(const CGRect &rect)
 {
     UITouch *touch = [touches anyObject];
     CGPoint locationInView = [touch locationInView:self];
-    CGFloat scaleFactor = [self contentScaleFactor];
-    QPoint p(locationInView.x * scaleFactor, locationInView.y * scaleFactor);
+    QPoint p(locationInView.x , locationInView.y);
 
     // TODO handle global touch point? for status bar?
     QWindowSystemInterface::handleMouseEvent(m_qioswindow->window(), (ulong)(event.timestamp*1000), p, p, buttons);
@@ -204,11 +203,21 @@ QIOSWindow::QIOSWindow(QWindow *window)
     , m_view([[EAGLView alloc] initWithQIOSWindow:this])
     , m_requestedGeometry(QPlatformWindow::geometry())
     , m_glData()
+    , m_devicePixelRatio(1.0)
 {
     if ([[UIApplication sharedApplication].delegate isKindOfClass:[QIOSApplicationDelegate class]])
         [[UIApplication sharedApplication].delegate.window.rootViewController.view addSubview:m_view];
 
     setWindowState(window->windowState());
+
+    // Retina support: get screen scale factor and set it in the content view.
+    // This will make framebufferObject() create a 2x frame buffer on retina
+    // displays. Also set m_devicePixelRatio which is used for scaling the
+    // paint device.
+    if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)] == YES) {
+        m_devicePixelRatio = [[UIScreen mainScreen] scale];
+        [m_view setContentScaleFactor : m_devicePixelRatio];
+    }
 }
 
 QIOSWindow::~QIOSWindow()
@@ -304,7 +313,8 @@ GLuint QIOSWindow::framebufferObject(const QIOSContext &context) const
 GLuint QIOSWindow::colorRenderbuffer(const QIOSContext &context) const
 {
     if (!m_glData.colorRenderbuffer ||
-        m_glData.renderbufferWidth != geometry().width() || m_glData.renderbufferHeight != geometry().height()) {
+        m_glData.renderbufferWidth != geometry().width() * m_devicePixelRatio ||
+        m_glData.renderbufferHeight != geometry().height() *m_devicePixelRatio) {
 
         glBindRenderbuffer(GL_RENDERBUFFER, m_glData.colorRenderbuffer);
         [context.nativeContext() renderbufferStorage:GL_RENDERBUFFER fromDrawable:static_cast<CAEAGLLayer *>(m_view.layer)];
@@ -329,4 +339,9 @@ GLuint QIOSWindow::colorRenderbuffer(const QIOSContext &context) const
     return m_glData.colorRenderbuffer;
 }
 
+qreal QIOSWindow::devicePixelRatio() const
+{
+    return m_devicePixelRatio;
+}
+
 QT_END_NAMESPACE