iOS: Flesh out initial QPlatformScreen implementation

We check the device's model identifier to tweak the screen values based
on the precense of older iPhone/iPod touch models, or the iPad Mini.
This does not work when running under the simulator, which reports its
model identifier as the architecture of the host platform. There doesn't
appear to be any APIs to get the simulated device of the simulator, but
if this becomes an issue we can always look at the UIDevice model and
screen resolution and apply a few heuristics.

We do not update the screen geometry on orientation-changes. This matches
what UIScreen reports for bounds, but may not be the most intuitive solution
from a Qt perspective compared to the way other platform-plugins work.

Change-Id: I74783e053601de9ce805f8b52b944c116f9a1e3e
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@digia.com>
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>

src/plugins/platforms/ios/qiosscreen.h

@@ -52,24 +52,21 @@ class QIOSScreen : public QPlatformScreen
 {
 public:
     QIOSScreen(unsigned int screenIndex);
-    ~QIOSScreen();
 
     enum ScreenIndex { MainScreen = 0 };
 
-    QRect geometry() const { return m_geometry; }
-    int depth() const { return m_depth; }
-    QImage::Format format() const { return m_format; }
-    QSizeF physicalSize() const { return m_physicalSize; }
+    QRect geometry() const;
+    int depth() const;
+    QImage::Format format() const;
+    QSizeF physicalSize() const;
 
     UIScreen *uiScreen() const;
 
-    void updateInterfaceOrientation();
 private:
     UIScreen *m_uiScreen;
     QRect m_geometry;
     int m_depth;
-    QImage::Format m_format;
-    QSize m_physicalSize;
+    QSizeF m_physicalSize;
 };
 
 QT_END_NAMESPACE

src/plugins/platforms/ios/qiosscreen.mm

@@ -42,47 +42,81 @@
 #include "qiosscreen.h"
 #include "qioswindow.h"
 
-#include <QtGui/QGuiApplication>
-
-#include <QtDebug>
+#include <sys/sysctl.h>
 
 QT_BEGIN_NAMESPACE
 
+/*!
+    Returns the model identifier of the device.
+
+    When running under the simulator, the identifier will not
+    match the simulated device, but will be x86_64 or i386.
+*/
+static QString deviceModelIdentifier()
+{
+    static const char key[] = "hw.machine";
+
+    size_t size;
+    sysctlbyname(key, NULL, &size, NULL, 0);
+
+    char value[size];
+    sysctlbyname(key, &value, &size, NULL, 0);
+
+    return QString::fromLatin1(value);
+}
+
 QIOSScreen::QIOSScreen(unsigned int screenIndex)
     : QPlatformScreen()
     , m_uiScreen([[UIScreen screens] objectAtIndex:qMin(screenIndex, [[UIScreen screens] count] - 1)])
 {
     NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
-    CGRect bounds = [m_uiScreen bounds];
-    CGFloat scale = [m_uiScreen scale];
-    updateInterfaceOrientation();
 
-    m_format = QImage::Format_ARGB32_Premultiplied;
+    QString deviceIdentifier = deviceModelIdentifier();
 
-    m_depth = 24;
-
-    const qreal inch = 25.4;
-    qreal unscaledDpi = 160.;
-    int dragDistance = 12 * scale;
-    if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad) {
-        unscaledDpi = 132.;
-        dragDistance = 10 * scale;
+    if (deviceIdentifier == QStringLiteral("iPhone2,1") /* iPhone 3GS */
+        || deviceIdentifier == QStringLiteral("iPod3,1") /* iPod touch 3G */) {
+        m_depth = 18;
+    } else {
+        m_depth = 24;
     }
-    m_physicalSize = QSize(qRound(bounds.size.width * inch / unscaledDpi), qRound(bounds.size.height * inch / unscaledDpi));
 
-    //qApp->setStartDragDistance(dragDistance);
+    int unscaledDpi = 163; // Regular iPhone DPI
+    if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad
+        && deviceIdentifier != QStringLiteral("iPad2,5") /* iPad Mini */) {
+        unscaledDpi = 132;
+    };
 
-    /*
-    QFont font; // system font is helvetica, so that is fine already
-    font.setPixelSize([UIFont systemFontSize] * scale);
-    qApp->setFont(font);
-     */
+    // UIScreen does not report different bounds for different orientations. We
+    // match this behavior by staying with a fixed QScreen geometry.
+    CGRect bounds = [m_uiScreen bounds];
+    m_geometry = QRect(bounds.origin.x, bounds.origin.y, bounds.size.width, bounds.size.height);
+
+    const qreal millimetersPerInch = 25.4;
+    m_physicalSize = QSizeF(m_geometry.size()) / unscaledDpi * millimetersPerInch;
 
     [pool release];
 }
 
-QIOSScreen::~QIOSScreen()
+QRect QIOSScreen::geometry() const
 {
+    // FIXME: Do we need to reimplement availableGeometry() to take the
+    // system statusbar into account?
+    return m_geometry;
+}
+
+int QIOSScreen::depth() const
+{
+    return m_depth;
+}
+
+QImage::Format QIOSScreen::format() const
+{
+    return QImage::Format_ARGB32_Premultiplied;
+}
+
+QSizeF QIOSScreen::physicalSize() const
+{
+    return m_physicalSize;
 }
 
 UIScreen *QIOSScreen::uiScreen() const
@@ -90,31 +124,4 @@ UIScreen *QIOSScreen::uiScreen() const
     return m_uiScreen;
 }
 
-void QIOSScreen::updateInterfaceOrientation()
-{
-    qDebug() << __FUNCTION__ << "not implemented";
-    /*
-    CGRect bounds = [uiScreen() bounds];
-    CGFloat scale = [uiScreen() scale];
-    switch ([[UIApplication sharedApplication] statusBarOrientation]) {
-    case UIInterfaceOrientationPortrait:
-    case UIInterfaceOrientationPortraitUpsideDown:
-        m_geometry = QRect(bounds.origin.x * scale, bounds.origin.y * scale,
-                           bounds.size.width * scale, bounds.size.height * scale);;
-        break;
-    case UIInterfaceOrientationLandscapeLeft:
-    case UIInterfaceOrientationLandscapeRight:
-        m_geometry = QRect(bounds.origin.x * scale, bounds.origin.y * scale,
-                           bounds.size.height * scale, bounds.size.width * scale);
-        break;
-    }
-    foreach (QWidget *widget, qApp->topLevelWidgets()) {
-        QIOSWindow *platformWindow = static_cast<QIOSWindow *>(widget->platformWindow());
-        if (platformWindow && platformWindow->platformScreen() == this) {
-            platformWindow->updateGeometryAndOrientation();
-        }
-    }
-    */
-}
-
 QT_END_NAMESPACE