Use qreal for devicePixelRatio everywhere

QPaintDevice::devicePixelRatio() -> devicePixelRatioF()
Implement PdmDevicePixelRatioScaled for QPaintDevice subclasses.

Remove instances of casting to int.

Change-Id: I6e769d21e889bf8f88aedc1c49b53fef20a6709c

4 files changed, 13 insertions, 14 deletions

diff --git a/src/gui/kernel/qopenglwindow.cpp b/src/gui/kernel/qopenglwindow.cpp
index a7ba57e85e..2853f05ef3 100644
--- a/src/gui/kernel/qopenglwindow.cpp
+++ b/src/gui/kernel/qopenglwindow.cpp
@@ -646,15 +646,10 @@ int QOpenGLWindow::metric(PaintDeviceMetric metric) const
             if (d->paintDevice)
                 return d->paintDevice->depth();
             break;
-        case PdmDevicePixelRatio:
-            if (d->paintDevice)
-                return devicePixelRatio();
-            break;
         default:
             break;
     }
     return QPaintDeviceWindow::metric(metric);
-
 }
 
 /*!
diff --git a/src/gui/kernel/qpaintdevicewindow.cpp b/src/gui/kernel/qpaintdevicewindow.cpp
index b32ab3b34d..32f0aeb6d5 100644
--- a/src/gui/kernel/qpaintdevicewindow.cpp
+++ b/src/gui/kernel/qpaintdevicewindow.cpp
@@ -144,8 +144,10 @@ int QPaintDeviceWindow::metric(PaintDeviceMetric metric) const
             return qRound(screen->physicalDotsPerInchY());
         break;
     case PdmDevicePixelRatio:
-        if (screen)
-            return screen->devicePixelRatio();
+        return int(QWindow::devicePixelRatio());
+        break;
+    case PdmDevicePixelRatioScaled:
+        return int(QWindow::devicePixelRatio() * devicePixelRatioFScale);
         break;
     default:
         break;
diff --git a/src/gui/kernel/qrasterwindow.cpp b/src/gui/kernel/qrasterwindow.cpp
index c04eb71420..fc1739ca0e 100644
--- a/src/gui/kernel/qrasterwindow.cpp
+++ b/src/gui/kernel/qrasterwindow.cpp
@@ -108,8 +108,6 @@ int QRasterWindow::metric(PaintDeviceMetric metric) const
     switch (metric) {
     case PdmDepth:
         return d->backingstore->paintDevice()->depth();
-    case PdmDevicePixelRatio:
-        return d->backingstore->paintDevice()->devicePixelRatio();
     default:
         break;
     }
diff --git a/src/gui/kernel/qwindow.cpp b/src/gui/kernel/qwindow.cpp
index 6b74bd66ed..e376df24cb 100644
--- a/src/gui/kernel/qwindow.cpp
+++ b/src/gui/kernel/qwindow.cpp
@@ -1082,13 +1082,17 @@ qreal QWindow::devicePixelRatio() const
 {
     Q_D(const QWindow);
 
-    // If there is no platform window, do the second best thing and
-    // return the app global devicePixelRatio. This is the highest
+    // Get the platform scale factor. If there is no platform window
+    // use the app global devicePixelRatio, which is the the highest
     // devicePixelRatio found on the system screens, and will be
     // correct for single-display systems (a very common case).
-    if (!d->platformWindow)
-        return qApp->devicePixelRatio();
-    return d->platformWindow->devicePixelRatio() * QHighDpiScaling::factor(this);
+    qreal ratio = d->platformWindow ? d->platformWindow->devicePixelRatio()
+                                    : qApp->devicePixelRatio();
+
+    //
+    ratio *= QHighDpiScaling::factor(this);
+
+    return ratio;
 }
 
 /*!