Wrong Device Pixel Ratio (DPR) when using multiple screens with different DPR

[bdg85]

Hi,

I have a retina mac book pro connected with a bigger screen:
Screen1: LCD (retina, devicePixelRatio=2) 1280x800 (in device points)
Screen2: LED Cinema Display (non retina, devicePixelRatio=1) 1920x1200

The problem is this:
If my QtQuick main window starts in Screen2, it detects the wrong screen (Screen1). Therefore, if I drag the window to Screen1, no signal is raised that the screen is changed. This prevents me to update my OpenGL renderer with the correct devicePixelRatio.

I have written a simple test application in QML to show this:

---

import QtQuick 2.4
import QtQuick.Controls 1.3
import QtQuick.Window 2.2

ApplicationWindow {
    id: appWin
    title: qsTr("Hello World")
    width: 440
    height: 320
    visible: true

    Screen.onDevicePixelRatioChanged: {
        console.log("dpr changed");
        dprSignalId.text = "dpr changed at seconds: " + new Date().getSeconds();
    }

    Column{
       Text{
           id: screenTextId
           text: Screen.name + " " + Screen.devicePixelRatio + " " + Screen.width + "x" + Screen.height
       }
       Text{
           id: dprSignalId
       }
    }
}

---