Enable making window-screen associations from QML

Qt Quick provides a Screen attached property to query information
about the screen an item's window belongs to. This is a good start,
but has two problems: it lacks some virtual desktop related info
(e.g. the position in the virtual desktop) and it cannot be used in
combination with the Window element in order to achieve a QML
equivalent of QWindow::setScreen().

Therefore add the missing virtualX and virtualY properties and
introduce Qt.application.screens. The latter is an equivalent to
QGuiApplication::screens() and is a JS array the elements of which
can be set as the value of the new Window.targetScreen property.

This means that a call like
window->setScreen(QGuiApplication::screens()[0]) translates to
Window { targetScreen: Qt.application.screens[0]; ... } when using the
Window type from QML. Screen addition or removal can be acted upon via
onScreensChanged.

QQuickScreenAttached has been split into two in order to allow reusing the
QScreen wrapping queries for other purposes as well.

Task-number: QTBUG-56115
Change-Id: I4b2fbd873315b40d0afe878da2fc50966c00e2e0
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

5 files changed, 91 insertions, 7 deletions

diff --git a/examples/quick/window/AllScreens.qml b/examples/quick/window/AllScreens.qml
new file mode 100644
index 0000000000..83a6c5f958
--- /dev/null
+++ b/examples/quick/window/AllScreens.qml
@@ -0,0 +1,75 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** You may use this file under the terms of the BSD license as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.3
+import QtQuick.Window 2.3
+import "../shared" as Shared
+
+Column {
+    id: root
+    spacing: 8
+
+    Shared.Label {
+        text: "Total number of screens: " + screenInfo.count
+        font.bold: true
+    }
+
+    Flow {
+        spacing: 12
+        width: parent.width
+
+        Repeater {
+            id: screenInfo
+            model: Qt.application.screens
+            Shared.Label {
+                lineHeight: 1.5
+                text: name + "\n" + virtualX + ", " + virtualY + " " + modelData.width + "x" + modelData.height
+            }
+        }
+    }
+
+    Component.onCompleted: {
+        var screens = Qt.application.screens;
+        for (var i = 0; i < screens.length; ++i)
+            console.log("screen " + screens[i].name + " has geometry " +
+                        screens[i].virtualX + ", " + screens[i].virtualY + " " +
+                        screens[i].width + "x" + screens[i].height)
+    }
+}
diff --git a/examples/quick/window/ScreenInfo.qml b/examples/quick/window/CurrentScreen.qml
index 7d7cd946c5..c65baab1f4 100644
--- a/examples/quick/window/ScreenInfo.qml
+++ b/examples/quick/window/CurrentScreen.qml
@@ -92,6 +92,9 @@ Item {
         Shared.Label { text: "available virtual desktop" }
         Shared.Label { text: Screen.desktopAvailableWidth + "x" + Screen.desktopAvailableHeight }
 
+        Shared.Label { text: "position in virtual desktop" }
+        Shared.Label { text: Screen.virtualX + ", " + Screen.virtualY }
+
         Shared.Label { text: "orientation" }
         Shared.Label { text: orientationToString(Screen.orientation) + " (" + Screen.orientation + ")" }
 
diff --git a/examples/quick/window/doc/src/window.qdoc b/examples/quick/window/doc/src/window.qdoc
index 5cd51beceb..2028b31383 100644
--- a/examples/quick/window/doc/src/window.qdoc
+++ b/examples/quick/window/doc/src/window.qdoc
@@ -73,7 +73,7 @@
     \l Screen has several properties which are generally useful to
     applications which need to rotate some content when the screen orientation
     changes, to position windows on the screen or to convert real units to
-    logical pixel units.  ScreenInfo.qml (which is displayed inline in
+    logical pixel units.  CurrentScreen.qml (which is displayed inline in
     window.qml, or can be run by itself with qmlscene) simply displays the
     property values, while the splash screen uses them to center the window on
     the screen.
diff --git a/examples/quick/window/window.qml b/examples/quick/window/window.qml
index f3052a7d62..d27ab3d0a3 100644
--- a/examples/quick/window/window.qml
+++ b/examples/quick/window/window.qml
@@ -39,7 +39,7 @@
 ****************************************************************************/
 
 import QtQuick 2.0
-import QtQuick.Window 2.1
+import QtQuick.Window 2.3
 import "../shared" as Shared
 
 QtObject {
@@ -47,7 +47,7 @@ QtObject {
     property SystemPalette palette: SystemPalette { }
 
     property var controlWindow: Window {
-        width: visibilityLabel.implicitWidth * 1.2
+        width: col.implicitWidth + defaultSpacing * 2
         height: col.implicitHeight + defaultSpacing * 2
         color: palette.window
         title: "Control Window"
@@ -127,12 +127,17 @@ QtObject {
                       " and has visibility " + parent.visibilityToString(testWindow.visibility)
             }
             Rectangle {
-                id: horizontalRule
-                color: "black"
+                color: palette.text
                 width: parent.width
                 height: 1
             }
-            ScreenInfo { }
+            CurrentScreen { }
+            Rectangle {
+                color: palette.text
+                width: parent.width
+                height: 1
+            }
+            AllScreens { width: parent.width }
         }
     }
 
diff --git a/examples/quick/window/window.qrc b/examples/quick/window/window.qrc
index dc211bdaaf..89d1de1b1f 100644
--- a/examples/quick/window/window.qrc
+++ b/examples/quick/window/window.qrc
@@ -2,6 +2,7 @@
     <qresource prefix="/window">
         <file>window.qml</file>
         <file>Splash.qml</file>
-        <file>ScreenInfo.qml</file>
+        <file>CurrentScreen.qml</file>
+        <file>AllScreens.qml</file>
     </qresource>
 </RCC>