Expose contentArea as contentItem in ApplicationWindow

This will intentionally shadow the QQuickWindow::contentItem

This enables users of ApplicationWindow to correctly set the
{min,max}imumHeight for the contents of the ApplicationWindow
(excluding menubar, toolbar and statusbar).

With this information at hand, the ApplicationWindow can easily deduct
the correct total size of its {min,max}imumHeight *including* the
menubar, toolbar and statusbar.

Previously, it was for instance not possible to set an exact
minimumHeight because it didn't take the toolbar, statusbar or
menubar into consideration

One small disadvantage is that the contentItem.minimumWidth
cannot be autocompleted. qmlplugindump does not inspect the members
of ContentItem.

Task-number: QTBUG-32443
Change-Id: I9903e7d4b5e6db7bd7c3c46351a2bb5578f67a57
Reviewed-by: J-P Nurmi <jpnurmi@digia.com>

3 files changed, 111 insertions, 0 deletions

diff --git a/src/controls/Private/ContentItem.qml b/src/controls/Private/ContentItem.qml
new file mode 100644
index 00000000..dbb4a50e
--- /dev/null
+++ b/src/controls/Private/ContentItem.qml
@@ -0,0 +1,109 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the Qt Quick Controls module 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 Digia Plc and its Subsidiary(-ies) 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 2.1
+import QtQuick.Layouts 1.1
+
+Item {
+    id: contentItem
+    property real minimumWidth: __calcMinimum('Width')
+    property real minimumHeight: __calcMinimum('Height')
+    property real maximumWidth: __calcMaximum('Width')
+    property real maximumHeight: __calcMaximum('Height')
+    implicitWidth: __calcImplicitWidth()
+    implicitHeight: __calcImplicitHeight()
+
+    /*! \internal */
+    property Item __layoutItem: contentItem.children.length === 1 ? contentItem.children[0] : null
+    /*! \internal */
+    property real __marginsWidth: __layoutItem ? __layoutItem.anchors.leftMargin + __layoutItem.anchors.rightMargin : 0
+    /*! \internal */
+    property real __marginsHeight: __layoutItem ? __layoutItem.anchors.topMargin + __layoutItem.anchors.bottomMargin : 0
+
+    /*! \internal */
+    property bool __noMinimumWidthGiven : false
+    /*! \internal */
+    property bool __noMinimumHeightGiven : false
+    /*! \internal */
+    property bool __noImplicitWidthGiven : false
+    /*! \internal */
+    property bool __noImplicitHeightGiven : false
+
+    function __calcImplicitWidth() {
+        if (__layoutItem && __layoutItem.anchors.fill)
+            return __calcImplicit('Width')
+        return contentItem.childrenRect.x + contentItem.childrenRect.width
+    }
+
+    function __calcImplicitHeight() {
+        if (__layoutItem && __layoutItem.anchors.fill)
+            return __calcImplicit('Height')
+        return contentItem.childrenRect.y + contentItem.childrenRect.height
+    }
+
+    function __calcImplicit(hw) {
+        var pref = __layoutItem.Layout['preferred' + hw]
+        if (pref < 0) {
+            pref = __layoutItem['implicit' + hw]
+        }
+        contentItem['__noImplicit' + hw + 'Given'] = (pref === 0 ? true : false)
+        pref += contentItem['__margins' + hw]
+        return pref
+    }
+
+    function __calcMinimum(hw) {  // hw is 'Width' or 'Height'
+        return (__layoutItem && __layoutItem.anchors.fill) ? __calcMinMax('minimum', hw) : 0
+    }
+
+    function __calcMaximum(hw) {  // hw is 'Width' or 'Height'
+        return (__layoutItem && __layoutItem.anchors.fill) ? __calcMinMax('maximum', hw) : Number.POSITIVE_INFINITY
+    }
+
+    function __calcMinMax(minMaxConstraint, hw) {
+        var attachedPropName = minMaxConstraint + hw
+        var extent = __layoutItem.Layout[attachedPropName]
+
+        if (minMaxConstraint === 'minimum')
+            contentItem['__noMinimum' + hw + 'Given'] = (extent === 0 ? true : false)
+
+        extent += contentItem['__margins' + hw]
+        return extent
+    }
+}
diff --git a/src/controls/Private/private.pri b/src/controls/Private/private.pri
index 30464974..7852edff 100644
--- a/src/controls/Private/private.pri
+++ b/src/controls/Private/private.pri
@@ -45,6 +45,7 @@ PRIVATE_QML_FILES += \
     $$PWD/ColumnMenuContent.qml \
     $$PWD/MenuContentItem.qml \
     $$PWD/MenuContentScroller.qml \
+    $$PWD/ContentItem.qml \
     $$PWD/qmldir
 
 QML_FILES += $$PRIVATE_QML_FILES
diff --git a/src/controls/Private/qmldir b/src/controls/Private/qmldir
index 35138780..5dc8061c 100644
--- a/src/controls/Private/qmldir
+++ b/src/controls/Private/qmldir
@@ -19,4 +19,5 @@ ToolButtonStyle 1.0 ../Styles/Base/ToolButtonStyle.qml
 MenuContentItem 1.0 MenuContentItem.qml
 MenuContentScroller 1.0 MenuContentScroller.qml
 ColumnMenuContent 1.0 ColumnMenuContent.qml
+ContentItem 1.0 ContentItem.qml
 singleton TextSingleton 1.0 TextSingleton.qml