Windows: add SelectionRectangle.qml

Add a SelectionRectangle to the Windows style. Since native windows
apps doesn't use selection handles, we just add some small
subtle triangles on the inside of the selection.

Note: If the developer want the handles to be completely hidden,
he can set the handle delegates to null.

Pick-to: 6.2
Change-Id: Id2a98127803c7feb341480e97c7dcb8ef8d75f81
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

src/quickcontrols2/windows/CMakeLists.txt

@@ -10,6 +10,7 @@ set(qml_files
     "GroupBox.qml"
     "ProgressBar.qml"
     "RadioButton.qml"
+    "SelectionRectangle.qml"
     "Slider.qml"
     "SpinBox.qml"
     "TextArea.qml"

src/quickcontrols2/windows/SelectionRectangle.qml

@@ -0,0 +1,92 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the Qt Quick Controls 2 module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL3$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPLv3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or later as published by the Free
+** Software Foundation and appearing in the file LICENSE.GPL included in
+** the packaging of this file. Please review the following information to
+** ensure the GNU General Public License version 2.0 requirements will be
+** met: http://www.gnu.org/licenses/gpl-2.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick
+import QtQuick.Templates as T
+import QtQuick.Shapes
+
+T.SelectionRectangle {
+    id: control
+
+    topLeftHandle: Item {
+        width: 20
+        height: 20
+        visible: control.active
+        property T.SelectionRectangle control: SelectionRectangle.control
+
+        Shape {
+            x: (parent.width / 2) + 2
+            y: (parent.height / 2) + 2
+            width: 10
+            height: 10
+
+            ShapePath {
+                fillColor: control.palette.alternateBase
+                strokeWidth: -1
+                startX: 0
+                startY: 0
+                PathLine { x: 0; y: 6 }
+                PathLine { x: 6; y: 0 }
+                PathLine { x: 0; y: 0 }
+            }
+        }
+    }
+
+    bottomRightHandle: Item {
+        width: 20
+        height: 20
+        visible: control.active
+        property T.SelectionRectangle control: SelectionRectangle.control
+
+        Shape {
+            x: (parent.width / 2) - 8
+            y: (parent.height / 2) - 8
+            width: 10
+            height: 10
+
+            ShapePath {
+                fillColor: control.palette.alternateBase
+                strokeWidth: -1
+                startX: 0
+                startY: 6
+                PathLine { x: 6; y: 6 }
+                PathLine { x: 6; y: 0 }
+                PathLine { x: 0; y: 6 }
+            }
+        }
+    }
+
+}

src/quickcontrols2/windows/windows.pri

@@ -6,6 +6,7 @@ QML_FILES += \
     $$PWD/GroupBox.qml \
     $$PWD/ProgressBar.qml \
     $$PWD/RadioButton.qml \
+    $$PWD/SelectionRectangle.qml \
     $$PWD/Slider.qml \
     $$PWD/SpinBox.qml \
     $$PWD/TextArea.qml \