iOS Style: Add ScrollBar control

Use the same assets as for the scroll indicator, as there is typically
no scrollbar on iOS, but we do support adding scrollbars to ScrollView
in our controls.

Change-Id: Icdf426d394548ac617b202ceed063a78f41a0225
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

2 files changed, 86 insertions, 0 deletions

diff --git a/src/quickcontrols2/ios/CMakeLists.txt b/src/quickcontrols2/ios/CMakeLists.txt
index 28532de34f..247460dfe5 100644
--- a/src/quickcontrols2/ios/CMakeLists.txt
+++ b/src/quickcontrols2/ios/CMakeLists.txt
@@ -23,6 +23,7 @@ set(qml_files
     "SwipeDelegate.qml"
     "StackView.qml"
     "TreeViewDelegate.qml"
+    "ScrollBar.qml"
 )
 set_source_files_properties(Slider.qml PROPERTIES
     QT_QML_SOURCE_VERSIONS "2.2;6.0"
diff --git a/src/quickcontrols2/ios/ScrollBar.qml b/src/quickcontrols2/ios/ScrollBar.qml
new file mode 100644
index 0000000000..b309d7a25d
--- /dev/null
+++ b/src/quickcontrols2/ios/ScrollBar.qml
@@ -0,0 +1,85 @@
+/****************************************************************************
+**
+** Copyright (C) 2022 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt Quick Controls 2 module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** 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 https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://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.LGPL3 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-3.0.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 (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick
+import QtQuick.Templates as T
+import QtQuick.Controls.iOS
+import QtQuick.Controls.impl
+
+T.ScrollBar {
+    id: control
+
+    implicitWidth: Math.max(implicitBackgroundWidth + leftInset + rightInset,
+                            implicitContentWidth + leftPadding + rightPadding)
+    implicitHeight: Math.max(implicitBackgroundHeight + topInset + bottomInset,
+                             implicitContentHeight + topPadding + bottomPadding)
+
+    visible: control.policy !== T.ScrollBar.AlwaysOff
+    minimumSize: orientation === Qt.Horizontal ? height / width : width / height
+
+    contentItem: NinePatchImage {
+        width: control.availableWidth
+        height: control.availableHeight
+
+        source: control.IOS.url + "scrollindicator-handle"
+        NinePatchImageSelector on source {
+            states: [
+                {"light": control.IOS.theme === IOS.Light},
+                {"dark": control.IOS.theme === IOS.Dark},
+                {"horizontal": control.horizontal},
+                {"vertical": control.vertical}
+            ]
+        }
+        opacity: 0.0
+    }
+
+    states: State {
+        name: "active"
+        when: control.policy === T.ScrollBar.AlwaysOn || (control.active && control.size < 1.0)
+        PropertyChanges { control.contentItem.opacity: 0.75 }
+    }
+
+    transitions: Transition {
+        from: "active"
+        SequentialAnimation {
+            PauseAnimation { duration: 450 }
+            NumberAnimation { target: control.contentItem; duration: 200; property: "opacity"; to: 0.0 }
+        }
+    }
+}