FluentWinUI3 Style: Add documentation

Task-number: QTBUG-125748
Pick-to: 6.8
Change-Id: Iaeedd4044c686d1dce4ef611a4cf9a7ea8060f83
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

src/quickcontrols/doc/src/qtquickcontrols-fluentwinui3.qdoc

@@ -0,0 +1,46 @@
+// Copyright (C) 2024 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only
+
+/*!
+    \page qtquickcontrols-fluentwinui3.html
+    \title FluentWinUI3 Style
+
+    The FluentWinUI3 Style is a modern, native-looking style designed for platforms
+    running Windows 11 and above.
+    \l {detailed-desc-FluentWinUI3}{More...}
+
+    \styleimport {QtQuick.Controls.FluentWinUI3} {Qt 6.8}
+
+    \section1 Detailed Description
+    \target detailed-desc-FluentWinUI3
+
+    The FluentWinUI3 style draws inspiration from the Fluent UI design and the WinUI3 framework.
+    It utilizes image assets for most of the visual elements while at the same time adhering
+    to the global theme colors configured on Windows systems and the \l {fluentwinui3-palette}{palette}.
+
+    The FluentWinUI3 style is not a native style and can be run on all supported platforms,
+    looking more or less identical everywhere. Minor differences may occur due to differences
+    in available system fonts and font rendering engines.
+
+    \include style-screenshots.qdocinc {file} {FluentWinUI3} {fluentwinui3}
+
+    To run an application with the FluentWinUI3 style, see
+    \l {Using Styles in Qt Quick Controls}.
+
+    \section2 Current state
+
+    The FluentWinUI3 style is under development, and some controls are not yet supported. Those controls
+    are: \l Dial, \l Dialog, \ DialogButtonBox, \l DelayButton, \l Drawer, \l HorizontalHeaderView,
+    \l RoundButton, \l SplitView, \l StackView, \l SwipeDelegate, \l SwipeView, \l ToolSeparator,
+    \l TreeViewDelegate, \l Tumbler, and \l VerticalHeaderView. Those will fall back to use the \l {Fusion Style}.
+
+    \section2 Customization
+
+    \section3 Palette
+    \target fluentwinui3-palette
+
+    The FluentWinUI3 style supports palette customization via the \l {Item::}{palette}
+    property and the \l {Palette Configuration}{qtquickcontrols2.conf} file. As with other styles,
+    the exact \l[QML]{Palette}{palette roles} that the FluentWinUI3 style uses are style-dependent.
+    \note Since the style incorporates image assets, certain elements of the control may not be customizable.
+*/

tests/manual/quickcontrols/styles/styles.qml

@@ -43,6 +43,7 @@
         QT_QUICK_CONTROLS_STYLE=Imagine $app 0 400 &
         QT_QUICK_CONTROLS_STYLE=iOS $app 400 0 &
         QT_QUICK_CONTROLS_STYLE=Universal $app 800 400 &
+        QT_QUICK_CONTROLS_STYLE=FluentWinUI3 $app 1200 400 &
         #QT_QUICK_CONTROLS_STYLE=Windows $app 1200 400 &
 
     Step 2
@@ -58,6 +59,8 @@
         mogrify -resize 50% qtquickcontrols-basic.png
         mogrify -resize 50% qtquickcontrols-fusion-light.png
         mogrify -resize 50% qtquickcontrols-fusion-dark.png
+        mogrify -resize 50% qtquickcontrols-fluentwinui3-light.png
+        mogrify -resize 50% qtquickcontrols-fluentwinui3-dark.png
         mogrify -resize 50% qtquickcontrols-imagine.png
         mogrify -resize 50% qtquickcontrols-ios-light.png
         mogrify -resize 50% qtquickcontrols-ios-dark.png