QIcon: document the support for icon fonts

Add a C++ snippet that shows how to use a named glyph from an icon font,
and add a QML snippet file that shows how to change the icon based on
the state of a tool button.

[ChangeLog][Gui][QIcon] QIcon can now generate icons from the named
glyphs of an icon font.

Change-Id: I1179ed93774c2c209094fffb910b2e06cbe2f572
Reviewed-by: Mitch Curtis <[email protected]>

2 files changed, 21 insertions, 0 deletions

diff --git a/src/gui/doc/snippets/code/src_gui_image_qicon.cpp b/src/gui/doc/snippets/code/src_gui_image_qicon.cpp
index a7f27a7fdd2..2901ddd592b 100644
--- a/src/gui/doc/snippets/code/src_gui_image_qicon.cpp
+++ b/src/gui/doc/snippets/code/src_gui_image_qicon.cpp
@@ -49,6 +49,11 @@ void wrapper1() {
 QIcon undoicon = QIcon::fromTheme(QIcon::ThemeIcon::EditUndo);
 //! [fromTheme]
 
+//! [iconFont]
+QIcon::setThemeName("Material Symbols Outlined");
+QIcon muteIcon = QIcon::fromTheme(u"volume_off"_s);
+//! [iconFont]
+
 } // wrapper1
 
 
diff --git a/src/gui/doc/snippets/code/src_gui_image_qicon.qml b/src/gui/doc/snippets/code/src_gui_image_qicon.qml
new file mode 100644
index 00000000000..e5a653f38bd
--- /dev/null
+++ b/src/gui/doc/snippets/code/src_gui_image_qicon.qml
@@ -0,0 +1,16 @@
+// Copyright (C) 2024 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+import QtQuick.Controls
+
+Window {
+
+//! [iconFont]
+ToolButton {
+    id: muteButton
+    checkable: true
+    icon.name: checked ? "volume_off" : "volume_up"
+}
+//! [iconFont]
+
+}