From bc0b0adb0187b2bc174822cf9faf32ed2db0fb36 Mon Sep 17 00:00:00 2001
From: Andrey Butirsky <butirsky@gmail.com>
Date: Wed, 25 Nov 2020 17:37:00 +0300
Subject: [PATCH] feat: Keyboard Layout applet: switch layout by mouse wheel

In parity with legacy layout Widget

FEATURE:
CCBUG: 390079
---
 components/keyboardlayout/keyboardlayout.cpp         |  5 +++++
 components/keyboardlayout/keyboardlayout.h           |  1 +
 .../keyboardlayout/org.kde.KeyboardLayouts.xml       |  2 ++
 components/workspace/KeyboardLayoutButton.qml        | 12 ++++++++++++
 4 files changed, 20 insertions(+)

diff --git a/components/keyboardlayout/keyboardlayout.cpp b/components/keyboardlayout/keyboardlayout.cpp
index 542d0371b..8b7377b9e 100644
--- a/components/keyboardlayout/keyboardlayout.cpp
+++ b/components/keyboardlayout/keyboardlayout.cpp
@@ -63,6 +63,11 @@ void KeyboardLayout::switchToNextLayout()
     if (mIface) mIface->switchToNextLayout();
 }
 
+void KeyboardLayout::switchToPreviousLayout()
+{
+    if (mIface) mIface->switchToPreviousLayout();
+}
+
 template<class T>
 void KeyboardLayout::requestDBusData(QDBusPendingReply<T> pendingReply, T &out, void (KeyboardLayout::*notify)())
 {
diff --git a/components/keyboardlayout/keyboardlayout.h b/components/keyboardlayout/keyboardlayout.h
index 3f368816b..74b210a46 100644
--- a/components/keyboardlayout/keyboardlayout.h
+++ b/components/keyboardlayout/keyboardlayout.h
@@ -41,6 +41,7 @@ Q_SIGNALS:
 
 protected Q_SLOTS:
     void switchToNextLayout();
+    void switchToPreviousLayout();
 
 private:
     enum DBusData {LayoutDisplayName, LayoutLongName, Layouts};
diff --git a/components/keyboardlayout/org.kde.KeyboardLayouts.xml b/components/keyboardlayout/org.kde.KeyboardLayouts.xml
index e802757cf..dd7eac09d 100644
--- a/components/keyboardlayout/org.kde.KeyboardLayouts.xml
+++ b/components/keyboardlayout/org.kde.KeyboardLayouts.xml
@@ -9,6 +9,8 @@
     </signal>
     <method name="switchToNextLayout">
     </method>
+    <method name="switchToPreviousLayout">
+    </method>
     <method name="setLayout">
       <arg type="b" direction="out"/>
       <arg name="layout" type="s" direction="in"/>
diff --git a/components/workspace/KeyboardLayoutButton.qml b/components/workspace/KeyboardLayoutButton.qml
index 32d32d489..b56f5583a 100644
--- a/components/workspace/KeyboardLayoutButton.qml
+++ b/components/workspace/KeyboardLayoutButton.qml
@@ -23,6 +23,18 @@ PlasmaComponents3.ToolButton {
 
     onClicked: layout.switchToNextLayout()
 
+    MouseArea {
+        anchors.fill: parent
+        acceptedButtons: Qt.NoButton
+        onWheel: {
+            if (wheel.angleDelta.y > 0) {
+                layout.switchToNextLayout()
+            } else {
+                layout.switchToPreviousLayout()
+            }
+        }
+    }
+
     KeyboardLayout {
         id: layout
     }