plugins: add a "hidecursor" effect

This hides the mouse cursor on inactivity or keypress (configurable in the KCM).

BUG: 465119

src/plugins/CMakeLists.txt

@@ -66,6 +66,7 @@ add_subdirectory(fallapart)
 add_subdirectory(frozenapp)
 add_subdirectory(fullscreen)
 add_subdirectory(glide)
+add_subdirectory(hidecursor)
 add_subdirectory(highlightwindow)
 add_subdirectory(idletime)
 add_subdirectory(invert)

src/plugins/hidecursor/CMakeLists.txt

@@ -0,0 +1,34 @@
+kwin_add_builtin_effect(hidecursor)
+
+target_sources(hidecursor PRIVATE
+    hidecursor.cpp
+    main.cpp
+)
+
+kconfig_add_kcfg_files(hidecursor
+    hidecursorconfig.kcfgc
+)
+
+target_link_libraries(hidecursor PRIVATE
+    kwin
+
+    KF6::ConfigGui
+)
+
+#######################################
+# Config
+if (KWIN_BUILD_KCMS)
+    set(kwin_hidecursor_config_SRCS hidecursor_config.cpp)
+    ki18n_wrap_ui(kwin_hidecursor_config_SRCS hidecursor_config.ui)
+    kconfig_add_kcfg_files(kwin_hidecursor_config_SRCS hidecursorconfig.kcfgc)
+
+    kwin_add_effect_config(kwin_hidecursor_config ${kwin_hidecursor_config_SRCS})
+
+    target_link_libraries(kwin_hidecursor_config
+        KF6::KCMUtils
+        KF6::CoreAddons
+        KF6::I18n
+        KF6::XmlGui
+        KWinEffectsInterface
+    )
+endif()

src/plugins/hidecursor/hidecursor.cpp

@@ -0,0 +1,107 @@
+/*
+    SPDX-FileCopyrightText: 2024 Jin Liu <m.liu.jin@gmail.com>
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+
+#include "hidecursor.h"
+#include "cursor.h"
+#include "effect/effecthandler.h"
+#include "hidecursorconfig.h"
+#include "input_event.h"
+
+namespace KWin
+{
+
+HideCursorEffect::HideCursorEffect()
+    : m_cursor(Cursors::self()->mouse())
+{
+    input()->installInputEventSpy(this);
+
+    m_inactivityTimer.setSingleShot(true);
+    connect(&m_inactivityTimer, &QTimer::timeout, this, [this]() {
+        hideCursor();
+    });
+
+    HideCursorConfig::instance(effects->config());
+    reconfigure(ReconfigureAll);
+}
+
+HideCursorEffect::~HideCursorEffect()
+{
+    showCursor();
+}
+
+bool HideCursorEffect::supported()
+{
+    return effects->waylandDisplay();
+}
+
+void HideCursorEffect::reconfigure(ReconfigureFlags flags)
+{
+    HideCursorConfig::self()->read();
+    m_inactivityDuration = HideCursorConfig::inactivityDuration() * 1000;
+    m_hideOnTyping = HideCursorConfig::hideOnTyping();
+
+    m_inactivityTimer.stop();
+    showCursor();
+    if (m_inactivityDuration > 0) {
+        m_inactivityTimer.start(m_inactivityDuration);
+    }
+}
+
+bool HideCursorEffect::isActive() const
+{
+    return false;
+}
+
+void HideCursorEffect::pointerEvent(MouseEvent *event)
+{
+    showCursor();
+    if (m_inactivityDuration > 0) {
+        m_inactivityTimer.start(m_inactivityDuration);
+    }
+}
+
+void HideCursorEffect::keyEvent(KeyEvent *event)
+{
+    if (m_hideOnTyping && event->type() == QEvent::KeyPress) {
+        auto key = event->key();
+        switch (key) {
+        case Qt::Key_Shift:
+        case Qt::Key_Control:
+        case Qt::Key_Meta:
+        case Qt::Key_Alt:
+        case Qt::Key_AltGr:
+        case Qt::Key_Super_L:
+        case Qt::Key_Super_R:
+        case Qt::Key_Hyper_L:
+        case Qt::Key_Hyper_R:
+        case Qt::Key_Escape:
+            break;
+
+        default:
+            hideCursor();
+        }
+    }
+}
+
+void HideCursorEffect::showCursor()
+{
+    if (m_cursorHidden) {
+        effects->showCursor();
+        m_cursorHidden = false;
+    }
+}
+
+void HideCursorEffect::hideCursor()
+{
+    if (!m_cursorHidden) {
+        effects->hideCursor();
+        m_cursorHidden = true;
+    }
+}
+
+} // namespace KWin
+
+#include "moc_hidecursor.cpp"

src/plugins/hidecursor/hidecursor.h

@@ -0,0 +1,47 @@
+/*
+    SPDX-FileCopyrightText: 2024 Jin Liu <m.liu.jin@gmail.com>
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+
+#pragma once
+
+#include "effect/effect.h"
+#include "input_event_spy.h"
+
+#include <QTimer>
+
+namespace KWin
+{
+
+class Cursor;
+
+class HideCursorEffect : public Effect, public InputEventSpy
+{
+    Q_OBJECT
+
+public:
+    HideCursorEffect();
+    ~HideCursorEffect() override;
+
+    static bool supported();
+
+    void reconfigure(ReconfigureFlags flags) override;
+    bool isActive() const override;
+
+    void pointerEvent(MouseEvent *event) override;
+    void keyEvent(KeyEvent *event) override;
+
+private:
+    void showCursor();
+    void hideCursor();
+
+    int m_inactivityDuration;
+    bool m_hideOnTyping;
+
+    Cursor *m_cursor;
+    bool m_cursorHidden = false;
+    QTimer m_inactivityTimer;
+};
+
+} // namespace KWin

src/plugins/hidecursor/hidecursor_config.cpp

@@ -0,0 +1,43 @@
+/*
+    SPDX-FileCopyrightText: 2024 Jin Liu <m.liu.jin@gmail.com>
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+#include "hidecursor_config.h"
+
+#include <config-kwin.h>
+
+// KConfigSkeleton
+#include "hidecursorconfig.h"
+
+#include <KPluginFactory>
+#include <kwineffects_interface.h>
+
+K_PLUGIN_CLASS(KWin::HideCursorEffectConfig)
+
+namespace KWin
+{
+
+HideCursorEffectConfig::HideCursorEffectConfig(QObject *parent, const KPluginMetaData &data)
+    : KCModule(parent, data)
+{
+    HideCursorConfig::instance(KWIN_CONFIG);
+    m_ui.setupUi(widget());
+
+    addConfig(HideCursorConfig::self(), widget());
+}
+
+void HideCursorEffectConfig::save()
+{
+    KCModule::save();
+    OrgKdeKwinEffectsInterface interface(QStringLiteral("org.kde.KWin"),
+                                         QStringLiteral("/Effects"),
+                                         QDBusConnection::sessionBus());
+    interface.reconfigureEffect(QStringLiteral("hidecursor"));
+}
+
+} // namespace
+
+#include "hidecursor_config.moc"
+
+#include "moc_hidecursor_config.cpp"

src/plugins/hidecursor/hidecursor_config.h

@@ -0,0 +1,30 @@
+/*
+    SPDX-FileCopyrightText: 2024 Jin Liu <m.liu.jin@gmail.com>
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+
+#pragma once
+
+#include <kcmodule.h>
+
+#include "ui_hidecursor_config.h"
+
+class KActionCollection;
+
+namespace KWin
+{
+class HideCursorEffectConfig : public KCModule
+{
+    Q_OBJECT
+public:
+    explicit HideCursorEffectConfig(QObject *parent, const KPluginMetaData &data);
+
+public Q_SLOTS:
+    void save() override;
+
+private:
+    Ui::HideCursorEffectConfig m_ui;
+};
+
+} // namespace

src/plugins/hidecursor/hidecursor_config.ui

@@ -0,0 +1,31 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>HideCursorEffectConfig</class>
+ <widget class="QWidget" name="HideCursorEffectConfig">
+  <layout class="QFormLayout" name="formLayout">
+   <item row="0" column="0">
+    <widget class="QLabel" name="label_InactivityDuration">
+     <property name="text">
+      <string>Inactivity duration (seconds):</string>
+     </property>
+    </widget>
+   </item>
+   <item row="0" column="1">
+    <widget class="QSpinBox" name="kcfg_InactivityDuration">
+     <property name="minimum">
+      <number>1</number>
+     </property>
+    </widget>
+   </item>
+   <item row="1" column="0">
+    <widget class="QCheckBox" name="kcfg_HideOnTyping">
+        <property name="text">
+        <string>Hide cursor on typing</string>
+        </property>
+    </widget>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections/>
+</ui>

src/plugins/hidecursor/hidecursorconfig.kcfg

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<kcfg xmlns="http://www.kde.org/standards/kcfg/1.0"
+      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+      xsi:schemaLocation="http://www.kde.org/standards/kcfg/1.0
+                          http://www.kde.org/standards/kcfg/1.0/kcfg.xsd" >
+    <kcfgfile arg="true"/>
+    <group name="Effect-hidecursor">
+        <entry name="InactivityDuration" type="UInt">
+            <default>5</default>
+        </entry>
+        <entry name="HideOnTyping" type="Bool">
+            <default>false</default>
+        </entry>
+    </group>
+</kcfg>

src/plugins/hidecursor/hidecursorconfig.kcfgc

@@ -0,0 +1,8 @@
+#     SPDX-FileCopyrightText: 2024 Jin Liu <m.liu.jin@gmail.com>
+#
+#     SPDX-License-Identifier: GPL-2.0-or-later
+
+File=hidecursorconfig.kcfg
+ClassName=HideCursorConfig
+NameSpace=KWin
+Singleton=true

src/plugins/hidecursor/main.cpp

@@ -0,0 +1,18 @@
+/*
+    SPDX-FileCopyrightText: 2024 Jin Liu <m.liu.jin@gmail.com>
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+
+#include "hidecursor.h"
+
+namespace KWin
+{
+
+KWIN_EFFECT_FACTORY_SUPPORTED(HideCursorEffect,
+                              "metadata.json.stripped",
+                              return HideCursorEffect::supported();)
+
+} // namespace KWin
+
+#include "main.moc"

src/plugins/hidecursor/metadata.json

@@ -0,0 +1,10 @@
+{
+    "KPlugin": {
+        "Category": "Accessibility",
+        "Description": "Hide mouse cursor on inactivity or keyboard input",
+        "EnabledByDefault": false,
+        "License": "GPL",
+        "Name": "Hide Cursor"
+    },
+    "X-KDE-ConfigModule": "kwin_hidecursor_config"
+}