From dbea569c88de01af838c19e47019c6cafb4d1e95 Mon Sep 17 00:00:00 2001
From: collecting <collecting@citron-emu.org>
Date: Wed, 29 Oct 2025 05:25:07 +0000
Subject: [PATCH] feat: Controller Overlay

---
 src/citron/controller_overlay.cpp | 123 ++++++++++++++++++++++++++++++
 1 file changed, 123 insertions(+)
 create mode 100644 src/citron/controller_overlay.cpp

diff --git a/src/citron/controller_overlay.cpp b/src/citron/controller_overlay.cpp
new file mode 100644
index 000000000..c843669bb
--- /dev/null
+++ b/src/citron/controller_overlay.cpp
@@ -0,0 +1,123 @@
+// SPDX-FileCopyrightText: Copyright 2025 citron Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "citron/controller_overlay.h"
+#include "citron/configuration/configure_input_player_widget.h"
+#include "citron/main.h"
+#include "core/core.h"
+#include "hid_core/hid_core.h"
+
+#include <QGridLayout>
+#include <QMouseEvent>
+#include <QPainter>
+#include <QPainterPath>
+#include <QSizeGrip>
+#include <QWindow> // Required for Wayland dragging
+#include <QResizeEvent>
+
+namespace {
+// Helper to get the active controller for Player 1
+Core::HID::EmulatedController* GetPlayer1Controller(Core::System* system) {
+    if (!system) return nullptr;
+    Core::HID::HIDCore& hid_core = system->HIDCore();
+    auto* handheld = hid_core.GetEmulatedController(Core::HID::NpadIdType::Handheld);
+    if (handheld && handheld->IsConnected()) {
+        return handheld;
+    }
+    return hid_core.GetEmulatedController(Core::HID::NpadIdType::Player1);
+}
+}
+
+ControllerOverlay::ControllerOverlay(GMainWindow* parent)
+    : QWidget(parent, Qt::Tool | Qt::FramelessWindowHint | Qt::WindowStaysOnTopHint),
+      main_window(parent) {
+
+    setAttribute(Qt::WA_TranslucentBackground);
+
+    auto* layout = new QGridLayout(this);
+    setLayout(layout);
+    // Set margins to 0 so the controller can go right to the edge of the resizable window
+    layout->setContentsMargins(0, 0, 0, 0);
+
+    // Create the widget that draws the controller and make it transparent
+    controller_widget = new PlayerControlPreview(this);
+    controller_widget->setAttribute(Qt::WA_TranslucentBackground);
+
+    // Disable the raw joystick (deadzone) visualization
+    controller_widget->SetRawJoystickVisible(false);
+
+    // Allow the widget to expand and shrink with the window
+    controller_widget->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
+    layout->addWidget(controller_widget, 0, 0);
+
+    // Add a size grip for resizing
+    size_grip = new QSizeGrip(this);
+    layout->addWidget(size_grip, 0, 0, Qt::AlignBottom | Qt::AlignRight);
+
+    // Start the timer for continuous updates
+    connect(&update_timer, &QTimer::timeout, this, &ControllerOverlay::UpdateControllerState);
+    update_timer.start(16); // ~60 FPS
+
+    // Set a minimum size and a default starting size
+    setMinimumSize(225, 175);
+    resize(450, 350);
+}
+
+ControllerOverlay::~ControllerOverlay() = default;
+
+void ControllerOverlay::UpdateControllerState() {
+    Core::System* system = main_window->GetSystem();
+    Core::HID::EmulatedController* controller = GetPlayer1Controller(system);
+    if (controller_widget && controller) {
+        controller_widget->SetController(controller);
+        controller_widget->UpdateInput();
+    }
+}
+
+// The paint event is now empty, which makes the background fully transparent.
+void ControllerOverlay::paintEvent(QPaintEvent* event) {
+    Q_UNUSED(event);
+    // Intentionally left blank to achieve a fully transparent window background.
+}
+
+// These functions handle dragging the frameless window
+void ControllerOverlay::mousePressEvent(QMouseEvent* event) {
+    if (event->button() == Qt::LeftButton && !size_grip->geometry().contains(event->pos())) {
+#if defined(Q_OS_LINUX)
+        // Use system move on Wayland/Linux for proper dragging
+        if (windowHandle()) {
+            windowHandle()->startSystemMove();
+        }
+#else
+        // Original dragging implementation for other platforms (Windows, etc.)
+        is_dragging = true;
+        drag_start_pos = event->globalPosition().toPoint() - this->pos();
+#endif
+        event->accept();
+    }
+}
+
+void ControllerOverlay::mouseMoveEvent(QMouseEvent* event) {
+#if !defined(Q_OS_LINUX)
+    if (is_dragging) {
+        move(event->globalPosition().toPoint() - drag_start_pos);
+        event->accept();
+    }
+#else
+    // On Linux, the window manager handles the move, so we do nothing here.
+    Q_UNUSED(event);
+#endif
+}
+
+void ControllerOverlay::mouseReleaseEvent(QMouseEvent* event) {
+    if (event->button() == Qt::LeftButton) {
+        is_dragging = false;
+        event->accept();
+    }
+}
+
+void ControllerOverlay::resizeEvent(QResizeEvent* event) {
+    QWidget::resizeEvent(event);
+    // This ensures the layout and its widgets (like the size grip) are correctly repositioned on resize.
+    layout()->update();
+}