refactor(windows): remove legacy mpv compositing, require DComp engine

windows/runner/CMakeLists.txt

@@ -11,9 +11,6 @@ add_executable(${BINARY_NAME} WIN32
   "main.cpp"
   "utils.cpp"
   "win32_window.cpp"
-  "mpv/utils.cpp"
-  "mpv/mpv_container.cpp"
-  "mpv/mpv_core.cpp"
   "mpv/display_mode_manager.cpp"
   "mpv/mpv_player.cpp"
   "mpv/mpv_plugin.cpp"

windows/runner/main.cpp

@@ -8,6 +8,14 @@
 
 int APIENTRY
 wWinMain(_In_ HINSTANCE instance, _In_opt_ HINSTANCE prev, _In_ wchar_t* command_line, _In_ int show_command) {
+  // Plezy requires the bundled flutter-plezy engine, which presents the Flutter
+  // UI on a topmost DirectComposition visual when FLUTTER_WINDOWS_DCOMP is set.
+  // The mpv video window is then a plain child composed beneath the UI in the
+  // same HWND: window capture (Discord/OBS) works, there is no transparency
+  // hack, and min/max animations are native. Must be set before the engine is
+  // created. (On a stock engine the flag is a no-op and compositing breaks.)
+  ::SetEnvironmentVariableW(L"FLUTTER_WINDOWS_DCOMP", L"1");
+
   // Single instance enforcement
   HANDLE mutex = CreateMutex(nullptr, TRUE, L"com.edde746.Plezy.SingleInstance");
   if (GetLastError() == ERROR_ALREADY_EXISTS) {

windows/runner/mpv/mpv_container.cpp

@@ -1,96 +0,0 @@
-#include "mpv_container.h"
-
-#include <dwmapi.h>
-
-namespace mpv {
-
-MpvContainer* MpvContainer::GetInstance() { return instance_.get(); }
-
-HWND MpvContainer::Create() {
-  auto window_class = WNDCLASSEX{};
-  ::SecureZeroMemory(&window_class, sizeof(window_class));
-  window_class.cbSize = sizeof(window_class);
-  window_class.style = 0;
-  window_class.lpfnWndProc = WindowProc;
-  window_class.hInstance = GetModuleHandle(nullptr);
-  window_class.lpszClassName = kClassName;
-  window_class.hCursor = ::LoadCursorW(nullptr, IDC_ARROW);
-  window_class.hbrBackground = ::CreateSolidBrush(RGB(0, 0, 0));
-
-  ::RegisterClassExW(&window_class);
-
-  // Use WS_POPUP for a borderless window without title bar.
-  // Use WS_EX_TOOLWINDOW | WS_EX_NOREDIRECTIONBITMAP to prevent shadow and DWM effects.
-  handle_ = ::CreateWindowExW(
-      WS_EX_TOOLWINDOW | WS_EX_NOACTIVATE | WS_EX_NOREDIRECTIONBITMAP, kClassName, kWindowName, WS_POPUP, 0, 0, 100,
-      100, nullptr, nullptr, GetModuleHandle(nullptr), nullptr);
-
-  // Disable DWM animations on the container.
-  auto disable_window_transitions = TRUE;
-  DwmSetWindowAttribute(
-      handle_, DWMWA_TRANSITIONS_FORCEDISABLED, &disable_window_transitions, sizeof(disable_window_transitions));
-
-  return handle_;
-}
-
-HWND MpvContainer::Get(HWND flutter_window) {
-  if (!handle_) {
-    Create();
-  }
-
-  RECT window_rect;
-  ::GetWindowRect(flutter_window, &window_rect);
-  ::SetWindowPos(
-      handle_, flutter_window, window_rect.left, window_rect.top, window_rect.right - window_rect.left,
-      window_rect.bottom - window_rect.top, SWP_NOACTIVATE);
-  ::SetWindowLongPtr(handle_, GWLP_USERDATA, reinterpret_cast<LONG_PTR>(flutter_window));
-
-  ::ShowWindow(handle_, SW_SHOWNOACTIVATE);
-  ::SetFocus(flutter_window);
-
-  return handle_;
-}
-
-LRESULT CALLBACK
-MpvContainer::WindowProc(HWND const window, UINT const message, WPARAM const wparam, LPARAM const lparam) noexcept {
-  switch (message) {
-    case WM_DESTROY: {
-      ::PostQuitMessage(0);
-      return 0;
-    }
-    case WM_MOUSEMOVE:
-    case WM_SIZE:
-    case WM_MOVE:
-    case WM_MOVING:
-    case WM_ACTIVATE:
-    case WM_WINDOWPOSCHANGED: {
-      // Redirect focus to Flutter window.
-      auto user_data = ::GetWindowLongPtr(window, GWLP_USERDATA);
-      if (user_data) {
-        HWND flutter_window = reinterpret_cast<HWND>(user_data);
-        // Don't try to foreground a minimized window (Windows refuses and flashes
-        // the taskbar button instead), and don't steal foreground from another
-        // application. Only redirect focus when our own window already owns the
-        // foreground.
-        if (!::IsIconic(flutter_window)) {
-          HWND foreground = ::GetForegroundWindow();
-          if (foreground == flutter_window || foreground == window) {
-            ::SetForegroundWindow(flutter_window);
-          }
-        }
-      }
-      break;
-    }
-    case WM_ERASEBKGND: {
-      // Prevent erasing to avoid flicker.
-      return 1;
-    }
-    default:
-      break;
-  }
-  return ::DefWindowProc(window, message, wparam, lparam);
-}
-
-std::unique_ptr<MpvContainer> MpvContainer::instance_ = std::make_unique<MpvContainer>();
-
-}  // namespace mpv

windows/runner/mpv/mpv_container.h

@@ -1,41 +0,0 @@
-#ifndef MPV_CONTAINER_H_
-#define MPV_CONTAINER_H_
-
-#include <Windows.h>
-
-#include <memory>
-
-namespace mpv {
-
-// Container window that holds the mpv video window behind Flutter.
-// This is a singleton that creates a hidden window with no taskbar entry.
-class MpvContainer {
- public:
-  static MpvContainer* GetInstance();
-
-  MpvContainer() = default;
-  ~MpvContainer() = default;
-
-  // Creates the container window.
-  HWND Create();
-
-  // Gets the container window handle, positioning it relative to the Flutter window.
-  HWND Get(HWND flutter_window);
-
-  // Returns the raw handle.
-  HWND handle() const { return handle_; }
-
- private:
-  static LRESULT CALLBACK WindowProc(HWND window, UINT message, WPARAM wparam, LPARAM lparam) noexcept;
-
-  HWND handle_ = nullptr;
-
-  static constexpr wchar_t kClassName[] = L"MPV_CONTAINER";
-  static constexpr wchar_t kWindowName[] = L"";
-
-  static std::unique_ptr<MpvContainer> instance_;
-};
-
-}  // namespace mpv
-
-#endif  // MPV_CONTAINER_H_

windows/runner/mpv/mpv_core.cpp

@@ -1,187 +0,0 @@
-#include "mpv_core.h"
-
-#include <dwmapi.h>
-
-#include "mpv_container.h"
-#include "utils.h"
-
-namespace mpv {
-
-MpvCore* MpvCore::GetInstance() { return instance_.get(); }
-
-void MpvCore::SetInstance(std::unique_ptr<MpvCore> instance) { instance_ = std::move(instance); }
-
-MpvCore::MpvCore(HWND flutter_window) : flutter_window_(flutter_window) {}
-
-MpvCore::~MpvCore() {
-  // Close all mpv views.
-  for (const auto& [mpv_view, rect] : mpv_views_) {
-    ::SendMessage(mpv_view, WM_CLOSE, 0, 0);
-  }
-  mpv_views_.clear();
-}
-
-void MpvCore::EnsureInitialized() {
-  // Get container - composition will be enabled in SetVisible() to batch DwmFlush calls
-  container_ = MpvContainer::GetInstance()->Get(flutter_window_);
-}
-
-void MpvCore::CreateMpvView(HWND mpv_hwnd, RECT rect, double device_pixel_ratio) {
-  ::SetParent(mpv_hwnd, container_);
-  ::ShowWindow(mpv_hwnd, SW_SHOW);
-
-  // Remove window decorations.
-  auto style = ::GetWindowLongPtr(mpv_hwnd, GWL_STYLE);
-  style &= ~(WS_CAPTION | WS_THICKFRAME | WS_MINIMIZEBOX | WS_MAXIMIZEBOX);
-  ::SetWindowLongPtr(mpv_hwnd, GWL_STYLE, style);
-
-  device_pixel_ratio_ = device_pixel_ratio;
-  mpv_views_[mpv_hwnd] = rect;
-
-  // Position the mpv view behind the Flutter window.
-  auto global_rect = GetGlobalRect(rect.left, rect.top, rect.right, rect.bottom);
-  ::SetWindowPos(
-      mpv_hwnd, flutter_window_, global_rect.left, global_rect.top, global_rect.right - global_rect.left,
-      global_rect.bottom - global_rect.top, SWP_NOACTIVATE);
-}
-
-void MpvCore::ResizeMpvView(HWND mpv_hwnd, RECT rect) {
-  mpv_views_[mpv_hwnd] = rect;
-  auto global_rect = GetGlobalRect(rect.left, rect.top, rect.right, rect.bottom);
-  // Use MoveWindow to trigger redraw.
-  ::MoveWindow(
-      mpv_hwnd, global_rect.left, global_rect.top, global_rect.right - global_rect.left,
-      global_rect.bottom - global_rect.top, TRUE);
-}
-
-void MpvCore::DisposeMpvView(HWND mpv_hwnd) {
-  ::SendMessage(mpv_hwnd, WM_CLOSE, 0, 0);
-  mpv_views_.erase(mpv_hwnd);
-}
-
-void MpvCore::SetVisible(bool visible) {
-  visible_ = visible;
-  if (container_) {
-    if (visible) {
-      EnableComposition();
-    } else {
-      DisableComposition();
-    }
-  }
-}
-
-std::optional<HRESULT> MpvCore::WindowProc(HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam) {
-  switch (message) {
-    case WM_ACTIVATE: {
-      RECT window_rect;
-      ::GetWindowRect(flutter_window_, &window_rect);
-      // Position container behind Flutter window.
-      ::SetWindowPos(
-          container_, flutter_window_, window_rect.left, window_rect.top, window_rect.right - window_rect.left,
-          window_rect.bottom - window_rect.top, SWP_NOACTIVATE);
-      break;
-    }
-    case WM_SIZE: {
-      // Handle Windows's minimize & maximize animations properly.
-      // During these transitions, we hide the container and make Flutter opaque,
-      // then restore after the animation completes using a Windows timer.
-      if (wparam != SIZE_RESTORED || last_wm_size_wparam_ == SIZE_MINIMIZED || last_wm_size_wparam_ == SIZE_MAXIMIZED ||
-          was_window_hidden_due_to_minimize_) {
-        was_window_hidden_due_to_minimize_ = false;
-        DisableComposition();
-
-        // Cancel any pending timer and set a new one.
-        ::KillTimer(flutter_window_, kCompositionRestoreTimerId);
-        ::SetTimer(flutter_window_, kCompositionRestoreTimerId, kPositionAndShowDelay, nullptr);
-      }
-      last_wm_size_wparam_ = wparam;
-      break;
-    }
-    case WM_TIMER: {
-      if (wparam == kCompositionRestoreTimerId) {
-        ::KillTimer(flutter_window_, kCompositionRestoreTimerId);
-
-        // Update container position to match current Flutter window bounds
-        RECT window_rect;
-        ::GetWindowRect(flutter_window_, &window_rect);
-        ::SetWindowPos(
-            container_, flutter_window_, window_rect.left, window_rect.top, window_rect.right - window_rect.left,
-            window_rect.bottom - window_rect.top, SWP_NOACTIVATE);
-
-        // Restore transparency if video is visible
-        if (visible_) {
-          EnableComposition();
-
-          // Force a redraw to ensure Flutter's render surface is correctly sized
-          ::RedrawWindow(flutter_window_, nullptr, nullptr, RDW_INVALIDATE | RDW_UPDATENOW | RDW_ALLCHILDREN);
-        }
-      }
-      break;
-    }
-    case WM_WINDOWPOSCHANGED: {
-      RECT window_rect;
-      ::GetWindowRect(flutter_window_, &window_rect);
-      if (window_rect.right - window_rect.left > 0 && window_rect.bottom - window_rect.top > 0) {
-        ::SetWindowPos(
-            container_, flutter_window_, window_rect.left, window_rect.top, window_rect.right - window_rect.left,
-            window_rect.bottom - window_rect.top, SWP_NOACTIVATE);
-        // Window is minimized (negative coordinates).
-        if (window_rect.left < 0 && window_rect.top < 0 && window_rect.right < 0 && window_rect.bottom < 0) {
-          DisableComposition();
-          was_window_hidden_due_to_minimize_ = true;
-        }
-      }
-      break;
-    }
-    case WM_CLOSE: {
-      ::SendMessage(container_, WM_CLOSE, 0, 0);
-      for (const auto& [mpv_view, rect] : mpv_views_) {
-        ::SendMessage(mpv_view, WM_CLOSE, 0, 0);
-      }
-      mpv_views_.clear();
-      break;
-    }
-    default:
-      break;
-  }
-  return std::nullopt;
-}
-
-RECT MpvCore::GetGlobalRect(int32_t left, int32_t top, int32_t right, int32_t bottom) {
-  // Expand client area to prevent transparent gaps.
-  left -= static_cast<int32_t>(ceil(device_pixel_ratio_));
-  top -= static_cast<int32_t>(ceil(device_pixel_ratio_));
-  right += static_cast<int32_t>(ceil(device_pixel_ratio_));
-  bottom += static_cast<int32_t>(ceil(device_pixel_ratio_));
-
-  RECT window_rect;
-  ::GetClientRect(flutter_window_, &window_rect);
-  RECT rect;
-  rect.left = window_rect.left + left;
-  rect.top = window_rect.top + top;
-  rect.right = window_rect.left + right;
-  rect.bottom = window_rect.top + bottom;
-  return rect;
-}
-
-void MpvCore::EnableComposition() {
-  ::SetWindowPos(
-      flutter_window_, nullptr, 0, 0, 0, 0, SWP_FRAMECHANGED | SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER | SWP_NOACTIVATE);
-  if (!composition_enabled_) {
-    SetWindowComposition(flutter_window_, 2, 0);
-    composition_enabled_ = true;
-  }
-  ::ShowWindow(container_, SW_SHOWNOACTIVATE);
-  ::DwmFlush();
-}
-
-void MpvCore::DisableComposition() {
-  SetWindowComposition(flutter_window_, 0, 0);
-  composition_enabled_ = false;
-  ::ShowWindow(container_, SW_HIDE);
-  ::DwmFlush();
-}
-
-std::unique_ptr<MpvCore> MpvCore::instance_ = nullptr;
-
-}  // namespace mpv

windows/runner/mpv/mpv_core.h

@@ -1,63 +0,0 @@
-#ifndef MPV_CORE_H_
-#define MPV_CORE_H_
-
-#include <Windows.h>
-
-#include <cmath>
-#include <map>
-#include <memory>
-#include <optional>
-
-namespace mpv {
-
-// Core class for managing z-order and window positioning for mpv video window.
-// Handles transparency, minimize/maximize animations, and position syncing.
-class MpvCore {
- public:
-  static constexpr auto kPositionAndShowDelay = 300;
-  static constexpr UINT_PTR kCompositionRestoreTimerId = 1001;
-
-  static MpvCore* GetInstance();
-  static void SetInstance(std::unique_ptr<MpvCore> instance);
-
-  explicit MpvCore(HWND flutter_window);
-  ~MpvCore();
-
-  // Initializes transparency on the Flutter window.
-  void EnsureInitialized();
-
-  // Creates and positions the mpv video view.
-  void CreateMpvView(HWND mpv_hwnd, RECT rect, double device_pixel_ratio);
-
-  // Updates the mpv view position.
-  void ResizeMpvView(HWND mpv_hwnd, RECT rect);
-
-  // Disposes the mpv view.
-  void DisposeMpvView(HWND mpv_hwnd);
-
-  // Shows or hides the mpv view.
-  void SetVisible(bool visible);
-
-  // Window procedure handler for Flutter window messages.
-  std::optional<HRESULT> WindowProc(HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam);
-
- private:
-  RECT GetGlobalRect(int32_t left, int32_t top, int32_t right, int32_t bottom);
-  void EnableComposition();
-  void DisableComposition();
-
-  HWND flutter_window_ = nullptr;
-  HWND container_ = nullptr;
-  double device_pixel_ratio_ = 1.0;
-  std::map<HWND, RECT> mpv_views_;
-  WPARAM last_wm_size_wparam_ = SIZE_RESTORED;
-  bool was_window_hidden_due_to_minimize_ = false;
-  bool visible_ = true;
-  bool composition_enabled_ = false;
-
-  static std::unique_ptr<MpvCore> instance_;
-};
-
-}  // namespace mpv
-
-#endif  // MPV_CORE_H_

windows/runner/mpv/mpv_player.cpp

@@ -1,35 +1,92 @@
 #include "mpv_player.h"
 
+#include <windowsx.h>
+
 #include "sanitize_utf8.h"
 
 namespace mpv {
 
+namespace {
+
+// DComp-mode input forwarding. mpv's inner window lives on mpv's own thread
+// and consumes the mouse input over the video (WS_EX_TRANSPARENT hit-test
+// skipping is same-thread-only, and disabling the subtree makes the system
+// drop the input entirely instead of routing it to a sibling). Subclass the
+// inner window (legal within one process, even across threads) and forward
+// mouse input to the Flutter view with coordinates translated into view
+// space. The subclass proc runs on mpv's thread and only uses thread-safe
+// calls (PostMessage / MapWindowPoints / CallWindowProc).
+WNDPROC g_mpv_inner_original_proc = nullptr;
+HWND g_mpv_inner_hwnd = nullptr;
+HWND g_forward_target_view = nullptr;
+
+LRESULT CALLBACK MpvInnerSubclassProc(HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam) {
+  if (message >= WM_MOUSEFIRST && message <= WM_MOUSELAST) {
+    HWND view = g_forward_target_view;
+    if (view) {
+      LPARAM forwarded = lparam;
+      if (message != WM_MOUSEWHEEL && message != WM_MOUSEHWHEEL) {
+        // Client coordinates: translate inner-window-space -> view-space.
+        // (Wheel messages carry screen coordinates; pass through unchanged.)
+        POINT pt = {GET_X_LPARAM(lparam), GET_Y_LPARAM(lparam)};
+        ::MapWindowPoints(hwnd, view, &pt, 1);
+        forwarded = MAKELPARAM(pt.x, pt.y);
+      }
+      ::PostMessage(view, message, wparam, forwarded);
+    }
+    return 0;
+  }
+  return ::CallWindowProc(g_mpv_inner_original_proc, hwnd, message, wparam, lparam);
+}
+
+// Subclass mpv's lazily-created inner window if it exists and isn't yet
+// subclassed (or was recreated). Idempotent; callable from any thread in
+// this process.
+void EnsureMpvInnerSubclassed(HWND host) {
+  if (!host) {
+    return;
+  }
+  HWND inner = ::FindWindowExW(host, nullptr, nullptr, nullptr);
+  if (inner && inner != g_mpv_inner_hwnd) {
+    g_mpv_inner_hwnd = inner;
+    g_mpv_inner_original_proc = reinterpret_cast<WNDPROC>(
+        ::SetWindowLongPtrW(inner, GWLP_WNDPROC, reinterpret_cast<LONG_PTR>(MpvInnerSubclassProc)));
+  }
+}
+
+}  // namespace
+
 MpvPlayer::MpvPlayer() {}
 
 MpvPlayer::~MpvPlayer() { Dispose(); }
 
-bool MpvPlayer::Initialize(HWND container, HWND flutter_window) {
+bool MpvPlayer::Initialize(HWND view) {
   if (mpv_) {
     return true;  // Already initialized.
   }
 
-  container_ = container;
-  flutter_window_ = flutter_window;
-
   // Create mpv instance.
   mpv_ = mpv_create();
   if (!mpv_) {
     return false;
   }
 
-  // Create a child window for mpv to render into.
+  // Create a child window for mpv to render into, parented to the Flutter
-  hwnd_ = ::CreateWindowW(
+  // |view|. The video child then sits in the view's own per-window layer
-      L"STATIC", L"", WS_CHILD | WS_VISIBLE, 0, 0, 100, 100, container, nullptr, GetModuleHandle(nullptr), nullptr);
+  // stack, above the view's (never-painted) layer-1 content and below the
+  // engine's topmost DComp visual carrying the UI. WS_CLIPSIBLINGS keeps it
+  // from painting over neighboring view children. Mouse input over the video
+  // is delivered to mpv's own inner window (on mpv's thread); the subclass
+  // installed in EnsureMpvInnerSubclassed forwards it back to the view.
+  hwnd_ = ::CreateWindowExW(
+      WS_EX_NOPARENTNOTIFY, L"STATIC", L"", WS_CHILD | WS_CLIPSIBLINGS, 0, 0, 100, 100, view, nullptr,
+      GetModuleHandle(nullptr), nullptr);
   if (!hwnd_) {
     mpv_destroy(mpv_);
     mpv_ = nullptr;
     return false;
   }
+  g_forward_target_view = view;
 
   // Set the wid option to embed mpv in our window.
   int64_t wid = reinterpret_cast<int64_t>(hwnd_);
@@ -114,6 +171,10 @@ void MpvPlayer::Dispose() {
     hwnd_ = nullptr;
   }
 
+  // The subclassed inner window died with hwnd_; clear the forwarding state.
+  g_mpv_inner_hwnd = nullptr;
+  g_mpv_inner_original_proc = nullptr;
+
   observed_properties_.clear();
 }
 
@@ -245,39 +306,19 @@ void MpvPlayer::ObserveProperty(const std::string& name, const std::string& form
 }
 
 void MpvPlayer::SetRect(RECT rect, double device_pixel_ratio) {
-  rect_ = rect;
+  if (!hwnd_) {
-  device_pixel_ratio_ = device_pixel_ratio;
+    return;
-
-  if (hwnd_ && container_ && flutter_window_) {
-    // The rect from Dart is in Flutter client area coordinates (0,0 is top-left of Flutter
-    // content). The container window is positioned to match the Flutter window's full bounds
-    // (including title bar). We need to offset the mpv window within the container to align with
-    // Flutter's client area.
-
-    // Get the Flutter window's window rect (screen coordinates, includes title bar)
-    RECT window_rect;
-    ::GetWindowRect(flutter_window_, &window_rect);
-
-    // Get the Flutter window's client rect (client coordinates, 0,0 based)
-    RECT client_rect;
-    ::GetClientRect(flutter_window_, &client_rect);
-
-    // Convert client area origin to screen coordinates
-    POINT client_origin = {0, 0};
-    ::ClientToScreen(flutter_window_, &client_origin);
-
-    // Calculate the offset from window origin to client area origin
-    int client_offset_x = client_origin.x - window_rect.left;
-    int client_offset_y = client_origin.y - window_rect.top;
-
-    // Position the mpv window within the container, offset by the title bar/border size
-    int left = rect.left + client_offset_x;
-    int top = rect.top + client_offset_y;
-    int width = rect.right - rect.left;
-    int height = rect.bottom - rect.top;
-
-    ::MoveWindow(hwnd_, left, top, width, height, TRUE);
   }
+
+  // The video window is a child of the Flutter view; the Dart rect is already
+  // in view physical pixels, which is exactly the child coordinate space. No
+  // screen mapping, no padding.
+  ::SetWindowPos(hwnd_, HWND_TOP, rect.left, rect.top, rect.right - rect.left, rect.bottom - rect.top, SWP_NOACTIVATE);
+
+  // mpv creates its inner window lazily on its own thread; subclass it (and
+  // re-subclass if mpv ever recreates it) so mouse input over the video is
+  // forwarded to the Flutter view.
+  EnsureMpvInnerSubclassed(hwnd_);
 }
 
 void MpvPlayer::SetVisible(bool visible) {
@@ -439,6 +480,10 @@ void MpvPlayer::HandleMpvEvent(mpv_event* event) {
       break;
     }
     case MPV_EVENT_PLAYBACK_RESTART: {
+      // mpv's inner window exists by now (vo is configured); make sure the
+      // DComp-mode input forwarding subclass is installed. SetRect alone can
+      // miss it: the rect often settles before mpv creates the window.
+      EnsureMpvInnerSubclassed(hwnd_);
       SendEvent("playback-restart");
       break;
     }

windows/runner/mpv/mpv_player.h

@@ -25,8 +25,11 @@ class MpvPlayer {
   MpvPlayer();
   ~MpvPlayer();
 
-  // Initializes mpv and creates the video window.
+  // Initializes mpv and creates the video window as a child of the Flutter
-  bool Initialize(HWND container, HWND flutter_window);
+  // |view| window. The flutter-plezy engine presents the UI on a topmost
+  // DirectComposition visual, so the video child composites beneath it in the
+  // same HWND.
+  bool Initialize(HWND view);
 
   // Disposes mpv and the video window.
   void Dispose();
@@ -87,10 +90,6 @@ class MpvPlayer {
 
   mpv_handle* mpv_ = nullptr;
   HWND hwnd_ = nullptr;
-  HWND container_ = nullptr;
-  HWND flutter_window_ = nullptr;
-  double device_pixel_ratio_ = 1.0;
-  RECT rect_ = {0, 0, 0, 0};
 
   std::thread event_thread_;
   std::atomic<bool> running_{false};

windows/runner/mpv/mpv_plugin.cpp

@@ -1,8 +1,5 @@
 #include "mpv_plugin.h"
 
-#include "mpv_container.h"
-#include "mpv_core.h"
-
 static flutter::EncodableMap DisplayModeToMap(const mpv::DisplayMode& mode) {
   flutter::EncodableMap m;
   m[flutter::EncodableValue("width")] = flutter::EncodableValue(static_cast<int32_t>(mode.width));
@@ -106,54 +103,43 @@ void MpvPlayerPlugin::HandleMethodCall(
   const auto& method = method_call.method_name();
 
   if (method == "initialize") {
-    // Set up MpvCore for z-order management.
     if (proc_id_) {
       registrar_->UnregisterTopLevelWindowProcDelegate(proc_id_.value());
       proc_id_ = std::nullopt;
     }
 
-    HWND flutter_window = GetWindow();
+    flutter_window_ = GetWindow();
-    flutter_window_ = flutter_window;
-
-    MpvCore::SetInstance(std::make_unique<MpvCore>(flutter_window));
 
+    // The only top-level message we care about is the platform-task wakeup;
+    // mouse-over-video input is forwarded by the mpv inner-window subclass
+    // (see MpvPlayer), and compositing/z-order is handled by the engine's
+    // topmost DComp visual — there is no separate container window to manage.
     proc_id_ =
         registrar_->RegisterTopLevelWindowProcDelegate([this](HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam) {
           if (message == kPlatformTaskMessage) {
             DrainPlatformTasks();
             return std::optional<HRESULT>(0);
           }
-
-          auto* core = MpvCore::GetInstance();
-          if (core) {
-            return core->WindowProc(hwnd, message, wparam, lparam);
-          }
           return std::optional<HRESULT>(std::nullopt);
         });
 
-    MpvCore::GetInstance()->EnsureInitialized();
+    // The video window is a child of the FLUTTER VIEW itself, so DWM's
+    // per-window layer model puts it above the view's own (layer 1) content
+    // and below the view's topmost DComp visual carrying the UI (layer 4). As
+    // a *sibling* of the view, either the view's never-painted white content
+    // covers the video or the video covers the UI — the in-subtree placement
+    // is the only ordering that yields white < video < UI.
+    HWND view = GetChildWindow();
 
-    // Create player - use the container from MpvCore which was set up by EnsureInitialized
     player_ = std::make_unique<MpvPlayer>();
-    HWND container = MpvContainer::GetInstance()->handle();
+    bool success = player_->Initialize(view);
-
-    if (!container) {
-      result->Error("INIT_FAILED", "Failed to create container window");
-      return;
-    }
-
-    bool success = player_->Initialize(container, flutter_window);
 
     if (success) {
       // Set up event callback.
       player_->SetEventCallback([this](const flutter::EncodableValue& event) { SendEvent(event); });
 
-      // Register the mpv window with core for z-order management.
-      RECT rect = {0, 0, 100, 100};
-      MpvCore::GetInstance()->CreateMpvView(player_->GetHwnd(), rect, 1.0);
-
       // Start hidden.
-      MpvCore::GetInstance()->SetVisible(false);
+      player_->SetVisible(false);
       result->Success(flutter::EncodableValue(true));
     } else {
       player_.reset();  // Clear the player so we don't have a half-initialized state
@@ -161,13 +147,8 @@ void MpvPlayerPlugin::HandleMethodCall(
     }
   } else if (method == "dispose") {
     if (player_) {
-      auto hwnd = player_->GetHwnd();
       player_->Dispose();
       player_.reset();
-
-      if (MpvCore::GetInstance() && hwnd) {
-        MpvCore::GetInstance()->DisposeMpvView(hwnd);
-      }
     }
     result->Success();
   } else if (method == "command") {
@@ -353,9 +334,6 @@ void MpvPlayerPlugin::HandleMethodCall(
     if (player_) {
       player_->SetVisible(visible);
     }
-    if (MpvCore::GetInstance()) {
-      MpvCore::GetInstance()->SetVisible(visible);
-    }
 
     result->Success();
   } else if (method == "setVideoRect") {
@@ -394,8 +372,7 @@ void MpvPlayerPlugin::HandleMethodCall(
     rect.bottom = get_int("bottom");
     double dpr = get_double("devicePixelRatio");
 
-    if (player_ && MpvCore::GetInstance()) {
+    if (player_) {
-      MpvCore::GetInstance()->ResizeMpvView(player_->GetHwnd(), rect);
       player_->SetRect(rect, dpr);
     }
 

windows/runner/mpv/mpv_plugin.h

@@ -15,7 +15,6 @@
 #include <queue>
 
 #include "display_mode_manager.h"
-#include "mpv_core.h"
 #include "mpv_player.h"
 
 // C-style registration function for the plugin.

windows/runner/mpv/utils.cpp

@@ -1,111 +0,0 @@
-#include "utils.h"
-
-namespace mpv {
-
-typedef enum _WINDOWCOMPOSITIONATTRIB {
-  WCA_UNDEFINED = 0,
-  WCA_NCRENDERING_ENABLED = 1,
-  WCA_NCRENDERING_POLICY = 2,
-  WCA_TRANSITIONS_FORCEDISABLED = 3,
-  WCA_ALLOW_NCPAINT = 4,
-  WCA_CAPTION_BUTTON_BOUNDS = 5,
-  WCA_NONCLIENT_RTL_LAYOUT = 6,
-  WCA_FORCE_ICONIC_REPRESENTATION = 7,
-  WCA_EXTENDED_FRAME_BOUNDS = 8,
-  WCA_HAS_ICONIC_BITMAP = 9,
-  WCA_THEME_ATTRIBUTES = 10,
-  WCA_NCRENDERING_EXILED = 11,
-  WCA_NCADORNMENTINFO = 12,
-  WCA_EXCLUDED_FROM_LIVEPREVIEW = 13,
-  WCA_VIDEO_OVERLAY_ACTIVE = 14,
-  WCA_FORCE_ACTIVEWINDOW_APPEARANCE = 15,
-  WCA_DISALLOW_PEEK = 16,
-  WCA_CLOAK = 17,
-  WCA_CLOAKED = 18,
-  WCA_ACCENT_POLICY = 19,
-  WCA_FREEZE_REPRESENTATION = 20,
-  WCA_EVER_UNCLOAKED = 21,
-  WCA_VISUAL_OWNER = 22,
-  WCA_HOLOGRAPHIC = 23,
-  WCA_EXCLUDED_FROM_DDA = 24,
-  WCA_PASSIVEUPDATEMODE = 25,
-  WCA_USEDARKMODECOLORS = 26,
-  WCA_LAST = 27
-} WINDOWCOMPOSITIONATTRIB;
-
-typedef struct _WINDOWCOMPOSITIONATTRIBDATA {
-  WINDOWCOMPOSITIONATTRIB Attrib;
-  PVOID pvData;
-  SIZE_T cbData;
-} WINDOWCOMPOSITIONATTRIBDATA;
-
-typedef enum _ACCENT_STATE {
-  ACCENT_DISABLED = 0,
-  ACCENT_ENABLE_GRADIENT = 1,
-  ACCENT_ENABLE_TRANSPARENTGRADIENT = 2,
-  ACCENT_ENABLE_BLURBEHIND = 3,
-  ACCENT_ENABLE_ACRYLICBLURBEHIND = 4,
-  ACCENT_ENABLE_HOSTBACKDROP = 5,
-  ACCENT_INVALID_STATE = 6
-} ACCENT_STATE;
-
-typedef struct _ACCENT_POLICY {
-  ACCENT_STATE AccentState;
-  DWORD AccentFlags;
-  DWORD GradientColor;
-  DWORD AnimationId;
-} ACCENT_POLICY;
-
-typedef BOOL(WINAPI* _SetWindowCompositionAttribute)(HWND, WINDOWCOMPOSITIONATTRIBDATA*);
-
-static _SetWindowCompositionAttribute g_set_window_composition_attribute = NULL;
-static bool g_set_window_composition_attribute_initialized = false;
-
-typedef LONG NTSTATUS, *PNTSTATUS;
-#define STATUS_SUCCESS (0x00000000)
-
-typedef NTSTATUS(WINAPI* RtlGetVersionPtr)(PRTL_OSVERSIONINFOW);
-
-static RTL_OSVERSIONINFOW GetWindowsVersion() {
-  static RTL_OSVERSIONINFOW cached = []() {
-    HMODULE hmodule = ::GetModuleHandleW(L"ntdll.dll");
-    if (hmodule) {
-      RtlGetVersionPtr rtl_get_version_ptr = (RtlGetVersionPtr)::GetProcAddress(hmodule, "RtlGetVersion");
-      if (rtl_get_version_ptr != nullptr) {
-        RTL_OSVERSIONINFOW rovi = {0};
-        rovi.dwOSVersionInfoSize = sizeof(rovi);
-        if (STATUS_SUCCESS == rtl_get_version_ptr(&rovi)) {
-          return rovi;
-        }
-      }
-    }
-    RTL_OSVERSIONINFOW rovi = {0};
-    return rovi;
-  }();
-  return cached;
-}
-
-void SetWindowComposition(HWND window, int32_t accent_state, int32_t gradient_color) {
-  if (GetWindowsVersion().dwBuildNumber >= 18362) {
-    if (!g_set_window_composition_attribute_initialized) {
-      auto user32 = ::GetModuleHandleA("user32.dll");
-      if (user32) {
-        g_set_window_composition_attribute =
-            reinterpret_cast<_SetWindowCompositionAttribute>(::GetProcAddress(user32, "SetWindowCompositionAttribute"));
-        if (g_set_window_composition_attribute) {
-          g_set_window_composition_attribute_initialized = true;
-        }
-      }
-    }
-    if (g_set_window_composition_attribute) {
-      ACCENT_POLICY accent = {static_cast<ACCENT_STATE>(accent_state), 2, static_cast<DWORD>(gradient_color), 0};
-      WINDOWCOMPOSITIONATTRIBDATA data;
-      data.Attrib = WCA_ACCENT_POLICY;
-      data.pvData = &accent;
-      data.cbData = sizeof(accent);
-      g_set_window_composition_attribute(window, &data);
-    }
-  }
-}
-
-}  // namespace mpv

windows/runner/mpv/utils.h

@@ -1,18 +0,0 @@
-#ifndef MPV_UTILS_H_
-#define MPV_UTILS_H_
-
-#include <Windows.h>
-#include <dwmapi.h>
-
-#include <cstdint>
-
-namespace mpv {
-
-// Sets window composition attribute for transparency.
-// accent_state = 6 enables per-pixel transparency.
-// accent_state = 0 makes window opaque.
-void SetWindowComposition(HWND window, int32_t accent_state, int32_t gradient_color);
-
-}  // namespace mpv
-
-#endif  // MPV_UTILS_H_

windows/tool/install-patched-engine.ps1

@@ -0,0 +1,74 @@
+# Download the published flutter-plezy patched Windows engine (DirectComposition)
+# and install it into the active Flutter SDK's artifact cache.
+#
+# Plezy requires this engine on Windows: it honors the FLUTTER_WINDOWS_DCOMP
+# environment variable (set in windows/runner/main.cpp) and presents the Flutter
+# UI on a topmost DirectComposition visual, so the mpv video window composites
+# *beneath* the UI in a single HWND (window capture works, no transparency
+# hacks). On a stock engine the flag is a no-op and compositing breaks.
+#
+# Used by CI (.github/workflows/build.yml) and by contributors building locally.
+# Engine developers who build their own artifacts use swap-engine.ps1 instead.
+#
+# The flutter tool validates the engine cache by engine.stamp string only (no
+# file hashing), so the swap sticks - but `flutter upgrade` /
+# `flutter precache --force` silently restore the stock engine; re-run this
+# afterwards. Run `flutter precache --windows` once before this script so the
+# cache layout and engine.stamp exist.
+#
+# Usage:
+#   flutter precache --windows
+#   windows/tool/install-patched-engine.ps1
+param(
+    # Engine zip published at flutter-plezy release windows-v3.44.0+1 - x64 + arm64
+    # (cache dirs windows-{x64,arm64}{,-release}). The asset name is the same across
+    # tags, so a version bump only changes the tag segment of the URL.
+    [string]$Url = 'https://github.com/edde746/flutter-plezy/releases/download/windows-v3.44.0+1/flutter-plezy-windows-3.44.0.zip',
+    [string]$Sha256 = '8de498d28f314c33971226856bea7aa54099e08e60cd7d208cbaf04693dc8274',
+    # Engine revision the artifacts were built from. Must match the SDK's
+    # engine.stamp (gen_snapshot/dart in the SDK must come from the same
+    # checkout), or the swapped binaries are ABI-incompatible with the build.
+    [string]$ExpectedEngine = '4c525dac5ebe5971c5708ef73558ed8edcf4a362'
+)
+
+$ErrorActionPreference = 'Stop'
+
+$flutterCmd = Get-Command flutter.bat -ErrorAction SilentlyContinue
+if (-not $flutterCmd) { $flutterCmd = Get-Command flutter }
+$sdkRoot = Split-Path -Parent (Split-Path -Parent $flutterCmd.Source)
+
+$stampPath = Join-Path $sdkRoot 'bin\cache\engine.stamp'
+if (-not (Test-Path $stampPath)) {
+    Write-Error "engine.stamp not found at $stampPath - run 'flutter precache --windows' first"
+}
+$stamp = (Get-Content $stampPath -Raw).Trim()
+if ($stamp -ne $ExpectedEngine) {
+    Write-Error "SDK engine.stamp is $stamp but the patched engine targets $ExpectedEngine - this flutter-plezy build is for a different SDK"
+}
+
+$engineDir = Join-Path $sdkRoot 'bin\cache\artifacts\engine'
+if (-not (Test-Path $engineDir)) {
+    Write-Error "engine cache not found: $engineDir - run 'flutter precache --windows' first"
+}
+
+$zip = Join-Path ([System.IO.Path]::GetTempPath()) 'flutter-plezy-windows.zip'
+
+# Invoke-WebRequest renders a per-byte progress bar in Windows PowerShell that
+# makes large downloads crawl; silence it.
+$ProgressPreference = 'SilentlyContinue'
+Write-Output "Downloading patched engine from $Url ..."
+Invoke-WebRequest -Uri $Url -OutFile $zip
+
+$actual = (Get-FileHash $zip -Algorithm SHA256).Hash.ToLower()
+if ($actual -ne $Sha256.ToLower()) {
+    Remove-Item $zip -Force
+    Write-Error "SHA256 mismatch: expected $Sha256 but got $actual"
+}
+
+# The zip holds top-level windows-x64/ (debug) and windows-x64-release/ folders;
+# extracting over the engine dir swaps both cache variants in place.
+Write-Output "Extracting patched engine into $engineDir ..."
+Expand-Archive -Path $zip -DestinationPath $engineDir -Force
+Remove-Item $zip -Force
+
+Write-Output "Installed patched DComp engine (windows-x64, windows-x64-release)."

windows/tool/swap-engine.ps1

@@ -0,0 +1,61 @@
+# Swap the flutter-plezy custom Windows engine into the Flutter SDK's artifact
+# cache (or restore stock). See flutter-plezy's README for how the artifacts
+# are built.
+#
+# The flutter tool validates the cache by stamp STRING only (no file hashing),
+# so swapped files stick - but `flutter upgrade` / `flutter precache --force`
+# silently restore stock; re-run this script afterwards.
+#
+# Usage:
+#   swap-engine.ps1 -Mode debug   -Zip C:\path\to\windows-x64-flutter.zip
+#   swap-engine.ps1 -Mode release -Zip ...
+#   swap-engine.ps1 -Mode debug -Restore
+param(
+    [ValidateSet('debug', 'release')][string]$Mode = 'debug',
+    [string]$Zip,
+    [switch]$Restore,
+    # Engine revision these artifacts were built from. Guards against swapping
+    # into a mismatched SDK (gen_snapshot/dart must come from the same checkout).
+    [string]$ExpectedEngine = '4c525dac5ebe5971c5708ef73558ed8edcf4a362'
+)
+
+$ErrorActionPreference = 'Stop'
+
+$flutterCmd = Get-Command flutter.bat -ErrorAction SilentlyContinue
+if (-not $flutterCmd) { $flutterCmd = Get-Command flutter }
+$sdkRoot = Split-Path -Parent (Split-Path -Parent $flutterCmd.Source)
+
+$stamp = (Get-Content (Join-Path $sdkRoot 'bin\cache\engine.stamp') -Raw).Trim()
+if ($stamp -ne $ExpectedEngine) {
+    Write-Error "SDK engine.stamp is $stamp but artifacts target $ExpectedEngine - rebuild flutter-plezy for this SDK first"
+}
+
+$cacheDir = if ($Mode -eq 'debug') { 'windows-x64' } else { 'windows-x64-release' }
+$target = Join-Path $sdkRoot "bin\cache\artifacts\engine\$cacheDir"
+if (-not (Test-Path $target)) { Write-Error "cache dir not found: $target (run 'flutter precache --windows')" }
+$backup = "$target.stock-backup"
+
+if ($Restore) {
+    if (-not (Test-Path $backup)) { Write-Error "no backup at $backup - nothing to restore" }
+    Get-ChildItem $backup -File | ForEach-Object { Copy-Item $_.FullName $target -Force }
+    Write-Output "restored stock engine into $target"
+    return
+}
+
+if (-not $Zip -or -not (Test-Path $Zip)) { Write-Error "pass -Zip <windows-x64-flutter.zip> (from flutter-plezy out\<v>\host_*\zip_archives\ or a Release)" }
+
+# One-time backup of the stock files we are about to overwrite.
+if (-not (Test-Path $backup)) {
+    New-Item -ItemType Directory $backup | Out-Null
+    Add-Type -AssemblyName System.IO.Compression.FileSystem
+    $entries = [System.IO.Compression.ZipFile]::OpenRead((Resolve-Path $Zip)).Entries | ForEach-Object { $_.FullName }
+    foreach ($name in $entries) {
+        $orig = Join-Path $target $name
+        if (Test-Path $orig) { Copy-Item $orig $backup -Force }
+    }
+    Write-Output "stock files backed up to $backup"
+}
+
+Expand-Archive $Zip -DestinationPath $target -Force
+Write-Output "swapped $(Split-Path $Zip -Leaf) into $target"
+Write-Output "NOTE: re-run after 'flutter upgrade' or 'flutter precache --force'."