feat: Windows增加分辨率适应，切换分辨率按钮修改

webrtc_controller_flutter/windows/runner/flutter_window.cpp

@@ -1,6 +1,7 @@
 #include "flutter_window.h"
 
 #include <optional>
+#include <variant>
 
 #include "flutter/generated_plugin_registrant.h"
 
@@ -27,6 +28,29 @@ bool FlutterWindow::OnCreate() {
   RegisterPlugins(flutter_controller_->engine());
   SetChildContent(flutter_controller_->view()->GetNativeWindow());
 
+  // 注册窗口控制通道：Dart 端可请求按视频比例调整窗口尺寸。
+  window_channel_ =
+      std::make_unique<flutter::MethodChannel<flutter::EncodableValue>>(
+          flutter_controller_->engine()->messenger(), "app/window",
+          &flutter::StandardMethodCodec::GetInstance());
+  window_channel_->SetMethodCallHandler(
+      [this](const flutter::MethodCall<flutter::EncodableValue>& call,
+             std::unique_ptr<flutter::MethodResult<flutter::EncodableValue>>
+                 result) {
+        if (call.method_name() == "resizeToVideoAspect") {
+          double aspect = 0.0;
+          if (const auto* value = std::get_if<double>(call.arguments())) {
+            aspect = *value;
+          } else if (const auto* ivalue = std::get_if<int>(call.arguments())) {
+            aspect = static_cast<double>(*ivalue);
+          }
+          ResizeToVideoAspect(aspect);
+          result->Success();
+        } else {
+          result->NotImplemented();
+        }
+      });
+
   flutter_controller_->engine()->SetNextFrameCallback([&]() {
     this->Show();
   });
@@ -47,6 +71,69 @@ void FlutterWindow::OnDestroy() {
   Win32Window::OnDestroy();
 }
 
+void FlutterWindow::ResizeToVideoAspect(double aspect) {
+  if (aspect <= 0.0) {
+    return;
+  }
+  HWND hwnd = GetHandle();
+  if (!hwnd) {
+    return;
+  }
+
+  RECT window_rect;
+  RECT client_rect;
+  GetWindowRect(hwnd, &window_rect);
+  GetClientRect(hwnd, &client_rect);
+
+  const int window_w = window_rect.right - window_rect.left;
+  const int window_h = window_rect.bottom - window_rect.top;
+  const int client_w = client_rect.right - client_rect.left;
+  const int client_h = client_rect.bottom - client_rect.top;
+  // 边框（含标题栏）占用的额外像素。
+  const int border_w = window_w - client_w;
+  const int border_h = window_h - client_h;
+
+  // 保持窗口宽度不变，按比例计算客户区高度。
+  int target_client_w = client_w;
+  int target_client_h = static_cast<int>(target_client_w / aspect + 0.5);
+  int target_window_w = window_w;
+  int target_window_h = target_client_h + border_h;
+
+  // 获取窗口所在显示器的可用工作区。
+  HMONITOR monitor = MonitorFromWindow(hwnd, MONITOR_DEFAULTTONEAREST);
+  MONITORINFO monitor_info;
+  monitor_info.cbSize = sizeof(MONITORINFO);
+  GetMonitorInfo(monitor, &monitor_info);
+  const int work_h = monitor_info.rcWork.bottom - monitor_info.rcWork.top;
+
+  // 高度超出屏幕：改为以屏幕高度为准的合适窗口大小。
+  if (target_window_h > work_h) {
+    target_window_h = work_h;
+    target_client_h = target_window_h - border_h;
+    target_client_w = static_cast<int>(target_client_h * aspect + 0.5);
+    target_window_w = target_client_w + border_w;
+  }
+
+  // 计算位置：尽量保持当前左上角，同时确保窗口落在工作区内。
+  int new_left = window_rect.left;
+  int new_top = window_rect.top;
+  if (new_left + target_window_w > monitor_info.rcWork.right) {
+    new_left = monitor_info.rcWork.right - target_window_w;
+  }
+  if (new_top + target_window_h > monitor_info.rcWork.bottom) {
+    new_top = monitor_info.rcWork.bottom - target_window_h;
+  }
+  if (new_left < monitor_info.rcWork.left) {
+    new_left = monitor_info.rcWork.left;
+  }
+  if (new_top < monitor_info.rcWork.top) {
+    new_top = monitor_info.rcWork.top;
+  }
+
+  SetWindowPos(hwnd, nullptr, new_left, new_top, target_window_w,
+               target_window_h, SWP_NOZORDER | SWP_NOACTIVATE);
+}
+
 LRESULT
 FlutterWindow::MessageHandler(HWND hwnd, UINT const message,
                               WPARAM const wparam,