host_window_regular.cc

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// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
 
#include "flutter/shell/platform/windows/host_window_regular.h"
 
#include "flutter/shell/platform/windows/flutter_windows_engine.h"
 
namespace flutter {
 
namespace {
 
// Returns the Win32 window style for a regular window.
//
// If |resizable| is false, the resize border (WS_THICKFRAME) and maximize
// button (WS_MAXIMIZEBOX) are omitted.
DWORD GetWindowStyleForRegular(bool resizable) {
  DWORD style = WS_OVERLAPPEDWINDOW;
  if (!resizable) {
    style &= ~(WS_THICKFRAME | WS_MAXIMIZEBOX);
  }
  return style;
}
 
}  // namespace
 
HostWindowRegular::HostWindowRegular(WindowManager* window_manager,
                                     FlutterWindowsEngine* engine,
                                     const WindowSizeRequest& preferred_size,
                                     const BoxConstraints& constraints,
                                     LPCWSTR title,
                                     bool sized_to_content,
                                     bool resizable)
    : HostWindowSized(window_manager, engine, resizable) {
  FML_CHECK(sized_to_content || preferred_size.has_preferred_view_size);
  DWORD const window_style = GetWindowStyleForRegular(resizable);
  InitializeFlutterView(HostWindowInitializationParams{
      .archetype = WindowArchetype::kRegular,
      .window_style = window_style,
      .extended_window_style = 0,
      .box_constraints = constraints,
      .initial_window_rect = GetInitialRect(engine, preferred_size, constraints,
                                            sized_to_content, resizable),
      .title = title,
      .owner_window = std::optional<HWND>(),
      .sizing_delegate = sized_to_content ? AsSizingDelegate() : nullptr,
      .is_sized_to_content = sized_to_content,
  });
}
 
Rect HostWindowRegular::GetInitialRect(FlutterWindowsEngine* engine,
                                       const WindowSizeRequest& preferred_size,
                                       const BoxConstraints& constraints,
                                       bool sized_to_content,
                                       bool resizable) {
  double client_width;
  double client_height;
  if (sized_to_content) {
    // Use the minimum constraint as the initial window size. The window will
    // be resized to match the rendered content after the first frame.
    client_width = std::max(1.0, constraints.smallest().width());
    client_height = std::max(1.0, constraints.smallest().height());
  } else {
    client_width = preferred_size.preferred_view_width;
    client_height = preferred_size.preferred_view_height;
  }
 
  std::optional<Size> const window_size =
      HostWindow::GetWindowSizeForClientSize(
          *engine->windows_proc_table(), Size(client_width, client_height),
          constraints.smallest(), constraints.biggest(),
          GetWindowStyleForRegular(resizable), 0, nullptr);
  return {{CW_USEDEFAULT, CW_USEDEFAULT},
          window_size ? *window_size : Size{CW_USEDEFAULT, CW_USEDEFAULT}};
}
 
}  // namespace flutter