Enable cropping window capturing for Win7 when Aero is disabled.

webrtc/modules/desktop_capture/window_capturer_win.cc

 /*
  *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #include "webrtc/modules/desktop_capture/window_capturer.h"
 
 #include <assert.h>
 
 #include "webrtc/base/scoped_ptr.h"
 #include "webrtc/base/win32.h"
 #include "webrtc/modules/desktop_capture/desktop_frame_win.h"
 #include "webrtc/modules/desktop_capture/win/window_capture_utils.h"
 #include "webrtc/system_wrappers/interface/logging.h"
 
 namespace webrtc {
 
 namespace {
 
-typedef HRESULT (WINAPI *DwmIsCompositionEnabledFunc)(BOOL* enabled);
-
 BOOL CALLBACK WindowsEnumerationHandler(HWND hwnd, LPARAM param) {
   WindowCapturer::WindowList* list =
       reinterpret_cast<WindowCapturer::WindowList*>(param);
 
   // Skip windows that are invisible, minimized, have no title, or are owned,
   // unless they have the app window style set.
   int len = GetWindowTextLength(hwnd);
   HWND owner = GetWindow(hwnd, GW_OWNER);
   LONG exstyle = GetWindowLong(hwnd, GWL_EXSTYLE);
   if (len == 0 || IsIconic(hwnd) || !IsWindowVisible(hwnd) ||
@@ skipping 37 matching lines @@
   // WindowCapturer interface.
   bool GetWindowList(WindowList* windows) override;
   bool SelectWindow(WindowId id) override;
   bool BringSelectedWindowToFront() override;
 
   // DesktopCapturer interface.
   void Start(Callback* callback) override;
   void Capture(const DesktopRegion& region) override;
 
  private:
-  bool IsAeroEnabled();
-
   Callback* callback_;
 
   // HWND and HDC for the currently selected window or NULL if window is not
   // selected.
   HWND window_;
 
-  // dwmapi.dll is used to determine if desktop compositing is enabled.
-  HMODULE dwmapi_library_;
-  DwmIsCompositionEnabledFunc is_composition_enabled_func_;
+  DesktopSize previous_size_;
 
-  DesktopSize previous_size_;
+  AeroChecker aero_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowCapturerWin);
 };
 
 WindowCapturerWin::WindowCapturerWin()
     : callback_(NULL),
       window_(NULL) {
-  // Try to load dwmapi.dll dynamically since it is not available on XP.
-  dwmapi_library_ = LoadLibrary(L"dwmapi.dll");
-  if (dwmapi_library_) {
-    is_composition_enabled_func_ =
-        reinterpret_cast<DwmIsCompositionEnabledFunc>(
-            GetProcAddress(dwmapi_library_, "DwmIsCompositionEnabled"));
-    assert(is_composition_enabled_func_);
-  } else {
-    is_composition_enabled_func_ = NULL;
-  }
 }
 
 WindowCapturerWin::~WindowCapturerWin() {
-  if (dwmapi_library_)
-    FreeLibrary(dwmapi_library_);
-}
-
-bool WindowCapturerWin::IsAeroEnabled() {
-  BOOL result = FALSE;
-  if (is_composition_enabled_func_)
-    is_composition_enabled_func_(&result);
-  return result != FALSE;
 }
 
 bool WindowCapturerWin::GetWindowList(WindowList* windows) {
   WindowList result;
   LPARAM param = reinterpret_cast<LPARAM>(&result);
   if (!EnumWindows(&WindowsEnumerationHandler, param))
     return false;
   windows->swap(result);
   return true;
 }
@@ skipping 85 matching lines @@
   // window flickering. Otherwise, we prefer PrintWindow() because BitBlt() may
   // render occluding windows on top of the desired window.
   //
   // When composition is enabled the DC returned by GetWindowDC() doesn't always
   // have window frame rendered correctly. Windows renders it only once and then
   // caches the result between captures. We hack it around by calling
   // PrintWindow() whenever window size changes, including the first time of
   // capturing - it somehow affects what we get from BitBlt() on the subsequent
   // captures.
 
-  if (!IsAeroEnabled() || !previous_size_.equals(frame->size())) {
+  if (!aero_checker_.IsAeroEnabled() || !previous_size_.equals(frame->size())) {
     result = PrintWindow(window_, mem_dc, 0);
   }
 
   // Aero is enabled or PrintWindow() failed, use BitBlt.
   if (!result) {
     result = BitBlt(mem_dc, 0, 0, frame->size().width(), frame->size().height(),
                     window_dc,
                     cropped_rect.left() - original_rect.left(),
                     cropped_rect.top() - original_rect.top(),
                     SRCCOPY);
@@ skipping 17 matching lines @@
 }
 
 }  // namespace
 
 // static
 WindowCapturer* WindowCapturer::Create(const DesktopCaptureOptions& options) {
   return new WindowCapturerWin();
 }
 
 }  // namespace webrtc