Icon Capture For Window Capturer

webrtc/modules/desktop_capture/window_capturer_win.cc

Index: webrtc/modules/desktop_capture/window_capturer_win.cc
diff --git a/webrtc/modules/desktop_capture/window_capturer_win.cc b/webrtc/modules/desktop_capture/window_capturer_win.cc
index c7c312a17e957b3d132ed00ec7ab6c2f4a1e3cf0..26529aa53ccda037159fca908105a04be9a0f9ea 100644
--- a/webrtc/modules/desktop_capture/window_capturer_win.cc
+++ b/webrtc/modules/desktop_capture/window_capturer_win.cc
@@ -25,6 +25,80 @@ namespace webrtc {
 
 namespace {
 
+void InitializeBitmapHeader(BITMAPV5HEADER* header, int width, int height) {
+  memset(header, 0, sizeof(BITMAPV5HEADER));
+  header->bV5Size = sizeof(BITMAPV5HEADER);
+
+  // Note that icons are created using top-down DIBs so we must negate the
+  // value used for the icon's height.
+  header->bV5Width = width;
+  header->bV5Height = -height;
+  header->bV5Planes = 1;
+  header->bV5Compression = BI_RGB;
+
+  // Initializing the bitmap format to 32 bit ARGB.
+  header->bV5BitCount = 32;
+  header->bV5RedMask = 0x00FF0000;
+  header->bV5GreenMask = 0x0000FF00;
+  header->bV5BlueMask = 0x000000FF;
+  header->bV5AlphaMask = 0xFF000000;
+
+  // Use the system color space.  The default value is LCS_CALIBRATED_RGB, which
+  // causes us to crash if we don't specify the approprite gammas, etc.  See
+  // <http://msdn.microsoft.com/en-us/library/ms536531(VS.85).aspx> and
+  // <http://b/1283121>.
+  header->bV5CSType = LCS_WINDOWS_COLOR_SPACE;
+
+  // Use a valid value for bV5Intent as 0 is not a valid one.
+  // <http://msdn.microsoft.com/en-us/library/dd183381(VS.85).aspx>
+  header->bV5Intent = LCS_GM_IMAGES;
+}
+
+std::unique_ptr<DesktopFrame> GetWindowIcon(HWND hwnd) {
+  HICON icon_handle =
+      reinterpret_cast<HICON>(SendMessage(hwnd, WM_GETICON, ICON_BIG, 0));
+  if (icon_handle == NULL)
+    icon_handle = (HICON)GetClassLongPtr(hwnd, GCLP_HICON);
+  if (icon_handle == NULL)
+    icon_handle =
+        reinterpret_cast<HICON>(SendMessage(hwnd, WM_GETICON, ICON_SMALL, 0));
+  if (icon_handle == NULL)
+    icon_handle =
+        reinterpret_cast<HICON>(SendMessage(hwnd, WM_GETICON, ICON_SMALL2, 0));
+  if (icon_handle == NULL)
+    icon_handle = (HICON)GetClassLongPtr(hwnd, GCLP_HICONSM);
+
+  if (icon_handle == NULL)
+    return nullptr;
+
+  ICONINFO icon_info;
+  ::GetIconInfo(icon_handle, &icon_info);
+
+  BITMAP bitmap_info = {0};
+  ::GetObject(icon_info.hbmMask, sizeof(bitmap_info), &bitmap_info);
+
+  std::unique_ptr<DesktopFrame> frame(new BasicDesktopFrame(
+      DesktopSize(bitmap_info.bmWidth, bitmap_info.bmHeight)));
+
+  BITMAPV5HEADER h;
+  InitializeBitmapHeader(&h, bitmap_info.bmWidth, bitmap_info.bmHeight);
+  HDC hdc = ::GetDC(NULL);
+  uint8_t* bits;
+  HBITMAP dib =
+      ::CreateDIBSection(hdc, reinterpret_cast<BITMAPINFO*>(&h), DIB_RGB_COLORS,
+                         reinterpret_cast<void**>(&bits), NULL, 0);
+  HDC dib_dc = CreateCompatibleDC(hdc);
+  ::SelectObject(dib_dc, dib);
+  ::DrawIconEx(dib_dc, 0, 0, icon_handle, bitmap_info.bmWidth,
+               bitmap_info.bmHeight, 0, NULL, DI_NORMAL);
+  for (int y = 0; y < bitmap_info.bmHeight; ++y) {
+    memcpy(frame->data() + frame->stride() * y,
+           bits + bitmap_info.bmWidth * DesktopFrame::kBytesPerPixel * y,
+           DesktopFrame::kBytesPerPixel * bitmap_info.bmWidth);
+  }
+  return frame;
+}
+
 BOOL CALLBACK WindowsEnumerationHandler(HWND hwnd, LPARAM param) {
   WindowCapturer::WindowList* list =
       reinterpret_cast<WindowCapturer::WindowList*>(param);
@@ -70,12 +144,13 @@ BOOL CALLBACK WindowsEnumerationHandler(HWND hwnd, LPARAM param) {
   // Truncate the title if it's longer than kTitleLength.
   GetWindowText(hwnd, window_title, kTitleLength);
   window.title = rtc::ToUtf8(window_title);
+  window.icon = GetWindowIcon(hwnd);
 
   // Skip windows when we failed to convert the title or it is empty.
   if (window.title.empty())
     return TRUE;
 
-  list->push_back(window);
+  list->push_back(std::move(window));
 
   return TRUE;
 }
@@ -116,11 +191,10 @@ WindowCapturerWin::WindowCapturerWin() {}
 WindowCapturerWin::~WindowCapturerWin() {}
 
 bool WindowCapturerWin::GetWindowList(WindowList* windows) {
-  WindowList result;
-  LPARAM param = reinterpret_cast<LPARAM>(&result);
+  windows->clear();
+  LPARAM param = reinterpret_cast<LPARAM>(windows);
   if (!EnumWindows(&WindowsEnumerationHandler, param))
     return false;
-  windows->swap(result);
 
   std::map<HWND, DesktopSize> new_map;
   for (const auto& item : *windows) {