[WebRTC] A real ScreenCapturer test

webrtc/modules/desktop_capture/screen_drawer_linux.cc

 /*
  *  Copyright (c) 2016 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 <memory>
 
 #include "webrtc/base/checks.h"
 #include "webrtc/modules/desktop_capture/screen_drawer.h"
 #include "webrtc/modules/desktop_capture/x11/shared_x_display.h"
+#include "webrtc/system_wrappers/include/sleep.h"
 
 namespace webrtc {
 
 namespace {
 
 // A ScreenDrawer implementation for X11.
 class ScreenDrawerLinux : public ScreenDrawer {
  public:
   ScreenDrawerLinux();
   ~ScreenDrawerLinux() override;
 
   // ScreenDrawer interface.
   DesktopRect DrawableRegion() override;
-  void DrawRectangle(DesktopRect rect, uint32_t rgba) override;
-  void Clear() override;
+  void DrawRectangle(DesktopRect rect, uint32_t bgra) override;
+  void WaitForPendingPaintings() override;
 
  private:
   rtc::scoped_refptr<SharedXDisplay> display_;
   Screen* screen_;
   int screen_num_;
   DesktopRect rect_;
   Window window_;
   GC context_;
   Colormap colormap_;
 };
@@ skipping 26 matching lines @@
 
 ScreenDrawerLinux::~ScreenDrawerLinux() {
   XUnmapWindow(display_->display(), window_);
   XDestroyWindow(display_->display(), window_);
 }
 
 DesktopRect ScreenDrawerLinux::DrawableRegion() {
   return rect_;
 }
 
-void ScreenDrawerLinux::DrawRectangle(DesktopRect rect, uint32_t rgba) {
-  int r = (rgba & 0xff00) >> 8;
-  int g = (rgba & 0xff0000) >> 16;
-  int b = (rgba & 0xff000000) >> 24;
+void ScreenDrawerLinux::DrawRectangle(DesktopRect rect, uint32_t bgra) {
+  int b = (bgra & 0xff000000) >> 24;
+  int g = (bgra & 0xff0000) >> 16;
+  int r = (bgra & 0xff00) >> 8;
   // X11 does not support Alpha.
   XColor color;
   // X11 uses 16 bits for each primary color.
-  color.red = r * 256;
-  color.green = g * 256;
-  color.blue = b * 256;
+  color.red = r * 256 + r;
+  color.green = g * 256 + g;
+  color.blue = b * 256 + b;
   color.flags = DoRed | DoGreen | DoBlue;
   XAllocColor(display_->display(), colormap_, &color);
   XSetForeground(display_->display(), context_, color.pixel);
   XFillRectangle(display_->display(), window_, context_, rect.left(),
                  rect.top(), rect.width(), rect.height());
   XFlush(display_->display());
 }
 
-void ScreenDrawerLinux::Clear() {
-  DrawRectangle(DrawableRegion(), 0);
+// TODO(zijiehe): Find the right signal from X11 to indicate the finish of all
+// pending paintings.
+void ScreenDrawerLinux::WaitForPendingPaintings() {
+  SleepMs(500);
 }
 
 }  // namespace
 
 // static
 std::unique_ptr<ScreenDrawer> ScreenDrawer::Create() {
-  return std::unique_ptr<ScreenDrawer>(new ScreenDrawerLinux());
+  if (SharedXDisplay::CreateDefault().get()) {
+    return std::unique_ptr<ScreenDrawer>(new ScreenDrawerLinux());
+  } else {
+    return nullptr;
+  }
 }
 
 }  // namespace webrtc