Use PW_RENDERFULLCONTENT to capture occluded windows on Win8.1 and Win10
On Win8.1 and Win10 when the window is occluded the cropping capturer
falls back to the PrintWindow API. But without a special flag it
fails when trying to capture apps that are using DirectComposition.
So just pass this undocumented flag named PW_RENDERFULLCONTENT to fix
the fallback case of the cropping capturer.
Due to new app framing on Win8 and Win10 the shadow of the window
are captured as black like if for the maximize case on Win7. So
just use the utility function webrtc::GetCroppedWindowRect and
remove the local GetWindowDrawableRect helper. The former returns
the same result as the later on Win7 so no real change is made here,
just that we make the WindowCapturerWin compatible with newer Windows.
Bug: webrtc:10734
Change-Id: Idb793ca0691261042569c30410669c4a5ad0c8ec
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/144960
Commit-Queue: Julien Isorce <julien.isorce@chromium.org>
Reviewed-by: Tommi <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28570}
diff --git a/modules/desktop_capture/window_capturer_win.cc b/modules/desktop_capture/window_capturer_win.cc
index 3dbec83..0c63893 100644
--- a/modules/desktop_capture/window_capturer_win.cc
+++ b/modules/desktop_capture/window_capturer_win.cc
@@ -12,6 +12,7 @@
#include <memory>
+#include "modules/desktop_capture/cropped_desktop_frame.h"
#include "modules/desktop_capture/desktop_capturer.h"
#include "modules/desktop_capture/desktop_frame_win.h"
#include "modules/desktop_capture/win/screen_capture_utils.h"
@@ -91,34 +92,6 @@
return TRUE;
}
-// Retrieves the rectangle of the window rect which is drawable by either OS or
-// the owner application. The returned DesktopRect is in system coordinates.
-// This function returns false if native APIs fail.
-//
-// When |window| is maximized, its borders and shadow effect will be ignored by
-// OS and leave black. So we prefer to use GetCroppedWindowRect() when capturing
-// its content to avoid the black area in the final DesktopFrame. But when the
-// window is in normal mode, borders and shadow should be included.
-bool GetWindowDrawableRect(HWND window,
- DesktopRect* drawable_rect,
- DesktopRect* original_rect) {
- if (!GetWindowRect(window, original_rect)) {
- return false;
- }
-
- bool is_maximized = false;
- if (!IsWindowMaximized(window, &is_maximized)) {
- return false;
- }
-
- if (is_maximized) {
- return GetCroppedWindowRect(window, drawable_rect,
- /* original_rect */ nullptr);
- }
- *drawable_rect = *original_rect;
- return true;
-}
-
class WindowCapturerWin : public DesktopCapturer {
public:
WindowCapturerWin();
@@ -235,7 +208,7 @@
DesktopRect cropped_rect;
DesktopRect original_rect;
- if (!GetWindowDrawableRect(window_, &cropped_rect, &original_rect)) {
+ if (!GetCroppedWindowRect(window_, &cropped_rect, &original_rect)) {
RTC_LOG(LS_WARNING) << "Failed to get drawable window area: "
<< GetLastError();
callback_->OnCaptureResult(Result::ERROR_TEMPORARY, nullptr);
@@ -287,7 +260,7 @@
}
std::unique_ptr<DesktopFrameWin> frame(
- DesktopFrameWin::Create(cropped_rect.size(), nullptr, window_dc));
+ DesktopFrameWin::Create(original_rect.size(), nullptr, window_dc));
if (!frame.get()) {
RTC_LOG(LS_WARNING) << "Failed to create frame.";
ReleaseDC(window_, window_dc);
@@ -315,17 +288,32 @@
// PrintWindow() whenever window size changes, including the first time of
// capturing - it somehow affects what we get from BitBlt() on the subsequent
// captures.
+ //
+ // For Windows 8.1 and later, we want to always use PrintWindow when the
+ // cropping screen capturer falls back to the window capturer. I.e.
+ // on Windows 8.1 and later, PrintWindow is only used when the window is
+ // occluded. When the window is not occluded, it is much faster to capture
+ // the screen and to crop it to the window position and size.
+ if (rtc::IsWindows8OrLater()) {
+ // Special flag that makes PrintWindow to work on Windows 8.1 and later.
+ // Indeed certain apps (e.g. those using DirectComposition rendering) can't
+ // be captured using BitBlt or PrintWindow without this flag. Note that on
+ // Windows 8.0 this flag is not supported so the block below will fallback
+ // to the other call to PrintWindow. It seems to be very tricky to detect
+ // Windows 8.0 vs 8.1 so a try/fallback is more approriate here.
+ const UINT flags = PW_RENDERFULLCONTENT;
+ result = PrintWindow(window_, mem_dc, flags);
+ }
- if (!window_capture_helper_.IsAeroEnabled() ||
- !previous_size_.equals(frame->size())) {
+ if (!result && (!window_capture_helper_.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);
+ window_dc, 0, 0, SRCCOPY);
}
SelectObject(mem_dc, previous_object);
@@ -338,14 +326,20 @@
frame->mutable_updated_region()->SetRect(
DesktopRect::MakeSize(frame->size()));
frame->set_top_left(
- cropped_rect.top_left().subtract(GetFullscreenRect().top_left()));
+ original_rect.top_left().subtract(GetFullscreenRect().top_left()));
- if (result) {
- callback_->OnCaptureResult(Result::SUCCESS, std::move(frame));
- } else {
+ if (!result) {
RTC_LOG(LS_ERROR) << "Both PrintWindow() and BitBlt() failed.";
callback_->OnCaptureResult(Result::ERROR_TEMPORARY, nullptr);
}
+
+ // Rect for the data is relative to the first pixel of the frame.
+ cropped_rect.Translate(-original_rect.left(), -original_rect.top());
+ std::unique_ptr<DesktopFrame> cropped_frame =
+ CreateCroppedDesktopFrame(std::move(frame), cropped_rect);
+ RTC_DCHECK(cropped_frame);
+
+ callback_->OnCaptureResult(Result::SUCCESS, std::move(cropped_frame));
}
} // namespace
