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/*
* Copyright (c) 2014 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 "modules/desktop_capture/win/screen_capturer_win_magnifier.h"
#include <utility>
#include "modules/desktop_capture/desktop_capture_metrics_helper.h"
#include "modules/desktop_capture/desktop_capture_options.h"
#include "modules/desktop_capture/desktop_capture_types.h"
#include "modules/desktop_capture/desktop_frame.h"
#include "modules/desktop_capture/desktop_frame_win.h"
#include "modules/desktop_capture/desktop_region.h"
#include "modules/desktop_capture/mouse_cursor.h"
#include "modules/desktop_capture/win/cursor.h"
#include "modules/desktop_capture/win/desktop.h"
#include "modules/desktop_capture/win/screen_capture_utils.h"
#include "rtc_base/checks.h"
#include "rtc_base/logging.h"
#include "rtc_base/time_utils.h"
#include "system_wrappers/include/metrics.h"
namespace webrtc {
namespace {
DWORD GetTlsIndex() {
static const DWORD tls_index = TlsAlloc();
RTC_DCHECK(tls_index != TLS_OUT_OF_INDEXES);
return tls_index;
}
} // namespace
// kMagnifierWindowClass has to be "Magnifier" according to the Magnification
// API. The other strings can be anything.
static wchar_t kMagnifierHostClass[] = L"ScreenCapturerWinMagnifierHost";
static wchar_t kHostWindowName[] = L"MagnifierHost";
static wchar_t kMagnifierWindowClass[] = L"Magnifier";
static wchar_t kMagnifierWindowName[] = L"MagnifierWindow";
ScreenCapturerWinMagnifier::ScreenCapturerWinMagnifier() = default;
ScreenCapturerWinMagnifier::~ScreenCapturerWinMagnifier() {
// DestroyWindow must be called before MagUninitialize. magnifier_window_ is
// destroyed automatically when host_window_ is destroyed.
if (host_window_)
DestroyWindow(host_window_);
if (magnifier_initialized_)
mag_uninitialize_func_();
if (mag_lib_handle_)
FreeLibrary(mag_lib_handle_);
if (desktop_dc_)
ReleaseDC(NULL, desktop_dc_);
}
void ScreenCapturerWinMagnifier::Start(Callback* callback) {
RTC_DCHECK(!callback_);
RTC_DCHECK(callback);
RecordCapturerImpl(DesktopCapturerId::kScreenCapturerWinMagnifier);
callback_ = callback;
if (!InitializeMagnifier()) {
RTC_LOG_F(LS_WARNING) << "Magnifier initialization failed.";
}
}
void ScreenCapturerWinMagnifier::SetSharedMemoryFactory(
std::unique_ptr<SharedMemoryFactory> shared_memory_factory) {
shared_memory_factory_ = std::move(shared_memory_factory);
}
void ScreenCapturerWinMagnifier::CaptureFrame() {
RTC_DCHECK(callback_);
if (!magnifier_initialized_) {
RTC_LOG_F(LS_WARNING) << "Magnifier initialization failed.";
callback_->OnCaptureResult(Result::ERROR_PERMANENT, nullptr);
return;
}
int64_t capture_start_time_nanos = rtc::TimeNanos();
// Switch to the desktop receiving user input if different from the current
// one.
std::unique_ptr<Desktop> input_desktop(Desktop::GetInputDesktop());
if (input_desktop.get() != NULL && !desktop_.IsSame(*input_desktop)) {
// Release GDI resources otherwise SetThreadDesktop will fail.
if (desktop_dc_) {
ReleaseDC(NULL, desktop_dc_);
desktop_dc_ = NULL;
}
// If SetThreadDesktop() fails, the thread is still assigned a desktop.
// So we can continue capture screen bits, just from the wrong desktop.
desktop_.SetThreadDesktop(input_desktop.release());
}
DesktopRect rect = GetScreenRect(current_screen_id_, current_device_key_);
queue_.MoveToNextFrame();
CreateCurrentFrameIfNecessary(rect.size());
// CaptureImage may fail in some situations, e.g. windows8 metro mode. So
// defer to the fallback capturer if magnifier capturer did not work.
if (!CaptureImage(rect)) {
RTC_LOG_F(LS_WARNING) << "Magnifier capturer failed to capture a frame.";
callback_->OnCaptureResult(Result::ERROR_PERMANENT, nullptr);
return;
}
// Emit the current frame.
std::unique_ptr<DesktopFrame> frame = queue_.current_frame()->Share();
frame->set_dpi(DesktopVector(GetDeviceCaps(desktop_dc_, LOGPIXELSX),
GetDeviceCaps(desktop_dc_, LOGPIXELSY)));
frame->mutable_updated_region()->SetRect(
DesktopRect::MakeSize(frame->size()));
int capture_time_ms = (rtc::TimeNanos() - capture_start_time_nanos) /
rtc::kNumNanosecsPerMillisec;
RTC_HISTOGRAM_COUNTS_1000(
"WebRTC.DesktopCapture.Win.MagnifierCapturerFrameTime", capture_time_ms);
frame->set_capture_time_ms(capture_time_ms);
frame->set_capturer_id(DesktopCapturerId::kScreenCapturerWinMagnifier);
callback_->OnCaptureResult(Result::SUCCESS, std::move(frame));
}
bool ScreenCapturerWinMagnifier::GetSourceList(SourceList* sources) {
return webrtc::GetScreenList(sources);
}
bool ScreenCapturerWinMagnifier::SelectSource(SourceId id) {
if (IsScreenValid(id, ¤t_device_key_)) {
current_screen_id_ = id;
return true;
}
return false;
}
void ScreenCapturerWinMagnifier::SetExcludedWindow(WindowId excluded_window) {
excluded_window_ = (HWND)excluded_window;
if (excluded_window_ && magnifier_initialized_) {
set_window_filter_list_func_(magnifier_window_, MW_FILTERMODE_EXCLUDE, 1,
&excluded_window_);
}
}
bool ScreenCapturerWinMagnifier::CaptureImage(const DesktopRect& rect) {
RTC_DCHECK(magnifier_initialized_);
// Set the magnifier control to cover the captured rect. The content of the
// magnifier control will be the captured image.
BOOL result = SetWindowPos(magnifier_window_, NULL, rect.left(), rect.top(),
rect.width(), rect.height(), 0);
if (!result) {
RTC_LOG_F(LS_WARNING) << "Failed to call SetWindowPos: " << GetLastError()
<< ". Rect = {" << rect.left() << ", " << rect.top()
<< ", " << rect.right() << ", " << rect.bottom()
<< "}";
return false;
}
magnifier_capture_succeeded_ = false;
RECT native_rect = {rect.left(), rect.top(), rect.right(), rect.bottom()};
TlsSetValue(GetTlsIndex(), this);
// OnCaptured will be called via OnMagImageScalingCallback and fill in the
// frame before set_window_source_func_ returns.
result = set_window_source_func_(magnifier_window_, native_rect);
if (!result) {
RTC_LOG_F(LS_WARNING) << "Failed to call MagSetWindowSource: "
<< GetLastError() << ". Rect = {" << rect.left()
<< ", " << rect.top() << ", " << rect.right() << ", "
<< rect.bottom() << "}";
return false;
}
return magnifier_capture_succeeded_;
}
BOOL ScreenCapturerWinMagnifier::OnMagImageScalingCallback(
HWND hwnd,
void* srcdata,
MAGIMAGEHEADER srcheader,
void* destdata,
MAGIMAGEHEADER destheader,
RECT unclipped,
RECT clipped,
HRGN dirty) {
ScreenCapturerWinMagnifier* owner =
reinterpret_cast<ScreenCapturerWinMagnifier*>(TlsGetValue(GetTlsIndex()));
TlsSetValue(GetTlsIndex(), nullptr);
owner->OnCaptured(srcdata, srcheader);
return TRUE;
}
// TODO(zijiehe): These functions are available on Windows Vista or upper, so we
// do not need to use LoadLibrary and GetProcAddress anymore. Use regular
// include and function calls instead of a dynamical loaded library.
bool ScreenCapturerWinMagnifier::InitializeMagnifier() {
RTC_DCHECK(!magnifier_initialized_);
if (GetSystemMetrics(SM_CMONITORS) != 1) {
// Do not try to use the magnifier in multi-screen setup (where the API
// crashes sometimes).
RTC_LOG_F(LS_WARNING) << "Magnifier capturer cannot work on multi-screen "
"system.";
return false;
}
desktop_dc_ = GetDC(nullptr);
mag_lib_handle_ = LoadLibraryW(L"Magnification.dll");
if (!mag_lib_handle_)
return false;
// Initialize Magnification API function pointers.
mag_initialize_func_ = reinterpret_cast<MagInitializeFunc>(
GetProcAddress(mag_lib_handle_, "MagInitialize"));
mag_uninitialize_func_ = reinterpret_cast<MagUninitializeFunc>(
GetProcAddress(mag_lib_handle_, "MagUninitialize"));
set_window_source_func_ = reinterpret_cast<MagSetWindowSourceFunc>(
GetProcAddress(mag_lib_handle_, "MagSetWindowSource"));
set_window_filter_list_func_ = reinterpret_cast<MagSetWindowFilterListFunc>(
GetProcAddress(mag_lib_handle_, "MagSetWindowFilterList"));
set_image_scaling_callback_func_ =
reinterpret_cast<MagSetImageScalingCallbackFunc>(
GetProcAddress(mag_lib_handle_, "MagSetImageScalingCallback"));
if (!mag_initialize_func_ || !mag_uninitialize_func_ ||
!set_window_source_func_ || !set_window_filter_list_func_ ||
!set_image_scaling_callback_func_) {
RTC_LOG_F(LS_WARNING) << "Failed to initialize ScreenCapturerWinMagnifier: "
"library functions missing.";
return false;
}
BOOL result = mag_initialize_func_();
if (!result) {
RTC_LOG_F(LS_WARNING) << "Failed to initialize ScreenCapturerWinMagnifier: "
"error from MagInitialize "
<< GetLastError();
return false;
}
HMODULE hInstance = nullptr;
result =
GetModuleHandleExA(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS |
GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,
reinterpret_cast<char*>(&DefWindowProc), &hInstance);
if (!result) {
mag_uninitialize_func_();
RTC_LOG_F(LS_WARNING) << "Failed to initialize ScreenCapturerWinMagnifier: "
"error from GetModulehandleExA "
<< GetLastError();
return false;
}
// Register the host window class. See the MSDN documentation of the
// Magnification API for more infomation.
WNDCLASSEXW wcex = {};
wcex.cbSize = sizeof(WNDCLASSEX);
wcex.lpfnWndProc = &DefWindowProc;
wcex.hInstance = hInstance;
wcex.hCursor = LoadCursor(nullptr, IDC_ARROW);
wcex.lpszClassName = kMagnifierHostClass;
// Ignore the error which may happen when the class is already registered.
RegisterClassExW(&wcex);
// Create the host window.
host_window_ =
CreateWindowExW(WS_EX_LAYERED, kMagnifierHostClass, kHostWindowName, 0, 0,
0, 0, 0, nullptr, nullptr, hInstance, nullptr);
if (!host_window_) {
mag_uninitialize_func_();
RTC_LOG_F(LS_WARNING) << "Failed to initialize ScreenCapturerWinMagnifier: "
"error from creating host window "
<< GetLastError();
return false;
}
// Create the magnifier control.
magnifier_window_ = CreateWindowW(kMagnifierWindowClass, kMagnifierWindowName,
WS_CHILD | WS_VISIBLE, 0, 0, 0, 0,
host_window_, nullptr, hInstance, nullptr);
if (!magnifier_window_) {
mag_uninitialize_func_();
RTC_LOG_F(LS_WARNING) << "Failed to initialize ScreenCapturerWinMagnifier: "
"error from creating magnifier window "
<< GetLastError();
return false;
}
// Hide the host window.
ShowWindow(host_window_, SW_HIDE);
// Set the scaling callback to receive captured image.
result = set_image_scaling_callback_func_(
magnifier_window_,
&ScreenCapturerWinMagnifier::OnMagImageScalingCallback);
if (!result) {
mag_uninitialize_func_();
RTC_LOG_F(LS_WARNING) << "Failed to initialize ScreenCapturerWinMagnifier: "
"error from MagSetImageScalingCallback "
<< GetLastError();
return false;
}
if (excluded_window_) {
result = set_window_filter_list_func_(
magnifier_window_, MW_FILTERMODE_EXCLUDE, 1, &excluded_window_);
if (!result) {
mag_uninitialize_func_();
RTC_LOG_F(LS_WARNING)
<< "Failed to initialize ScreenCapturerWinMagnifier: "
"error from MagSetWindowFilterList "
<< GetLastError();
return false;
}
}
magnifier_initialized_ = true;
return true;
}
void ScreenCapturerWinMagnifier::OnCaptured(void* data,
const MAGIMAGEHEADER& header) {
DesktopFrame* current_frame = queue_.current_frame();
// Verify the format.
// TODO(jiayl): support capturing sources with pixel formats other than RGBA.
int captured_bytes_per_pixel = header.cbSize / header.width / header.height;
if (header.format != GUID_WICPixelFormat32bppRGBA ||
header.width != static_cast<UINT>(current_frame->size().width()) ||
header.height != static_cast<UINT>(current_frame->size().height()) ||
header.stride != static_cast<UINT>(current_frame->stride()) ||
captured_bytes_per_pixel != DesktopFrame::kBytesPerPixel) {
RTC_LOG_F(LS_WARNING)
<< "Output format does not match the captured format: "
"width = "
<< header.width
<< ", "
"height = "
<< header.height
<< ", "
"stride = "
<< header.stride
<< ", "
"bpp = "
<< captured_bytes_per_pixel
<< ", "
"pixel format RGBA ? "
<< (header.format == GUID_WICPixelFormat32bppRGBA) << ".";
return;
}
// Copy the data into the frame.
current_frame->CopyPixelsFrom(
reinterpret_cast<uint8_t*>(data), header.stride,
DesktopRect::MakeXYWH(0, 0, header.width, header.height));
magnifier_capture_succeeded_ = true;
}
void ScreenCapturerWinMagnifier::CreateCurrentFrameIfNecessary(
const DesktopSize& size) {
// If the current buffer is from an older generation then allocate a new one.
// Note that we can't reallocate other buffers at this point, since the caller
// may still be reading from them.
if (!queue_.current_frame() || !queue_.current_frame()->size().equals(size)) {
std::unique_ptr<DesktopFrame> frame =
shared_memory_factory_
? SharedMemoryDesktopFrame::Create(size,
shared_memory_factory_.get())
: std::unique_ptr<DesktopFrame>(new BasicDesktopFrame(size));
queue_.ReplaceCurrentFrame(SharedDesktopFrame::Wrap(std::move(frame)));
}
}
} // namespace webrtc