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/*
* 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 <windows.h>
#include <memory>
#include "modules/desktop_capture/screen_drawer.h"
#include "rtc_base/thread.h"
namespace webrtc {
namespace {
static constexpr TCHAR kMutexName[] =
TEXT("Local\\ScreenDrawerWin-da834f82-8044-11e6-ac81-73dcdd1c1869");
class ScreenDrawerLockWin : public ScreenDrawerLock {
public:
ScreenDrawerLockWin();
~ScreenDrawerLockWin() override;
private:
HANDLE mutex_;
};
ScreenDrawerLockWin::ScreenDrawerLockWin() {
while (true) {
mutex_ = CreateMutex(NULL, FALSE, kMutexName);
if (GetLastError() != ERROR_ALREADY_EXISTS && mutex_ != NULL) {
break;
} else {
if (mutex_) {
CloseHandle(mutex_);
}
Thread::SleepMs(1000);
}
}
}
ScreenDrawerLockWin::~ScreenDrawerLockWin() {
CloseHandle(mutex_);
}
DesktopRect GetScreenRect() {
HDC hdc = GetDC(NULL);
DesktopRect rect = DesktopRect::MakeWH(GetDeviceCaps(hdc, HORZRES),
GetDeviceCaps(hdc, VERTRES));
ReleaseDC(NULL, hdc);
return rect;
}
HWND CreateDrawerWindow(DesktopRect rect) {
HWND hwnd = CreateWindowA(
"STATIC", "DrawerWindow", WS_POPUPWINDOW | WS_VISIBLE, rect.left(),
rect.top(), rect.width(), rect.height(), NULL, NULL, NULL, NULL);
SetForegroundWindow(hwnd);
return hwnd;
}
COLORREF ColorToRef(RgbaColor color) {
// Windows device context does not support alpha.
return RGB(color.red, color.green, color.blue);
}
// A ScreenDrawer implementation for Windows.
class ScreenDrawerWin : public ScreenDrawer {
public:
ScreenDrawerWin();
~ScreenDrawerWin() override;
// ScreenDrawer interface.
DesktopRect DrawableRegion() override;
void DrawRectangle(DesktopRect rect, RgbaColor color) override;
void Clear() override;
void WaitForPendingDraws() override;
bool MayDrawIncompleteShapes() override;
WindowId window_id() const override;
private:
// Bring the window to the front, this can help to avoid the impact from other
// windows or shadow effects.
void BringToFront();
// Draw a line with `color`.
void DrawLine(DesktopVector start, DesktopVector end, RgbaColor color);
// Draw a dot with `color`.
void DrawDot(DesktopVector vect, RgbaColor color);
const DesktopRect rect_;
HWND window_;
HDC hdc_;
};
ScreenDrawerWin::ScreenDrawerWin()
: ScreenDrawer(),
rect_(GetScreenRect()),
window_(CreateDrawerWindow(rect_)),
hdc_(GetWindowDC(window_)) {
// We do not need to handle any messages for the `window_`, so disable Windows
// from processing windows ghosting feature.
DisableProcessWindowsGhosting();
// Always use stock pen (DC_PEN) and brush (DC_BRUSH).
SelectObject(hdc_, GetStockObject(DC_PEN));
SelectObject(hdc_, GetStockObject(DC_BRUSH));
BringToFront();
}
ScreenDrawerWin::~ScreenDrawerWin() {
ReleaseDC(NULL, hdc_);
DestroyWindow(window_);
// Unfortunately there is no EnableProcessWindowsGhosting() API.
}
DesktopRect ScreenDrawerWin::DrawableRegion() {
return rect_;
}
void ScreenDrawerWin::DrawRectangle(DesktopRect rect, RgbaColor color) {
if (rect.width() == 1 && rect.height() == 1) {
// Rectangle function cannot draw a 1 pixel rectangle.
DrawDot(rect.top_left(), color);
return;
}
if (rect.width() == 1 || rect.height() == 1) {
// Rectangle function cannot draw a 1 pixel rectangle.
DrawLine(rect.top_left(), DesktopVector(rect.right(), rect.bottom()),
color);
return;
}
SetDCBrushColor(hdc_, ColorToRef(color));
SetDCPenColor(hdc_, ColorToRef(color));
Rectangle(hdc_, rect.left(), rect.top(), rect.right(), rect.bottom());
}
void ScreenDrawerWin::Clear() {
DrawRectangle(rect_, RgbaColor(0, 0, 0));
}
// TODO(zijiehe): Find the right signal to indicate the finish of all pending
// paintings.
void ScreenDrawerWin::WaitForPendingDraws() {
BringToFront();
Thread::SleepMs(50);
}
bool ScreenDrawerWin::MayDrawIncompleteShapes() {
return true;
}
WindowId ScreenDrawerWin::window_id() const {
return reinterpret_cast<WindowId>(window_);
}
void ScreenDrawerWin::DrawLine(DesktopVector start,
DesktopVector end,
RgbaColor color) {
POINT points[2];
points[0].x = start.x();
points[0].y = start.y();
points[1].x = end.x();
points[1].y = end.y();
SetDCPenColor(hdc_, ColorToRef(color));
Polyline(hdc_, points, 2);
}
void ScreenDrawerWin::DrawDot(DesktopVector vect, RgbaColor color) {
SetPixel(hdc_, vect.x(), vect.y(), ColorToRef(color));
}
void ScreenDrawerWin::BringToFront() {
if (SetWindowPos(window_, HWND_TOPMOST, 0, 0, 0, 0,
SWP_NOMOVE | SWP_NOSIZE) != FALSE) {
return;
}
long ex_style = GetWindowLong(window_, GWL_EXSTYLE);
ex_style |= WS_EX_TOPMOST;
if (SetWindowLong(window_, GWL_EXSTYLE, ex_style) != 0) {
return;
}
BringWindowToTop(window_);
}
} // namespace
// static
std::unique_ptr<ScreenDrawerLock> ScreenDrawerLock::Create() {
return std::unique_ptr<ScreenDrawerLock>(new ScreenDrawerLockWin());
}
// static
std::unique_ptr<ScreenDrawer> ScreenDrawer::Create() {
return std::unique_ptr<ScreenDrawer>(new ScreenDrawerWin());
}
} // namespace webrtc
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