我使用DirectX和GDI分别在Windows上捕获屏幕,这些屏幕分别基于操作系统(DirectX(桌面复制) - 适用于Win7及以上版本和G7 for Win7及以下版本,或者在DirectX方法出现任何错误时作为后备)
在某些机器上我很少得到GDI和DirectX在winlogon屏幕上返回ACCESS_DENIED错误。
正在检测并正确设置桌面开关&应用程序以提升的用户权限运行,桌面设置期间没有错误。捕获屏幕的同一个线程正在调用将当前桌面设置为当前线程的函数。该应用程序未在任何RDP会话上运行,例如here&提到的问题。 here
我做了很多分析和研究。我确实浏览了开源屏幕捕获应用程序的源代码,但我没有找到任何有用的东西。我已经花了一个星期没有在这个问题上取得任何进展。
以下是设置当前桌面的代码
if (GetCurrentDesktop(aCurrentDesktop) && _tcscmp(aCurrentDesktop, aPrevDesktop) != 0)
{
ScreenCaptureUtils::SetProcessWindowStation();
HDESK hcurrentInputDesktop = OpenInputDesktop(0, FALSE, GENERIC_READ | GENERIC_WRITE | GENERIC_EXECUTE);
if(hcurrentInputDesktop != NULL)
{
if(!SetThreadDesktop(hcurrentInputDesktop))
{
errorCode = GetLastError();
LOG << _T("setCurrentInputDesktop: SetThreadDesktop failed. Error code: ") << errorCode;
}
else
{
errorCode = ERROR_SUCCESS;
_tcscpy_s (aPrevDesktop, MAX_PATH, aCurrentDesktop);
LOG << _T("setCurrentInputDesktop: SetThreadDesktop succeeded.");
}
hPrevDesk = hcurrentInputDesktop;
CloseDesktop(hcurrentInputDesktop);
}
else
{
errorCode = GetLastError();
LOG << _T("setCurrentInputDesktop: OpenInputDesktop failed. Error code: ") << errorCode;
}
}
else
{
LOG << _T("setCurrentInputDesktop: OpenInputDesktop failed. Error code: ") << errorCode;
}
bool GetCurrentDesktop ( TCHAR * desktopName )
{
{
HDESK hDesktop = ::OpenInputDesktop(0, FALSE, GENERIC_READ | GENERIC_WRITE | GENERIC_EXECUTE);
if (!hDesktop)
{
return false;
}
DWORD dw = 0;
TCHAR szName[MAX_PATH];
::memset(szName, 0, sizeof(szName));
if (!::GetUserObjectInformation(hDesktop, UOI_NAME, &szName, sizeof(szName), &dw))
{
::CloseDesktop(hDesktop);
return false;
}
_tcscpy(desktopName, szName);
::CloseDesktop(hDesktop);
}
}
捕获屏幕的代码类似于以下代码
int screenCapture()
{
int result = -1;
int width = 1000;
int height = 700;
HDC hdcTemp, hdc;
BYTE* bitPointer;
hdc = GetDC(HWND_DESKTOP);
if (hdc != NULL)
{
hdcTemp = CreateCompatibleDC(hdc);
if (hdcTemp != NULL)
{
BITMAPINFO bitmap;
bitmap.bmiHeader.biSize = sizeof(bitmap.bmiHeader);
bitmap.bmiHeader.biWidth = width;
bitmap.bmiHeader.biHeight = -height;
bitmap.bmiHeader.biPlanes = 1;
bitmap.bmiHeader.biBitCount = 24;
bitmap.bmiHeader.biCompression = BI_RGB;
bitmap.bmiHeader.biSizeImage = 0;
bitmap.bmiHeader.biClrUsed = 0;
bitmap.bmiHeader.biClrImportant = 0;
HBITMAP hBitmap = CreateDIBSection(hdcTemp, &bitmap, DIB_RGB_COLORS, (void**)&bitPointer, NULL, NULL);
if (hBitmap != NULL)
{
HBITMAP hPrevBitmap = SelectObject(hdcTemp, hBitmap);
BitBlt(hdcTemp, 0, 0, width, height, hdc, 0, 0, SRCCOPY);
result = (int) bitPointer[0];
SelectObject(hdcTemp, hPrevBitmap);
DeleteObject(hBitmap);
}
DeleteDC(hdcTemp);
}
ReleaseDC(HWND_DESKTOP, hdc);
}
return result;
}
我用当前监视器的名称调用GetDC。这是否与调用GetDC以NULL为参数有关?但根据this,这看起来并不像是一个问题。
任何帮助将不胜感激。提前谢谢。