切换屏幕旋转模式通过调用 ChangeDisplaySettingsEx 来实现，如：
DEVMODE devmode = {0};
devmode.dmSize = sizeof(DEVMODE);
devmode.dmDisplayOrientation = DMDO_90; //水平模式
devmode.dmFields = DM_DISPLAYORIENTATION;
ChangeDisplaySettingsEx(NULL, &devmode, NULL, 0, NULL);
取得当前模式的代码如下：
DEVMODE devmode = {0};
devmode.dmSize = sizeof(DEVMODE);
devmode.dmFields = DM_DISPLAYORIENTATION;
ChangeDisplaySettingsEx(NULL, &devmode, 0, CDS_TEST, NULL);
通过 devmode.dmDisplayOrientation 的值可以判断当前模式。
值得注意的是，这样切换模式并不是永久的，当设备重新起动后，就会还原为初始状态。
如果你需要在保留切换的屏幕模式，可以通过设置注册表中HKEY_LOCAL_MACHINE\System\GDI\Rotation 下的两个键值实现
Angle - DWORD (0, 90, 180, 270)
LandscapeMode - DWORD (0,1)
12.拷屏并保存为bmp图片
void SaveDCToBMP(HDC hDC,int nStartX,int nStartY,
int nWidth,int nHeight,LPCTSTR szFileName)
{
//定义图形色深
int iPixel = 32;
//位图信息头
LPBITMAPINFO lpbmih = new BITMAPINFO;
lpbmih->bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
lpbmih->bmiHeader.biWidth = nWidth;
lpbmih->bmiHeader.biHeight = nHeight;
lpbmih->bmiHeader.biPlanes = 1;
lpbmih->bmiHeader.biBitCount = iPixel;
lpbmih->bmiHeader.biCompression = BI_RGB;
lpbmih->bmiHeader.biSizeImage = 0;
lpbmih->bmiHeader.biXPelsPerMeter = 0;
lpbmih->bmiHeader.biYPelsPerMeter = 0;
lpbmih->bmiHeader.biClrUsed = 0;
lpbmih->bmiHeader.biClrImportant = 0;
//创建位图数据
HDC hdcMem;
HBITMAP hBitMap = NULL;
CBitmap *pBitMap = NULL;
CDC *pMemDC = NULL;
BYTE *pBits;
hdcMem = CreateCompatibleDC(hDC);
hBitMap = CreateDIBSection(hdcMem,lpbmih,DIB_PAL_COLORS,(void **)&pBits,NULL,0);
pBitMap = new CBitmap;
pBitMap->Attach(hBitMap);
pMemDC = new CDC;
pMemDC->Attach(hdcMem);
pMemDC->SelectObject(pBitMap);
pMemDC->BitBlt(0,0,nWidth,nHeight,CDC::FromHandle(hDC),nStartX,nStartY,SRCCOPY);
BITMAPFILEHEADER bmfh;//位图文件头
ZeroMemory(&bmfh,sizeof(BITMAPFILEHEADER));
*((char *)&bmfh.bfType) = 'B';
*(((char *)&bmfh.bfType) + 1) = 'M';
bmfh.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);
bmfh.bfSize = bmfh.bfOffBits + (nWidth * nHeight) * iPixel / 8;
int iBMPBytes = nWidth * nHeight * iPixel / 8;
CFile file;
if(file.Open(szFileName,CFile::modeWrite | CFile::modeCreate))
{
file.Write(&bmfh,sizeof(BITMAPFILEHEADER));
file.Write(&(lpbmih->bmiHeader),sizeof(BITMAPINFOHEADER));
file.Write(pBits,iBMPBytes);
file.Close();
}
DeleteObject(hBitMap);
DeleteObject(hDC);
pMemDC->DeleteDC();
delete pMemDC; pMemDC = NULL;
delete pBitMap; pBitMap = NULL;
delete lpbmih; lpbmih = NULL;
}
13.识别当前系统语言一般系统语言的表示是
0409 // Enaglish US
0404 // 繁体中文
0804 // 简体中文
可以用GetSystemDefaultLangID()) 或GetUserDefaultLangID()来获取
switch(GetSystemDefaultLangID()/*GetUserDefaultLangID()*/) {
case 0x0804:
break;
case 0x0404:
break;
case 0x0409:
break;
}