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分享屏幕截图，为什么在桌面的窗口被透明了，只截到桌面。
窗口在桌面上显示，但截图时，这个窗口被透明化。只显示了桌面。
BOOL ScreenCapture(const char* filename, LPRECT lpRect)
{
BOOL ret = FALSE;
if (filename != NULL)
{
//HDC hScreenDC = GetDC(GetDesktopWindow());
HDC hScreenDC = CreateDCA("DISPLAY", NULL, NULL, NULL); //通过指定DISPLAY来获取一个显示设备上下文环境
HDC hmemDC = CreateCompatibleDC(hScreenDC); //该函数创建一个与指定设备兼容的内存设备上下文环境（DC）
//截图x位置 //截图y位置 //截图宽度//截图高度
int startX, startY, width, height;
long BitmapSize;
DWORD BitsOffset;
DWORD ImageSize;
DWORD FileSize;
BITMAPINFOHEADER bmInfo; //BITMAPINFOHEADER结构所包含的成员表明了图像的尺寸、原始设备的颜色格式、以及数据压缩方案
BITMAPFILEHEADER bmFileHeader;
DWORD dwWritten;
if (lpRect == NULL)
{
startX = startY = 0;
width = GetDeviceCaps(hScreenDC, HORZRES); //获取指定设备的性能参数（此处获取屏幕宽度）;
height = GetDeviceCaps(hScreenDC, VERTRES); //获取指定设备的性能参数（此处获取屏幕高度）;
}
else
{
float fact = factor();
startX = (int)(fact*lpRect->left);
startY = (int)(fact*lpRect->top);
width = (int)(fact*lpRect->right) - startX;
height = (int)(fact*lpRect->bottom) - startY;
}
int iBits = GetDeviceCaps(hScreenDC, BITSPIXEL) * GetDeviceCaps(hScreenDC, PLANES);
if (iBits <= 1)
iBits = 1;
else if (iBits <= 4)
iBits = 4;
else if (iBits <= 8)
iBits = 8;
else if (iBits <= 24)
iBits = 24;
else
iBits = 32;
//创建一张长width，宽height的画布，用于后面绘制图形
HBITMAP hBitmap = CreateCompatibleBitmap(hScreenDC, width, height);
//该函数选择一对象到指定的设备上下文环境中，该新对象替换先前的相同类型的对象。
HBITMAP hOldBM = (HBITMAP)SelectObject(hmemDC, hBitmap);
//该函数对指定的源设备环境区域中的像素进行位块（bit_block）转换，以传送到目标设备环境。
BitBlt(hmemDC, 0, 0, width, height, hScreenDC, startX, startY, SRCCOPY);
hBitmap = (HBITMAP)SelectObject(hmemDC, hOldBM);
BitmapSize = ((((width * iBits) + iBits) / iBits) * 4)*height;
//用来在指定的堆上分配内存，并且分配后的内存不可移动(HEAP_NO_SERIALIZE 不使用连续存取)
PVOID lpData = HeapAlloc(GetProcessHeap(), HEAP_NO_SERIALIZE, BitmapSize);//内存分配成功返回的指向所分配内存块的首地址指针
ZeroMemory(lpData, BitmapSize);
ZeroMemory(&bmInfo, sizeof(BITMAPINFOHEADER));
bmInfo.biSize = sizeof(BITMAPINFOHEADER); //位图信息结构长度 ,必须为40
bmInfo.biWidth = width; //图像宽度 单位是像素
bmInfo.biHeight = height; //图像高度 单位是像素
bmInfo.biPlanes = 1; //必须为1
bmInfo.biBitCount = iBits; //设置图像的位数。比如8位，16位，32位位数越高分辨率越高
bmInfo.biCompression = BI_RGB; //位图是否压缩 BI_RGB为不压缩
ZeroMemory(&bmFileHeader, sizeof(BITMAPFILEHEADER));
BitsOffset = sizeof(BITMAPFILEHEADER) + bmInfo.biSize;
ImageSize = ((((bmInfo.biWidth*bmInfo.biBitCount) + iBits -1) / iBits) * 4)*bmInfo.biHeight;
FileSize = BitsOffset + ImageSize;
bmFileHeader.bfType = 0x4d42;//'B'+('M'<<8);
bmFileHeader.bfSize = FileSize;
bmFileHeader.bfOffBits = BitsOffset;
HANDLE hpal = GetStockObject(DEFAULT_PALETTE);
HANDLE holdpal = NULL;
if (hpal)
{
holdpal = SelectPalette(hmemDC, (HPALETTE)hpal, FALSE);
RealizePalette(hmemDC);
}
GetDIBits(hmemDC, hBitmap, 0, bmInfo.biHeight, lpData, (BITMAPINFO *)&bmInfo, DIB_RGB_COLORS);
if (holdpal)
{
SelectPalette(hmemDC, (HPALETTE)holdpal, TRUE);
RealizePalette(hmemDC);
}
HANDLE bmFile = CreateFileA(filename, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
if (bmFile != INVALID_HANDLE_VALUE)
{
WriteFile(bmFile, &bmFileHeader, sizeof(BITMAPFILEHEADER), &dwWritten, NULL);
WriteFile(bmFile, &bmInfo, sizeof(BITMAPINFOHEADER), &dwWritten, NULL);
WriteFile(bmFile, lpData, ImageSize, &dwWritten, NULL);
CloseHandle(bmFile);
ret = TRUE;
}
HeapFree(GetProcessHeap(), HEAP_NO_SERIALIZE, lpData);
//::ReleaseDC(0, hScreenDC);
DeleteDC(hScreenDC);
DeleteDC(hmemDC);
DeleteObject(hBitmap);
}
return ret;
}
...全文
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赵4老师 2022-10-28
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仅供参考：
//GDI与DX截屏API操作
LPDIRECTDRAW lpDD = NULL;
LPDIRECTDRAWSURFACE lpDDSPrime = NULL;
LPDIRECTDRAWSURFACE lpDDSBack = NULL;
LPDIRECTDRAWSURFACE lpDDSGdi = NULL;
LPDIRECTDRAWSURFACE lpSurf = NULL;
DDSURFACEDESC DDSdesc;
BOOL m_b24=TRUE;
//rfbServerInitMsg m_scrinfo;
RECT m_bmrect;
struct _BMInfo {
BITMAPINFO bmi ;
BOOL truecolour;
RGBQUAD cmap[256] ;
} m_bminfo; // 用来保存位图信息的结构
int DX_Init() {// DirectX初始化。返回当前表面获取一张屏幕位图的存储空间大小
HRESULT hr;
// 初始化directX
hr = DirectDrawCreate(0, &lpDD, 0);
if (FAILED(hr)) return FALSE;
hr = lpDD->SetCooperativeLevel(NULL, DDSCL_NORMAL);
if (FAILED(hr)) return FALSE;
ZeroMemory(&DDSdesc, sizeof(DDSdesc));
DDSdesc.dwSize = sizeof(DDSdesc);
DDSdesc.dwFlags = DDSD_CAPS;
DDSdesc.ddsCaps.dwCaps = DDSCAPS_PRIMARYSURFACE;
hr = lpDD->CreateSurface(&DDSdesc, &lpDDSPrime, 0);
if (FAILED(hr)) return FALSE;
hr = lpDD->GetGDISurface(&lpDDSGdi);
if (FAILED(hr)) return FALSE;
ZeroMemory(&DDSdesc, sizeof(DDSdesc));
DDSdesc.dwSize = sizeof(DDSdesc);
DDSdesc.dwFlags = DDSD_ALL;
hr = lpDDSPrime->GetSurfaceDesc(&DDSdesc);
if (FAILED(hr)) return FALSE;
// 初始化位图信息
if ((DDSdesc.dwFlags & DDSD_WIDTH) && (DDSdesc.dwFlags & DDSD_HEIGHT)) {
m_bmrect.left = m_bmrect.top = 0;
m_bmrect.right = DDSdesc.dwWidth;
m_bmrect.bottom = DDSdesc.dwHeight;
} else return FALSE;
m_bminfo.bmi.bmiHeader.biCompression = BI_RGB;//BI_BITFIELDS;
m_bminfo.bmi.bmiHeader.biBitCount = DDSdesc.ddpfPixelFormat.dwRGBBitCount;
// m_bminfo.truecolour = DDSdesc.ddpfPixelFormat.dwFlags & DDPF_RGB;
if (m_bminfo.bmi.bmiHeader.biBitCount > 8)
m_bminfo.truecolour = TRUE;
else
m_bminfo.truecolour = FALSE;
ZeroMemory(&DDSdesc, sizeof(DDSdesc));
DDSdesc.dwSize = sizeof(DDSdesc);
DDSdesc.dwFlags = DDSD_CAPS | DDSD_HEIGHT |DDSD_WIDTH;
DDSdesc.ddsCaps.dwCaps = DDSCAPS_OFFSCREENPLAIN;
DDSdesc.dwHeight = m_bmrect.bottom - m_bmrect.top;
DDSdesc.dwWidth = m_bmrect.right - m_bmrect.left;
hr = lpDD->CreateSurface(&DDSdesc, &lpDDSBack, 0);
if (FAILED(hr)) return FALSE;
// hr = lpDDSPrime->QueryInterface( IID_IDirectDrawSurface3, (LPVOID *)&lpSurf);
// if (FAILED(hr)) return FALSE;
switch (m_bminfo.bmi.bmiHeader.biBitCount) {
case 32:
case 24:
// Update the bitmapinfo header
m_b24 = TRUE;
m_bminfo.bmi.bmiHeader.biSize = sizeof( BITMAPINFOHEADER );
m_bminfo.bmi.bmiHeader.biWidth = 1024;
m_bminfo.bmi.bmiHeader.biHeight = 768;
m_bminfo.bmi.bmiHeader.biPlanes = 1;
// m_bminfo.bmi.bmiHeader.biBitCount = 24;
m_bminfo.bmi.bmiHeader.biCompression = BI_RGB;
m_bminfo.bmi.bmiHeader.biSizeImage = abs((m_bminfo.bmi.bmiHeader.biWidth * m_bminfo.bmi.bmiHeader.biHeight * m_bminfo.bmi.bmiHeader.biBitCount)/8);
m_bminfo.bmi.bmiHeader.biXPelsPerMeter = (1024*1000)/1024;
m_bminfo.bmi.bmiHeader.biYPelsPerMeter = (768*1000)/768;
m_bminfo.bmi.bmiHeader.biClrUsed = 0;
m_bminfo.bmi.bmiHeader.biClrImportant = 0;
break;
}
return m_bminfo.bmi.bmiHeader.biSizeImage;
}
BOOL CaptureScreen(RECT &rect, BYTE *scrBuff, UINT scrBuffSize) {// 捕捉屏幕。rect: 区域。scrBuff: 输出缓冲。scrBuffSize: 缓冲区大小
HRESULT hr=0;
hr = lpDDSBack->BltFast(rect.left,rect.top,lpDDSPrime,&rect,DDBLTFAST_NOCOLORKEY | DDBLTFAST_WAIT);
if (FAILED(hr)) return FALSE;
DDSURFACEDESC surfdesc;
ZeroMemory(&surfdesc, sizeof(surfdesc));
surfdesc.dwSize = sizeof(surfdesc);
hr = lpDDSBack->Lock(&rect, &surfdesc, DDLOCK_READONLY | DDLOCK_WAIT | DDLOCK_SURFACEMEMORYPTR /*|DDLOCK_NOSYSLOCK*/, NULL);
// hr = lpDDSPrime->Lock(&rect, &surfdesc, DDLOCK_READONLY | DDLOCK_WAIT | DDLOCK_SURFACEMEMORYPTR /*|DDLOCK_NOSYSLOCK*/, NULL);
if (FAILED(hr)) return FALSE;
// copy the data into our buffer
BYTE * destbuffpos, * srcbuffpos;
// m_scrinfo.format.bitsPerPixel = 24;
srcbuffpos = (BYTE *) surfdesc.lpSurface;
destbuffpos = scrBuff;
memcpy( destbuffpos, srcbuffpos,m_bminfo.bmi.bmiHeader.biSizeImage);
// unlock the primary surface
// lpDDSPrime->Unlock(surfdesc.lpSurface);
lpDDSBack->Unlock(surfdesc.lpSurface);
return TRUE;
}
int SaveBitmapToFile(BITMAP *bitmap, LPSTR lpFileName,char *lpBuf) {
DWORD dwWritten;
BITMAPFILEHEADER bmfHdr;
BITMAPINFOHEADER bi;
HANDLE fh=NULL;
bi.biSize = sizeof(BITMAPINFOHEADER);
bi.biWidth= bitmap->bmWidth;
bi.biHeight = bitmap->bmHeight;
bi.biPlanes = 1;
bi.biBitCount = bitmap->bmBitsPixel*8;
bi.biCompression = BI_RGB;
bi.biSizeImage = 0;
bi.biXPelsPerMeter = 0;
bi.biYPelsPerMeter = 0;
bi.biClrUsed = 0;
bi.biClrImportant = 0;
fh = CreateFile(lpFileName, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN, NULL);
if (fh == INVALID_HANDLE_VALUE) return FALSE;
bmfHdr.bfType = 0x4D42; // "BM"
bmfHdr.bfSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER)+bitmap->bmWidth*bitmap->bmHeight*bitmap->bmBitsPixel;
bmfHdr.bfReserved1 = 0;
bmfHdr.bfReserved2 = 0;
bmfHdr.bfOffBits = (DWORD)sizeof(BITMAPFILEHEADER) + (DWORD)sizeof(BITMAPINFOHEADER);
WriteFile(fh, (LPSTR)&bmfHdr, sizeof(BITMAPFILEHEADER), &dwWritten, NULL);
WriteFile(fh, (char *)&bi,sizeof(BITMAPINFOHEADER), &dwWritten, NULL);
WriteFile(fh, (char *)lpBuf,bitmap->bmWidth*bitmap->bmHeight*bitmap->bmBitsPixel, &dwWritten, NULL);
FlushFileBuffers(fh);
CloseHandle(fh);
return true;
}
//(1)获取屏幕绘图设备
//(2)创建一个与屏幕绘图设备相兼容的内存绘图设备
//(2)在内存中创建一个与屏幕绘图设备相兼容的图像对象
//(3)将屏幕设备中的图像复制到内存绘图设备中
//(4)将内存图像保存到文件中
//相关函数：
//GetDIBits:按位的方式返回指定的BITMAP，并按指定的格式存储到内存中
int GetBitmapFromScreen(char *lpFileName) {
char *lpBuf;
HBITMAP hBitmap,hOld ;
HDC hDC,hcDC;
BITMAP bb;
BITMAPINFO b;
HANDLE hp,fh=NULL;
DWORD dwX,dwY;
dwX=GetSystemMetrics(SM_CXSCREEN);
dwY=GetSystemMetrics(SM_CYSCREEN);
hDC=GetDC(NULL);
hcDC=CreateCompatibleDC(hDC);
hBitmap=CreateCompatibleBitmap(hDC,dwX,dwY);
hOld=(HBITMAP)SelectObject(hcDC,hBitmap);
BitBlt(hcDC,0, 0,dwX,dwY, hDC, 0, 0, SRCCOPY);
bb.bmWidth=dwX;
bb.bmHeight =dwY;
bb.bmPlanes = 1;
bb.bmWidthBytes=bb.bmWidth*3;
bb.bmBitsPixel=3;
bb.bmType=0;
b.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
b.bmiHeader.biWidth =dwX;
b.bmiHeader.biHeight =dwY;
b.bmiHeader.biPlanes =1;
b.bmiHeader.biBitCount =3*8;
b.bmiHeader.biCompression =BI_RGB;
b.bmiHeader.biSizeImage =0;
b.bmiHeader.biXPelsPerMeter=0;
b.bmiHeader.biYPelsPerMeter=0;
b.bmiHeader.biClrUsed =0;
b.bmiHeader.biClrImportant =0;
b.bmiColors[0].rgbBlue =8;
b.bmiColors[0].rgbGreen =8;
b.bmiColors[0].rgbRed =8;
b.bmiColors[0].rgbReserved =0;
hp=GetProcessHeap();
lpBuf=(char *)HeapAlloc(hp,HEAP_ZERO_MEMORY,bb.bmHeight*bb.bmWidth*4);
GetDIBits(hcDC,hBitmap,0,dwY,lpBuf,&b,DIB_RGB_COLORS);
SaveBitmapToFile(&bb,lpFileName,lpBuf);
ReleaseDC(NULL,hDC);
DeleteDC(hcDC);
DeleteObject(hBitmap);
DeleteObject(hOld);
HeapFree(hp,0,lpBuf);
return true;
}
玉生香 2022-10-30
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已解决 ，
