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MFC 屏幕截图(libjpeg bmp转jpg)
项目中需要用到的功能。
void Screenshot() { CDC *pDC; pDC = CDC::FromHandle(GetDC(GetDesktopWindow())); if(pDC == NULL) return; int BitPerPixel = pDC->GetDeviceCaps(BITSPIXEL); int Width = pDC->GetDeviceCaps(HORZRES); int Height = pDC->GetDeviceCaps(VERTRES); CDC memDC; if(memDC.CreateCompatibleDC(pDC) == 0) return; CBitmap memBitmap, *oldmemBitmap; if(memBitmap.CreateCompatibleBitmap(pDC, Width, Height) == NULL) return; oldmemBitmap = memDC.SelectObject(&memBitmap); if(oldmemBitmap == NULL) return; if(memDC.BitBlt(0, 0, Width, Height, pDC, 0, 0, SRCCOPY) == 0) return; CPoint po; GetCursorPos(&po); HICON hinco = (HICON)GetCursor(); memDC.DrawIcon(po.x-10 , po.y - 10 , hinco); BITMAP bmp; memBitmap.GetBitmap(&bmp); BITMAPINFOHEADER bih = {0}; bih.biBitCount = bmp.bmBitsPixel; bih.biCompression = BI_RGB; bih.biHeight = bmp.bmHeight; bih.biPlanes = 1; bih.biSize = sizeof(BITMAPINFOHEADER); bih.biSizeImage = bmp.bmWidthBytes * bmp.bmHeight; bih.biWidth = bmp.bmWidth; BITMAPFILEHEADER bfh = {0}; bfh.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER); bfh.bfSize = bfh.bfOffBits + bmp.bmWidthBytes * bmp.bmHeight; bfh.bfType = (WORD)0x4d42; BYTE* pImgBuff = new BYTE[bmp.bmWidthBytes * bmp.bmHeight]; GetDIBits(memDC.m_hDC, (HBITMAP) memBitmap.m_hObject , 0, Height, pImgBuff, (LPBITMAPINFO) &bih, DIB_RGB_COLORS); memDC.SelectObject(oldmemBitmap); BYTE* pJpg = NULL; int nJpgSize = BmpToJpeg(pImgBuff, bmp.bmWidth, bmp.bmHeight, &pJpg); if (NULL != pJpg) { delete[] pJpg; } delete [] pImgBuff; }
附上 BmpToJpeg
int BmpToJpeg(BYTE *pSrc, int nWidth, int nHeight, BYTE** ppDes) { struct jpeg_compress_struct cinfo; struct jpeg_error_mgr jerr; JSAMPROW row_pointer[1]; int row_stride; cinfo.err = jpeg_std_error(&jerr); jpeg_create_compress(&cinfo); DWORD dwLen = nWidth * nHeight * 3; jpeg_mem_dest(&cinfo, ppDes, &dwLen); cinfo.image_width = nWidth; cinfo.image_height = nHeight; cinfo.input_components = 3; cinfo.in_color_space = JCS_RGB; jpeg_set_defaults(&cinfo); jpeg_set_quality(&cinfo, JPEG_QUALITY, TRUE); jpeg_start_compress(&cinfo, TRUE); row_stride = nWidth * 3; for (int i=0, j=0; j < nWidth*nHeight*4; i+=3, j+=4) //BGRA => RGB { *(pSrc+i)=*(pSrc+j+2); *(pSrc+i+1)=*(pSrc+j+1); *(pSrc+i+2)=*(pSrc+j); } while (cinfo.next_scanline < cinfo.image_height) { row_pointer[0] = &pSrc[(cinfo.image_height - cinfo.next_scanline - 1) * row_stride]; (void) jpeg_write_scanlines(&cinfo, row_pointer, 1); } jpeg_finish_compress(&cinfo); jpeg_destroy_compress(&cinfo); return dwLen; }
需要用到的头文件
#define JPEG_QUALITY 50 extern "C" { #include "jpeglib.h" #include "jmorecfg.h" #include "jconfig.h" }
MFC 屏幕截图(libjpeg bmp转jpg)
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