上回分享了一个全屏截图的代码，保存为BMP，参考：C++实现屏幕截图（全屏截图）
实际使用的过程中我发现截图文件实在大，无奈又整成了PNG截图，现在分享出来。
MakePNG.h
//MakePNG.h #pragma once #include <GdiPlus.h> using namespace Gdiplus; #pragma comment(lib,"GdiPlus.lib") class CMakePNG { public: CMakePNG(void); ~CMakePNG(void); BOOL MakePNG(HDC hDC,CRect rect,CString strFilePath); BOOL BMptoPNG(LPCWSTR StrBMp,LPCWSTR StrPNG); BOOL PNGtoBMp(LPCWSTR StrPNG,LPCWSTR StrBMp); BOOL GetEncoderClsid(WCHAR* pFormat,CLSID* pClsid); private: GdiplusStartupInput m_gdiplusStartupInput; ULONG_PTR m_pGdiToken; };
MakePNG.cpp
//MakePNG.cpp #include "StdAfx.h" #include "MakePNG.h" CMakePNG::CMakePNG(void) { GdiplusStartup(&m_pGdiToken,&m_gdiplusStartupInput,NULL); } CMakePNG::~CMakePNG(void) { } /***************************************************************************/ /* 功能： 根据rect屏幕抓图，保存为文件名为strFilePath的PNG图像文件 */ /* 输入参数： HDC hDC 屏幕HDC； */ /* CRect rect 需要的矩形; */ /* CString strFilePath 保存文件全路径（含后缀名）; */ /***************************************************************************/ BOOL CMakePNG::MakePNG(HDC hDC, CRect rect, CString strFilePath) { BITMAP bmp; PBITMAPINFO pbmi; PBITMAPINFOHEADER pbih; // bitmap info-header BITMAPFILEHEADER hdr; // bitmap file-header WORD cClrBits; LPBYTE lpBits; // memory pointer DWORD dwTmp; DWORD cb; // incremental count of bytes BYTE *hp; // byte pointer HANDLE hfile; // file handle CString szBMPFilename = strFilePath.Left(strFilePath.GetLength() - 3) + _T("bmp");//先保存成位图 HDC hdcCompatible = CreateCompatibleDC(hDC); HBITMAP hbmScreen = CreateCompatibleBitmap(hDC, rect.Width(), rect.Height()); if (hbmScreen == NULL) { AfxMessageBox(_T("CreateCompatibleBitmap() error")); return FALSE; } // Select the bitmaps into the compatible DC. if (!SelectObject(hdcCompatible, hbmScreen)) { AfxMessageBox(_T("Compatible Bitmap Selection error")); return FALSE; } //Copy color data for the entire display into a //bitmap that is selected into a compatible DC. if (!BitBlt(hdcCompatible, 0,0, rect.Width(), rect.Height(), hDC, rect.left,rect.top, SRCCOPY)) { AfxMessageBox(_T("Screen to Compat Blt Failed")); return FALSE; } // Retrieve the bitmap's color format, width, and height. if (!GetObject(hbmScreen, sizeof(BITMAP), (LPSTR)&bmp)) { AfxMessageBox(_T("GetObject()出错！")); return FALSE; } // Convert the color format to a count of bits. cClrBits = (WORD)(bmp.bmPlanes * bmp.bmBitsPixel); if (cClrBits == 1) cClrBits = 1; else if (cClrBits <= 4) cClrBits = 4; else if (cClrBits <= 8) cClrBits = 8; else if (cClrBits <= 16) cClrBits = 16; else if (cClrBits <= 24) cClrBits = 24; else cClrBits = 32; // Allocate memory for the BITMAPINFO structure. (This structure // contains a BITMAPINFOHEADER structure and an array of RGBQUAD // data structures.) if (cClrBits != 24) pbmi = (PBITMAPINFO) LocalAlloc(LPTR, sizeof(BITMAPINFOHEADER) + sizeof(RGBQUAD) * (1<< cClrBits)); // There is no RGBQUAD array for the 24-bit-per-pixel format. else pbmi = (PBITMAPINFO) LocalAlloc(LPTR, sizeof(BITMAPINFOHEADER)); // Initialize the fields in the BITMAPINFO structure. pbmi->bmiHeader.biSize = sizeof(BITMAPINFOHEADER); pbmi->bmiHeader.biWidth = bmp.bmWidth; pbmi->bmiHeader.biHeight = bmp.bmHeight; pbmi->bmiHeader.biPlanes = bmp.bmPlanes; pbmi->bmiHeader.biBitCount = bmp.bmBitsPixel; if (cClrBits < 24) pbmi->bmiHeader.biClrUsed = (1<<cClrBits); // If the bitmap is not compressed, set the BI_RGB flag. pbmi->bmiHeader.biCompression = BI_RGB; // Compute the number of bytes in the array of color // indices and store the result in biSizeImage. pbmi->bmiHeader.biSizeImage = ((pbmi->bmiHeader.biWidth * cClrBits +31) & ~31) /8 * pbmi->bmiHeader.biHeight; // Set biClrImportant to 0, indicating that all of the device colors are important. pbmi->bmiHeader.biClrImportant = 0; pbih = (PBITMAPINFOHEADER) pbmi; lpBits = (LPBYTE) GlobalAlloc(GMEM_FIXED, pbih->biSizeImage); if (!lpBits) { AfxMessageBox(_T("内存分配错误！")); return FALSE; } // Retrieve the color table (RGBQUAD array) and the bits // (array of palette indices) from the DIB. if (!GetDIBits(hDC, hbmScreen, 0, (WORD) pbih->biHeight, lpBits, pbmi, DIB_RGB_COLORS)) { AfxMessageBox(_T("GetDIBits() error")); return FALSE; } // Create the .BMP file. hfile = CreateFile(szBMPFilename, GENERIC_READ | GENERIC_WRITE, (DWORD) 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, (HANDLE) NULL); if (hfile == INVALID_HANDLE_VALUE) { AfxMessageBox(_T("创建文件失败")); return false; } hdr.bfType = 0x4d42; // 0x42 = "B" 0x4d = "M" // Compute the size of the entire file. hdr.bfSize = (DWORD) (sizeof(BITMAPFILEHEADER) + pbih->biSize + pbih->biClrUsed * sizeof(RGBQUAD) + pbih->biSizeImage); hdr.bfReserved1 = 0; hdr.bfReserved2 = 0; // Compute the offset to the array of color indices. hdr.bfOffBits = (DWORD) sizeof(BITMAPFILEHEADER) + pbih->biSize + pbih->biClrUsed * sizeof (RGBQUAD); // Copy the BITMAPFILEHEADER into the .BMP file. if (!WriteFile(hfile, (LPVOID) &hdr, sizeof(BITMAPFILEHEADER), (LPDWORD) &dwTmp, NULL)) { AfxMessageBox(_T("写BMP文件头失败")); return FALSE; } // Copy the BITMAPINFOHEADER and RGBQUAD array into the file. if (!WriteFile(hfile, (LPVOID) pbih, sizeof(BITMAPINFOHEADER) + pbih->biClrUsed * sizeof (RGBQUAD), (LPDWORD) &dwTmp, ( NULL))) { AfxMessageBox(_T("写BMP文件头失败")); return FALSE; } // Copy the array of color indices into the .BMP file. cb = pbih->biSizeImage; hp = lpBits; if (!WriteFile(hfile, (LPSTR) hp, (int) cb, (LPDWORD) &dwTmp,NULL)) { AfxMessageBox(_T("写入BMP文件失败")); return FALSE; } // Close the .BMP file. if (!CloseHandle(hfile)) { AfxMessageBox(_T("Can't close BMP file.")); } // Free memory. GlobalFree((HGLOBAL)lpBits); //转换成PNG if(!BMptoPNG(szBMPFilename,strFilePath)) { DeleteFile(szBMPFilename); return FALSE; } DeleteObject(hbmScreen); DeleteFile(szBMPFilename); return TRUE; } // //转换BMP文件为PNG文件 BOOL CMakePNG::BMptoPNG(LPCWSTR StrBMp,LPCWSTR StrPNG) { CLSID encoderClsid; Status stat; Image* image = NULL; image = Bitmap::FromFile(StrBMp,TRUE); if (!GetEncoderClsid(L"image/png",&encoderClsid)) { return FALSE; } stat = image->Save(StrPNG,&encoderClsid,NULL); if (stat != Ok) { return FALSE; } delete image; return TRUE; } // 功能描述: 转换PNG文件为BMP文件 BOOL CMakePNG::PNGtoBMp(LPCWSTR StrPNG,LPCWSTR StrBMp) { CLSID encoderClsid; Status stat; Image* pImage; pImage = Bitmap::FromFile(StrPNG,TRUE); if (!GetEncoderClsid(L"image/bmp",&encoderClsid)) { return FALSE; } stat = pImage->Save(StrBMp,&encoderClsid,NULL); if (stat != Ok) { return FALSE; } delete pImage; return TRUE; } BOOL CMakePNG::GetEncoderClsid(WCHAR* pFormat,CLSID* pClsid) { UINT num = 0,size = 0; ImageCodecInfo* pImageCodecInfo = NULL; GetImageEncodersSize(&num,&size); if (size == 0) { return FALSE; } pImageCodecInfo = (ImageCodecInfo*)(malloc(size)); if (pImageCodecInfo == NULL) { return FALSE; } GetImageEncoders(num,size,pImageCodecInfo); BOOL bfound = FALSE; for (UINT i = 0;!bfound && i < num; i++) { if (_wcsicmp(pImageCodecInfo[i].MimeType,pFormat) == 0) { *pClsid = pImageCodecInfo[i].Clsid; bfound = TRUE; } } free(pImageCodecInfo); return bfound; }
以上两个文件实际上是CMakePNG类，使用时需要把他们添加到项目中，调用方法如下：
wstring GetAppPathW() { wchar_t szExePath[MAX_PATH] = {0}; GetModuleFileNameW(NULL, szExePath, MAX_PATH); wchar_t *pstr = wcsrchr(szExePath, '\\'); memset(pstr + 1, 0, 2); wstring strAppPath(szExePath); return strAppPath; } // 屏幕截图 CString CDemoDlg::ScreenShot(void) { CWnd *pDesktop = GetDesktopWindow(); CDC *pDC = pDesktop->GetDC(); CRect rect; //获取窗口的大小 pDesktop->GetClientRect(&rect); //保存到的文件名 CString strFileName(GetAppPathW().c_str()); strFileName += _T("ScreenShot\\"); CreateDirectory((LPCTSTR)strFileName,NULL); CTime t = CTime::GetCurrentTime(); CString tt = t.Format("%Y%m%d_%H%M%S"); strFileName += tt; strFileName += _T(".PNG"); //保存为PNG CMakePNG MakePNG; MakePNG.MakePNG(pDC->m_hDC,rect,strFileName); ReleaseDC(pDC); return strFileName; }
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。
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