一直对win32 程序没什么研究，今次需要从基础抓起，写了一个测试程序，显示bmp图片，首先还是windows 基本程序，然后处理win_paint消息，置入如下函数
void OnBnClickedBtnShowBmp(HWND hWnd) { static TCHAR szFileName[MAX_PATH]; HWND hwnd; HDC hdc; hwnd = hWnd; hdc = ::GetDC(hwnd); BITMAP bitmap; HDC hdcMem; BITMAPFILEHEADER bmfh; BITMAPINFO * pbmi; BYTE * pBits; BOOL bSuccess; DWORD dwInfoSize, dwBytesRead; HANDLE hFile; HBITMAP hBitmap; memcpy(szFileName, _T(".\\qr_code.bmp"), 50); hFile = CreateFile(szFileName, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, 0, NULL); if (hFile == INVALID_HANDLE_VALUE) return; // Read in the BITMAPFILEHEADER bSuccess = ReadFile(hFile, &bmfh, sizeof (BITMAPFILEHEADER), &dwBytesRead, NULL); if (!bSuccess || (dwBytesRead != sizeof (BITMAPFILEHEADER)) || (bmfh.bfType != *(WORD *) "BM")) { CloseHandle(hFile); return; } // Allocate memory for the BITMAPINFO structure & read it in dwInfoSize = bmfh.bfOffBits - sizeof (BITMAPFILEHEADER); pbmi = (BITMAPINFO *)malloc(dwInfoSize); bSuccess = ReadFile(hFile, pbmi, dwInfoSize, &dwBytesRead, NULL); if (!bSuccess || (dwBytesRead != dwInfoSize)) { free(pbmi); CloseHandle(hFile); return; } // Create the DIB Section hBitmap = CreateDIBSection(NULL, pbmi, DIB_RGB_COLORS, (void **)&pBits, NULL, 0); if (hBitmap == NULL) { free(pbmi); CloseHandle(hFile); return; } // Read in the bitmap bits ReadFile(hFile, pBits, bmfh.bfSize - bmfh.bfOffBits, &dwBytesRead, NULL); free(pbmi); CloseHandle(hFile); //return hBitmap ; if (hBitmap) { GetObject(hBitmap, sizeof (BITMAP), &bitmap); hdcMem = CreateCompatibleDC(hdc); SelectObject(hdcMem, hBitmap); BitBlt(hdc, 0, 0, bitmap.bmWidth, bitmap.bmHeight, hdcMem, 0, 0, SRCCOPY); DeleteDC(hdcMem); } if (hBitmap) { DeleteObject(hBitmap); hBitmap = NULL; } }如此就可以在起始处显示bmp图片了。
下面的方式是把bmp转化位png图片的windows 插件实现，通过gdiplus读取了图片，然后转化为png
BOOL GetEncoderClsid(WCHAR* pFormat, CLSID* pClsid) { GdiplusStartupInput gdiplusStartupInput; ULONG_PTR gdiplusToken; GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);
UINT num = 0, size = 0; ImageCodecInfo* pImageCodecInfo = NULL; GetImageEncodersSize(&num, &size); if (size == 0) { return FALSE; } pImageCodecInfo = (Gdiplus::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; } } GdiplusShutdown(gdiplusToken); free(pImageCodecInfo); return bfound; }
BOOL BMptoPNG(LPCWSTR StrBMp, LPCWSTR StrPNG) { GdiplusStartupInput gdiplusStartupInput; ULONG_PTR gdiplusToken; Gdiplus::GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);
CLSID encoderClsid; Status stat; Image* image = NULL; image = Gdiplus::Bitmap::FromFile(StrBMp, TRUE); if (!GetEncoderClsid(L"image/png", &encoderClsid)) { return FALSE; } stat = image->Save(StrPNG, &encoderClsid, NULL); if (stat != Gdiplus::Ok) { return FALSE; } //Gdiplus::GdiplusShutdown(gdiplusToken); delete image; return TRUE; }
