修改png图像中指定点的颜色，保持透明度

// TestGdiPlus.cpp : 定义控制台应用程序的入口点。 // #include "stdafx.h" #include <Windows.h> #include <string> using namespace std; #include <GdiPlus.h> #pragma comment(lib, "gdiplus.lib") using namespace Gdiplus; //获取特定图片类型的编码 int GetEncoderClsid(const WCHAR* format, CLSID* pClsid) { UINT num = 0, size = 0; Gdiplus::GetImageEncodersSize(&num, &size); if(size == 0) return -1; // Failure Gdiplus::ImageCodecInfo* pImageCodecInfo = (Gdiplus::ImageCodecInfo*)(malloc(size)); Gdiplus::GetImageEncoders(num, size, pImageCodecInfo); bool found = false; for (UINT ix = 0; !found && ix < num; ++ix) { if (_wcsicmp(pImageCodecInfo[ix].MimeType, format) == 0) { *pClsid = pImageCodecInfo[ix].Clsid; found = true; break; } } free(pImageCodecInfo); return found; } bool SavePngToPngFile(LPCTSTR lpszOldPicFileName, LPCTSTR lpszPicFileName) { if (lpszOldPicFileName == NULL || lpszPicFileName == NULL ) { return false; } Gdiplus::Bitmap* pBitmap = NULL; Gdiplus::Bitmap* pWrapBitmap = NULL; do { pWrapBitmap = Gdiplus::Bitmap::FromFile( lpszOldPicFileName ); if (!pWrapBitmap) { break; } Gdiplus::BitmapData bitmapData; Gdiplus::Rect rcImage(0, 0, pWrapBitmap->GetWidth(), pWrapBitmap->GetHeight()); pWrapBitmap->LockBits(&rcImage, Gdiplus::ImageLockModeRead, pWrapBitmap->GetPixelFormat(), &bitmapData); DWORD *pStart = (DWORD*)bitmapData.Scan0; for ( unsigned int i = 0; i < bitmapData.Width; i ++ ) { for ( unsigned int j = 0; j < bitmapData.Height; j ++ ) { DWORD& dwPix = pStart[ j * bitmapData.Stride / 4 + i]; DWORD dwRgb = dwPix & 0x00FFFFFF; if ( dwRgb > 0x00888888 ) { // 符合某些规则的颜色值做修改 dwPix = dwPix & 0xFF000000 | 0x0000FF00; } } printf("\n" ); } pBitmap = new (Gdiplus::Bitmap)(bitmapData.Width, bitmapData.Height, bitmapData.Stride, PixelFormat32bppARGB, (BYTE*)bitmapData.Scan0); pWrapBitmap->UnlockBits(&bitmapData); CLSID encoderCLSID; GetEncoderClsid(_T("image/png"), &encoderCLSID); Gdiplus::Status st= pBitmap->Save(lpszPicFileName ,&encoderCLSID, NULL); if( st != Gdiplus::Ok ) break; } while (false); if (pBitmap) { delete pBitmap; } if (pWrapBitmap) { delete pWrapBitmap; } return true; } int _tmain(int argc, _TCHAR* argv[]) { if ( argc != 3 ) { wprintf( L"Usage:\n%s source.png target.png\n", argv[0] ); ::system( "pause" ); return 1; } GdiplusStartupInput gdiplusStartupInput; ULONG_PTR gdiplusToken; GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL); SavePngToPngFile( argv[1], argv[2] ); GdiplusShutdown(gdiplusToken); return 0; }