GDI+ 儲存指定的視窗為JPEG檔案（X Y軸鏡像功能可選）

 

#include <rpc.h>   #include <rpcndr.h>   #include <unknwn.h>   #include <gdiplus.h>  using namespace Gdiplus;  #pragma comment(lib, "gdiplus.lib")   struct _GdiplusToken  {    Gdiplus::GdiplusStartupInput gdiplusStartupInput;    ULONG_PTR gdiplusToken;    _GdiplusToken()    {      if(Gdiplus::GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL) != Ok)      {        MessageBox(NULL, _T("GdiplusStartup failed"), _T("Error"), MB_OK);      }    }    ~_GdiplusToken()    {      Gdiplus::GdiplusShutdown(gdiplusToken);    }    }GdiplusToken;  int GetEncoderClsid(const WCHAR* format, CLSID* pClsid)  {    UINT  num = 0;          // number of image encoders     UINT  size = 0;         // size of the image encoder array in bytes     ImageCodecInfo* pImageCodecInfo = NULL;    Gdiplus::GetImageEncodersSize(&num, &size);    if(size == 0)      return -1;  // Failure     pImageCodecInfo = (ImageCodecInfo*)(malloc(size));    if(pImageCodecInfo == NULL)      return -1;  // Failure     Gdiplus::GetImageEncoders(num, size, pImageCodecInfo);    for(UINT j = 0; j < num; ++j)    {      if( wcscmp(pImageCodecInfo[j].MimeType, format) == 0 )      {        *pClsid = pImageCodecInfo[j].Clsid;        free(pImageCodecInfo);        return j;  // Success       }        }    free(pImageCodecInfo);    return -1;  // Failure   }  void SaveWndToJpeg(HWND hSrcWnd, //源視窗                   BOOL bXMirror, //X軸鏡像？                   BOOL bYMirror, //Y軸鏡像？                   LPCWSTR wcsFileName) //目標檔案名{  HDC hSrcDC = GetDC(hSrcWnd);  int nWdith = GetDeviceCaps(hSrcDC, HORZRES);  int nHeigth = GetDeviceCaps(hSrcDC, VERTRES);    HDC hMemDC = CreateCompatibleDC(hSrcDC);  HBITMAP hMemBitmap = CreateCompatibleBitmap(hSrcDC, nWdith, nHeigth);  HBITMAP hOldBitmap = (HBITMAP)SelectObject(hMemDC, hMemBitmap);  //映射模式  int iMapMode = SetMapMode(hMemDC, MM_ANISOTROPIC);  SIZE szViewportExt, szWindowExt;  SetViewportExtEx(hMemDC, bXMirror? -1:1, //-1:X軸鏡像 1X軸不鏡像    bYMirror? -1:1, //-1Y軸鏡像 1Y軸不鏡像    &szViewportExt);  SetWindowExtEx(hMemDC, 1, 1, &szWindowExt);  //座標原點  POINT ptOrg;  SetViewportOrgEx(hMemDC, bXMirror? nWdith:0, bYMirror? nHeigth:0, //設定座標原點    &ptOrg);  //繪製代碼  BitBlt(hMemDC, 0, 0, nWdith, nHeigth, hSrcDC, 0, 0, SRCCOPY);  //恢複映射模式、座標軸方向及座標原點      SetMapMode(hMemDC, iMapMode);  SetViewportExtEx(hMemDC, szViewportExt.cx, szViewportExt.cy, NULL);  SetWindowExtEx(hMemDC, szWindowExt.cx, szWindowExt.cy, NULL);  SetViewportOrgEx(hMemDC, ptOrg.x, ptOrg.y, NULL);  //使用GDI+儲存成jpeg  Gdiplus::Bitmap image(hMemBitmap, NULL);  CLSID pngClsid;  GetEncoderClsid(L"image/jpeg", &pngClsid);  image.Save(wcsFileName, &pngClsid, NULL);  //結束恢複  SelectObject(hMemDC, hOldBitmap);  DeleteDC(hMemDC);  DeleteObject(hMemBitmap);  ReleaseDC(hSrcWnd, hSrcDC);}

 

//WIN32下的測試代碼LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam){  int wmId, wmEvent;  PAINTSTRUCT ps;  HDC hdc;  switch (message)  {  case WM_COMMAND:    wmId    = LOWORD(wParam);    wmEvent = HIWORD(wParam);    // 分析菜單選擇:    switch (wmId)    {    default:      return DefWindowProc(hWnd, message, wParam, lParam);    case IDM_X0_Y0:      SaveWndToJpeg(GetDesktopWindow(), FALSE, FALSE, L"C:\\x0y0.jpg");      break;    case IDM_X0_Y1:      SaveWndToJpeg(GetDesktopWindow(), FALSE, TRUE, L"C:\\x0y1.jpg");      break;    case IDM_X1_Y0:      SaveWndToJpeg(GetDesktopWindow(), TRUE, FALSE, L"C:\\x1y0.jpg");      break;    case IDM_X1_Y1:      SaveWndToJpeg(GetDesktopWindow(), TRUE, TRUE, L"C:\\x1y1.jpg");      break;    case IDM_ABOUT:      DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About);      break;    case IDM_EXIT:      DestroyWindow(hWnd);      break;    }    break;  case WM_PAINT:    hdc = BeginPaint(hWnd, &ps);    // TODO: 在此添加任意繪圖代碼...    EndPaint(hWnd, &ps);    break;  case WM_DESTROY:    PostQuitMessage(0);    break;  default:    return DefWindowProc(hWnd, message, wParam, lParam);  }  return 0;}

測試輸出圖片(0不鏡像 1鏡像）   X0Y0    X1Y0    X0Y1     X1Y1