使用GDI＋對圖檔進行操作

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1、圖檔的顯示

// 下面是GDI+要使用的幾個頭檔案

#ifndef ULONG_PTR

#define ULONG_PTR unsigned long*

#endif

#include "Gdiplus.h"

#include <afxole.h>

#include <Atlbase.h>

Gdiplus::GdiplusStartupInput m_gdiplusStartupInput;

ULONG_PTR m_gdiplusToken;

// 初始化GDI+庫

void InitGuiPlus()

{

 Gdiplus::GdiplusStartup(&m_gdiplusToken, &m_gdiplusStartupInput, NULL);

}

// 關閉GDI+庫

void CleanupGuiPlus()

{

 Gdiplus::GdiplusShutdown(m_gdiplusToken);

}

Gdiplus::Bitmap * m_pBmp;

// 加載圖檔

Gdiplus::Bitmap * LoadPic(LPCSTR szPicUrl)

{

 Gdiplus::Bitmap * pBmp ＝ NULL;

 CFileFind fFind;

 if (!fFind.FindFile(szPicUrl))

 {

  return pBmp;

 }

 USES_CONVERSION;

 // 打開剛才浏覽的圖檔

 pBmp = new Gdiplus::Bitmap(A2W(szPicUrl));

 return pBmp;

}

// 解除安裝圖檔

void UnLoadPic()

{

 if (m_pBmp != NULL)

 {

  delete m_pBmp;

  m_pBmp = NULL;

 }

}

// 顯示圖檔 （在WM_PAINT的響應處理函數對其調用）

void ShowPic(CDC *pDC, Gdiplus::Bitmap *pbmpSrc, int nSrcWidth, int nSrcHeight)

{

 ASSERT(pbmpSrc != NULL);

 Gdiplus::Graphics graphics(pDC->m_hDC);

 graphics.DrawImage(pbmpSrc, 0, 0, nSrcWidth, nSrcHeight);

}

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2、利用GDI+對圖檔縮放後儲存(頭檔案和初始化代碼同1)

// 擷取圖檔的編碼資訊

BOOL GetImageEncoderCLSID( CLSID& clsid, const wchar_t* format)

{

     UINT num=0, size=0;

     Gdiplus::GetImageEncodersSize(&num, &size);

     Gdiplus::ImageCodecInfo* pImageCodecInfo = (Gdiplus::ImageCodecInfo*)malloc(size);

     if(pImageCodecInfo == NULL)

 {

   return FALSE;

 }

     Gdiplus::GetImageEncoders(num, size, pImageCodecInfo );

     for( UINT i = 0; i<num; ++i )

     {

         if( wcscmp(pImageCodecInfo[i].MimeType, format) == 0 )

         {

              clsid = pImageCodecInfo[i].Clsid;

              free(pImageCodecInfo);

              return TRUE;

         }

     }

     free(pImageCodecInfo);

 pImageCodecInfo = NULL;

     return FALSE;

}

// 按尺寸儲存圖檔

BOOL SavePicture(LPCSTR pszFileUrl, Gdiplus::Image *pSrcBmp, int nSavedWidth, int nSavedHeight)

{

 ASSERT(pSrcBmp != NULL);

 // 建立預儲存的圖檔

 Gdiplus::Bitmap bmpSaved(nSavedWidth, nSavedHeight);

 Gdiplus::Graphics * pGraphics = Gdiplus::Graphics::FromImage(&bmpSaved);

 // 将pSrcBmp畫到pGraphics中

 pGraphics->DrawImage(pSrcBmp, 0, 0, nSavedWidth, nSavedHeight);

 if (pGraphics == NULL)

 {

  return FALSE;

 }

 CLSID clImageClsid;

 // 擷取圖檔的編碼資訊

 if (GetImageEncoderCLSID(clImageClsid, L"image/jpeg"))

 {

  USES_CONVERSION;

  // 儲存入片

  bmpSaved.Save(A2W(pszFileUrl), &clImageClsid, NULL);

  delete pGraphics;

  pGraphics = NULL;

  return TRUE;

 }

 delete pGraphics;

 pGraphics = NULL;

 return FALSE;

}