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VC 实现BMP转换到JPG、JPG转换到BMP

2013年12月10日 ⁄ 综合 ⁄ 共 2581字 ⁄ 字号 评论关闭
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;   
    GetImageEncodersSize(&num, &size);   
    if(size == 0)   
        return -1;     //   Failure   
    
    pImageCodecInfo = (ImageCodecInfo*)(malloc(size));   
    if(pImageCodecInfo == NULL)   
        return -1;     //   Failure   
    
    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   
}


/****************BMP转JPG*********用法示例**************************

Bitmap newbitmap(L"d:\\d.bmp");//加载BMP
const unsigned short *pFileName=L"d:\\new.jpg";//保存路径
SaveFile(&newbitmap,pFileName );

************************************************************/

void SaveFile(Bitmap* pImage, const wchar_t* pFileName)//
{
    EncoderParameters encoderParameters;
    CLSID jpgClsid; 
GetEncoderClsid(L"image/jpeg", &jpgClsid);
    encoderParameters.Count = 1;
    encoderParameters.Parameter[0].Guid = EncoderQuality;
    encoderParameters.Parameter[0].Type = EncoderParameterValueTypeLong;
    encoderParameters.Parameter[0].NumberOfValues = 1;

    // Save the image as a JPEG with quality level 100.
    ULONG             quality;
    quality = 100;
    encoderParameters.Parameter[0].Value = &quality;
    Status status = pImage->Save(pFileName, &jpgClsid, &encoderParameters);
    if (status != Ok) 
    {
        wprintf(L"%d Attempt to save %s failed.\n", status, pFileName);
    }
}


// 将当前屏幕保存成为jpg图片       
// 参数   xs = 图象x岽笮?   ys = 图象y轴大小,   quality = jpeg图象质量       
void SaveCurScreenJpg(LPCWSTR   pszFileName,   int   xs,   int   ys,   int   quality)   
{   
    HWND hwnd = ::GetDesktopWindow();   
    HDC hdc = GetWindowDC(NULL);   
    int x = GetDeviceCaps(hdc, HORZRES);   
    int y = GetDeviceCaps(hdc, VERTRES);   
    HBITMAP hbmp = ::CreateCompatibleBitmap(hdc, x, y), hold;   
    HDC hmemdc = ::CreateCompatibleDC(hdc);   
    hold = (HBITMAP)::SelectObject(hmemdc,   hbmp);   
    BitBlt(hmemdc, 0, 0, x, y, hdc, 0, 0, SRCCOPY);   
    SelectObject(hmemdc, hold);   
    
    Bitmap bit(xs, ys), bit2(hbmp, NULL);   
    Graphics g(&bit);   
    g.ScaleTransform((float)xs/x,   (float)ys/y);   
    g.DrawImage(&bit2,   0,   0);   
    
    CLSID                           encoderClsid;   
    EncoderParameters   encoderParameters;   
    
    encoderParameters.Count   =   1;   
    encoderParameters.Parameter[0].Guid   =   EncoderQuality;   
    encoderParameters.Parameter[0].Type   =   EncoderParameterValueTypeLong;   
    encoderParameters.Parameter[0].NumberOfValues   =   1;   
    encoderParameters.Parameter[0].Value   =   &quality;   
    
    GetEncoderClsid(L"image/jpeg",   &encoderClsid);   
    bit.Save(pszFileName,   &encoderClsid,   &encoderParameters);   
   
    ::DeleteObject(hbmp);   
    ::DeleteObject(hmemdc);   
    return;   
}  


HBITMAP   ReturnHBITMAP(CString   FileName)//FileName可能是bmp、dib、png、gif、jpeg/jpg、tiff、emf等文件的文件名 
{ 
          Bitmap   tempBmp(FileName.AllocSysString())   ; 
        Color       backColor;       
        HBITMAP       HBitmap;   
        tempBmp.GetHBITMAP(backColor,&HBitmap); 
        return   HBitmap;

}

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