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代码如下:(将图象变为200*200)
GdiplusStartupInput gdiplusStartupInput;
ULONG_PTR gdiplusToken;
GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);
CLSID encoderClsid;
EncoderParameters encoderParameters;
ULONG quality;
Status stat;
Image image(L"1.jpg");
Bitmap bitmap(200, 200, PixelFormat32bppARGB);
Graphics graph(&bitmap);
graph.DrawImage(&image, Rect(0,0,200,200));
GetEncoderClsid(L"image/jpeg", &encoderClsid);
//构造编码参数列表
//数组中只包含一个EncoderParameter对象
encoderParameters.Count = 1;
encoderParameters.Parameter[0].Guid = EncoderQuality;
//参数类型为LONG
encoderParameters.Parameter[0].Type = EncoderParameterValueTypeLong;
//只设置一个参数
encoderParameters.Parameter[0].NumberOfValues = 1;
//设置JPEG图片质量为最好
quality = 100;
encoderParameters.Parameter[0].Value = &quality;
stat = bitmap.Save(L"1_2.jpg", &encoderClsid, &encoderParameters);
GdiplusShutdown(gdiplusToken);