Graphics.DrawImage函数其中一种的用法

原型

Status DrawImage(IN Image* image,
                     IN const RectF& destRect,
                     IN REAL srcx,
                     IN REAL srcy,
                     IN REAL srcwidth,
                     IN REAL srcheight,
                     IN Unit srcUnit,
                     IN const ImageAttributes* imageAttributes = NULL,
                     IN DrawImageAbort callback = NULL,
                     IN VOID* callbackData = NULL)

使用图片加载并绘制图片的一部分

Image* pImage=Gdiplus::Image::FromFile(L"c:\\small.png");
    RectF grect;
      //  grect.X=m_rcRect.left, grect.Y=m_rcRect.top; grect.Width = (int)(nStringWidth*g_dbDpi); grect.Height = (int)(iHeight*g_dbDpi);
    grect.X= 450;
    grect.Y=500;

    int iWidth = pImage->GetWidth()/4;
    int iHeight = pImage->GetHeight();

    grect.X= 600;
    grect.Y=500;
    grect.Width=200;
    graphics.DrawImage(pImage, grect, iWidth*0,0,100,iHeight, UnitPixel);

   此处可以看出，在RectF中确定的width是画出的图片的实际宽度，而参数srcwidth是加载图片的宽度，如果加载的图片宽度小于实际的宽度就会进行加长填充，反之则会压缩加载图片