C#图像缩放与裁剪

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文笔不好，不废话，直接进入正题，不解释，相信大家都看得懂。

按百分比缩放图像：

public static Image ScaleByPercent(Image imgPhoto, int Percent)
{
    float nPercent = ((float)Percent/100);

    int sourceWidth = imgPhoto.Width;
    int sourceHeight = imgPhoto.Height;
    int sourceX = 0;
    int sourceY = 0;

    int destX = 0;
    int destY = 0; 
    int destWidth  = (int)(sourceWidth * nPercent);
    int destHeight = (int)(sourceHeight * nPercent);

    Bitmap bmPhoto = new Bitmap(destWidth, destHeight, 
                             PixelFormat.Format24bppRgb);
    bmPhoto.SetResolution(imgPhoto.HorizontalResolution, 
                            imgPhoto.VerticalResolution);

    Graphics grPhoto = Graphics.FromImage(bmPhoto);
    grPhoto.InterpolationMode = InterpolationMode.HighQualityBicubic;

    grPhoto.DrawImage(imgPhoto, 
        new Rectangle(destX,destY,destWidth,destHeight),
        new Rectangle(sourceX,sourceY,sourceWidth,sourceHeight),
        GraphicsUnit.Pixel);

    grPhoto.Dispose();
    return bmPhoto;
}

按指定大小缩放图像：

public static Image FixedSize(Image imgPhoto, int Width, int Height)
{
    int sourceWidth = imgPhoto.Width;
    int sourceHeight = imgPhoto.Height;
    int sourceX = 0;
    int sourceY = 0;
    int destX = 0;
    int destY = 0; 

    float nPercent = 0;
    float nPercentW = 0;
    float nPercentH = 0;

    nPercentW = ((float)Width/(float)sourceWidth);
    nPercentH = ((float)Height/(float)sourceHeight);
    if(nPercentH < nPercentW)
    {
        nPercent = nPercentH;
        destX = System.Convert.ToInt16((Width - 
                      (sourceWidth * nPercent))/2);
    }
    else
    {
        nPercent = nPercentW;
        destY = System.Convert.ToInt16((Height - 
                      (sourceHeight * nPercent))/2);
    }

    int destWidth  = (int)(sourceWidth * nPercent);
    int destHeight = (int)(sourceHeight * nPercent);

    Bitmap bmPhoto = new Bitmap(Width, Height, 
                      PixelFormat.Format24bppRgb);
    bmPhoto.SetResolution(imgPhoto.HorizontalResolution, 
                     imgPhoto.VerticalResolution);

    Graphics grPhoto = Graphics.FromImage(bmPhoto);
    grPhoto.Clear(Color.Red);
    grPhoto.InterpolationMode = 
            InterpolationMode.HighQualityBicubic;

    grPhoto.DrawImage(imgPhoto, 
        new Rectangle(destX,destY,destWidth,destHeight),
        new Rectangle(sourceX,sourceY,sourceWidth,sourceHeight),
        GraphicsUnit.Pixel);

    grPhoto.Dispose();
    return bmPhoto;
}

按指定位置裁剪指定大小图像：

public static Image Crop(Image imgPhoto, int Width, 
                    int Height, AnchorPosition Anchor)
{
    int sourceWidth = imgPhoto.Width;
    int sourceHeight = imgPhoto.Height;
    int sourceX = 0;
    int sourceY = 0;
    int destX = 0;
    int destY = 0;

    float nPercent = 0;
    float nPercentW = 0;
    float nPercentH = 0;

    nPercentW = ((float)Width/(float)sourceWidth);
    nPercentH = ((float)Height/(float)sourceHeight);

    if(nPercentH < nPercentW)
    {
        nPercent = nPercentW;
        switch(Anchor)
        {
            case AnchorPosition.Top:
                destY = 0;
                break;
            case AnchorPosition.Bottom:
                destY = (int)
                    (Height - (sourceHeight * nPercent));
                    break;
            default:
                destY = (int)
                    ((Height - (sourceHeight * nPercent))/2);
                break;
        }
    }
    else
    {
        nPercent = nPercentH;
        switch(Anchor)
        {
            case AnchorPosition.Left:
                destX = 0;
                break;
            case AnchorPosition.Right:
                destX = (int)
                  (Width - (sourceWidth * nPercent));
                break;
            default:
                destX = (int)
                  ((Width - (sourceWidth * nPercent))/2);
                break;
        } 
    }

    int destWidth  = (int)(sourceWidth * nPercent);
    int destHeight = (int)(sourceHeight * nPercent);

    Bitmap bmPhoto = new Bitmap(Width, 
            Height, PixelFormat.Format24bppRgb);
    bmPhoto.SetResolution(imgPhoto.HorizontalResolution, 
            imgPhoto.VerticalResolution);

    Graphics grPhoto = Graphics.FromImage(bmPhoto);
    grPhoto.InterpolationMode = 
            InterpolationMode.HighQualityBicubic;

    grPhoto.DrawImage(imgPhoto, 
        new Rectangle(destX,destY,destWidth,destHeight),
        new Rectangle(sourceX,sourceY,sourceWidth,sourceHeight),
        GraphicsUnit.Pixel);

    grPhoto.Dispose();
    return bmPhoto;
}

 

 

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