C# 剪裁图片并保存

2018-06-22 06:05:54来源：未知阅读 ()

最近需要将一张图片上传并按指定位置剪裁，后来在网上找了一个剪裁图片的插件，但是只有前台没有后端，然后我各种百度，并最终完成，特此写一篇博客略表纪念。

前台我就不说了，用的cropper插件，有兴趣的自己去百度找找吧。jQuery之家有这个插件。

下面是代码：

        HttpPostedFile file = context.Request.Files["avatar_file"];
        string datasize = context.Request.Params["avatar_data"];
        //{"x":30.003846153846148,"y":16.715384615384625,"height":300.8,"width":300.8,"rotate":0}     剪裁之后参数
        JavaScriptSerializer jss = new JavaScriptSerializer();
        ImgSize imagesize = jss.Deserialize<ImgSize>(datasize);

        byte[] FileByte = SetFileToByteArray(file);//图片数组
        string strtExtension = System.IO.Path.GetExtension(file.FileName);//图片格式

        MemoryStream ms1 = new MemoryStream(FileByte);
        Bitmap sBitmap = (Bitmap)Image.FromStream(ms1);
        Rectangle section = new Rectangle(new Point(imagesize.ToInt(imagesize.x), imagesize.ToInt(imagesize.y)), new Size(imagesize.ToInt(imagesize.width), imagesize.ToInt(imagesize.height)));
        Bitmap CroppedImage = MakeThumbnailImage(sBitmap, section.Width, section.Height, section.Width, section.Height, section.X, section.Y);

上面代码中用到我自己创建了一个ImgSize类，代码如下：

    class ImgSize
    {
        //{"x":30.003846153846148,"y":16.715384615384625,"height":300.8,"width":300.8,"rotate":0}
        public double x { get; set; }
        public double y { get; set; }
        public double width { get; set; }
        public double height { get; set; }
        public int rotate { get; set; }

        public int ToInt(double doubleValue)
        {
            return Convert.ToInt32(doubleValue);
        }
    }

上面代码中使用到的几个方法：

文件转化：

    /// <summary>
    /// 将From表单file文件转化为byte数组
    /// </summary>
    /// <param name="File">from提交文件流</param>
    /// <returns></returns>
    private byte[] SetFileToByteArray(HttpPostedFile File)
    {
        Stream stream = File.InputStream;
        byte[] AyyayByte = new byte[File.ContentLength];
        stream.Read(AyyayByte, 0, File.ContentLength);
        stream.Close();
        return AyyayByte;
    }

核心剪裁方法：

    /// <summary>
    /// 裁剪图片并保存
    /// </summary>
    /// <param name="Image">图片信息</param>
    /// <param name="maxWidth">缩略图宽度</param>
    /// <param name="maxHeight">缩略图高度</param>
    /// <param name="cropWidth">裁剪宽度</param>
    /// <param name="cropHeight">裁剪高度</param>
    /// <param name="X">X轴</param>
    /// <param name="Y">Y轴</param>
    public static Bitmap MakeThumbnailImage(Image originalImage, int maxWidth, int maxHeight, int cropWidth, int cropHeight, int X, int Y)
    {
        Bitmap b = new Bitmap(cropWidth, cropHeight);
        try
        {
            using (Graphics g = Graphics.FromImage(b))
            {
                //清空画布并以透明背景色填充
                g.Clear(Color.Transparent);
                //在指定位置并且按指定大小绘制原图片的指定部分
                g.DrawImage(originalImage, new Rectangle(0, 0, cropWidth, cropHeight), X, Y, cropWidth, cropHeight, GraphicsUnit.Pixel);
                Image displayImage = new Bitmap(b, maxWidth, maxHeight);
                displayImage.Save("E:\\cutimg.jpg", System.Drawing.Imaging.ImageFormat.Jpeg);
                Bitmap bit = new Bitmap(b, maxWidth, maxHeight);
                return bit;
            }
        }
        catch (System.Exception e)
        {
            throw e;
        }
        finally
        {
            originalImage.Dispose();
            b.Dispose();
        }
    }