unity 压缩图片

第一篇博客

###################################################################

小菜鸟咸鱼咸鱼一波

######################################################################

随便做了一个类似订餐系统  ，局域网内使用

想服务器有食物的照片通过字节直接和客户端交互 

但是这样图片如果太大就不行了

所以就试试图片压缩

本文记录压缩时遇到的问题

########################################################################

填几个坑

1. unity 添加 System.Drawing 引用 (http://www.manew.com/thread-44136-1-1.html)
- [在Unity的安装路径中找到System.Drawing.dll，将其复制到我们的项目文件夹]
- [
System.Drawing.dll的具体位置：%Unity根目录%\Editor\Data\Mono\lib\mono\2.0\System.Drawing.dll ]
- [在Unity编辑器界面打开Player Settings面板->Other Settings,将Api Compatibility Level 从 ".NET 2.0 Subset" 改为 ".NET 2.0"]

2.在保存压缩图片时出现的错误
- [System.InvalidOperationException: The operation is invalid [GDI+ status: Win32Error]
 ]
    ++查找文档(https://msdn.microsoft.com/zh-cn/library/ytz20d80(v=vs.80).aspx)发现，备注里写的：不允许将图像保存到构造该图像的文件，这样会引发异常。++
    ++我原本是把图片存储在Application.streamingAssetsPath +“/Icon”路径不存在，所以会报错 试着将图片存在c盘就可以了++

脚本[（参考）](http://blog.youkuaiyun.com/qq_16542775/article/details/51792149)

    /// <summary>
    /// 无损压缩图片    
    /// </summary>
    /// <param name="sFile">原图片</param>    
    /// <param name="dFile">压缩后保存位置</param>    
    /// <param name="dHeight">高度</param>    
    /// <param name="dWidth"></param>    
    /// <param name="flag">压缩质量(数字越小压缩率越高) 1-100</param>    
    /// <returns></returns>    
    public static bool GetPicThumbnail(string sFile, string dFile,/*int dHeight, int dWidth,*/  int flag)
    {
        System.Drawing.Image iSource = System.Drawing.Image.FromFile(sFile);
        ImageFormat tFormat = iSource.RawFormat;

        int sW = 0, sH = 0;

        //按比例缩放  
        Size tem_size = new Size(iSource.Width, iSource.Height);

        int dHeight = iSource.Height;//不进行比例缩放
        int dWidth = iSource.Width;

        //if (tem_size.width > dheight || tem_size.width > dwidth)
        //{
        //    if ((tem_size.width * dheight) > (tem_size.width * dwidth))
        //    {
        //        sw = dwidth;
        //        sh = (dwidth * tem_size.height) / tem_size.width;
        //    }
        //    else
        //    {
        //        sh = dheight;
        //        sw = (tem_size.width * dheight) / tem_size.height;
        //    }
        //}
        //else
        //{
            sW = tem_size.Width;
            sH = tem_size.Height;
    //}
    //int dWidth = sW;
    //int dHeight = sH;

    Bitmap ob = new Bitmap(dWidth, dHeight);
        System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(ob);

        g.Clear(System.Drawing.Color.WhiteSmoke);
        g.CompositingQuality = CompositingQuality.HighQuality;
        g.SmoothingMode = SmoothingMode.HighQuality;
        g.InterpolationMode = InterpolationMode.HighQualityBicubic;

        g.DrawImage(iSource, new Rectangle((dWidth - sW) / 2, (dHeight - sH) / 2, sW, sH), 0, 0, iSource.Width, iSource.Height, GraphicsUnit.Pixel);

        g.Dispose();
        //以下代码为保存图片时，设置压缩质量    
        EncoderParameters ep = new EncoderParameters();
        long[] qy = new long[1];
        qy[0] = flag;//设置压缩的比例1-100    
        EncoderParameter eParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, qy);
        ep.Param[0] = eParam;
        try
        {
            ImageCodecInfo[] arrayICI = ImageCodecInfo.GetImageEncoders();
            ImageCodecInfo jpegICIinfo = null;
            for (int x = 0; x < arrayICI.Length; x++)
            {
                if (arrayICI[x].FormatDescription.Equals("JPEG"))
                {
                    jpegICIinfo = arrayICI[x];
                    break;
                }
            }
            if (jpegICIinfo != null)
            {
                //这里有坑
                ob.Save(dFile, jpegICIinfo, ep);//dFile是压缩后的新路径   
            }
            else
            {
                ob.Save(dFile, tFormat);//这里有坑
            }
            return true;
        }
        catch(Exception ex)
        {
            Debug.LogError(ex);
            return false;
        }
        finally
        {
            iSource.Dispose();
            ob.Dispose();
        }
    }

最后加上自己图片字节转换 = =。

/// <summary>
    /// 字节流转换成图片
    /// </summary>
    public static Texture2D BytToImg(byte[] byt)
    {
        Texture2D img = new Texture2D(140, 140);
        img.LoadImage(byt);
        return img;
    }
    //
    /// <summary>
    /// 根据图片路径返回图片的字节流byte[]
    /// </summary>
    /// <param name="imagePath">图片路径</param>
    /// <returns>返回的字节流</returns>
    public static byte[] GetImageByte(Texture2D imag)
    {
        byte[] imgByte = ((Texture2D)imag).EncodeToPNG();
        Debug.LogFormat("根据图片路径返回图片的字节流byte:{0}", imgByte.Length);
        return imgByte;
    }