SourceCode/RFrameGenerate.Common/PicThumbnail.cs

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using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.Linq;
using System.Text;

namespace RFrameGenerate.Common
{
    public class Thumbnail
    {
        /// <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 1-100</param>
        /// <returns></returns>
        public static bool GetPicThumbnail(Image iSource, string dFile, int dHeight, int dWidth, int flag)
        {
            ImageFormat tFormat = iSource.RawFormat;
            int sW = 0, sH = 0;
            //按比例缩放
            Size tem_size = new Size(iSource.Width, iSource.Height);
            if (tem_size.Width > dHeight || tem_size.Width > dWidth)
            {
                if ((tem_size.Width * dHeight) > (tem_size.Height * 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;
            }
            Bitmap ob = new Bitmap(dWidth, dHeight);
            Graphics g = Graphics.FromImage(ob);
            g.Clear(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();
            EncoderParameters ep = new EncoderParameters(3);
            ep.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Compression, (long)EncoderValue.CompressionCCITT4);
            ep.Param[1] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, new long[1] { flag });
            ep.Param[2] = new EncoderParameter(System.Drawing.Imaging.Encoder.ColorDepth, 1L);

            //EncoderParameter eParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, new long[1] { flag });
            //ep.Param[0] = eParam;