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图片缩略图处理类.

原创 Linux操作系统 作者:tclywork 时间:2019-04-15 15:51:05 0 删除 编辑

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Drawing.Imaging;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.IO;

namespace TEWeb.Commond
{

    public static class PhotoUtils
    {
        /**/
        ///


        /// ========================================================
        /// 2009-7-3
        /// Tclywork Studio
        /// tclywork@163.com
        /// http://space.itpub.net/54654
        /// 图片缩略图处理类.
        /// ========================================================
        ///

        // *** Jpeg Format ***
        private static ImageCodecInfo GetEncoderInfo(string mimeType)
        {
            int j;
            ImageCodecInfo[] encoders = ImageCodecInfo.GetImageEncoders();
            for (j = 0; j < encoders.Length; ++j)
            {
                if (encoders[j].MimeType == mimeType)
                    return encoders[j];
            }
            return null;
        }

        public static void SaveToJpeg(Bitmap bitmap, string filePath, long qualityPercent)
        {
            ImageCodecInfo imageCodecInfo = GetEncoderInfo("image/jpeg");
            Encoder encoder = Encoder.Quality;
            EncoderParameters encoderParameters = new EncoderParameters(1);
            encoderParameters.Param[0] = new EncoderParameter(encoder, qualityPercent);
            bitmap.Save(filePath, imageCodecInfo, encoderParameters);
        }

        // *** Thumbnails ***
        public static Bitmap CreateThumbnail(System.Drawing.Image image, int thumbnailSize)
        {
            int w;
            int h;
            if (image.Width > image.Height)
            {
                h = thumbnailSize;
                w = (int)((image.Width * (float)h) / (float)image.Height);
            }
            else
            {
                w = thumbnailSize;
                h = (int)((image.Height * (float)w) / (float)image.Width);
            }
            Bitmap newImage = new Bitmap(thumbnailSize, thumbnailSize, PixelFormat.Format24bppRgb);
            using (Graphics canvas = Graphics.FromImage(newImage))
            {
                canvas.SmoothingMode = SmoothingMode.AntiAlias;
                canvas.InterpolationMode = InterpolationMode.HighQualityBicubic;
                canvas.PixelOffsetMode = PixelOffsetMode.HighQuality;
                canvas.DrawImage(image, new Rectangle(0, 0, w, h));
            }
            return newImage;
        }
        ///


        /// 生成缩略图
        ///

        /// 源图路径(物理路径)
        /// 缩略图路径(物理路径)
        /// 缩略图宽度
        /// 缩略图高度
        /// 生成缩略图的方式   
        public static void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, string mode)
        {
            if (!File.Exists(originalImagePath))
            {
                thumbnailPath = originalImagePath;
                return;
            }
            System.Drawing.Image riginalImage = System.Drawing.Image.FromFile(originalImagePath);

            int towidth = width;
            int toheight = height;

            int x = 0;
            int y = 0;
            int w = originalImage.Width;
            int h = originalImage.Height;

            switch (mode)
            {
                case "HW"://指定高宽缩放(可能变形)               
                    break;
                case "W"://指定宽,高按比例                   
                    toheight = originalImage.Height * width / originalImage.Width;
                    break;
                case "H"://指定高,宽按比例
                    towidth = originalImage.Width * height / originalImage.Height;
                    break;
                case "Cut"://指定高宽裁减(不变形)               
                    if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight)
                    {
                        h = originalImage.Height;
                        w = originalImage.Height * towidth / toheight;
                        y = 0;
                        x = (originalImage.Width - ow) / 2;
                    }
                    else
                    {
                        w = originalImage.Width;
                        h = originalImage.Width * height / towidth;
                        x = 0;
                        y = (originalImage.Height - oh) / 2;
                    }
                    break;
                default:
                    break;
            }

            //新建一个bmp图片
            System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth, toheight);

            //新建一个画板
            Graphics g = System.Drawing.Graphics.FromImage(bitmap);

            //设置高质量插值法
            g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;

            //设置高质量,低速度呈现平滑程度
            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

            //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, towidth, toheight),
                new Rectangle(x, y, ow, oh),
                GraphicsUnit.Pixel);

            try
            {
                //以jpg格式保存缩略图
                bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
            }
            catch (System.Exception e)
            {
                throw e;
            }
            finally
            {
                originalImage.Dispose();
                bitmap.Dispose();
                g.Dispose();
            }
        }

        ///


        /// A better alternative to Image.GetThumbnail. Higher quality but slightly slower
        ///

        ///
        ///
        ///
        ///
        public static Bitmap CreateThumbnail(Bitmap source, int thumbWi, int thumbHi, bool maintainAspect)
        {
            // return the source image if it's smaller than the designated thumbnail
            if (source.Width < thumbWi && source.Height < thumbHi) return source;

            System.Drawing.Bitmap ret = null;
            try
            {
                int wi, hi;

                wi = thumbWi;
                hi = thumbHi;

                if (maintainAspect)
                {
                    // maintain the aspect ratio despite the thumbnail size parameters
                    if (source.Width > source.Height)
                    {
                        wi = thumbWi;
                        hi = (int)(source.Height * ((decimal)thumbWi / source.Width));
                    }
                    else
                    {
                        hi = thumbHi;
                        wi = (int)(source.Width * ((decimal)thumbHi / source.Height));
                    }
                }

                // original code that creates lousy thumbnails
                // System.Drawing.Image ret = source.GetThumbnailImage(wi,hi,null,IntPtr.Zero);
                ret = new Bitmap(wi, hi);
                using (Graphics g = Graphics.FromImage(ret))
                {
                    g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
                    g.FillRectangle(Brushes.White, 0, 0, wi, hi);
                    g.DrawImage(source, 0, 0, wi, hi);
                }
            }
            catch
            {
                ret = null;
            }
            /* 压缩图片
            ////Configure JPEG Compression Engine
            //System.Drawing.Imaging.EncoderParameters encoderParams = new System.Drawing.Imaging.EncoderParameters();
            //long[] quality = new long[1];
            //quality[0] = 75;
            //System.Drawing.Imaging.EncoderParameter encoderParam = new System.Drawing.Imaging.EncoderParameter(System.Drawing.Imaging.Encoder.Quality, quality);
            //encoderParams.Param[0] = encoderParam;

            //System.Drawing.Imaging.ImageCodecInfo[] arrayICI = System.Drawing.Imaging.ImageCodecInfo.GetImageEncoders();
            //System.Drawing.Imaging.ImageCodecInfo jpegICI = null;
            //for (int x = 0; x < arrayICI.Length; x++)
            //{
            //    if (arrayICI[x].FormatDescription.Equals("JPEG"))
            //    {
            //        jpegICI = arrayICI[x];
            //        break;
            //    }
            //}
            ////myThumbnail.Save(Path.Combine(SavePathThumb, fileName), jpegICI, encoderParams);
            ////myThumbnail.Dispose();
             * */
            return ret;
        }

        public static void CreateThumbnailFile(string filePath, int thumbnailSize, string thumbnailFilePath, long qualityPercent)
        {
            if (File.Exists(filePath))
            {
                using (FileStream stream = new FileStream(filePath, FileMode.Open  ))
                {
                    using (System.Drawing.Image image =
                        System.Drawing.Image.FromStream(stream))
                    {

                        if (image.Width == thumbnailSize && image.Height == thumbnailSize)
                        {
                            File.Copy(filePath, thumbnailFilePath, true);
                        }
                        else
                        {
                            using (Bitmap bitmap =
                                CreateThumbnail(image, thumbnailSize))
                            {
                                SaveToJpeg(bitmap, thumbnailFilePath, qualityPercent);
                            }
                        }
                    }                   
                }
            }
        }

        public static void CreateThumbnailFile(string filePath, int thumbnailSize,string thumbnailFilePath)
        {
            CreateThumbnailFile(filePath, thumbnailSize, thumbnailFilePath, 90L);
        }
        // 按模版比例生成缩略图(以流的方式获取源文件)
        //生成缩略图函数
        //顺序参数:源图文件流、缩略图存放地址、模版宽、模版高
        //注:缩略图大小控制在模版区域内
        public static void MakeSmallImg(string  strImageFile, string strThumbnailFile, System.Double templateWidth, System.Double templateHeight)
        {
            //从文件取得图片对象,并使用流中嵌入的颜色管理信息
            System.Drawing.Image myImage = System.Drawing.Image.FromFile(strImageFile, true);
            //缩略图宽、高
            System.Double newWidth = myImage.Width, newHeight = myImage.Height;
            //if (myImage.Width > templateWidth)  //如果图片的宽度大于模板宽度
            //{
            //    if (myImage.Height > templateHeight)    //如果图片的高度大于模板高度
            //    {
            //        if (myImage.Height / templateHeight < myImage.Width / templateWidth)    //确定缩略的原则,是宽度还是高度,采用比率小的为准
            //        {
                       
            //        }
            //        else
            //    }
            //}
            //else
            //{
               
            //}

            //宽大于模版的横图
            if (myImage.Width > myImage.Height || myImage.Width == myImage.Height)
            {
                if (myImage.Width > templateWidth)
                {
                    //宽按模版,高按比例缩放
                    newWidth = templateWidth;
                    newHeight = myImage.Height * (newWidth / myImage.Width);
                }
            }
            //高大于模版的竖图
            else
            {
                if (myImage.Height > templateHeight)
                {
                    //高按模版,宽按比例缩放
                    newHeight = templateHeight;
                    newWidth = myImage.Width * (newHeight / myImage.Height);
                }
            }

            //取得图片大小
            System.Drawing.Size mySize = new Size((int)newWidth, (int)newHeight);
            //新建一个bmp图片
            System.Drawing.Image bitmap = new System.Drawing.Bitmap(mySize.Width, mySize.Height);
            //新建一个画板
            System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap);
            //设置高质量插值法
            g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
            //设置高质量,低速度呈现平滑程度
            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
            //清空一下画布
            g.Clear(Color.White);
            //在指定位置画图
            g.DrawImage(myImage, new System.Drawing.Rectangle(0, 0, bitmap.Width, bitmap.Height),
            new System.Drawing.Rectangle(0, 0, myImage.Width, myImage.Height),
            System.Drawing.GraphicsUnit.Pixel);

            ///文字水印
            //System.Drawing.Graphics G=System.Drawing.Graphics.FromImage(bitmap);
            //System.Drawing.Font f=new Font("宋体",10);
            //System.Drawing.Brush b=new SolidBrush(Color.Black);
            //G.DrawString("myohmine",f,b,10,10);
            //G.Dispose();

            ///图片水印
            //System.Drawing.Image copyImage = System.Drawing.Image.FromFile(System.Web.HttpContext.Current.Server.MapPath("pic/1.gif"));
            //Graphics a = Graphics.FromImage(bitmap);
            //a.DrawImage(copyImage, new Rectangle(bitmap.Width-copyImage.Width,bitmap.Height-copyImage.Height,copyImage.Width, copyImage.Height),0,0, copyImage.Width, copyImage.Height, GraphicsUnit.Pixel);

            //copyImage.Dispose();
            //a.Dispose();
            //copyImage.Dispose();

            //保存缩略图
            bitmap.Save(strThumbnailFile, System.Drawing.Imaging.ImageFormat.Jpeg);

            g.Dispose();
            myImage.Dispose();
            bitmap.Dispose();
        }
    }
}

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