• C# 切图 无觉


    using System;
    using System.Collections.Generic;
    using System.Text;
    using System.IO;
    using System.Drawing;
    using System.Drawing.Drawing2D;
    using System.Drawing.Imaging;
    
    namespace WuJian.Common
    {
        /// <summary>
        /// 图片处理
        /// http://www.cnblogs.com/wu-jian/
        /// 
        /// 吴剑 2011-02-20 创建
        /// 吴剑 2012-08-08 修改
        /// </summary>
        public class Image
        {
            #region 正方型裁剪并缩放
    
            /// <summary>
            /// 正方型裁剪
            /// 以图片中心为轴心,截取正方型,然后等比缩放
            /// 用于头像处理
            /// </summary>
            /// <remarks>吴剑 2012-08-08</remarks>
            /// <param name="fromFile">原图Stream对象</param>
            /// <param name="fileSaveUrl">缩略图存放地址</param>
            /// <param name="side">指定的边长(正方型)</param>
            /// <param name="quality">质量(范围0-100)</param>
            public static void CutForSquare(System.IO.Stream fromFile, string fileSaveUrl, int side, int quality)
            {
                //创建目录
                string dir = Path.GetDirectoryName(fileSaveUrl);
                if (!Directory.Exists(dir))
                    Directory.CreateDirectory(dir);
    
                //原始图片(获取原始图片创建对象,并使用流中嵌入的颜色管理信息)
                System.Drawing.Image initImage = System.Drawing.Image.FromStream(fromFile, true);
    
                //原图宽高均小于模版,不作处理,直接保存
                if (initImage.Width <= side && initImage.Height <= side)
                {
                    initImage.Save(fileSaveUrl, System.Drawing.Imaging.ImageFormat.Jpeg);
                }
                else
                {
                    //原始图片的宽、高
                    int initWidth = initImage.Width;
                    int initHeight = initImage.Height;
    
                    //非正方型先裁剪为正方型
                    if (initWidth != initHeight)
                    {
                        //截图对象
                        System.Drawing.Image pickedImage = null;
                        System.Drawing.Graphics pickedG = null;
    
                        //宽大于高的横图
                        if (initWidth > initHeight)
                        {
                            //对象实例化
                            pickedImage = new System.Drawing.Bitmap(initHeight, initHeight);
                            pickedG = System.Drawing.Graphics.FromImage(pickedImage);
                            //设置质量
                            pickedG.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
                            pickedG.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                            //定位
                            Rectangle fromR = new Rectangle((initWidth - initHeight) / 2, 0, initHeight, initHeight);
                            Rectangle toR = new Rectangle(0, 0, initHeight, initHeight);
                            //画图
                            pickedG.DrawImage(initImage, toR, fromR, System.Drawing.GraphicsUnit.Pixel);
                            //重置宽
                            initWidth = initHeight;
                        }
                        //高大于宽的竖图
                        else
                        {
                            //对象实例化
                            pickedImage = new System.Drawing.Bitmap(initWidth, initWidth);
                            pickedG = System.Drawing.Graphics.FromImage(pickedImage);
                            //设置质量
                            pickedG.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
                            pickedG.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                            //定位
                            Rectangle fromR = new Rectangle(0, (initHeight - initWidth) / 2, initWidth, initWidth);
                            Rectangle toR = new Rectangle(0, 0, initWidth, initWidth);
                            //画图
                            pickedG.DrawImage(initImage, toR, fromR, System.Drawing.GraphicsUnit.Pixel);
                            //重置高
                            initHeight = initWidth;
                        }
    
                        //将截图对象赋给原图
                        initImage = (System.Drawing.Image)pickedImage.Clone();
                        //释放截图资源
                        pickedG.Dispose();
                        pickedImage.Dispose();
                    }
    
                    //缩略图对象
                    System.Drawing.Image resultImage = new System.Drawing.Bitmap(side, side);
                    System.Drawing.Graphics resultG = System.Drawing.Graphics.FromImage(resultImage);
                    //设置质量
                    resultG.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
                    resultG.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                    //用指定背景色清空画布
                    resultG.Clear(Color.White);
                    //绘制缩略图
                    resultG.DrawImage(initImage, new System.Drawing.Rectangle(0, 0, side, side), new System.Drawing.Rectangle(0, 0, initWidth, initHeight), System.Drawing.GraphicsUnit.Pixel);
    
                    //关键质量控制
                    //获取系统编码类型数组,包含了jpeg,bmp,png,gif,tiff
                    ImageCodecInfo[] icis = ImageCodecInfo.GetImageEncoders();
                    ImageCodecInfo ici = null;
                    foreach (ImageCodecInfo i in icis)
                    {
                        if (i.MimeType == "image/jpeg" || i.MimeType == "image/bmp" || i.MimeType == "image/png" || i.MimeType == "image/gif")
                        {
                            ici = i;
                        }
                    }
                    EncoderParameters ep = new EncoderParameters(1);
                    ep.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, (long)quality);
    
                    //保存缩略图
                    resultImage.Save(fileSaveUrl, ici, ep);
    
                    //释放关键质量控制所用资源
                    ep.Dispose();
    
                    //释放缩略图资源
                    resultG.Dispose();
                    resultImage.Dispose();
    
                    //释放原始图片资源
                    initImage.Dispose();
                }
            }
    
            #endregion
    
            #region 自定义裁剪并缩放
    
            /// <summary>
            /// 指定长宽裁剪
            /// 按模版比例最大范围的裁剪图片并缩放至模版尺寸
            /// </summary>
            /// <remarks>吴剑 2012-08-08</remarks>
            /// <param name="fromFile">原图Stream对象</param>
            /// <param name="fileSaveUrl">保存路径</param>
            /// <param name="maxWidth">最大宽(单位:px)</param>
            /// <param name="maxHeight">最大高(单位:px)</param>
            /// <param name="quality">质量(范围0-100)</param>
            public static void CutForCustom(System.IO.Stream fromFile, string fileSaveUrl, int maxWidth, int maxHeight, int quality)
            {
                //从文件获取原始图片,并使用流中嵌入的颜色管理信息
                System.Drawing.Image initImage = System.Drawing.Image.FromStream(fromFile, true);
    
                //原图宽高均小于模版,不作处理,直接保存
                if (initImage.Width <= maxWidth && initImage.Height <= maxHeight)
                {
                    initImage.Save(fileSaveUrl, System.Drawing.Imaging.ImageFormat.Jpeg);
                }
                else
                {
                    //模版的宽高比例
                    double templateRate = (double)maxWidth / maxHeight;
                    //原图片的宽高比例
                    double initRate = (double)initImage.Width / initImage.Height;
    
                    //原图与模版比例相等,直接缩放
                    if (templateRate == initRate)
                    {
                        //按模版大小生成最终图片
                        System.Drawing.Image templateImage = new System.Drawing.Bitmap(maxWidth, maxHeight);
                        System.Drawing.Graphics templateG = System.Drawing.Graphics.FromImage(templateImage);
                        templateG.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
                        templateG.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                        templateG.Clear(Color.White);
                        templateG.DrawImage(initImage, new System.Drawing.Rectangle(0, 0, maxWidth, maxHeight), new System.Drawing.Rectangle(0, 0, initImage.Width, initImage.Height), System.Drawing.GraphicsUnit.Pixel);
                        templateImage.Save(fileSaveUrl, System.Drawing.Imaging.ImageFormat.Jpeg);
                    }
                    //原图与模版比例不等,裁剪后缩放
                    else
                    {
                        //裁剪对象
                        System.Drawing.Image pickedImage = null;
                        System.Drawing.Graphics pickedG = null;
    
                        //定位
                        Rectangle fromR = new Rectangle(0, 0, 0, 0);//原图裁剪定位
                        Rectangle toR = new Rectangle(0, 0, 0, 0);//目标定位
    
                        //宽为标准进行裁剪
                        if (templateRate > initRate)
                        {
                            //裁剪对象实例化
                            pickedImage = new System.Drawing.Bitmap(initImage.Width, (int)System.Math.Floor(initImage.Width / templateRate));
                            pickedG = System.Drawing.Graphics.FromImage(pickedImage);
    
                            //裁剪源定位
                            fromR.X = 0;
                            fromR.Y = (int)System.Math.Floor((initImage.Height - initImage.Width / templateRate) / 2);
                            fromR.Width = initImage.Width;
                            fromR.Height = (int)System.Math.Floor(initImage.Width / templateRate);
    
                            //裁剪目标定位
                            toR.X = 0;
                            toR.Y = 0;
                            toR.Width = initImage.Width;
                            toR.Height = (int)System.Math.Floor(initImage.Width / templateRate);
                        }
                        //高为标准进行裁剪
                        else
                        {
                            pickedImage = new System.Drawing.Bitmap((int)System.Math.Floor(initImage.Height * templateRate), initImage.Height);
                            pickedG = System.Drawing.Graphics.FromImage(pickedImage);
    
                            fromR.X = (int)System.Math.Floor((initImage.Width - initImage.Height * templateRate) / 2);
                            fromR.Y = 0;
                            fromR.Width = (int)System.Math.Floor(initImage.Height * templateRate);
                            fromR.Height = initImage.Height;
    
                            toR.X = 0;
                            toR.Y = 0;
                            toR.Width = (int)System.Math.Floor(initImage.Height * templateRate);
                            toR.Height = initImage.Height;
                        }
    
                        //设置质量
                        pickedG.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
                        pickedG.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
    
                        //裁剪
                        pickedG.DrawImage(initImage, toR, fromR, System.Drawing.GraphicsUnit.Pixel);
    
                        //按模版大小生成最终图片
                        System.Drawing.Image templateImage = new System.Drawing.Bitmap(maxWidth, maxHeight);
                        System.Drawing.Graphics templateG = System.Drawing.Graphics.FromImage(templateImage);
                        templateG.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
                        templateG.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                        templateG.Clear(Color.White);
                        templateG.DrawImage(pickedImage, new System.Drawing.Rectangle(0, 0, maxWidth, maxHeight), new System.Drawing.Rectangle(0, 0, pickedImage.Width, pickedImage.Height), System.Drawing.GraphicsUnit.Pixel);
    
                        //关键质量控制
                        //获取系统编码类型数组,包含了jpeg,bmp,png,gif,tiff
                        ImageCodecInfo[] icis = ImageCodecInfo.GetImageEncoders();
                        ImageCodecInfo ici = null;
                        foreach (ImageCodecInfo i in icis)
                        {
                            if (i.MimeType == "image/jpeg" || i.MimeType == "image/bmp" || i.MimeType == "image/png" || i.MimeType == "image/gif")
                            {
                                ici = i;
                            }
                        }
                        EncoderParameters ep = new EncoderParameters(1);
                        ep.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, (long)quality);
    
                        //保存缩略图
                        templateImage.Save(fileSaveUrl, ici, ep);
                        //templateImage.Save(fileSaveUrl, System.Drawing.Imaging.ImageFormat.Jpeg);
    
                        //释放资源
                        templateG.Dispose();
                        templateImage.Dispose();
    
                        pickedG.Dispose();
                        pickedImage.Dispose();
                    }
                }
    
                //释放资源
                initImage.Dispose();
            }
            #endregion
    
            #region 等比缩放
    
            /// <summary>
            /// 图片等比缩放
            /// </summary>
            /// <remarks>吴剑 2012-08-08</remarks>
            /// <param name="fromFile">原图Stream对象</param>
            /// <param name="savePath">缩略图存放地址</param>
            /// <param name="targetWidth">指定的最大宽度</param>
            /// <param name="targetHeight">指定的最大高度</param>
            /// <param name="watermarkText">水印文字(为""表示不使用水印)</param>
            /// <param name="watermarkImage">水印图片路径(为""表示不使用水印)</param>
            public static void ZoomAuto(System.IO.Stream fromFile, string savePath, System.Double targetWidth, System.Double targetHeight, string watermarkText, string watermarkImage)
            {
                //创建目录
                string dir = Path.GetDirectoryName(savePath);
                if (!Directory.Exists(dir))
                    Directory.CreateDirectory(dir);
    
                //原始图片(获取原始图片创建对象,并使用流中嵌入的颜色管理信息)
                System.Drawing.Image initImage = System.Drawing.Image.FromStream(fromFile, true);
    
                //原图宽高均小于模版,不作处理,直接保存
                if (initImage.Width <= targetWidth && initImage.Height <= targetHeight)
                {
                    //文字水印
                    if (watermarkText != "")
                    {
                        using (System.Drawing.Graphics gWater = System.Drawing.Graphics.FromImage(initImage))
                        {
                            System.Drawing.Font fontWater = new Font("黑体", 10);
                            System.Drawing.Brush brushWater = new SolidBrush(Color.White);
                            gWater.DrawString(watermarkText, fontWater, brushWater, 10, 10);
                            gWater.Dispose();
                        }
                    }
    
                    //透明图片水印
                    if (watermarkImage != "")
                    {
                        if (File.Exists(watermarkImage))
                        {
                            //获取水印图片
                            using (System.Drawing.Image wrImage = System.Drawing.Image.FromFile(watermarkImage))
                            {
                                //水印绘制条件:原始图片宽高均大于或等于水印图片
                                if (initImage.Width >= wrImage.Width && initImage.Height >= wrImage.Height)
                                {
                                    Graphics gWater = Graphics.FromImage(initImage);
    
                                    //透明属性
                                    ImageAttributes imgAttributes = new ImageAttributes();
                                    ColorMap colorMap = new ColorMap();
                                    colorMap.OldColor = Color.FromArgb(255, 0, 255, 0);
                                    colorMap.NewColor = Color.FromArgb(0, 0, 0, 0);
                                    ColorMap[] remapTable = { colorMap };
                                    imgAttributes.SetRemapTable(remapTable, ColorAdjustType.Bitmap);
    
                                    float[][] colorMatrixElements = { 
                                       new float[] {1.0f,  0.0f,  0.0f,  0.0f, 0.0f},
                                       new float[] {0.0f,  1.0f,  0.0f,  0.0f, 0.0f},
                                       new float[] {0.0f,  0.0f,  1.0f,  0.0f, 0.0f},
                                       new float[] {0.0f,  0.0f,  0.0f,  0.5f, 0.0f},//透明度:0.5
                                       new float[] {0.0f,  0.0f,  0.0f,  0.0f, 1.0f}
                                    };
    
                                    ColorMatrix wmColorMatrix = new ColorMatrix(colorMatrixElements);
                                    imgAttributes.SetColorMatrix(wmColorMatrix, ColorMatrixFlag.Default, ColorAdjustType.Bitmap);
                                    gWater.DrawImage(wrImage, new Rectangle(initImage.Width - wrImage.Width, initImage.Height - wrImage.Height, wrImage.Width, wrImage.Height), 0, 0, wrImage.Width, wrImage.Height, GraphicsUnit.Pixel, imgAttributes);
    
                                    gWater.Dispose();
                                }
                                wrImage.Dispose();
                            }
                        }
                    }
    
                    //保存
                    initImage.Save(savePath, System.Drawing.Imaging.ImageFormat.Jpeg);
                }
                else
                {
                    //缩略图宽、高计算
                    double newWidth = initImage.Width;
                    double newHeight = initImage.Height;
    
                    //宽大于高或宽等于高(横图或正方)
                    if (initImage.Width > initImage.Height || initImage.Width == initImage.Height)
                    {
                        //如果宽大于模版
                        if (initImage.Width > targetWidth)
                        {
                            //宽按模版,高按比例缩放
                            newWidth = targetWidth;
                            newHeight = initImage.Height * (targetWidth / initImage.Width);
                        }
                    }
                    //高大于宽(竖图)
                    else
                    {
                        //如果高大于模版
                        if (initImage.Height > targetHeight)
                        {
                            //高按模版,宽按比例缩放
                            newHeight = targetHeight;
                            newWidth = initImage.Width * (targetHeight / initImage.Height);
                        }
                    }
    
                    //生成新图
                    //新建一个bmp图片
                    System.Drawing.Image newImage = new System.Drawing.Bitmap((int)newWidth, (int)newHeight);
                    //新建一个画板
                    System.Drawing.Graphics newG = System.Drawing.Graphics.FromImage(newImage);
    
                    //设置质量
                    newG.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
                    newG.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
    
                    //置背景色
                    newG.Clear(Color.White);
                    //画图
                    newG.DrawImage(initImage, new System.Drawing.Rectangle(0, 0, newImage.Width, newImage.Height), new System.Drawing.Rectangle(0, 0, initImage.Width, initImage.Height), System.Drawing.GraphicsUnit.Pixel);
    
                    //文字水印
                    if (watermarkText != "")
                    {
                        using (System.Drawing.Graphics gWater = System.Drawing.Graphics.FromImage(newImage))
                        {
                            System.Drawing.Font fontWater = new Font("宋体", 10);
                            System.Drawing.Brush brushWater = new SolidBrush(Color.White);
                            gWater.DrawString(watermarkText, fontWater, brushWater, 10, 10);
                            gWater.Dispose();
                        }
                    }
    
                    //透明图片水印
                    if (watermarkImage != "")
                    {
                        if (File.Exists(watermarkImage))
                        {
                            //获取水印图片
                            using (System.Drawing.Image wrImage = System.Drawing.Image.FromFile(watermarkImage))
                            {
                                //水印绘制条件:原始图片宽高均大于或等于水印图片
                                if (newImage.Width >= wrImage.Width && newImage.Height >= wrImage.Height)
                                {
                                    Graphics gWater = Graphics.FromImage(newImage);
    
                                    //透明属性
                                    ImageAttributes imgAttributes = new ImageAttributes();
                                    ColorMap colorMap = new ColorMap();
                                    colorMap.OldColor = Color.FromArgb(255, 0, 255, 0);
                                    colorMap.NewColor = Color.FromArgb(0, 0, 0, 0);
                                    ColorMap[] remapTable = { colorMap };
                                    imgAttributes.SetRemapTable(remapTable, ColorAdjustType.Bitmap);
    
                                    float[][] colorMatrixElements = { 
                                       new float[] {1.0f,  0.0f,  0.0f,  0.0f, 0.0f},
                                       new float[] {0.0f,  1.0f,  0.0f,  0.0f, 0.0f},
                                       new float[] {0.0f,  0.0f,  1.0f,  0.0f, 0.0f},
                                       new float[] {0.0f,  0.0f,  0.0f,  0.5f, 0.0f},//透明度:0.5
                                       new float[] {0.0f,  0.0f,  0.0f,  0.0f, 1.0f}
                                    };
    
                                    ColorMatrix wmColorMatrix = new ColorMatrix(colorMatrixElements);
                                    imgAttributes.SetColorMatrix(wmColorMatrix, ColorMatrixFlag.Default, ColorAdjustType.Bitmap);
                                    gWater.DrawImage(wrImage, new Rectangle(newImage.Width - wrImage.Width, newImage.Height - wrImage.Height, wrImage.Width, wrImage.Height), 0, 0, wrImage.Width, wrImage.Height, GraphicsUnit.Pixel, imgAttributes);
                                    gWater.Dispose();
                                }
                                wrImage.Dispose();
                            }
                        }
                    }
    
                    //保存缩略图
                    newImage.Save(savePath, System.Drawing.Imaging.ImageFormat.Jpeg);
    
                    //释放资源
                    newG.Dispose();
                    newImage.Dispose();
                    initImage.Dispose();
                }
            }
    
            #endregion
    
            #region 其它
    
            /// <summary>
            /// 判断文件类型是否为WEB格式图片
            /// (注:JPG,GIF,BMP,PNG)
            /// </summary>
            /// <param name="contentType">HttpPostedFile.ContentType</param>
            /// <returns></returns>
            public static bool IsWebImage(string contentType)
            {
                if (contentType == "image/pjpeg" || contentType == "image/jpeg" || contentType == "image/gif" || contentType == "image/bmp" || contentType == "image/png")
                {
                    return true;
                }
                else
                {
                    return false;
                }
            }
    
            #endregion
    
        }//end class
    }

    转自http://www.cnblogs.com/wu-jian/

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  • 原文地址:https://www.cnblogs.com/LiMin/p/3046823.html
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