C#图片处理基本应用(裁剪,缩放,清晰度,水印)

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>

/// 图片处理类

/// 吴剑 2008-07-02 创建

/// 吴剑 2011-01-21 修改

/// </summary>

public class PTImage

{

#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 2010-11-23</remarks>

/// <param name="postedFile">原图HttpPostedFile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.Web.HttpPostedFile postedFile, 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(postedFile.InputStream, 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), newSystem.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();

}

}

/// <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 2010-11-23</remarks>

/// <param name="postedFile">原图HttpPostedFile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), newSystem.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 固定模版裁剪并缩放

/// <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 2010-11-15</remarks>

/// <param name="postedFile">原图HttpPostedFile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.Web.HttpPostedFile postedFile, string fileSaveUrl, int maxWidth, intmaxHeight, 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(postedFile.InputStream, 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), newSystem.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)Math.Floor(initImage.Width / templateRate));

pickedG = System.Drawing.Graphics.FromImage(pickedImage);

//裁剪源定位

fromR.X = 0;

fromR.Y = (int)Math.Floor((initImage.Height - initImage.Width / templateRate) / 2);

fromR.Width = initImage.Width;

fromR.Height = (int)Math.Floor(initImage.Width / templateRate);

//裁剪目标定位

toR.X = 0;

toR.Y = 0;

toR.Width = initImage.Width;

toR.Height = (int)Math.Floor(initImage.Width / templateRate);

}

//高为标准进行裁剪

else

{

pickedImage = new System.Drawing.Bitmap((int)Math.Floor(initImage.Height * templateRate), initImage.Height);

pickedG = System.Drawing.Graphics.FromImage(pickedImage);

fromR.X = (int)Math.Floor((initImage.Width - initImage.Height * templateRate) / 2);

fromR.Y = 0;

fromR.Width = (int)Math.Floor(initImage.Height * templateRate);

fromR.Height = initImage.Height;

toR.X = 0;

toR.Y = 0;

toR.Width = (int)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), newSystem.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 2011-01-21</remarks>

/// <param name="postedFile">原图HttpPostedFile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.Web.HttpPostedFile postedFile, 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(postedFile.InputStream, 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), newSystem.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

}