C# 无损图片压缩—— 基于Framework.40 类库实现

分为两部分，一个是操作类，另外一个是测试。直接上代码了

一、测试代码

private void button1_Click(object sender, EventArgs e)

{

string newSourcePath = ImgPath;//源图存放目录

string newNewDir = MakePath; //新图存放目录

string sourceFile = Path.Combine(ImgPath, "app1.jpg"); //获取原图路径

string newFile = string.Empty; //新图路径

ImgThumbnail iz = new ImgThumbnail();

Action<ImgThumbnail.ImgThumbnailType> Thumbnail = (type =>

{

//生成质量

for (int i = 100; i >= 10; i -= 10)

{

//计算新图路径，测试命名：原图名_new_缩放类型_压缩质量.jpg

newFile = Path.Combine(newNewDir, string.Format("app1_new_{1}_{0}.jpg", i, type.ToString()));

//压缩图片

iz.Thumbnail(sourceFile, newFile, 100, 100, i, type);

}

});

Thumbnail(ImgThumbnail.ImgThumbnailType.Cut);//裁剪压缩（裁剪压缩还不好用，待调整！）

Thumbnail(ImgThumbnail.ImgThumbnailType.H); //以高度为参照压缩，不变形

Thumbnail(ImgThumbnail.ImgThumbnailType.W); //以宽度为参照压缩，不变形

Thumbnail(ImgThumbnail.ImgThumbnailType.WH); //固定宽高压缩，变形

MessageBox.Show("完成");

}

二、操作类

using System.Drawing;

using System.Drawing.Drawing2D;

using System.Drawing.Imaging;

namespace MagickNet.App

{

/// <summary>

/// 图片压缩

/// </summary>

public class ImgThumbnail

{

#region 枚举

/// <summary>

/// 指定缩放类型

/// </summary>

public enum ImgThumbnailType

{

/// <summary>

/// 无

/// </summary>

Nothing=0,

/// <summary>

/// 指定高宽缩放（可能变形）

/// </summary>

WH = 1,

/// <summary>

/// 指定宽，高按比例

/// </summary>

W = 2,

/// <summary>

/// 指定高，宽按比例

/// </summary>

H = 3,

/// <summary>

/// 指定高宽裁减（不变形）

/// </summary>

Cut = 4,

/// <summary>

/// 按照宽度成比例缩放后，按照指定的高度进行裁剪

/// </summary>

W_HCut = 5,

}

#endregion

#region Thumbnail

/// <summary>

/// 无损压缩图片

/// </summary>

/// <param name="sourceFile">原图片</param>

/// <param name="stream">压缩后保存到流中</param>

/// <param name="height">高度</param>

/// <param name="width"></param>

/// <param name="quality">压缩质量 1-100</param>

/// <param name="type">压缩缩放类型</param>

/// <returns></returns>

private static Bitmap Thumbnail(string sourceFile, int width, int height, int quality

, ImgThumbnailType type, out ImageFormat tFormat)

{

using (System.Drawing.Image iSource = System.Drawing.Image.FromFile(sourceFile))

{

tFormat = iSource.RawFormat;

//缩放后的宽度和高度

int toWidth = width;

int toHeight = height;

//

int x = 0;

int y = 0;

int oWidth = iSource.Width;

int oHeight = iSource.Height;

switch (type)

{

case ImgThumbnailType.WH://指定高宽缩放（可能变形）

{

break;

}

case ImgThumbnailType.W://指定宽，高按比例

{

toHeight = iSource.Height * width / iSource.Width;

break;

}

case ImgThumbnailType.H://指定高，宽按比例

{

toWidth = iSource.Width * height / iSource.Height;

break;

}

case ImgThumbnailType.Cut://指定高宽裁减（不变形）

{

if ((double)iSource.Width / (double)iSource.Height > (double)toWidth / (double)toHeight)

{

oHeight = iSource.Height;

oWidth = iSource.Height * toWidth / toHeight;

y = 0;

x = (iSource.Width - oWidth) / 2;

}

else

{

oWidth = iSource.Width;

oHeight = iSource.Width * height / toWidth;

x = 0;

y = (iSource.Height - oHeight) / 2;

}

break;

}

case ImgThumbnailType.W_HCut://按照宽度成比例缩放后，按照指定的高度进行裁剪

{

toHeight = iSource.Height * width / iSource.Width;

if (height < toHeight)

{

oHeight = oHeight * height / toHeight;

toHeight = toHeight * height / toHeight;

}

break;

}

default:

break;

}

Bitmap ob = new Bitmap(toWidth, toHeight);

//ImgWaterMark iwm = new ImgWaterMark();

//iwm.AddWaterMark(ob, towidth, toheight, "www.****.com");

Graphics g = 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(x, y, toWidth, toHeight)

, new Rectangle(0, 0, oWidth, oHeight)

, GraphicsUnit.Pixel);

g.Dispose();

return ob;

}

}

#endregion

}

}

转载请保留：http://write.blog.csdn.net/postedit/7715729