C#生成小容量高质量的缩略图

C#成小容量高质量的缩略图代码如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Drawing;
using System.IO;
namespace ConsoleApplication3_ThumbnailImg
{
class Program
{
const int HEIGHT = 190;
const int WIDTH = 190;
static void Main(string[] args)
{
string srcImgPath = @"G:\photoes\20060725\Picture 057.jpg";
string targetFolder = @"E:\Diary\Test\thumbnail";
SetThumbnail_1(srcImgPath, targetFolder);
SetThumbnail_2(srcImgPath, targetFolder);
SetThumbnail_3(srcImgPath, targetFolder);
Console.Read();
}
static void SetThumbnail_1(string srcImgPath, string targetFolder)
{
using (Bitmap source = new Bitmap(srcImgPath))
{
// return the source image if it's smaller than the designated thumbnail
int wi, hi;
wi = WIDTH;
hi = HEIGHT;
// maintain the aspect ratio despite the thumbnail size parameters
if (source.Width > source.Height)
{
wi = WIDTH;
hi = (int)(source.Height * ((decimal)WIDTH / source.Width));
}
else
{
hi = HEIGHT;
wi = (int)(source.Width * ((decimal)HEIGHT / source.Height));
}
using (Image thumb = source.GetThumbnailImage(wi, hi, null, IntPtr.Zero))
{
string targetPath = Path.Combine(targetFolder, "th_1.jpg");
thumb.Save(targetPath);
}
}
}
static void SetThumbnail_2(string srcImgPath, string targetFolder)
{
using (Bitmap source = new Bitmap(srcImgPath))
{
// return the source image if it's smaller than the designated thumbnail
int wi, hi;
wi = WIDTH;
hi = HEIGHT;
// maintain the aspect ratio despite the thumbnail size parameters
if (source.Width > source.Height)
{
wi = WIDTH;
hi = (int)(source.Height * ((decimal)WIDTH / source.Width));
}
else
{
hi = HEIGHT;
wi = (int)(source.Width * ((decimal)HEIGHT / source.Height));
}
// original code that creates lousy thumbnails
// System.Drawing.Image ret = source.GetThumbnailImage(wi,hi,null,IntPtr.Zero);
using (System.Drawing.Bitmap thumb = new Bitmap(wi, hi))
{
using (Graphics g = Graphics.FromImage(thumb))
{
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
g.FillRectangle(Brushes.White, 0, 0, wi, hi);
g.DrawImage(source, 0, 0, wi, hi);
}
string targetPath = Path.Combine(targetFolder, "th_2.jpg");
thumb.Save(targetPath);
}
}
}
static void SetThumbnail_3(string srcImgPath, string targetFolder)
{
//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 source.Height)
{
wi = WIDTH;
hi = (int)(source.Height * ((decimal)WIDTH / source.Width));
}
else
{
hi = HEIGHT;
wi = (int)(source.Width * ((decimal)HEIGHT / source.Height));
}
// original code that creates lousy thumbnails
// System.Drawing.Image ret = source.GetThumbnailImage(wi,hi,null,IntPtr.Zero);
using (System.Drawing.Bitmap thumb = new Bitmap(wi, hi))
{
using (Graphics g = Graphics.FromImage(thumb))
{
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
g.FillRectangle(Brushes.White, 0, 0, wi, hi);
g.DrawImage(source, 0, 0, wi, hi);
}
string targetPath = Path.Combine(targetFolder, "th_3.jpg");
thumb.Save(targetPath, jpegICI, encoderParams);
}
}
}
}
} 有用  |  无用 取消

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