C# 创建略图程序
参考:http://www.cnblogs.com/xxssran/articles/1340980.html
稍作改动
public enum ThumbnailMode
{
/// <summary>
/// 指定高宽裁减(不变形)
/// </summary>
Cut,
/// <summary>
/// 指定宽,高按比例
/// </summary>
Width,
/// <summary>
/// 指定高,宽按比例
/// </summary>
Height,
/// <summary>
/// 指定高宽缩放(可能变形)
/// </summary>
HeightWidth,
}
/// <summary>
/// 生成缩略图
/// </summary>
/// <param name="originalImagePath">源图路径(物理路径)</param>
/// <param name="thumbnailPath">缩略图路径(物理路径)</param>
/// <param name="width">缩略图宽度</param>
/// <param name="height">缩略图高度</param>
/// <param name="mode">生成缩略图的方式</param>
/// <remarks>如果目标文件存在,将被覆盖</remarks>
public static void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, ThumbnailMode mode)
{
// 如果原始文件不存在就不需要处理
if (!File.Exists(originalImagePath))
{
return;
}
using (Image originalImage = Image.FromFile(originalImagePath))
{
Rectangle destRect, srcRect;
GetThumbnailSize(width, height, mode, originalImage, out destRect, out srcRect);
//新建一个bmp图片
using (Image bitmap = new System.Drawing.Bitmap(destRect.Width, destRect.Height))
{
//新建一个画板
using (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, destRect, srcRect, GraphicsUnit.Pixel);
}
//以jpg格式保存缩略图
bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
}
}
}
/// <summary>
/// 计算缩略图处理大小
/// </summary>
/// <param name="towidth">缩略图目标宽度</param>
/// <param name="toheight">缩略图目标高度</param>
/// <param name="mode">缩放模式</param>
/// <param name="originalImage">原始图像</param>
/// <param name="destRect">目标大小</param>
/// <param name="srcRect">处理范围</param>
private static void GetThumbnailSize(int towidth, int toheight, ThumbnailMode mode, Image originalImage, out Rectangle destRect, out Rectangle srcRect)
{
int x = 0, y = 0;
int ow = originalImage.Width;
int oh = originalImage.Height;
switch (mode)
{
case ThumbnailMode.HeightWidth://指定高宽缩放(可能变形)
break;
case ThumbnailMode.Width://指定宽,高按比例
toheight = originalImage.Height * towidth / originalImage.Width;
break;
case ThumbnailMode.Height://指定高,宽按比例
towidth = originalImage.Width * toheight / originalImage.Height;
break;
case ThumbnailMode.Cut://指定高宽裁减(不变形)
if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight)
{
oh = originalImage.Height;
ow = originalImage.Height * towidth / toheight;
y = 0;
x = (originalImage.Width - ow) / 2;
}
else
{
ow = originalImage.Width;
oh = originalImage.Width * toheight / towidth;
x = 0;
y = (originalImage.Height - oh) / 2;
}
break;
default:
break;
}
destRect = new Rectangle(0, 0, towidth, toheight);
srcRect = new Rectangle(x, y, ow, oh);
}
完整处理程序在这里下载
http://download.csdn.net/detail/greenery/7220333
执行方式 MakeThumbnail.exe 图片名称 缩略图.jpg
缩略图大小在配置文件中读取
输出格式固定为jpg