关于文件缩略图

问题描述

大家好，

有人知道如何使用C#提取文件的缩略图吗?如果知道，请告诉我，谢谢.

Does anybody know how to extract the file'thumbnail use C# ?.If you know, please tell me,thank you.

推荐答案

在Windows资源管理器中看到的缩略图"存储在Windows生成的thumbs.db系统文件中，每当您以缩略图"查看模式查看文件夹时.如果您从不使用Windows资源管理器中的缩略图"视图，则该文件甚至不存在.

The 'thumbnails' you see in Windows Explorer are stored in the thumbs.db system file that is generated by Windows whenever you view a folder in 'Thumbnail' view mode. If you never use the Thumbnail view in Windows explorer, the file won't even exist.

基本上，有两种从图片中获取缩略图的方法.

Basically, there are 2 means of getting a thumbnail from a picture.

2.创建自己的缩略图.

2. Create your own thumbnail.

对于第一种方法，您需要一个EXIF解析器才能从JPEG读取EXIF标签.这实际上很复杂，但是这是一个带有库的示例，您可以下载http://www.vbaccelerator.com/home/NET/Code/Libraries/Graphics/Reading_EXIF_Tags_from_JPG_Files/article .asp

对于第二种方法，这是一种将创建指定大小&尺寸的图像的缩略图的方法.保持宽高比:

For the second method, here's a method that will create a thumbnail of an image in the specified size & keeps the aspect ratio:

int sourceHeight = img.Height;

int sourceHeight = img.Height;

int sourceX = 0;

int sourceX = 0;

int sourceY = 0;

int sourceY = 0;

int destX = 0;

int destX = 0;

int destY = 0;

int destY = 0;

float nPercent = 0;

float nPercent = 0;

浮动 nPercentW = 0;

float nPercentW = 0;

浮动 nPercentH = 0;

float nPercentH = 0;

nPercentW =((( float )Width/( float )sourceWidth);

nPercentW = ((float)Width / (float)sourceWidth);

nPercentH =(( float )高度/( float )sourceHeight);

nPercentH = ((float)Height / (float)sourceHeight);

nPercent = nPercentH;

nPercent = nPercentH;

destX =系统. 转换 .ToInt16((Width-

destX = System.Convert.ToInt16((Width -

(sourceWidth * nPercent))/2);

(sourceWidth * nPercent)) / 2);

int destWidth =( int )(sourceWidth * nPercent);

int destWidth = (int)(sourceWidth * nPercent);

int destHeight =( int )(sourceHeight * nPercent);

int destHeight = (int)(sourceHeight * nPercent);

System.Drawing. 位图 bmPhoto = 新建 系统绘图. 位图 (宽度，高度，

System.Drawing.Bitmap bmPhoto = new System.Drawing.Bitmap(Width, Height,

System.Drawing.Imaging. PixelFormat .Format24bppRgb);

System.Drawing.Imaging.PixelFormat.Format24bppRgb);

bmPhoto.SetResolution(img.Horizo​​ntalResolution，

bmPhoto.SetResolution(img.HorizontalResolution,

img.VerticalResolution);

img.VerticalResolution);

使用 (System.Drawing. 图形 grPhoto = System.Drawing. 图形 .FromImage(bmPhoto) ){

using (System.Drawing.Graphics grPhoto = System.Drawing.Graphics.FromImage(bmPhoto)) {

grPhoto.InterpolationMode =

grPhoto.InterpolationMode =

System.Drawing.Drawing2D. InterpolationMode .HighQualityBicubic;

System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;

grPhoto.DrawImage(img，

grPhoto.DrawImage(img,

新 System.Drawing. 矩形 (destX，destY，destWidth，destHeight)

new System.Drawing.Rectangle(destX, destY, destWidth, destHeight),

新 System.Drawing. 矩形 (sourceX，sourceY，sourceWidth，sourceHeight)

new System.Drawing.Rectangle(sourceX, sourceY, sourceWidth, sourceHeight),

System.Drawing. GraphicsUnit .Pixel);

System.Drawing.GraphicsUnit.Pixel);

}

返回 bmPhoto;

return bmPhoto;

}

注意:从文件流加载图像以获得最佳性能:

System.IO. FileInfo fi = new System.IO. FileInfo ( @" c:\ image.jpg" );

System.IO.FileInfo fi = new System.IO.FileInfo(@"c:\image.jpg");

使用 (System.IO. FileStream str = fi.OpenRead()){

using (System.IO.FileStream str = fi.OpenRead()) {

}

//创建100 * 100缩略图

图片缩略图 = GetImage (img，100，100);

Image thumb = GetImage(img, 100, 100);

希望这会有所帮助

这篇关于关于文件缩略图的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！