关于上传图片生成缩略图的程序
我在网上找到这么一个生成缩略图的程序，生成的缩略图很清晰，容量也很小，但就是宽、高比例失调,代码如下:
/// <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>
public static void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, string mode)
{
Image originalImage = Image.FromFile(originalImagePath);

int towidth = width;
int toheight = height;

int x = 0;
int y = 0;
int ow = originalImage.Width;
int oh = originalImage.Height;

switch (mode)
{
case "HW "://指定高宽缩放（可能变形）
break;
case "W "://指定宽，高按比例
toheight = originalImage.Height * width/originalImage.Width;

break;
case "H "://指定高，宽按比例
towidth = originalImage.Width * height/originalImage.Height;
break;
case "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*height/towidth;
x = 0;
y = (originalImage.Height - oh)/2;

}
break;
default :
break;
}

//新建一个bmp图片
Image bitmap = new System.Drawing.Bitmap(towidth,toheight);

//新建一个画板
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, new Rectangle(0, 0, towidth, toheight),
new Rectangle(x, y, ow,oh),
GraphicsUnit.Pixel);

try
{
//以jpg格式保存缩略图
bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
}
catch(System.Exception e)

{
throw e;
}
finally
{
originalImage.Dispose();
bitmap.Dispose();
g.Dispose();
}
}

当生成缩略图的方式mode选择 "cut "时,所生成的图片不完整,下面有的都截掉了
选H或者W时所生成缩略图的大小不改变似的，不知大家有没有碰到这样的问题

如果有更好的程序拿出来的的话，非常感谢！


[解决办法]
给你一个我自用的简洁点的

/// <summary>
/// by vengair
/// </summary>
/// <param name= "image "> </param>
/// <param name= "percentage "> </param>
/// <returns> </returns>
private static Image GenerateThumbnailImage(Image image, int percentage)
{
Bitmap myBitmap = new Bitmap((int)(image.Width * percentage / 100), (int)(image.Height * percentage / 100));
Graphics myGraphics = Graphics.FromImage(myBitmap);

// 绘制边框和背景
myGraphics.FillRectangle(Brushes.Gray, new Rectangle(0, 0, myBitmap.Width, myBitmap.Height));
myGraphics.FillRectangle(Brushes.White, new Rectangle(1, 1, myBitmap.Width - 2, myBitmap.Height - 2));

myGraphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
myGraphics.SmoothingMode = SmoothingMode.HighQuality;
myGraphics.DrawImage(image, new Rectangle(2, 2, myBitmap.Width - 4, myBitmap.Height - 4));
myGraphics.Dispose();

return (Image)myBitmap;
}
[解决办法]
wsImage3.5