请问 asp.net中 缩略图怎么使用，最好能够详细点!谢谢了！
------解决方案--------------------
public Image GetThumbnailImage(
int thumbWidth,
int thumbHeight,
Image..::..GetThumbnailImageAbort callback,
IntPtr callbackData
)
生成
public static void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, string mode)
{
System.Drawing.Image originalImage = System.Drawing.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":
break;
case "W":
toheight = originalImage.Height * width / originalImage.Width;
break;
case "H":
towidth = originalImage.Width * height / originalImage.Height;
break;
case "Cut":
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;
}
System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth, toheight);
System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap);
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
g.Clear(System.Drawing.Color.Transparent);
g.DrawImage(originalImage, new System.Drawing.Rectangle(0, 0, towidth, toheight),
new System.Drawing.Rectangle(x, y, ow, oh),
System.Drawing.GraphicsUnit.Pixel);
try
{
bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
}
catch (System.Exception e)
{
throw e;
}
finally
{
originalImage.Dispose();
bitmap.Dispose();
g.Dispose();
}
}
------解决方案--------------------
- C# code
private void MakeThumbImage(string path, string stpath, int width, int height, string mode) { System.Drawing.Image image = System.Drawing.Image.FromFile(path); int tw = width; int th = height; ///原始图片的宽度和高度 int sw = image.Width; int sh = image.Height; int x = 0, y = 0; switch (mode) { case "HW": ///指定高宽缩放 break; case "W": ///指定图片的宽度，计算图片的高度 th = image.Height * width / image.Width; break; case "H": ///指定图片的高度，计算图片的宽度 tw = image.Width * height / image.Height; break; case "CUT": ///计算缩略图的大小 if ((double)tw / (double)th < (double)width / (double)height) { sw = image.Width; sh = image.Width * height / tw; x = 0; y = (image.Height - sh) / 2; } else { sh = image.Height; sw = image.Height * tw / th; y = 0; x = (image.Width - sw) / 2; } break; default: break; } ///创建bmp图片 System.Drawing.Image bitmap = new System.Drawing.Bitmap(tw, th); ///创建Graphics对象g System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap); ///设置图像的插补模式 g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High; ///设置图像的平滑程度 g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality; ///清空画布，并以透明背景色填充 g.Clear(System.Drawing.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(image, new System.Drawing.Rectangle(0, 0, tw, th), new System.Drawing.Rectangle(x, y, sw, sh), System.Drawing.GraphicsUnit.Pixel); try { ///采用jpg格式保存缩略图 bitmap.Save(stpath, System.Drawing.Imaging.ImageFormat.Jpeg); } catch (Exception ex) { Response.Write(ex.Message); return; } finally { ///释放资源 image.Dispose(); bitmap.Dispose(); g.Dispose(); } } MakeThumbImage(Server.MapPath("Images/xp.jpg"), Server.MapPath("Images/xp_01.jpg"), 80, 60, "CUT");