生成高质量不变形缩略图片代码,Asp.Net代码库,德仔网

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【Asp.Net】生成高质量不变形缩略图片

作者:Dezai.CN / 发布于2012/12/11/ 562

/// <summary> 
///Class1 的摘要说明 
/// </summary> 
public class Class1 
{ 
public static void SendSmallImage(string fileName, string newFile, int maxHeight, int maxWidth) 
{ 
System.Drawing.Image img = System.Drawing.Image.FromFile(fileName); 
System.Drawing.Imaging.ImageFormat thisFormat = img.RawFormat; 
 
Size newSize = NewSize(maxWidth, maxHeight, img.Width, img.Height); 
Bitmap outBmp = new Bitmap(newSize.Width, newSize.Height); 
Graphics g = Graphics.FromImage(outBmp); 
 
// 设置画布的描绘质量 
g.CompositingQuality = CompositingQuality.HighQuality; 
g.SmoothingMode = SmoothingMode.HighQuality; 
g.InterpolationMode = InterpolationMode.HighQualityBicubic; 
 
g.DrawImage(img, new Rectangle(0, 0, newSize.Width, newSize.Height), 
0, 0, img.Width, img.Height, GraphicsUnit.Pixel); 
g.Dispose(); 
 
// 以下代码为保存图片时，设置压缩质量 
EncoderParameters encoderParams = new EncoderParameters(); 
long[] quality = new long[1]; 
quality[0] = 80; 
 
EncoderParameter encoderParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, quality); 
encoderParams.Param[0] = encoderParam; 
 
//获得包含有关内置图像编码解码器的信息的ImageCodecInfo 对象。 
ImageCodecInfo[] arrayICI = ImageCodecInfo.GetImageEncoders(); 
ImageCodecInfo jpegICI = null; 
for (int x = 0; x < arrayICI.Length; x++) 
{ 
string Format = arrayICI[x].FormatDe script _ ion; 
if (arrayICI[x].FormatDe script _ ion.Equals("JPEG")) 
{ 
jpegICI = arrayICI[x];//设置JPEG编码 
break; 
} 
} 
 
if (jpegICI != null) 
{ 
outBmp.Save(newFile, jpegICI, encoderParams); 
} 
else 
{ 
outBmp.Save(newFile, thisFormat); 
} 
 
img.Dispose(); 
outBmp.Dispose(); 
} 
 
private static Size NewSize(int maxWidth, int maxHeight, int width, int height) 
{ 
double w = 0.0; 
double h = 0.0; 
double sw = Convert.ToDouble(width); 
double sh = Convert.ToDouble(height); 
double mw = Convert.ToDouble(maxWidth); 
double mh = Convert.ToDouble(maxHeight); 
 
if (sw < mw && sh < mh) 
{ 
w = sw; 
h = sh; 
} 
else if ((sw / sh) > (mw / mh)) 
{ 
w = maxWidth; 
h = (w * sh) / sw; 
} 
else 
{ 
h = maxHeight; 
w = (h * sw) / sh; 
} 
 
return new Size(Convert.ToInt32(w), Convert.ToInt32(h)); 
} 
 
 
}

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