/// <summary>
/// 生成缩略图
/// </summary>
/// <param name="sourceFile">原始图片文件</param>
/// <param name="quality">质量压缩比</param>
/// <param name="multiple">收缩倍数</param>
/// <param name="outputFile">输出文件名</param>
/// <returns>成功返回true,失败则返回false</returns>
public static bool getThumImage(string sourceFile, long quality, int multiple, string outputFile)
{
try
{
long imageQuality = quality;
Bitmap sourceImage = new Bitmap(sourceFile);
ImageCodecInfo myImageCodecInfo = GetEncoderInfo("image/jpeg");
Encoder myEncoder = Encoder.Quality;
EncoderParameters myEncoderParameters = new EncoderParameters(1);
EncoderParameter myEncoderParameter = new EncoderParameter(myEncoder, imageQuality);
myEncoderParameters.Param[0] = myEncoderParameter;
float xWidth = sourceImage.Width;
float yWidth = sourceImage.Height;
Bitmap newImage = new Bitmap((int)(xWidth / multiple), (int)(yWidth / multiple));
Graphics g = Graphics.FromImage(newImage);
g.DrawImage(sourceImage, 0, 0, xWidth / multiple, yWidth / multiple);
g.Dispose();
newImage.Save(outputFile, myImageCodecInfo, myEncoderParameters);
return true;
}
catch (Exception ex)
{
return false;
}
}
/// <summary>
/// 获取图片编码信息
/// </summary>
private static ImageCodecInfo GetEncoderInfo(string mimeType)
{
int j;
ImageCodecInfo[] encoders;
encoders = ImageCodecInfo.GetImageEncoders();
for (j = 0; j < encoders.Length; ++j)
{
if (encoders[j].MimeType == mimeType)
return encoders[j];
}
return null;
}
C# 图片缩略图
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