我需要从用户那里获取具有不同格式扩展名的图片,并且我希望始终将其保存为"jpg",以便于处理。在c#中有没有一种不需要武装质量就能做到这一点的好方法?
发布于 2012-06-05 17:47:15
来自:http://msdn.microsoft.com/en-us/library/system.drawing.imaging.encoderparameter.aspx
private void VaryQualityLevel()
{
// Get a bitmap.
Bitmap bmp1 = new Bitmap(@"c:\TestPhoto.jpg");
ImageCodecInfo jpgEncoder = GetEncoder(ImageFormat.Jpeg);
// Create an Encoder object based on the GUID
// for the Quality parameter category.
System.Drawing.Imaging.Encoder myEncoder =
System.Drawing.Imaging.Encoder.Quality;
// Create an EncoderParameters object.
// An EncoderParameters object has an array of EncoderParameter
// objects. In this case, there is only one
// EncoderParameter object in the array.
EncoderParameters myEncoderParameters = new EncoderParameters(1);
EncoderParameter myEncoderParameter = new EncoderParameter(myEncoder,
50L);
myEncoderParameters.Param[0] = myEncoderParameter;
bmp1.Save(@"c:\TestPhotoQualityFifty.jpg", jpgEncoder,
myEncoderParameters);
myEncoderParameter = new EncoderParameter(myEncoder, 100L);
myEncoderParameters.Param[0] = myEncoderParameter;
bmp1.Save(@"c:\TestPhotoQualityHundred.jpg", jpgEncoder,
myEncoderParameters);
// Save the bitmap as a JPG file with zero quality level compression.
myEncoderParameter = new EncoderParameter(myEncoder, 0L);
myEncoderParameters.Param[0] = myEncoderParameter;
bmp1.Save(@"c:\TestPhotoQualityZero.jpg", jpgEncoder,
myEncoderParameters);
}
...
private ImageCodecInfo GetEncoder(ImageFormat format)
{
ImageCodecInfo[] codecs = ImageCodecInfo.GetImageDecoders();
foreach (ImageCodecInfo codec in codecs)
{
if (codec.FormatID == format.Guid)
{
return codec;
}
}
return null;
}
发布于 2013-07-29 19:08:29
我使用这个简单的扩展来转换流,它所做的只是转换它,而不是对质量做任何事情。
public static Stream ConvertImage(this Stream originalStream, ImageFormat format)
{
var image = Image.FromStream(originalStream);
var stream = new MemoryStream();
image.Save(stream, format);
stream.Position = 0;
return stream;
}
用法:
var outputStream = gifStream.ConvertImage(ImageFormat.Png);
发布于 2015-09-10 22:31:26
试试这个:
public static class BitmapExtension
{
public static void Save(this Bitmap bitmap, String fileName, ImageFormat imageFormat, long quality = 75L)
{
using (var encoderParameters = new EncoderParameters(1))
using (encoderParameters.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, quality))
{
ImageCodecInfo[] codecs = ImageCodecInfo.GetImageDecoders();
bitmap.Save(fileName, codecs.Single(codec => codec.FormatID == imageFormat.Guid), encoderParameters);
}
}
}
...
Bitmap bitmap = new Bitmap("myImage.bmp");
bitmap.Save("myImage.jpg", ImageFormat.Jpeg, 50L);
https://stackoverflow.com/questions/10894836
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