拍摄以下两个图像:
开发版-IIS7 Windows 7 Pro 64位计算机
实时版本-IIS7 Windows Server 2008 64位计算机
请注意,Live Version如何“像素化”并看上去质量低下,而Dev Version却平滑,抗锯齿且看起来不错。它们都是由相同的代码生成的:
' Settings
Dim MaxHeight As Integer = 140
Dim MaxWidth As Integer = 140
Dim WorkingFolderPath As String = "\\server\share\bla\"
Dim AllowedFileExtensions As New ArrayList
AllowedFileExtensions.Add(".jpg")
AllowedFileExtensions.Add(".jpeg")
' Select an image to use from the WorkingFolder
Dim ImageFileName As String = ""
Dim WorkingFolder As New IO.DirectoryInfo(WorkingFolderPath)
Dim SourceImages As IO.FileInfo() = WorkingFolder.GetFiles()
For Each SourceImage As IO.FileInfo In SourceImages
If AllowedFileExtensions.Contains(SourceImage.Extension.ToLower) = True Then
ImageFileName = SourceImage.Name
End If
Next
' Determine path to selected image (if no image was found use a placeholder)
Dim PhysicalPath As String = ""
If ImageFileName = "" Then
' No Image was found, use the filler image
PhysicalPath = Server.MapPath("ProductOfTheMonthMissing.jpg")
Else
' An Image was found, Redirect to it / build path for Thumnailing
If Request.QueryString("FullSize") = "true" Then
Response.Redirect("../share/bla/" & ImageFileName)
Else
PhysicalPath = WorkingFolderPath & ImageFileName
End If
End If
' Load image and output in binary (resizing if necessary)
Using ProductImage As System.Drawing.Image = System.Drawing.Image.FromFile(PhysicalPath)
Dim newWidth As Integer = ProductImage.Width
Dim newHeight As Integer = ProductImage.Height
' Check if selected size is too big, if so, determine new size
If ProductImage.Width > MaxWidth Or ProductImage.Height > MaxHeight Then
Dim ratioX As Double = CDbl(MaxWidth) / ProductImage.Width
Dim ratioY As Double = CDbl(MaxHeight) / ProductImage.Height
Dim ratio As Double = Math.Min(ratioX, ratioY)
newWidth = CInt(ProductImage.Width * ratio)
newHeight = CInt(ProductImage.Height * ratio)
End If
' Create a new bitmap from the image with new size
Dim Codecs As ImageCodecInfo() = ImageCodecInfo.GetImageEncoders()
Dim CodecInfo As ImageCodecInfo = Nothing
Dim ProductOfTheMonth As New Bitmap(ProductImage, newWidth, newHeight)
Dim ReSizer As Graphics = Graphics.FromImage(ProductOfTheMonth)
ReSizer.InterpolationMode = InterpolationMode.HighQualityBicubic
ReSizer.SmoothingMode = SmoothingMode.HighQuality
ReSizer.PixelOffsetMode = PixelOffsetMode.HighQuality
ReSizer.CompositingQuality = CompositingQuality.HighQuality
' Ensure the encoder uses the best quality settings
Dim EncoderParams As New EncoderParameters(3)
EncoderParams.Param(0) = New EncoderParameter(System.Drawing.Imaging.Encoder.Quality, 100L)
EncoderParams.Param(1) = New EncoderParameter(System.Drawing.Imaging.Encoder.ScanMethod, CInt(EncoderValue.ScanMethodInterlaced))
EncoderParams.Param(2) = New EncoderParameter(System.Drawing.Imaging.Encoder.RenderMethod, CInt(EncoderValue.RenderProgressive))
' Set jpeg as the output codec
For Each Codec As ImageCodecInfo In Codecs
If Codec.MimeType = "image/jpeg" Then
CodecInfo = Codec
End If
Next
' Ready a memory stream and byte array
Dim MemStream As New MemoryStream()
Dim bmpBytes As Byte()
' Save the image the the memory stream & prep ContentType for HTTP reasponse
Response.ContentType = "image/jpeg"
ProductOfTheMonth.Save(MemStream, CodecInfo, EncoderParams)
' Flush memory stream into byte array & flush to browser
bmpBytes = MemStream.GetBuffer()
Response.BinaryWrite(bmpBytes)
' Cleanup
ProductOfTheMonth.Dispose()
MemStream.Close()
ProductImage.Dispose()
End Using
这背后的原因是什么?我该如何解决这个问题?大概是实时网络服务器上的GD问题-但我不知道是什么-我试图在设置图形和编解码器设置方面尽可能地透彻,但仍然有所不同?
编辑:源图像在两个示例中也相同(位于中央unc共享上)-源图像here的副本
最佳答案
我曾经在这里回答过类似的问题:Graphics wrong image interpolation in .Net,但总之,似乎不同的平台使用了不同的内部算法(或者可能是GDI中的内部舍入问题)。
无论如何,问题出在设置中。因此,请尝试以下操作:
Using s As Bitmap = DirectCast(Bitmap.FromFile(PhysicalPath), Bitmap)
Dim scale As Double = Math.Min(140.0 / s.Width, 140.0 / s.Height)
Using d As New Bitmap(CInt(Math.Floor(scale * s.Width)), CInt(Math.Floor(scale * s.Height)), System.Drawing.Imaging.PixelFormat.Format24bppRgb)
Using dg As Graphics = Graphics.FromImage(d)
dg.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic
dg.SmoothingMode = SmoothingMode.HighQuality
dg.PixelOffsetMode = PixelOffsetMode.HighQuality
dg.CompositingQuality = CompositingQuality.HighQuality
dg.Clear(Color.White)
dg.DrawImage(s, New Rectangle(0, 0, d.Width, d.Height), New Rectangle(0, 0, s.Width, s.Height), GraphicsUnit.Pixel)
End Using
Dim jpegArgs As New EncoderParameters(3)
jpegArgs.Param(0) = New EncoderParameter(System.Drawing.Imaging.Encoder.Quality, 100L)
jpegArgs.Param(1) = New EncoderParameter(System.Drawing.Imaging.Encoder.ScanMethod, CInt(EncoderValue.ScanMethodInterlaced))
jpegArgs.Param(2) = New EncoderParameter(System.Drawing.Imaging.Encoder.RenderMethod, CInt(EncoderValue.RenderProgressive))
Dim Codecs As ImageCodecInfo() = ImageCodecInfo.GetImageEncoders()
Dim jpegParams As ImageCodecInfo = Nothing
'#### Set jpeg as the output codec
For Each Codec As ImageCodecInfo In Codecs
If Codec.MimeType = "image/jpeg" Then
jpegParams = Codec
End If
Next
Response.Clear()
Response.ContentType = "image/jpeg"
d.Save(Response.OutputStream, jpegParams, jpegArgs)
End Using
End Using
祝你好运!
关于.net - 相同的代码在不同的服务器上产生不一致的图像质量,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/20069100/