But the thumbnail image looks grainy. If I take the same image, resample it in corel photopaint at 72dpi, the image is nice and small and not grainy at all ( sharp ).
I was wondering if there is anything else that can be done to a jpg as you are compressing it down to a smaller jpg, so you do not end up with a grainy image.
I found this - but I cant seem to convert it to vb.
// Prepare for a controlled-quality JPEG exportImageCodecInfo jpegCodec = GetEncoderInfo("image/jpeg"); Encoder jpegEncoder = Encoder.Quality; EncoderParameters jpegEncoderParameters = new EncoderParameters(1); EncoderParameter jpegEncoderQuality = new EncoderParameter(jpegEncoder, jpegQuality); jpegEncoderParameters.Param[0] = jpegEncoderQuality;string thumbnailPath; // some path to save your JPEG to thumbnail.Save(thumbnailPath, jpegCodec, jpegEncoderParameters);
> But the thumbnail image looks grainy. > If I take the same image, resample it in corel photopaint at 72dpi, the > image is nice and small and not grainy at all ( sharp ).
> I was wondering if there is anything else that can be done to a jpg as you > are compressing it down to a smaller jpg, so you do not end up with a > grainy image.
> > But the thumbnail image looks grainy. > > If I take the same image, resample it in corel photopaint at 72dpi, the > > image is nice and small and not grainy at all ( sharp ).
> > I was wondering if there is anything else that can be done to a jpg as you > > are compressing it down to a smaller jpg, so you do not end up with a > > grainy image.
> > Thanks,
> > Miro
' Prepare for a controlled-quality JPEG Dim jpegCodec As exportImageCodecInfo = GetEncoderInfo("image/jpeg") Dim jpegEncoder As Encoder = Encoder.Quality Dim jpegEncoderParameters As New EncoderParameters(1) Dim jpegEncoderQuality As New EncoderParameter(jpegEncoder, jpegQuality) jpegEncoderParameters.Param(0) = jpegEncoderQuality Dim thumbnailPath As String ' some path to save your JPEG to thumbnail.Save(thumbnailPath, jpegCodec, jpegEncoderParameters)
this got me on the right track but my image is still more grainy than if I do it in something like corel photopaint.
Here is my code below. Perhaps I have a logical error somehwere ? Take note of the 1000L ...if I put 100L or anything higher it does not get better, but a value of 0 is really really grainy...so I was hoping this was some kind of a weird calculated value.
Private Sub generateThumbnail(ByVal filepath As String, ByVal FileName As String)
'Create a new Bitmap Image loading from location of origional file 'Dim bm As Bitmap = System.Drawing.Image.FromFile(filepath & FileName) Dim jpg As System.Drawing.Image = System.Drawing.Image.FromFile(filepath & FileName)
'Declare Thumbnails Height and Width Dim newWidth As Integer = 125 'Dim newHeight As Integer = (newWidth / bm.Width) * bm.Height Dim newHeight As Integer = (newWidth / jpg.Width) * jpg.Height Dim resizedBMP As Bitmap = New Bitmap(jpg, newWidth, newHeight)
' Prepare for a controlled-quality JPEG Dim jpegCodec As ImageCodecInfo = GetEncoderInfo("image/jpeg") Dim jpegEncoder As Encoder = Encoder.Quality Dim jpegEncoderParameters As New EncoderParameters(1) Dim jpegEncoderQuality As New EncoderParameter(jpegEncoder, 1000L) jpegEncoderParameters.Param(0) = jpegEncoderQuality 'Dim thumbnailPath As String ' some path to save your JPEG to Dim newStrFileName As String = filepath & "ThumbNails/" & FileName resizedBMP.Save(newStrFileName, jpegCodec, jpegEncoderParameters) End Sub
Private Function GetEncoderInfo(ByVal mimeType As String) _ As ImageCodecInfo Dim j As Integer Dim encoders As ImageCodecInfo() encoders = ImageCodecInfo.GetImageEncoders() For j = 0 To encoders.Length If encoders(j).MimeType = mimeType Then Return encoders(j) End If Next j Return Nothing End Function
Miro
"Alexey Smirnov" <alexey.smir...@gmail.com> wrote in message
> > But the thumbnail image looks grainy. > > If I take the same image, resample it in corel photopaint at 72dpi, the > > image is nice and small and not grainy at all ( sharp ).
> > I was wondering if there is anything else that can be done to a jpg as > > you > > are compressing it down to a smaller jpg, so you do not end up with a > > grainy image.
> > Thanks,
> > Miro
' Prepare for a controlled-quality JPEG Dim jpegCodec As exportImageCodecInfo = GetEncoderInfo("image/jpeg") Dim jpegEncoder As Encoder = Encoder.Quality Dim jpegEncoderParameters As New EncoderParameters(1) Dim jpegEncoderQuality As New EncoderParameter(jpegEncoder, jpegQuality) jpegEncoderParameters.Param(0) = jpegEncoderQuality Dim thumbnailPath As String ' some path to save your JPEG to thumbnail.Save(thumbnailPath, jpegCodec, jpegEncoderParameters)
Rewrote it a bit...but still grainy - found some differnet code- hoping that would work.
Dim bm As Bitmap = System.Drawing.Image.FromFile(filepath & FileName) Dim newWidth As Integer = 125 Dim newHeight As Integer = (newWidth / bm.Width) * bm.Height Dim resizedBMP As Bitmap = New Bitmap(bm, newWidth, newHeight)
Dim info As ImageCodecInfo = ImageCodecInfo.GetImageEncoders(1) Dim Params As EncoderParameters = New EncoderParameters(1) Params.Param(0) = New EncoderParameter(System.Drawing.Imaging.Encoder.Quality, 100L) Dim newStrFileName As String = filepath & "ThumbNails/" & FileName resizedBMP.Save(newStrFileName, info, Params)
> this got me on the right track but my image is still more grainy than if I > do it in something like corel photopaint.
> Here is my code below. Perhaps I have a logical error somehwere ? > Take note of the 1000L ...if I put 100L or anything higher it does not get > better, but a value of 0 is really really grainy...so I was hoping this > was some kind of a weird calculated value.
> Private Sub generateThumbnail(ByVal filepath As String, ByVal FileName > As String)
> 'Create a new Bitmap Image loading from location of origional file > 'Dim bm As Bitmap = System.Drawing.Image.FromFile(filepath & > FileName) > Dim jpg As System.Drawing.Image = > System.Drawing.Image.FromFile(filepath & FileName)
> 'Declare Thumbnails Height and Width > Dim newWidth As Integer = 125 > 'Dim newHeight As Integer = (newWidth / bm.Width) * bm.Height > Dim newHeight As Integer = (newWidth / jpg.Width) * jpg.Height > Dim resizedBMP As Bitmap = New Bitmap(jpg, newWidth, newHeight)
> ' Prepare for a controlled-quality JPEG > Dim jpegCodec As ImageCodecInfo = GetEncoderInfo("image/jpeg") > Dim jpegEncoder As Encoder = Encoder.Quality > Dim jpegEncoderParameters As New EncoderParameters(1) > Dim jpegEncoderQuality As New EncoderParameter(jpegEncoder, 1000L) > jpegEncoderParameters.Param(0) = jpegEncoderQuality > 'Dim thumbnailPath As String > ' some path to save your JPEG to > Dim newStrFileName As String = filepath & "ThumbNails/" & FileName > resizedBMP.Save(newStrFileName, jpegCodec, jpegEncoderParameters) > End Sub
> Private Function GetEncoderInfo(ByVal mimeType As String) _ > As ImageCodecInfo > Dim j As Integer > Dim encoders As ImageCodecInfo() > encoders = ImageCodecInfo.GetImageEncoders() > For j = 0 To encoders.Length > If encoders(j).MimeType = mimeType Then > Return encoders(j) > End If > Next j > Return Nothing > End Function
>> > But the thumbnail image looks grainy. >> > If I take the same image, resample it in corel photopaint at 72dpi, the >> > image is nice and small and not grainy at all ( sharp ).
>> > I was wondering if there is anything else that can be done to a jpg as >> > you >> > are compressing it down to a smaller jpg, so you do not end up with a >> > grainy image.
>> > Thanks,
>> > Miro
> ' Prepare for a controlled-quality JPEG > Dim jpegCodec As exportImageCodecInfo = GetEncoderInfo("image/jpeg") > Dim jpegEncoder As Encoder = Encoder.Quality > Dim jpegEncoderParameters As New EncoderParameters(1) > Dim jpegEncoderQuality As New EncoderParameter(jpegEncoder, > jpegQuality) > jpegEncoderParameters.Param(0) = jpegEncoderQuality > Dim thumbnailPath As String > ' some path to save your JPEG to > thumbnail.Save(thumbnailPath, jpegCodec, jpegEncoderParameters)
> On Nov 6, 9:06 pm, "Miro" <m...@beero.com> wrote: >> I found this - but I cant seem to convert it to vb.
I assume that commercial products contain more evolved compression algorithms than the .NET Framework's default JPEG encoder. Adobe Photoshop, for example, provides a better quality/file size ratio than the .NET Framework's JPEG encoder too. The encoder used by GIMP is worse than Photoshop's encoder.
Depending on the type of images you may want to consider using the PNG format instead of JPEG (it's more suitable for screenshots, for example).
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