saving image to jpeg and resizing... works but...

[Kiweed]

Previously in VB6 I managed to hook into a DLL created from the Intel graphics library.

I had a speedy way to create thumbnails and to save a loaded images to a jpeg file where I can set the quality and other attributes.

Now in vb.net this is very simple withbuilt in methods but...

i) I do not know what type of sampling the thumbnail uses as the Intel library had a few choices depending on a tradeoff between speed and quality.

ii) The jpeg save justs saves but does not seem to offer a control over the quality.

Q. Is there a way to set the quality or other parameters when saving?

There seems to be a lack of documentation or examples around that do any more than the basics.

[Cander]

yeah using EncoderParameters

Dim imgCodecs() As ImageCodecInfo  = ImageCodecInfo.GetImageEncoders()

Dim params As New EncoderParameters  = EncoderParameters(1)
Dim quality As New EncoderParameter EncoderParameter(Encoder.Quality, 50)
'Set quality to 50
params.Param(0) = quality

yourimage.Save("c:\output.jpg",imgCodecs(1), params)

btw imgCodecs(1) means JPEG not sure what the other array values would be if you need other image types

[Cander]

oops..I knew I sghould have tested that...just kind of guessed..but there were some errors..here is the WORKING code

Dim imgCodecs() As ImageCodecInfo  = ImageCodecInfo.GetImageEncoders()
	
Dim params As EncoderParameters = New EncoderParameters(1)
Dim quality As EncoderParameter = New EncoderParameter(System.Drawing.Imaging.Encoder.Quality, 50)
'Set quality to 50
params.Param(0) = quality
	
newBitmap.Save("c:\blah.jpg", imgCodecs(1), params)

[Kiweed]

I had a feeling it was one of the other more complicated options.

In typical Microsoft fashion it can be done...if you know where to find it.

Would be nice if they had a few functions like

SaveAsJPG(name as string, quality as integer, descr as string, ...)

Maybe I'll just create such a function myself

[Cander]

well it is just that the EncoderParameter covers more than just JPegs..it was written that way to cover a wider range of use...BTW here are the other Parameters you can set

ChrominanceTable
ColorDepth
Compression
LuminanceTable
RenderMethod
SaveFlag
ScanMethod
Transformation
Version

I may look into wrapping all this stuff into a dll to make it easier when i get the time.