User1796367390 posted
I have followed most of the common techinques for improving the quality of jpeg images when they are resized. Code is below:
Private Shared Function ResizeImageFile(ByVal imageFile() As Byte, ByVal targetSize As Integer) As Byte()
Using oldImage As System.Drawing.Image = System.Drawing.Image.FromStream(New MemoryStream(imageFile))
Dim newSize As Size = CalculateDimensions(oldImage.Size, targetSize)
Using newImage As Bitmap = New Bitmap(newSize.Width, newSize.Height, PixelFormat.Format24bppRgb)
Using canvas As Graphics = Graphics.FromImage(newImage)
canvas.SmoothingMode = SmoothingMode.HighQuality
canvas.InterpolationMode = InterpolationMode.HighQualityBicubic
canvas.PixelOffsetMode = PixelOffsetMode.HighQuality
canvas.CompositingQuality = CompositingQuality.HighQuality
canvas.DrawImage(oldImage, New Rectangle(New Point(0, 0), newSize))
Dim info() As ImageCodecInfo = ImageCodecInfo.GetImageEncoders()
Dim params As EncoderParameters = New Imaging.EncoderParameters(1)
params.Param(0) = New EncoderParameter(Encoder.Quality, 100L)
Dim m As New MemoryStream
newImage.Save(m, info(1), params)
Return m.GetBuffer
End Using
End Using
End Using
End Function
Im using a HttpHandler to retrieve the images. Is there anything that can be done when rendering the images to improve the quality. I am using something like below to output the image stream:
' Write image stream to the response stream
Dim buffersize As Integer = (1024 * 16)
Dim buffer() As Byte = New Byte((buffersize) - 1) {}
Dim count As Integer = s.Read(buffer, 0, buffersize)
Do While (count > 0)
context.Response.OutputStream.Write(buffer, 0, count)
count = s.Read(buffer, 0, buffersize)
Loop
Failing this, can anyone recommend anything else that can be done to further improve my image resizing method (it's pretty good already but want it to be as good as possible)
Thanks,
Ben
