Thread: Show image according to column width

thanx RR, let me have a look

ok i tried code from RR's link, i made this function

Code:

    Public Shared Function CreateThumbnail(ByVal lcFilename As String, ByVal lnWidth As Integer, ByVal lnHeight As Integer) As Bitmap
        'http://www.west-wind.com/Weblog/posts/283.aspx
        Dim bmpOut As System.Drawing.Bitmap
        Try
            Dim loBMP As New Bitmap(lcFilename)
            Dim loFormat As ImageFormat = loBMP.RawFormat

            Dim lnRatio, lnTemp As Decimal
            Dim lnNewWidth As Integer = 0
            Dim lnNewHeight As Integer = 0

            'If image is smaller than a thumbnail, return it as such
            If loBMP.Width < lnWidth And loBMP.Height < lnHeight Then
                Return loBMP
            End If


            If loBMP.Width > loBMP.Height Then
                lnRatio = lnWidth / loBMP.Width
                lnNewWidth = lnWidth
                lnTemp = loBMP.Height * lnRatio
                lnNewHeight = CInt(lnTemp)

            Else
                lnRatio = lnHeight / loBMP.Height
                lnNewHeight = lnHeight
                lnTemp = loBMP.Width * lnRatio
                lnNewWidth = CInt(lnTemp)
            End If

            bmpOut = New Bitmap(lnNewWidth, lnNewHeight)
            Dim g As Graphics = Graphics.FromImage(bmpOut)
            g.InterpolationMode = Drawing2D.InterpolationMode.HighQualityBicubic
            g.FillRectangle(Brushes.White, 0, 0, lnNewWidth, lnNewHeight)
            g.DrawImage(loBMP, 0, 0, lnNewWidth, lnNewHeight)
            loBMP.Dispose()

        Catch ex As Exception
            'Return False
        End Try

        Return bmpOut

    End Function

and calling it like

Code:

Dim bmp As Bitmap = CreateThumbnail(strImage, 150, 150)

where strImage is a url coming from database.
but now how do i show this image?
i am using an .net image control.

any ideas/suggestions??

in the example, he saves it as a file, which i dont want.
but he also streams it to the browser like (C# code)

Code:

Response.ContentType = "image/jpeg";
bmp.Save(Response.OutputStream,System.Drawing.Imaging.ImageFormat.Jpeg);

but i dont know how it works!!

also i cant set bitmap as null
i used it like this

Code:

Dim bmp As Bitmap = CGlobal.CreateThumbnail(strImage, 150, 150)
Response.ContentType = "image/jpeg"
bmp.Save(Response.OutputStream, ImageFormat.Jpeg)
bmp.Dispose()

but it gives me this error at red line

Code:

System.NullReferenceException: Object reference not set to an instance of an object.

Originally Posted by richyrich

I think the first parameter of the Save method should be the filename as a String

yes, but i think that wud be in case if the file is wished to be saved.

I dont want to save the resized image, i just want to show it.

hmm, i get this error

Code:

System.ArgumentException: URI formats are not supported. at System.IO.Path.NormalizePathFast(String path, Boolean fullCheck) at System.IO.Path.GetFullPathInternal(String path) at System.IO.Path.GetFullPath(String path) at System.Drawing.IntSecurity.UnsafeGetFullPath(String fileName) at System.Drawing.IntSecurity.DemandReadFileIO(String fileName)

at this line

Code:

Dim loBMP As New Bitmap(strImage)