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Tip of the Day
Language: VB7
Expertise: Intermediate
Dec 16, 2002

ShowImage - Output an image as a binary stream to the Response object

' Output an image as a binary stream to the Response object
Sub ShowImage(ByVal bmp As Bitmap)
    ' Clear current content and set returned content type
    HttpContext.Current.Response.Clear()
    HttpContext.Current.Response.ContentType = "image/jpeg"
    ' Save to the Response.OutputStream object
    bmp.Save(HttpContext.Current.Response.OutputStream, _
        Imaging.ImageFormat.Jpeg)

    bmp.Dispose()
    HttpContext.Current.Response.End()
End Sub


' Example:

Private Sub Page_Load(ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles MyBase.Load
    ' Create a bitmap with given width, height, and color depth.
    Dim bmp As New Bitmap(400, 200, _
        Drawing.Imaging.PixelFormat.Format16bppRgb565)
    ' Get the underlying Graphics object.
    Dim gr As Graphics = Graphics.FromImage(bmp)
    ' Clear its background.
    gr.Clear(Color.Red)

    ' create a font
    Dim fnt As New Font("Arial", 16, FontStyle.Regular, GraphicsUnit.Point)

    Dim angle As Single
    For angle = 0 To 360 Step 30
        ' Reset coordinate transforms.
        gr.ResetTransform()
        ' Translate and rotate the coordinate system.
        gr.TranslateTransform(200, 100)
        gr.RotateTransform(angle)
        ' Draw the (rotated) string.
        gr.DrawString("   hello", fnt, Brushes.Yellow, 0, 0)
    Next
    ' Release resources.
    fnt.Dispose()
    gr.Dispose()

    ShowImage(bmp)
End Sub


' Note: This code is taken from Francesco Balena's
' "Programming Microsoft Visual Basic .NET" - MS Press 2002, ISBN 0735613753
' You can read a free chapter of the book at 
' http://www.vb2themax.com/HtmlDoc.asp?Table=Books&ID=101000
Francesco Balena
 
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