Private Function DrawImageCallback(callBackData As IntPtr) As Boolean
' Test for call that passes callBackData parameter.
If callBackData.Equals(IntPtr.Zero) Then
' If no callBackData passed, abort DrawImage method.
Return True
Else
' If callBackData passed, continue DrawImage method.
Return False
End If
End Function
Public Sub DrawImageRect4FloatAttribAbortData(e As PaintEventArgs)
' Create callback method.
Dim imageCallback As New _
Graphics.DrawImageAbort(AddressOf DrawImageCallback)
Dim imageCallbackData As New IntPtr(1)
' Create image.
Dim newImage As Image = Image.FromFile("SampImag.jpg")
' Create rectangle for displaying original image.
Dim destRect1 As New Rectangle(100, 25, 450, 150)
' Create coordinates of rectangle for source image.
Dim x As Single = 50F
Dim y As Single = 50F
Dim width As Single = 150F
Dim height As Single = 150F
Dim units As GraphicsUnit = GraphicsUnit.Pixel
' Draw original image to screen.
e.Graphics.DrawImage(newImage, destRect1, x, y, width, _
height, units)
' Create rectangle for adjusted image.
Dim destRect2 As New Rectangle(100, 175, 450, 150)
' Create image attributes and set large gamma.
Dim imageAttr As New ImageAttributes()
imageAttr.SetGamma(4F)
' Draw adjusted image to screen.
Try
' Draw adjusted image to screen.
e.Graphics.DrawImage(newImage, destRect2, x, y, width, _
height, units, imageAttr, imageCallback, imageCallbackData)
Catch ex As Exception
e.Graphics.DrawString(ex.ToString(), New Font("Arial", 8), _
Brushes.Black, New PointF(0, 0))
End Try
End Sub
