Visual basic Code Sample Alpha Blending

How to use Visual Basic .net to create Alpha Blended Images from two different images. Visual Basic is a great image Processing development environment, with speed equal to any other Visual language in the .net family! All .net language compile to the same IL(intermediate Language), removing the speed Plague to visual basic.

Definition of: alpha blending
In computer graphics, the combining of the alpha channel with other layers in an image in order to show translucency. The alpha channel is an additional eight bits used with each pixel in a 32-bit graphics system that can represent 256 levels of translucency. Black and white represent opaque and fully transparent, while various gray levels represent levels of translucency.
The function below allows the user to choose how much of the images will be alpha blended in the saved graphic.

Starting Image 1	Starting Image 2	Alpha Blended Image 75%

Imports System.Drawing Imports System.Drawing.Graphics Imports System.Drawing.Imaging Public Class MyFilters Public Function AlphaRGB(ByVal MyImage As Image, ByVal bm As Image, ByVal threshold As Integer) As Image Dim bitmap As New Bitmap(MyImage) Dim bitmap2 As New Bitmap(bm) Dim cm As ColorMatrix If threshold = 0 Then threshold = 128 End If cm = New ColorMatrix(New Single()() { _ New Single() {1, 0, 0, 0, 0},_ New Single() {0, 1, 0, 0, 0}, _ New Single() {0, 0, 1, 0, 0}, _ New Single() {0, 0, 0, threshold, 0}, _ New Single() {0, 0, 0, 0, 1}}) Dim imageAtt As New System.Drawing.Imaging.ImageAttributes() imageAtt.SetColorMatrix(cm, System.Drawing.Imaging.ColorMatrixFlag.Default,System.Drawing.Imaging.ColorAdjustType.Bitmap) Dim r1 As RectangleF r1.X = 0 r1.Y = 0 r1.Width = MyImage.Width r1.Height = MyImage.Height Dim r2 As RectangleF r2.X = 0 r2.Y = 0 r2.Width = bitmap2.Width r2.Height = bitmap2.Height Dim graphics1 As Graphics graphics1 = Graphics.FromImage(bitmap2) Dim brush3 As New TextureBrush(bitmap, r1, imageAtt) brush3.WrapMode = Drawing2D.WrapMode.Tile graphics1.CompositingMode = Drawing2D.CompositingMode.SourceOver graphics1.FillRectangle(brush3, r2) graphics1.DrawImage(bitmap, New Rectangle(0, 0, 1700, 1700), 0, 0,bitmap.Width, bitmap.Height, GraphicsUnit.Pixel, imageAtt) Return bitmap2 brush3.Dispose() graphics1.Dispose() End Function End Class

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