Setting this property to a value >=0, makes the alpha channel an 8 bit gray scale paintable bitmap.
This means that you can draw on the alpha channel using TCanvas object.
The value (0..255) specifies the transparency, 0=fully transparent, 255=fully opaque.
ImageEnView1.IEBitmap.AlphaChannel.CanvasCurrentAlpha := 128; with ImageEnView1.IEBitmap.AlphaChannel.Canvas do begin FillRect(0, 0, 100, 100); Ellipse(10, 10, 200, 200); end;
// Draw a line on the IEBitmap canvas and ensure it also make opaque on the transparency With ImageEnView1 do begin IEBitmap.Canvas.Pen.Color := clRed; IEBitmap.Canvas.MoveTo( 10, 10 ) ; IEBitmap.Canvas.LineTo( 100, 100 );