title: How to add an image with transparency to a TDbgrid column in delphi?
body: <p>I am trying to add an image to a column on a TDbgrid that takes transparency into account.  When drawing the image from a TImageList on the canvas in the DBGridDrawColumnCell procedure, I need the background of the image (the same color as the pixel in the lower left corner) to take on transparency.  I want this transparency area to show the highlight color or non-highlight color, especially when themes are used, such as Aero.  I have been able to accomplish this in older versions of Windows with color values of clHighlight or clWindow as the background color.  But with Aero themes, it always paints a box behind the non-transparent part of the image instead of the gradient blue highlight color that Aero uses.  How can I accomplish this?</p>
  
  <p>I believe I am supposed to use alpha channel but I'm not sure how to do this from a TImageList to a canvas.  I believe the cell is painted completely with the actual highlight color before I start drawing on the canvas in the cell.  I just want to draw the non-transparency part of the image and leave the background.</p>