Extracting PNG images from Delphi 2009 imagelist

3
votes

The TImageList of Delphi 2009 has support for PNG images by adding them in the imagelist editor. Is there any way to extract a TPngImage from a TImagelist and preserving the alpha channel?

What I want to do is actually to extract the images from one TImageList, make a disabled version of them and then add them to another TImageList. During this operation I would of course like to preserve the alpha channel of the PNG images.

1
delphipngdelphi-2009imagelist

1 Answers

1
votes

I did something like this with Delphi 2006.

TImageList contains a protected method GetImages. It can be accessed using the "protected bug"

type
  TGetImageImageList = class (TImageList) // Please use a better name!
  end;

You can cast the imagelist to the TGetImageImageList to get to the GetImages. 

begin
  TGetImageList(ImageList).GetImages(index, bitmap, mask);
end;

Bitmap contains the bitmap and mask is a black and white bitmap that determines the transparant sections.

You now can change the bitmap and store it using:

function Add(Image, Mask: TBitmap): Integer;

I hope this gives you enough pointers to explore further.