Bitmap transparency (lack of)

[sggaunt]

My application needs to quickly display a number of bitmaps (and Icons), so rather than loading from file when required I load them all into an image list (VCL)
and then extract as required.
But I require the bitmaps to have a transparent background, in this example it is Black.
The problem is that they do not display transparently (I see the bitmaps on a black square)

The image list is setup as follows:-
BkColor = ClBlack
BlendColor = ClNone
Drawing Style = dsTransparent
ImageType = itImage
Masked = false


The following code loads the Imagelist 'ActorImages'
I am using addmasked as this should force transparency ??

procedure TForm1.LoadActors(FName: TFilename);
var Bmp: TBitMap;
    Temp: string;
    A: integer;
begin
   ActorImages.Clear;
   Bmp := TBitMap.Create;
   for a := 0 to NumberofBMs -1 do
        begin
           Temp := FName;
           Temp := changefileext(Temp,'');
           Bmp.LoadFromFile(Temp + inttostr(a)+'.bmp');
           ActorImages.AddMasked(Bmp, $00000000);
       end;
   Bmp.Free;
end;

The following code creates objects (both types) dynamically from a file stream, and extracts the associated images from the imagelists (one for icons one for bitmaps).
As you can see I have tried to force transparency at this point, still no luck!

constructor TThings.CreateFromStream(Fs : TFileStream );
begin
   inherited Create;
   ReadFromStream(Fs);
   objectico := TImage.create(objectico);
        with objectico do
           begin
              if objtype = inanimate then
                  begin
                     Enabled := True;
                     Width := 32;
                     Height := 32;
                     Top  := YPos;
                     Left := XPos;
                     Form1.ImageList.GetIcon(ImageIndex[0], Picture.Icon);
                     Tag := index;
                     OnMouseDown := MouseDown;
                     OnMouseMove := MouseMove;
                     OnMouseUp := MouseUp;
                     Hint := ObjectName;
                     ShowHint := True;
                  //   PopUpMenu := Menu;
                  end
             else
                  begin
                     Enabled := True;
                     Width := 128;
                     Height := 128;
                     Top := 240;
                     Left := 650;

                     Form1.ActorImages.GetBitmap(ImageIndex[0], Picture.BitMap);

                     Picture.Bitmap.TransparentColor := $00000000;
                     Picture.Bitmap.Transparent := true;
                     Tag := index;
                  end
      end;
end;

Steve: N.M.N.F.
If something is popular, it must be wrong: Mark Twain

 

[auditdi30]

Hello!

Maybee you could find your answer at this site??

http://www.efg2.com/Lab/Library/Delphi/Graphics/Algorithms.htm

Regards Kåre!

 

[sggaunt]

Cheers
I will have a look (a lot to work through), this problem has been on the back burner for a couple of years now I need to sort it.

Steve: N.M.N.F.
If something is popular, it must be wrong: Mark Twain

 

[sggaunt]

Ok Fixed it (not from the link just tried a few more things)
Fix [simplified version]

 objectico := TImage.create(objectico);
        with objectico do
           begin  
              Form1.ActorImages.GetBitmap(ImageIndex[0], Picture.BitMap);
              Picture.Bitmap.TransparentMode := TmAuto;       
            [s] Picture.Bitmap.Transparent := true; [/s]
           [red]Transparent := True;[/red] 
              Tag := index;  
 end;

The trick seems to be to make the parent object transparent, perhaps its (default) non transparency is inherited ?
The change to Auto transparency is not part of the fix just simplifies making the bitmaps.

Steve: N.M.N.F.
If something is popular, it must be wrong: Mark Twain