[solved] drawing with layers

[speter]

G'Day Folks,

I have written a program to draw on a number of layers; the program allows the user to show / hide layers and all that works okay.

What doesn't work is clearing the layer(s).

The layering is implemented by having multiple Timages with the transparent colour set; this works fine - first time around - but doesn't work when "erasing" the existing graphics...

I've attached the project and 2 images to show what I mean; in one image you see a number of coloured polygons; in the other the previous polygons are now black (the "transparent" colour).

Any help / suggestions would be very welcome!

cheers
S.

[paweld]

Code: Pascal  [Select][+][-]

1. procedure TForm1.Button1Click(Sender: TObject);
2. var
3.   a : byte;
4.   b : TButton;
5.   h,w : integer;
6. begin
7.   b := TButton(sender);
8.   if b.caption = 'Draw' then
9.     begin
10.       for a := 1 to num_layers do
11.         draw_layer(a);
12.  
13.       b.caption := 'Clear';
14.     end
15.   else
16.     begin
17.       w := image_layer1.Width;
18.       h := image_layer1.Height;
19.  
20.       for a := 1 to num_layers do
21.         layers[a].Picture.Clear; //<---------
22.  
23.       b.caption := 'Draw';
24.     end;
25. end;

[speter]

Thanks very much @ paweld.

cheers
S.