How to extract frames from a TGifImage into Bitmaps? - delphi

Question

The demo below tries to draw the GIF on form's canvas. It doesn't work. The image won't advance. How to make it work?
procedure TForm1.FormCreate(Sender: TObject);
begin
GIF := TGIFImage.Create;
GIF.LoadFromFile('c:\2.gif');
end;
procedure TForm1.FormDestroy(Sender: TObject);
begin
GIF.Free;
end;
procedure TForm1.Button1Click(Sender: TObject);
VAR i: Integer;
begin
REPEAT
for i:= 0 to GIF.Images.Count-1 DO
begin
DisplayGifFrame(i);
Sleep(30);
end;
UNTIL FALSE;
end;
procedure TForm1.DisplayGifFrame(AIndex: Integer);
VAR
Renderer: TGIFRenderer;
begin
Renderer := TGIFRenderer.Create(GIF);
TRY
Renderer.Animate := TRUE;
Renderer.FrameIndex := AIndex;
Renderer.Draw(Canvas, Canvas.ClipRect);
{save frame in a bitmap here. save bitmap to disk}
// xxx
FINALLY
Renderer.Free;
end;
end;
What I want to achieve:
I want to extract all frames from a GIF and put each frame IN A UNIQUE bitmap.
Update:
Continued here: Cannot draw GIF on dynamically created TBitmap(s)

Answer 1

Try this:
procedure TForm1.Button1Click(Sender: TObject);
var
GIF: TGIFImage;
Bitmap: TBitmap;
I: Integer;
GR: TGIFRenderer;
R: TRect;
begin
GIF := TGIFImage.Create;
Bitmap := TBitmap.Create;
try
GIF.LoadFromFile('c:\test\test.gif');
Bitmap.SetSize(GIF.Width, GIF.Height);
GR := TGIFRenderer.Create(GIF);
try
for I := 0 to GIF.Images.Count - 1 do
begin
if GIF.Images[I].Empty then Break;
GR.Draw(Bitmap.Canvas, Bitmap.Canvas.ClipRect);
GR.NextFrame;
Bitmap.SaveToFile(Format('%.2d.bmp', [I]));
end;
finally
GR.Free;
end;
finally
GIF.Free;
Bitmap.Free;
end;
end;
The above code takes into account Frame's Disposal method. see related question here.