Yunan.WPF.ImageAnim.GifAnimation.NextFrame C# (CSharp) Method

        public void NextFrame(object sender, EventArgs e)
        {
            frameTimer.Stop();
            if (_numberOfFrames == 0) return;
            if (_frameList[_frameCounter].disposalMethod == 2)
            {
                // dispose = background, tricky code to make transparent last frames region
                for (int fc = 0; fc < _frameCounter; fc++)
                {
                    if (_frameList[fc].Visibility == Visibility.Visible)
                    {
                        GifFrame gf = _frameList[_frameCounter];
                        RectangleGeometry rg2 = new RectangleGeometry(new Rect(gf.left, gf.top, gf.width, gf.height));
                        totalTransparentGeometry = new CombinedGeometry(GeometryCombineMode.Union, totalTransparentGeometry, rg2);

                        GifFrame gfBack = _frameList[fc];
                        RectangleGeometry rgBack = new RectangleGeometry(new Rect(gfBack.left, gfBack.top, gfBack.width, gfBack.height));
                        CombinedGeometry cg = new CombinedGeometry(GeometryCombineMode.Exclude, rgBack, totalTransparentGeometry);
                        GeometryDrawing gd = new GeometryDrawing(Brushes.Black, new Pen(Brushes.Black, 0), cg);
                        DrawingBrush db = new DrawingBrush(gd);
                        _frameList[fc].OpacityMask = db;
                    }
                }

                _frameList[_frameCounter].Visibility = Visibility.Hidden;
            }
            if (_frameList[_frameCounter].disposalMethod >= 3)
            {
                _frameList[_frameCounter].Visibility = Visibility.Hidden;
            }
            _frameCounter++;

            if (_frameCounter < _numberOfFrames)
            {
                _frameList[_frameCounter].Visibility = Visibility.Visible;
                frameTimer.Interval = new TimeSpan(0, 0, 0, 0, _frameList[_frameCounter].delayTime * 10);
                frameTimer.Start();
            }
            else
            {
                if (_numberOfLoops != 0)
                {
                    _currentLoop++;
                }
                if (_currentLoop < _numberOfLoops || _numberOfLoops == 0)
                {
                    for (int f = 0; f < _frameList.Count; f++)
                    {
                        _frameList[f].Visibility = Visibility.Hidden;
                        _frameList[f].OpacityMask = null;
                    }
                    totalTransparentGeometry = null;
                    _frameCounter = 0;
                    _frameList[_frameCounter].Visibility = Visibility.Visible;
                    frameTimer.Interval = new TimeSpan(0, 0, 0, 0, _frameList[_frameCounter].delayTime * 10);
                    frameTimer.Start();
                }
            }
        }

            public void NextFrame(object sender, EventArgs args)
            {
                GifAnimation b = (GifAnimation)this.Target;

                if (b != null)
                {
                    b.NextFrame(sender, args);
                }
                else
                {
                    DispatcherTimer c = sender as DispatcherTimer;
                    if (c != null)
                    {
                        c.Tick -= new EventHandler(this.NextFrame);
                    }
                }
            }