Outline Generator

public Sprite GenerateOutline(Sprite sprite)
    {
        Vector2Int originSize = new Vector2Int((int)sprite.rect.width, (int)sprite.rect.height);
        Vector2Int originPivot = new Vector2Int((int)sprite.rect.x, (int)sprite.rect.y);
        Texture2D origin = sprite.texture;
        Vector2Int outlineSize = (originSize + Vector2Int.one) * 2;
        Texture2D outline = new Texture2D(outlineSize.x, outlineSize.y)
        {
            filterMode = FilterMode.Point
        };
        Color[] colors = outline.GetPixels();
        for (int i = 0; i < colors.Length; i++)
        {
            colors[i] = Color.clear;
        }
        outline.SetPixels(colors);
        for (int x = 0; x < originSize.x; x++)
        {
            for (int y = 0; y < originSize.y; y++)
            {
                Color color = origin.GetPixel(originPivot.x + x, originPivot.y + y);
                for (int cX = 0; cX < 2; cX++)
                {
                    for (int cY = 0; cY < 2; cY++)
                    {
                        outline.SetPixel(x * 2 + cX + 1, y * 2 + cY + 1, color);
                    }
                }
            }
        }
        colors = outline.GetPixels();
        Vector2Int[] neighbours = new Vector2Int[] { Vector2Int.up, Vector2Int.right, Vector2Int.down, Vector2Int.left };
        for (int x = 1; x < outlineSize.x - 1; x++)
        {
            for (int y = 1; y < outlineSize.y - 1; y++)
            {
                if (colors[x + y * outlineSize.y].a != 0f)
                {
                    for (int n = 0; n < 4; n++)
                    {
                        Vector2Int position = new Vector2Int(x, y) + neighbours[n];
                        if (colors[position.x + position.y * outlineSize.y].a == 0f)
                        {
                            outline.SetPixel(position.x, position.y, Color.black);
                        }
                    }
                }
            }
        }
        outline.Apply();
        return Sprite.Create(outline, new Rect(0f, 0f, outlineSize.x, outlineSize.y), Vector2.one / 2f, 16f);
    }