/* 創建一個Button */   UIButton * button = [UIButton buttonWithType:(UIButtonTypeSystem)];   [button setFrame:CGRectMake(100, 100, 100, 100)];   [self addSubview:button]; /* 正廠的圓角需求處理方法 */  button.layer.cornerRadius = 10.0f; //弧度  button.layer.masksToBounds = YES;/* 貝塞爾曲線切割 */  /**   *   * @param UIRectCorner    * 左上 UIRectCornerTopLeft   = 1 << 0,     左下 UIRectCornerBottomLeft = 1 << 2,     右下 UIRectCornerBottomRight = 1 << 3,     所有角 UIRectCornerAllCorners = ~0UL   *   */UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:button.bounds byRoundingCorners:UIRectCornerTopLeft | UIRectCornerBottomLeft cornerRadii:button.bounds.size];  CAShapeLayer *maskLayer = [[CAShapeLayer alloc]init];  //設置大小  maskLayer.frame = button.bounds;  //設置圖形樣子  maskLayer.path = maskPath.CGPath;  button.layer.mask = maskLayer;