ios 图片处理-专辑封面头像旋转-裁剪圆形图片

专辑封面头像旋转

- (void)startAnimation
{imageangle = imageangle+0.5;//全局变量，控制图片每次旋转的角度
    CGAffineTransform endAngle = CGAffineTransformMakeRotation(imageangle* (M_PI / 180.0f));

    [UIView animateWithDuration:0.01 delay:0 options:UIViewAnimationOptionCurveLinear animations:^{
        self.bacImage.transform = endAngle;
    } completion:^(BOOL finished) {
        [self startAnimation];
    }];

}

裁剪圆形图片：给UIImage写一个分类

-(UIImage *)circleImage{
    /*开启图形上下文*/
    UIGraphicsBeginImageContextWithOptions(self.size, NO, 0.0);
    /*获取图形上下文*/
    CGContextRef ctx = UIGraphicsGetCurrentContext();
    /*添加一个圆*/
    CGRect rect  = CGRectMake(0, 0, self.size.width, self.size.height);
    CGContextAddEllipseInRect(ctx, rect);
    /*裁剪*/
    CGContextClip(ctx);
    /*将图片画上去*/
    [self drawInRect:rect];
    /*获取当前图片*/
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    /*结束图形上下文*/
    UIGraphicsEndImageContext();
    return image;
}