iOS-边框图片,头像边框

项目中偶尔会有带边框图片的需求,或是头像亦或是logo.在原型图片外围加一自定义颜色的边框,思路是根据上下文绘制,写了Demo和解释. 
带边框的图片Demo:

-(void)borderImage{    //1.加载图片    UIImage *image = [UIImage imageNamed:@"baby"];    //2.边框宽度    CGFloat borderW = 10;    //3.开启图片上下文    CGSize size = CGSizeMake(image.size.width+2*borderW, image.size.height+2*borderW);    UIGraphicsBeginImageContextWithOptions(size, NO, 0);    //4.先描述一个大圆作为填充    UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 0, size.width, size.height)];    [[UIColor redColor] set];    [path fill];    //5.在添加一个小圆设为剪裁区域    path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(borderW, borderW, image.size.width, image.size.height)];    [path addClip];    //6.把图片绘制上下文    [image drawInRect:CGRectMake(borderW, borderW, image.size.width, image.size.height)];    //7.生成图片    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();    //8.关闭上下文    UIGraphicsEndImageContext();    self.imageV.image = newImage;}
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方便调用的UIIamge的分类:

/** *  带边框的图片 * *  @param imageName   图片名 *  @param imageWidth  图片宽度 *  @param imageHeight 图片高度 *  @param borderWidth 边框宽度 *  @param borderColor 边框颜色 * *  @return 带边框的图片 */+(UIImage *)imageWithImageName:(NSString *)imageName imageWidth:(CGFloat)imageWidth imageHeight:(CGFloat)imageHeight borderWidth:(CGFloat)borderWidth borderColor:(UIColor *)borderColor{    UIImage *image = [UIImage imageNamed:imageName];    CGSize size = CGSizeMake(imageWidth + 2 * borderWidth, imageHeight + 2 * borderWidth);    UIGraphicsBeginImageContextWithOptions(size, NO, 0);    UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 0, size.width, size.height)];    [borderColor set];    [path fill];    path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(borderWidth, borderWidth, imageWidth, imageHeight)];    [path addClip];    [image drawInRect:CGRectMake(borderWidth, borderWidth, imageWidth, imageHeight)];    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();    UIGraphicsEndImageContext();    return newImage;}
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完整项目Demo链接: 
https://github.com/qxuewei/XWBorderImage