1 #import <UIKit/UIKit.h>
 2
 3 @interface UIImage (NJ)
 4 /**
 5  *  生成头像
 6  *
 7  *  @param icon   头像图片名称
 8  *  @param border 头像边框大小
 9  *  @param color  头像边框的颜色
10  *
11  *  @return 生成好的头像
12  */
13 + (instancetype)imageWithIcon:(NSString *)icon border:(NSInteger)border color:(UIColor *)color;
14 @end
15
16
17 #import "UIImage+NJ.h"
18 @implementation UIImage (NJ)
19
20 + (instancetype)imageWithIcon:(NSString *)icon border:(NSInteger)border color:(UIColor *)color
21 {
22     // 0. 加载原有图片
23     UIImage *image = [UIImage imageNamed:icon];
24
25     // 1.创建图片上下文
26     CGFloat margin = border;
27     CGSize size = CGSizeMake(image.size.width + margin, image.size.height + margin);
28
29     // YES 不透明 NO 透明
30     UIGraphicsBeginImageContextWithOptions(size, NO, 0);
31     // 2.绘制大圆
32     CGContextRef ctx = UIGraphicsGetCurrentContext();
33     CGContextAddEllipseInRect(ctx, CGRectMake(0, 0, size.width, size.height));
34     [color set];
35     CGContextFillPath(ctx);
36
37     // 3.绘制小圆
38     CGFloat smallX = margin * 0.5;
39     CGFloat smallY = margin * 0.5;
40     CGFloat smallW = image.size.width;
41     CGFloat smallH = image.size.height;
42     CGContextAddEllipseInRect(ctx, CGRectMake(smallX, smallY, smallW, smallH));
43     //    [[UIColor greenColor] set];
44     //    CGContextFillPath(ctx);
45     // 4.指定可用范围, 可用范围的适用范围是在指定之后,也就说在在指定剪切的范围之前绘制的东西不受影响
46     CGContextClip(ctx);
47
48     // 5.绘图图片
49     [image drawInRect:CGRectMake(smallX, smallY, smallW, smallH)];
50
51     // 6.取出图片
52     UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
53
54     return newImage;
55
56 }
57 @end