iOS实现带文字的圆形头像效果

@interface RoundHeadView()
@property (nonatomic, copy) NSString *title;//需要绘制的标题
@property (nonatomic, assign) CGFloat colorPoint;//用户后面计算颜色的随机值
//设置文字
- (void)setTitle:(NSString *)title;
@end
@implementation RoundHeadView
-(instancetype)initWithFrame:(CGRect)frame{
  self = [super initWithFrame:frame];
  if (self) {
    self.backgroundColor = [UIColor clearColor];
  }
  return self;
}
@end

-(void)drawRect:(CGRect)rect{
  
  //一个不透明类型的Quartz 2D绘画环境,相当于一个画布,你可以在上面任意绘画
   CGContextRef context = UIGraphicsGetCurrentContext();
   [self caculateColor];//计算颜色
  
  /*画圆*/
   CGContextSetRGBFillColor (context,_colorPoint, 0.5, 0.5, 1.0);//设置填充颜色 颜色这里随机设置的，后面会根据文字来计算颜色
  
  //填充圆，无边框
  CGContextAddArc(context, self.frame.size.width/2.0, self.frame.size.width/2.0, self.frame.size.width/2.0, 0, 2*M_PI, 0); //添加一个圆
  CGContextDrawPath(context, kCGPathFill);//绘制填充
  }

- (void)setTitle:(NSString *)title{
  _title = [[self subStringWithLendth:2 string:title] copy];
  [self setNeedsDisplay];//调用这个方法 进行重新绘制 view会重新调用drawRect方法
}

/**
 截取字符串，截取字符串最开始的两个 汉子和英文一样处理
 @param length 截取的字符长度（汉子和英文同样计算）
 @param string 需要截取的字符串
 @return 返回截取的字符串
 */
-(NSString *)subStringWithLendth:(int)length string:(NSString *)string{
  
  NSString *copyStr = [string copy];
  NSMutableString *realStr = [[NSMutableString alloc] init];
  
  for(int i = 0; i < copyStr.length; i  ){
    if(length == 0){
      break;
    }
    unichar ch = [copyStr characterAtIndex:0];
    if (0x4e00 < ch && ch < 0x9fff)//如何判断是汉字
    {
      //如果是汉子需要做其他处理 可以在这里做处理
    }
    //若为汉字
    [realStr appendString:[copyStr substringWithRange:NSMakeRange(i,1)]];
      
    length = length - 1;
  }
  return realStr;
}

/**
 计算文字的尺寸，在绘制图像时，保证文字总是处于图像的正中
 文字的尺寸可以自己计算 这里定义的是 宽度的1/3 我看使用起来比较合适 当然
 你可以自己定义的
 @return 文字的宽高
 */
- (CGSize)caculateLableSize{
  UILabel *lable = [[UILabel alloc] initWithFrame:CGRectZero];
  lable.font = [UIFont fontWithName:@"Arial-BoldMT" size:self.frame.size.width/3.0];
  lable.text = self.title;
  [lable sizeToFit];
  CGSize size = lable.frame.size;
  return size;
}

/**
 获取汉子拼音
 @param originalStr 原始中文字符
 @return 汉子的全拼
 */
- (NSString *)pinyin: (NSString *)originalStr{
  NSMutableString *str = [originalStr mutableCopy];
  CFStringTransform(( CFMutableStringRef)str, NULL, kCFStringTransformMandarinLatin, NO);
  CFStringTransform((CFMutableStringRef)str, NULL, kCFStringTransformStripDiacritics, NO);
  return [str stringByReplacingOccurrencesOfString:@" " withString:@""];
}

/**
 随机一个颜色
 填充圆形头像的底色
 根据字符的拼音计算出的颜色
 */
- (void)caculateColor{
  if (_title.length == 0) {
    return;
  }
  if (_title.length>1) {
    NSString *firstStr = [_title substringWithRange:NSMakeRange(0,1)];
    NSString *secondStr = [_title substringWithRange:NSMakeRange(1, 1)];
    NSString *firstPinyin = [self pinyin:firstStr];
    NSString *secondPinyin = [self pinyin:secondStr];
    NSUInteger count = firstPinyin.length secondPinyin.length;
    if (count>10) {
      count-=10;
      self.colorPoint = count/10.0;
    }else{
      self.colorPoint = count/10.0;
    }
  }else{
    NSString *firstStr = [_title substringWithRange:NSMakeRange(0,1)];
    NSString *firstPinyin = [self pinyin:firstStr];
    NSUInteger count = firstPinyin.length;
    self.colorPoint = count/10.0;
  }
}

-(void)drawRect:(CGRect)rect{
  
  //一个不透明类型的Quartz 2D绘画环境,相当于一个画布,你可以在上面任意绘画
  CGContextRef context = UIGraphicsGetCurrentContext();
  [self caculateColor];//计算颜色
  
  /*画圆*/
  CGContextSetRGBFillColor (context,_colorPoint, 0.5, 0.5, 1.0);//设置填充颜色
  //  CGContextSetRGBStrokeColor(context,red,green,blue,1.0);//画笔线的颜色
  
  //填充圆，无边框
  CGContextAddArc(context, self.frame.size.width/2.0, self.frame.size.width/2.0, self.frame.size.width/2.0, 0, 2*M_PI, 0); //添加一个圆
  CGContextDrawPath(context, kCGPathFill);//绘制填充
  
  
  /*写文字*/
  //  CGContextSetRGBFillColor (context, 1, 0, 0, 1.0);//设置填充颜色
  NSDictionary* dic = [NSDictionary dictionaryWithObjectsAndKeys:[UIFont fontWithName:@"Arial-BoldMT" size:self.frame.size.width/3.0], NSFontAttributeName,[UIColor whiteColor],NSForegroundColorAttributeName, nil];
  CGSize size = [self caculateLableSize];
  CGFloat X = (self.frame.size.width-size.width)/2.0;
  CGFloat Y = (self.frame.size.height-size.height)/2.0;
  [self.title drawInRect:CGRectMake(X, Y, self.frame.size.width, self.frame.size.width) withAttributes:dic];
}

UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(10, 50, 300, 20)];
label.text = @"文字不同，背景颜色也不会相同";
[self.view addSubview:label];
NSArray *strs = @[@"为我",@"样的",@"好啊",@"H在",@"hc",@"2才",@"哈哈",@"打算打算打算的",@"还有人v",@"哈哈"];
for (int i=0; i<10; i  ) {
  RoundHeadView *head = [[RoundHeadView alloc] initWithFrame:CGRectMake(30, 100 (40*i), 40, 40)];
  [head setTitle:strs[i]];
  [self.view addSubview:head];
}