需求來源：

我們項(xiàng)目中使用的字體不是很標(biāo)準(zhǔn)，顯示到label上會造成偏上兩個(gè)像素的效果，解決此問題重寫了一個(gè)label。

UILabel有兩個(gè)接口是專門用來重寫，以此來自定義自己的label，如下：

 // override points. can adjust rect before calling super.
// label has default content mode of UIViewContentModeRedraw
– textRectForBounds:limitedToNumberOfLines:
– drawTextInRect:

上面這兩個(gè)方法不是用來調(diào)用的，只適合被UILabel子類重寫

– textRectForBounds:limitedToNumberOfLines:
用來改變label里面文字展示窗口的大小，你可以自己根據(jù)文字的多少，來計(jì)算窗口的大小

– drawTextInRect:
在繪圖環(huán)境實(shí)現(xiàn)文字的繪制，這個(gè)方法里面里面已經(jīng)配置好了繪圖環(huán)境，使用方式如下：
1.直接獲得當(dāng)前繪圖上下文，
2.接著更改繪圖環(huán)境設(shè)置
3.調(diào)用super方法來繪制即可

• .h 文件

@interface FLBaseMiddleLabel : UILabel
@property (assign, nonatomic) UIEdgeInsets edgeInsets;
@property (assign, nonatomic) CGFloat offset;
@end

• .m文件

@implementation FLBaseMiddleLabel

- (instancetype)init
{
    self = [super init];
    if (self) {
        [self defaultSetting];
    }
    return self;
}

- (instancetype)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        [self defaultSetting];
    }
    return self;
}

-(void)defaultSetting {
    self.offset = 0;
    self.edgeInsets = UIEdgeInsetsZero;
}

// 修改繪制文字的區(qū)域，edgeInsets增加bounds
- (CGRect)textRectForBounds:(CGRect)bounds limitedToNumberOfLines:(NSInteger)numberOfLines {
    CGRect rect = [super textRectForBounds:UIEdgeInsetsInsetRect(bounds, self.edgeInsets) limitedToNumberOfLines:numberOfLines];
    rect.origin.x -= self.edgeInsets.left;
    rect.origin.y -= self.edgeInsets.top;
    rect.size.width += self.edgeInsets.left + self.edgeInsets.right;
    rect.size.height += self.edgeInsets.top + self.edgeInsets.bottom;
    return rect;
}

//繪制文字
- (void)drawTextInRect:(CGRect)rect {
    CGRect newRect = rect;
    newRect.origin.y += self.offset;
    if (self.text && ![self.text isEqualToString:@""]) {
        [super drawTextInRect:UIEdgeInsetsInsetRect(newRect, self.edgeInsets)];
        self.hidden = NO;
    } else {
        [super drawTextInRect:UIEdgeInsetsInsetRect(newRect, UIEdgeInsetsZero)];
        self.hidden = YES;
    }
}