版本记录
| 版本号 | 时间 |
|---|---|
| V1.0 | 2018.03.20 |
前言
iOS圈内有几个人大家基本都知道，比如说王巍、唐巧，还有YYKit框架的作者现任职于滴滴的郭曜源 - ibireme等。这里有一篇唐巧对他的专访，还有他的 GitHub - Yaoyuan 和 博客，这里贴出来框架YYKit 框架。接下来几篇我们就一起来看一下这个框架。感兴趣的可以看上面写的几篇。
1. YYKit源码探究（一） —— 基本概览
2. YYKit源码探究（二） —— NSString分类之Hash（一）
3. YYKit源码探究（三） —— NSString分类之Encode and decode（二）
回顾
上一篇我们分析了NSString分类NSString+YYAdd的Encode and decode部分，这一篇我们就看一下Drawing部分。
API 接口
/**
Returns the size of the string if it were rendered with the specified constraints.
@param font The font to use for computing the string size.
@param size The maximum acceptable size for the string. This value is
used to calculate where line breaks and wrapping would occur.
@param lineBreakMode The line break options for computing the size of the string.
For a list of possible values, see NSLineBreakMode.
@return The width and height of the resulting string's bounding box.
These values may be rounded up to the nearest whole number.
*/
- (CGSize)sizeForFont:(UIFont *)font size:(CGSize)size mode:(NSLineBreakMode)lineBreakMode;
/**
Returns the width of the string if it were to be rendered with the specified
font on a single line.
@param font The font to use for computing the string width.
@return The width of the resulting string's bounding box. These values may be
rounded up to the nearest whole number.
*/
- (CGFloat)widthForFont:(UIFont *)font;
/**
Returns the height of the string if it were rendered with the specified constraints.
@param font The font to use for computing the string size.
@param width The maximum acceptable width for the string. This value is used
to calculate where line breaks and wrapping would occur.
@return The height of the resulting string's bounding box. These values
may be rounded up to the nearest whole number.
*/
- (CGFloat)heightForFont:(UIFont *)font width:(CGFloat)width;
1. - (CGSize)sizeForFont:(UIFont *)font size:(CGSize)size mode:(NSLineBreakMode)lineBreakMode;
这个方法的作用就是返回给定的字符串边界的宽度和高度。这里size参数的意思是字符串的最大可接受大小。 此值用于计算行会发生断裂和换行的位置。
示例调用
下面我们看一下方法的示例调用。
NSString *str = @"主卧室胡搜花生豆我就搜好的生动和我胡搜红色吼吼吼2个为WIFI个我哦狗狗狗会NOI哈哈那是嘉实基金。";
CGSize stringSize = [str sizeForFont:[UIFont systemFontOfSize:16.0] size:CGSizeMake(200, 500) mode:NSLineBreakByWordWrapping];
NSLog(@"字符串大小为 = %@", NSStringFromCGSize(stringSize));
下面看一下输出结果
2018-03-19 09:57:22.261885+0800 JJWebImage[29086:4093284] 字符串大小为 = {195.83999999999997, 76.375}
方法实现
下面我们就看一下方法实现
- (CGSize)sizeForFont:(UIFont *)font size:(CGSize)size mode:(NSLineBreakMode)lineBreakMode {
CGSize result;
if (!font) font = [UIFont systemFontOfSize:12];
if ([self respondsToSelector:@selector(boundingRectWithSize:options:attributes:context:)]) {
NSMutableDictionary *attr = [NSMutableDictionary new];
attr[NSFontAttributeName] = font;
if (lineBreakMode != NSLineBreakByWordWrapping) {
NSMutableParagraphStyle *paragraphStyle = [NSMutableParagraphStyle new];
paragraphStyle.lineBreakMode = lineBreakMode;
attr[NSParagraphStyleAttributeName] = paragraphStyle;
}
CGRect rect = [self boundingRectWithSize:size
options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading
attributes:attr context:nil];
result = rect.size;
} else {
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
result = [self sizeWithFont:font constrainedToSize:size lineBreakMode:lineBreakMode];
#pragma clang diagnostic pop
}
return result;
}
这里其实还是利用NSString原生的方法boundingRectWithSize:options:attributes:context:。
2. - (CGFloat)widthForFont:(UIFont *)font;
该方法的作用就是返回一行指定字体的字符串的宽度。
示例调用
下面我们就看一下示例调用。
NSString *str = @"主卧室胡搜花生豆我就搜好的生动和我胡搜红色吼吼吼2个为WIFI个我哦狗狗狗会NOI哈哈那是嘉实基金。";
CGFloat fontWidth = [str widthForFont:[UIFont systemFontOfSize:20.0]];
NSLog(@"字符串宽度为 = %lf", fontWidth);
下面看一下实现结果
2018-03-19 10:12:01.718661+0800 JJWebImage[29090:4096887] 字符串宽度为 = 941.292031
方法实现
下面我们就看一下方法实现
- (CGFloat)widthForFont:(UIFont *)font {
CGSize size = [self sizeForFont:font size:CGSizeMake(HUGE, HUGE) mode:NSLineBreakByWordWrapping];
return size.width;
}
- (CGSize)sizeForFont:(UIFont *)font size:(CGSize)size mode:(NSLineBreakMode)lineBreakMode {
CGSize result;
if (!font) font = [UIFont systemFontOfSize:12];
if ([self respondsToSelector:@selector(boundingRectWithSize:options:attributes:context:)]) {
NSMutableDictionary *attr = [NSMutableDictionary new];
attr[NSFontAttributeName] = font;
if (lineBreakMode != NSLineBreakByWordWrapping) {
NSMutableParagraphStyle *paragraphStyle = [NSMutableParagraphStyle new];
paragraphStyle.lineBreakMode = lineBreakMode;
attr[NSParagraphStyleAttributeName] = paragraphStyle;
}
CGRect rect = [self boundingRectWithSize:size
options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading
attributes:attr context:nil];
result = rect.size;
} else {
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
result = [self sizeWithFont:font constrainedToSize:size lineBreakMode:lineBreakMode];
#pragma clang diagnostic pop
}
return result;
}
这里默认传入到第二个方法中的size参数为
CGSizeMake(HUGE, HUGE)
#define HUGE MAXFLOAT
传入的换行模式为NSLineBreakByWordWrapping。
3. - (CGFloat)heightForFont:(UIFont *)font width:(CGFloat)width;
该方法的作用就是返回字符串的高度，这里width的作用就是用来计算换行发生的地方。
示例调用
下面我们就看一下示例调用。
NSString *str = @"主卧室胡搜花生豆我就搜好的生动和我胡搜红色吼吼吼2个为WIFI个我哦狗狗狗会NOI哈哈那是嘉实基金。";
CGFloat fontHeight = [str heightForFont:[UIFont systemFontOfSize:20.0] width:100];
NSLog(@"字符串高度为 = %lf", fontHeight);
下面看一下输出结果
2018-03-19 10:22:44.503334+0800 JJWebImage[29095:4099678] 字符串高度为 = 286.406250
方法实现
下面我们就看一下方法实现
- (CGFloat)widthForFont:(UIFont *)font {
CGSize size = [self sizeForFont:font size:CGSizeMake(HUGE, HUGE) mode:NSLineBreakByWordWrapping];
return size.width;
}
同样，这里也是调用上面那个方法，size还是默认为CGSizeMake(HUGE, HUGE)，mode默认为NSLineBreakByWordWrapping。
后记
本篇我们分析了Drawing部分的功能，主要就是获取指定字符串的size、width和height，喜欢的给个赞~~~
