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指示根视图:(准备几张图片,把label加载在window上)
- CustomLable *label = [[CustomLable alloc]initWithFrame:CGRectMake(0, 60, self.window.bounds.size.width, self.window.bounds.size.height)];
- label.backgroundColor = [UIColor greenColor];
- [self.window addSubview:label];
引进框架:
#import <CoreText/CoreText.h>
建一个类,继承自UILabel
返回图片的高:
- // 返回图片的高
- CGFloat runDelegateGetAscentCallback(voidvoid *refcon) {
- NSString *imageName = (__bridge NSString *)refcon;
- return [UIImage imageNamed:imageName].size.height;
- }
- // 返回图片的宽
- CGFloat runDelegateGetWidthCallback(voidvoid *refcon) {
- // NSString *imageName = (__bridge NSString *)refcon;
- // 让绘制图片的宽度为屏幕的宽, 使文本中只要遇到图片就换行(配合上面的换行模式)
- // 如果不想换行可以直接返回图片的宽
- return [UIScreen mainScreen].bounds.size.width;
- }
- CGFloat runDelegateGetDescentCallback(voidvoid *refcon){
- return 0;
- }
开始绘制及相关计算:
- #import "CustomLable.h"
- #import <CoreText/CoreText.h>
- @implementation CustomLable
- - (void)drawRect:(CGRect)rect
- {
- [super drawRect:rect];
- // 创建绘制区域
- CGMutablePathRef path = CGPathCreateMutable();
- CGPathAddRect(path, nil, CGRectMake(0, 0, self.bounds.size.width, self.bounds.size.height));
- // 获取当前用于绘制画布的上下文, 用于后续将内容绘制到画布上
- CGContextRef context = UIGraphicsGetCurrentContext();
- // 翻转坐标系
- // 参数1:文本宽度占Label的比例(0 ~ 1)
- // 参数2:水平方向文字逐渐往下(参数 > 0, 往上: 参数 < 0)偏移,如果是正数,逐渐向上偏移
- // 参数3:在竖直方向上,从下往上每行文字逐渐往右(参数 > 0, 往左: 参数 < 0)偏移
- // 参数4:文本首行的纵坐标占Label的比例(-1 ~ 0)
- // 参数5:文本整体往右(参数 > 0, 往左: 参数 < 0)偏移量
- // 参数6:文本整体在纵坐标方向的偏移量,参数 > label的高度, 往下偏移, 参数 < label的高度, 往上偏移
- CGContextConcatCTM(context, CGAffineTransformMake(1, 0, 0, -1, 0, self.bounds.size.height));
- // 准备文本
- NSMutableAttributedString *attrString = [[NSMutableAttributedString alloc]initWithString:@"iOS程序在启动时会创建一个主线程,而在一个线程只能执行一件事情,如果在主线程执行某些耗时操作,例如加载网络图片,下载资源文件等会阻塞主线程(导致界面卡死,无法交互),所以就需要使用多线程技术来避免这类情况。iOS中有三种多线程技术 NSThread,NSOperation,GCD,这三种技术是随着IOS发展引入的,抽象层次由低到高,使用也越来越简单。"];
- // 改变字体大小
- [attrString addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:24] range:NSMakeRange(0, 5)];
- // 改变字体颜色
- [attrString addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:NSMakeRange(0, 5)];
- // 换行模式 (当Label的宽度不够显示内容或图片的时候就自动换行) (默认状态下如果不够显示图片, 不会自动换行, 部分图片就会看不见)
- CTParagraphStyleSetting lineBreakMode;
- CTLineBreakMode lineBreak = kCTLineBreakByCharWrapping;
- lineBreakMode.spec = kCTParagraphStyleSpecifierLineBreakMode;
- lineBreakMode.value = &lineBreak;
- lineBreakMode.valueSize = sizeof(CTLineBreakMode);
- CTParagraphStyleSetting setting[] = {lineBreakMode};
- CTParagraphStyleRef style = CTParagraphStyleCreate(setting, 1);
- NSMutableDictionary *attributes = [NSMutableDictionary dictionaryWithObject:(__bridge id)style forKey:(id)kCTParagraphStyleAttributeName];
- [attrString addAttributes:attributes range:NSMakeRange(0, attrString.length)];
- // 设置CTRunDelegateCallbacks 获取图片大小
- CTRunDelegateCallbacks imageCallbacks;
- imageCallbacks.version = kCTRunDelegateVersion1;
- // 获取图片的高 (可自由设置返回的高)
- imageCallbacks.getAscent = runDelegateGetAscentCallback;
- // 设置图片下一行文字距离图片的距离
- imageCallbacks.getDescent = runDelegateGetDescentCallback;
- // 获取图片的宽 (可自由设置返回宽度)
- imageCallbacks.getWidth = runDelegateGetWidthCallback;
- // 空格用于给图片留个位置
- NSMutableAttributedString *imageAttributedString = [[NSMutableAttributedString alloc]initWithString:@" "];
- // 根据图片占用尺寸的大小给图片留位置显示
- CTRunDelegateRef runDelegate = CTRunDelegateCreate(&imageCallbacks, (__bridge voidvoid *)(@"Untitled.png"));
- [imageAttributedString addAttribute:(NSString *)kCTRunDelegateAttributeName value:(__bridge id)runDelegate range:NSMakeRange(0, 1)];
- // 将图片显示在指定位置
- NSString *imageKey = @"imageName";
- [imageAttributedString addAttribute:imageKey value:@"Untitled.png" range:NSMakeRange(0, 1)];
- // 设置插入图片的位置
- [attrString insertAttributedString:imageAttributedString atIndex:38];
- //根据NSMutableAttributedString生成frame
- CTFrameRef frame = CTFramesetterCreateFrame(CTFramesetterCreateWithAttributedString((CFAttributedStringRef)attrString), CFRangeMake(0, attrString.length), path, nil);
- // 开始绘制
- CTFrameDraw(frame, context);
- CFArrayRef lines = CTFrameGetLines(frame);
- CGPoint lineOrigins[CFArrayGetCount(lines)];
- CTFrameGetLineOrigins(frame, CFRangeMake(0, 0), lineOrigins);
- for (int i = 0; i < CFArrayGetCount(lines); i++) {
- CTLineRef line = CFArrayGetValueAtIndex(lines, i);
- CFArrayRef runs = CTLineGetGlyphRuns(line);
- for (int j = 0; j < CFArrayGetCount(runs); j++) {
- CGFloat runAscent;
- CGFloat runDescent;
- CGPoint lineOrigin = lineOrigins[i];
- CTRunRef run = CFArrayGetValueAtIndex(runs, j);
- NSDictionary *mAttrinbutes = (NSDictionary *)CTRunGetAttributes(run);
- CGRect runRect;
- runRect.size.width = CTRunGetTypographicBounds(run, CFRangeMake(0, 0), &runAscent, &runDescent, NULL);
- runRect = CGRectMake(lineOrigin.x + CTLineGetOffsetForStringIndex(line, CTRunGetStringRange(run).location, NULL), lineOrigin.y - runDescent, runRect.size.width, runAscent + runDescent);
- NSString *imageName = [mAttrinbutes objectForKey:imageKey];
- // 图片的渲染逻辑
- if (imageName) {
- UIImage *image = [UIImage imageNamed:imageName];
- CGRect imageDrawRect;
- imageDrawRect.size = image.size;
- /*
- * 这才是放置图片的真正坐标
- */
- // 设置图片的在X坐标的位置
- // imageDrawRect.origin.x = runRect.origin.x + lineOrigin.x;
- // 将图片放在Label的中间
- imageDrawRect.origin.x = (self.bounds.size.width - image.size.width) / 2;
- // 设置图片在y坐标的位置
- imageDrawRect.origin.y = lineOrigin.y;
- // 绘制图片
- CGContextDrawImage(context, imageDrawRect, image.CGImage);
- }
- }
- }
- }
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原文地址:http://blog.csdn.net/qq_31810357/article/details/50124869