iOS CoreText类库的详细介绍

转载自：http://www.sjsjw.com/kf_mobile/article/5_27181_27580.asp

iOS 编程中如何使用CoreText类库 

从框架图中我们可以看出： 
CTFrame 作为一个整体的画布(Canvas)，其中由行(CTLine)组成，而每行可以分为一个或多个小方块（CTRun）。 
注意：你不需要自己创建CTRun，Core Text将根据NSAttributedString的属性来自动创建CTRun。每个CTRun对象对应不同的属性，正因此，你可以自由的控制字体、颜色、字间距等等信息。 
通常处理步聚： 
1.使用core text就是先有一个要显示的string，然后定义这个string每个部分的样式－>attributedString －> 生成 CTFramesetter -> 得到CTFrame -> 绘制（CTFrameDraw）
其中可以更详细的设置换行方式，对齐方式，绘制区域的大小等。
2.绘制只是显示，点击事件就需要一个判断了。
CTFrame 包含了多个CTLine,并且可以得到各个line的其实位置与大小。判断点击处在不在某个line上。CTLine 又可以判断这个点(相对于ctline的坐标)处的文字范围。然后遍历这个string的所有NSTextCheckingResult，根据result的rang判断点击处在不在这个rang上，从而得到点击的链接与位置。 
首先，创建工程，添加系统库CoreText 

////  CoreTextView.m//  CoreTextDemo////  Created by swplzj on 13-10-30.//  Copyright (c) 2013年 swplzj. All rights reserved.//#import "CoreTextView.h"#import <CoreText/CoreText.h>#import <math.h>@implementation CoreTextViewstatic inline double radians (double degrees){    return degrees * M_PI / 180;}void ctLineAndRun(CTFrameRef frame){    int lineIndex = 1;    //获取frame中的所有行    CFArrayRef allLines = CTFrameGetLines(frame);    //获取frame中第一行的元素    CTLineRef firstLineRef = CFArrayGetValueAtIndex(allLines, lineIndex);    //获得frame中所有的行数    int linesCount = CFArrayGetCount(allLines);    NSLog(@"ctLine的总数量：%d", linesCount);    //获取frame中的所有CTRun    CFArrayRef ctRun = CTLineGetGlyphRuns(firstLineRef);//    CTRunRef firstRun = CFArrayGetValueAtIndex(ctRun, 0);//    int runsNum = CTLineGetGlyphCount(ctRun);    NSLog(@"ctRun的数量：%ld", CFArrayGetCount(ctRun));    //按长度截断字符串：省略号    NSAttributedString *attributedStr = [[NSAttributedString alloc] initWithString:@"\u2026"];    CTLineRef lineToken = CTLineCreateWithAttributedString((CFAttributedStringRef) attributedStr);    //截断的方式    CTLineTruncationType lineTruncationType = kCTLineTruncationEnd;    CTLineRef newLine = CTLineCreateTruncatedLine(firstLineRef, 260, lineTruncationType, lineToken);    CGContextRef context = UIGraphicsGetCurrentContext();    //重置画布    CGContextSetTextMatrix(context, CGAffineTransformIdentity);    //保存Context状态    CGContextSaveGState(context);        CGMutablePathRef path = CGPathCreateMutable();    CGRect bounds = CGRectInset((CGRect) {{40, 40}, {320 - 80, 40}}, 0.0f, 0.0f);    CGPathAddRect(path, NULL, bounds);    CGContextAddPath(context, path);    CGContextSetFillColorWithColor(context, [UIColor orangeColor].CGColor);    CGContextFillPath(context);    CGContextSetTextPosition(context, 40, 40);    CTLineDraw(newLine, context);    CGPathCloseSubpath(path);    CGPathRelease(path);    //获取一行文字中，指定charIndex字符(也就是StringRange的Location)相对ctline本身x原点的偏移量（譬如第一个字符很显然是0），返回值与secondaryOffset同为一个值,另外也可以用来求一行字符所占的像素长度    //第二个字符index位置是在ctframe整个中的位置，譬如第二行的第一个字符的index是加上第一行所有字符后的index    CGFloat secondaryOffSet;    CGFloat primaryOffSet = CTLineGetOffsetForStringIndex(firstLineRef, CTLineGetStringRange(firstLineRef).location, &secondaryOffSet);    NSLog(@"第%ld个字符与本身x原点的偏移量:%f",CTLineGetStringRange(firstLineRef).location + 1,primaryOffSet);        //获取相对于Flush的偏移量    //    CGFloat penOffset = CTLineGetPenOffsetForFlush(firstLine, NSTextAlignmentLeft, 240);    //    NSLog(@"相对于Flush的偏移量:%f",penOffset);        //CTLineGetStringIndexForPosition 这个方法主要是获得某个ctline中某个位置（position）的character在整个ctframe中的index.这个方法在当有段前缩进或者首行缩进的时候，并不准确，不会跟着缩进而进行偏移，所以段前缩进多少，就需要把position的x值减去多少（譬如段前缩进是20，则要减去20个单位），所以，这个方法最好的用处就是判断一行ctline最多容纳多少的字符，只需把这个point的x位置调很大（超过ctframe path的宽度）就可以了。    CGPoint origins[linesCount];    CTFrameGetLineOrigins(frame,CFRangeMake(0, 0), origins);    CGPoint indexPoint = origins[lineIndex];    indexPoint.x -= 20;//段前缩进20,需要减去20//indexPoint.x += 300;可以求    CFIndex index = CTLineGetStringIndexForPosition(firstLineRef, indexPoint);    NSLog(@"ctframe中%@位置（position）的字符索引:%ld",NSStringFromCGPoint(indexPoint),index);        //CTLine在整个文本中所处的range，location是该行前面n行的字符数和，换行符也包括    //    CFRange range = CTLineGetStringRange(firstLine);    //    NSLog(@"location:%ld=====length:%ld",range.location,range.length);        //获取一行中上行高(ascent)，下行高(descent)，行距(leading),整行高为(ascent+|descent|+leading) 返回值为整行字符串长度占有的像素宽度。    //    CGFloat asc,des,lead;    //    double lineWidth = CTLineGetTypographicBounds(firstLine, &asc, &des, &lead);    //    NSLog(@"ascent = %f,descent = %f,leading = %f,lineWidth = %f",asc,des,lead,lineWidth);        //获取一行文字最佳可视范围（会把所有文字都包含进去）    //    CGRect lineRect = CTLineGetImageBounds(firstLine, context);    //    NSLog(@"整行的范围:%@",NSStringFromCGRect(lineRect));    CGContextRestoreGState(context);}- (id)initWithFrame:(CGRect)frame{    self = [super initWithFrame:frame];    if (self) {        // Initialization code    }    return self;}// Only override drawRect: if you perform custom drawing.// An empty implementation adversely affects performance during animation.- (void)drawRect:(CGRect)rect{    NSMutableAttributedString *attributedStr = [[NSMutableAttributedString alloc] initWithString:@"北京出现严重雾霾后，网友纷纷给PM2.5取中文名字。严肃点就叫“公雾源”，高端点就叫“京尘”，霸气点就叫“尘疾思汗”，乐观点就叫“尘世美”，娱乐点就叫“尘惯吸”。但直到那五个字映入眼帘，才明白了中文的强大和词汇的无穷魅力：喂人民服雾！"];    [self setAttributedStringParagraphStyle:attributedStr];//    [self setAttributesStringAttributes:attributedStr];    CTFramesetterRef frameSetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef) attributedStr);    CGMutablePathRef path = CGPathCreateMutable();    CGRect bounds = CGRectInset((CGRect) {{20, 100}, {CGRectGetWidth(self.bounds) - 40, 400}}, 10.0f, 10.0f);    CGPathAddRect(path, NULL, bounds);    CTFrameRef frame = CTFramesetterCreateFrame(frameSetter, CFRangeMake(0, 0), path, NULL);        CGContextRef context = UIGraphicsGetCurrentContext();    CGContextTranslateCTM(context, 0, self.bounds.size.height);//转换CTM    CGContextScaleCTM(context, 1.0, -1.0);    CGContextSaveGState(context);//向图形状态栈中保存context状态        //ctLine的相关操作    ctLineAndRun(frame);        CGContextSetTextMatrix(context, CGAffineTransformIdentity);//重置画布    CGContextAddPath(context, path);    CGContextSetFillColorWithColor(context, [UIColor yellowColor].CGColor);    CGContextFillPath(context);        //CTLineGetImageBounds的应用，获取一行文字的范围， 就是指把这一行文字点有的像素矩阵作为一个image图片，来得到整个矩形区域    CFArrayRef Lines = CTFrameGetLines(frame);    int lineCount = CFArrayGetCount(Lines);        CGPoint origins[lineCount];    CTFrameGetLineOrigins(frame, CFRangeMake(0, 0), origins);    NSInteger lineIndex = 0;        for (id oneLine in (NSArray *)Lines) {        //相对于每一行基线原点的偏移量和宽高（例如：{{1.2， -2.57227}, {208.025, 19.2523}}，就是相对于本身的基线原点向右偏移1.2个单位，向下偏移2.57227个单位，后面是宽高）        CGRect lineBounds = CTLineGetImageBounds((CTLineRef)oneLine, context);                //每一行的起始点（相对于context）加上相对于本身基线原点的偏移量        lineBounds.origin.x += origins[lineIndex].x + 30;        lineBounds.origin.y += origins[lineIndex].y + 110;                lineIndex++;                //填充        CGContextSetStrokeColorWithColor(context, [[UIColor redColor] CGColor]);        CGContextSetLineWidth(context, 1.0);        //设置长方形4个顶点        CGPoint points[] = {CGPointMake(lineBounds.origin.x, lineBounds.origin.y), CGPointMake(lineBounds.origin.x + lineBounds.size.width, lineBounds.origin.y), CGPointMake(lineBounds.origin.x + lineBounds.size.width, lineBounds.origin.y + lineBounds.size.height), CGPointMake(lineBounds.origin.x, lineBounds.origin.y + lineBounds.size.height)};        CGContextAddLines(context, points, 4);        CGContextClosePath(context);        CGContextStrokePath(context);    }        //画    CTFrameDraw(frame, context);    CGPathRelease(path);    CFRelease(frame);    CFRelease(frameSetter);        //恢复状态栈中原有的状态    CGContextRestoreGState(context);}- (void)setAttributesStringAttributes:(NSMutableAttributedString *)attributedString{    //设置字体    CTFontRef font = CTFontCreateWithName(CFSTR("Georgia"), 20, NULL);    [attributedString addAttribute:(id)kCTFontAttributeName value:(id)font range:NSMakeRange(0, 4)];        //设置字间距    long kernNumber = 5;    CFNumberRef kernNum = CFNumberCreate(kCFAllocatorDefault, kCFNumberSInt8Type, &kernNumber);    [attributedString addAttribute:(id)kCTKernAttributeName value:(id)kernNum range:(NSRange){0, 4}];        //设置字体颜色    long strokeNumber = 2;    CFNumberRef strokeNum = CFNumberCreate(kCFAllocatorDefault, kCFNumberSInt8Type, &strokeNumber);    [attributedString addAttribute:(id)kCTStrokeWidthAttributeName value:(id)strokeNum range:(NSRange){0, 4}];    [attributedString addAttribute:(id)kCTStrokeColorAttributeName value:(id)[UIColor redColor].CGColor range:NSMakeRange(0, 4)];        //设置下划线    [attributedString addAttribute:(id)kCTUnderlineStyleAttributeName value:(id)[NSNumber numberWithInt:kCTUnderlineStyleSingle] range:NSMakeRange(0, 4)];    [attributedString addAttribute:(id)kCTUnderlineStyleAttributeName value:(id)[UIColor redColor] range:(NSRange){0, 4}];        //多属性设置    UIColor *color = [UIColor redColor];    NSMutableDictionary *attributes = [[NSMutableDictionary alloc] initWithObjectsAndKeys:(id)font, kCTFontAttributeName, kernNum, kCTKernAttributeName, color.CGColor, kCTForegroundColorAttributeName, nil];    [attributedString setAttributes:attributes range:NSMakeRange(0, 4)];}- (void)setAttributedStringParagraphStyle:(NSMutableAttributedString *)attributedString{    //对齐方式    CTTextAlignment textAlignment = kCTLeftTextAlignment;    CTParagraphStyleSetting alignmentStyleSetting;    alignmentStyleSetting.spec = kCTParagraphStyleSpecifierAlignment;    alignmentStyleSetting.valueSize = sizeof(textAlignment);    alignmentStyleSetting.value = &textAlignment;        //首行缩进    CGFloat firstLineIndentSize = 55.0f;    CTParagraphStyleSetting firstLineIndent;    firstLineIndent.spec = kCTParagraphStyleSpecifierFirstLineHeadIndent;    firstLineIndent.value = &firstLineIndentSize;    firstLineIndent.valueSize = sizeof(float);        //段前缩进（文字左侧距离context最左侧的距离）    CGFloat headIndentSize = 20.0f;    CTParagraphStyleSetting headIndent;    headIndent.spec = kCTParagraphStyleSpecifierHeadIndent;    headIndent.valueSize = sizeof(float);    headIndent.value = &headIndentSize;        //断尾缩进(文字右侧距离context最左侧的距离)    CGFloat tailIndentSize = 251.0f;    //文字最左侧到文字最右侧的距离    CTParagraphStyleSetting tailIndent;    tailIndent.spec = kCTParagraphStyleSpecifierTailIndent;    tailIndent.value = &tailIndentSize;    tailIndent.valueSize = sizeof(float);        //换行模式    CTLineBreakMode lineBreak = kCTLineBreakByCharWrapping;    CTParagraphStyleSetting lineBreakMode;    lineBreakMode.spec = kCTParagraphStyleSpecifierLineBreakMode;    lineBreakMode.value = &lineBreak;    lineBreakMode.valueSize = sizeof(CTLineBreakMode);        //最大行高    CGFloat maxHeightSize = 50.0f;  //最大行高不能超过50个像素，超过按照最大像素来    CTParagraphStyleSetting maxHeightSetting;    maxHeightSetting.spec = kCTParagraphStyleSpecifierMaximumLineHeight;    maxHeightSetting.value = &maxHeightSize;    maxHeightSetting.valueSize = sizeof(float);        //多行高    CGFloat multipleHeight = 1.2f;  //1.2倍原来的高度    CTParagraphStyleSetting multipleHeightSetting;    multipleHeightSetting.spec = kCTParagraphStyleSpecifierLineHeightMultiple;    multipleHeightSetting.value = &multipleHeight;    multipleHeightSetting.valueSize = sizeof(float);        //最大行距    CGFloat maxLineSpace = 5.0f;//最大行距不能超过5像素，超过了按最大行距画图，最小行距同理，行距调整只在中间值中进行    CTParagraphStyleSetting maxLineSpaceSetting;    maxLineSpaceSetting.spec = kCTParagraphStyleSpecifierMaximumLineSpacing;    maxLineSpaceSetting.valueSize = sizeof(float);    maxLineSpaceSetting.value = &maxLineSpace;        //行距    CGFloat lineSpace = 25.0f;  //行距25像素    CTParagraphStyleSetting lineSpaceSetting;    lineSpaceSetting.spec = kCTParagraphStyleSpecifierLineSpacing;    lineSpaceSetting.value = &lineSpace;    lineSpaceSetting.valueSize = sizeof(float);        //段前间隔    CGFloat paragraghSpace = 15.0f;    CTParagraphStyleSetting paragraghInterval;    paragraghInterval.spec = kCTParagraphStyleSpecifierParagraphSpacing;    paragraghInterval.valueSize = sizeof(float);    paragraghInterval.value = ?graghSpace;        CTParagraphStyleSetting settingsArray[] = {alignmentStyleSetting, firstLineIndent, headIndent, tailIndent, lineBreakMode, maxLineSpaceSetting, multipleHeightSetting, lineSpaceSetting, maxLineSpaceSetting, paragraghInterval};        //采用setting里面前10个的段落设置，不够10个，就按照setting拥有的最大段落设置个数来算    CTParagraphStyleRef paragraphStyle = CTParagraphStyleCreate(settingsArray, 10);    NSDictionary *paragraphStyleDic = [[NSDictionary alloc] initWithObjectsAndKeys:(id)paragraphStyle, kCTParagraphStyleAttributeName, nil];    [attributedString setAttributes:paragraphStyleDic range:(NSRange){0, [attributedString length]}];}- (void)ctLineAndRun{    }@end

关于CoreText的官方API： 

https://developer.apple.com/library/mac/#documentation/Carbon/Reference/CoreText_Framework_Ref/_index.html