CoreText使用

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1.如若各项参数无需动态调节则可无视characterSpacing_及linesSpacing_.
MartinCustomLabel.h

#import<Foundation/Foundation.h>#import<UIKit/UIKit.h>@interface MartinCustomLabel : UILabel{    @private    CGFloat characterSpacing_;       //字间距    long    linesSpacing_;           //行间距}@property(nonatomic,assign) CGFloat characterSpacing;@property(nonatomic,assign) long    linesSpacing;/* *绘制前获取label高度 */- (int)getAttributedStringHeightWidthValue:(int)width;@end

2.因为我无需动态调节行,字,段.所以我在代码中是写的常量.可按自身需求修改.
MartinCustomLabel.m

#import "MartinCustomLabel.h"#import<CoreText/CoreText.h>@interface MartinCustomLabel(){    @private    NSMutableAttributedString *attributedString;}- (void) initAttributedString;@end@implementation MartinCustomLabel@synthesize characterSpacing = characterSpacing_;@synthesize linesSpacing = linesSpacing_;-(id) initWithFrame:(CGRect)frame{    //初始化字间距、行间距    if(self =[super initWithFrame:frame])            {        self.characterSpacing = 1.5f;        self.linesSpacing = 4.0f;    }        return self;}//外部调用设置字间距-(void)setCharacterSpacing:(CGFloat)characterSpacing{    characterSpacing_ = characterSpacing;    [self setNeedsDisplay];}//外部调用设置行间距-(void)setLinesSpacing:(long)linesSpacing{    linesSpacing_ = linesSpacing;    [self setNeedsDisplay];}/* *初始化AttributedString并进行相应设置 */- (void) initAttributedString{    if(attributedString==nil){        //去掉空行        NSString *labelString = self.text;        NSString *myString = [labelString stringByReplacingOccurrencesOfString:@"\r\n" withString:@"\n"];                //创建AttributeString        attributedString =[[NSMutableAttributedString alloc]initWithString:myString];                //设置字体及大小        CTFontRef helveticaBold = CTFontCreateWithName((CFStringRef)self.font.fontName,self.font.pointSize,NULL);        [attributedString addAttribute:(id)kCTFontAttributeName value:(id)helveticaBold range:NSMakeRange(0,[attributedString length])];                //设置字间距        long number = 1.5f;        CFNumberRef num = CFNumberCreate(kCFAllocatorDefault,kCFNumberSInt8Type,&number);        [attributedString addAttribute:(id)kCTKernAttributeName value:(id)num range:NSMakeRange(0,[attributedString length])];        CFRelease(num);        /*        if(self.characterSpacing)        {            long number = self.characterSpacing;            CFNumberRef num = CFNumberCreate(kCFAllocatorDefault,kCFNumberSInt8Type,&number);            [attributedString addAttribute:(id)kCTKernAttributeName value:(id)num range:NSMakeRange(0,[attributedString length])];            CFRelease(num);        }        */                //设置字体颜色        [attributedString addAttribute:(id)kCTForegroundColorAttributeName value:(id)(self.textColor.CGColor) range:NSMakeRange(0,[attributedString length])];                //创建文本对齐方式        CTTextAlignment alignment = kCTLeftTextAlignment;        if(self.textAlignment == UITextAlignmentCenter)        {            alignment = kCTCenterTextAlignment;        }        if(self.textAlignment == UITextAlignmentRight)        {            alignment = kCTRightTextAlignment;        }        CTParagraphStyleSetting alignmentStyle;                alignmentStyle.spec = kCTParagraphStyleSpecifierAlignment;                alignmentStyle.valueSize = sizeof(alignment);                alignmentStyle.value = &alignment;                //设置文本行间距        /*        CGFloat lineSpace = self.linesSpacing;         */        CGFloat lineSpace = 4.0f;        CTParagraphStyleSetting lineSpaceStyle;        lineSpaceStyle.spec = kCTParagraphStyleSpecifierLineSpacingAdjustment;        lineSpaceStyle.valueSize = sizeof(lineSpace);        lineSpaceStyle.value =&lineSpace;                //设置文本段间距        CGFloat paragraphSpacing = 15.0;        CTParagraphStyleSetting paragraphSpaceStyle;        paragraphSpaceStyle.spec = kCTParagraphStyleSpecifierParagraphSpacing;        paragraphSpaceStyle.valueSize = sizeof(CGFloat);        paragraphSpaceStyle.value = &paragraphSpacing;                //创建设置数组        CTParagraphStyleSetting settings[ ] ={alignmentStyle,lineSpaceStyle,paragraphSpaceStyle};        CTParagraphStyleRef style = CTParagraphStyleCreate(settings ,3);                //给文本添加设置        [attributedString addAttribute:(id)kCTParagraphStyleAttributeName value:(id)style range:NSMakeRange(0 , [attributedString length])];        CFRelease(helveticaBold);    }}/* *覆写setText方法 */- (void) setText:(NSString *)text{    [super setText:text];    [self initAttributedString];}/* *开始绘制 */-(void) drawTextInRect:(CGRect)requestedRect{    [self initAttributedString];        //排版        CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)attributedString);        CGMutablePathRef leftColumnPath = CGPathCreateMutable();        CGPathAddRect(leftColumnPath, NULL ,CGRectMake(0 , 0 ,self.bounds.size.width , self.bounds.size.height));        CTFrameRef leftFrame = CTFramesetterCreateFrame(framesetter,CFRangeMake(0, 0), leftColumnPath , NULL);        //翻转坐标系统（文本原来是倒的要翻转下）        CGContextRef context = UIGraphicsGetCurrentContext();        CGContextSetTextMatrix(context , CGAffineTransformIdentity);        CGContextTranslateCTM(context , 0 ,self.bounds.size.height);        CGContextScaleCTM(context, 1.0 ,-1.0);        //画出文本        CTFrameDraw(leftFrame,context);        //释放        CGPathRelease(leftColumnPath);        CFRelease(framesetter);        UIGraphicsPushContext(context);}/* *绘制前获取label高度 */- (int)getAttributedStringHeightWidthValue:(int)width{    [self initAttributedString];        int total_height = 0;        CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)attributedString);    //string 为要计算高度的NSAttributedString    CGRect drawingRect = CGRectMake(0, 0, width, 100000);  //这里的高要设置足够大    CGMutablePathRef path = CGPathCreateMutable();    CGPathAddRect(path, NULL, drawingRect);    CTFrameRef textFrame = CTFramesetterCreateFrame(framesetter,CFRangeMake(0,0), path, NULL);    CGPathRelease(path);    CFRelease(framesetter);        NSArray *linesArray = (NSArray *) CTFrameGetLines(textFrame);        CGPoint origins[[linesArray count]];    CTFrameGetLineOrigins(textFrame, CFRangeMake(0, 0), origins);        int line_y = (int) origins[[linesArray count] -1].y;  //最后一行line的原点y坐标        CGFloat ascent;    CGFloat descent;    CGFloat leading;        CTLineRef line = (CTLineRef) [linesArray objectAtIndex:[linesArray count]-1];    CTLineGetTypographicBounds(line, &ascent, &descent, &leading);        total_height = 100000 - line_y + (int) descent +1;//+1为了纠正descent转换成int小数点后舍去的值        CFRelease(textFrame);        return total_height;    }@end

3.创建调用步骤:

MartinCustomLabel *readNewsLable =[[MartinCustomLabel alloc] initWithFrame:CGRectZero];        readNewsLable.textColor = textCor;        readNewsLable.lineBreakMode = UILineBreakModeWordWrap;        readNewsLable.backgroundColor = [UIColor clearColor];        readNewsLable.font = TEXT_FONT_NAME([AccessData getNewsConnectFont]);        [readNewsLable setText:text];        /*设置label的frame值*/        [readNewsLable setFrame:CGRectMake(10, aboveY, WINDOW_W-20, [readNewsLable getAttributedStringHeightWidthValue:WINDOW_W-20])];        readNewsLable.numberOfLines = 0;        [readNewsLable setTag:TEXT_LABEL_TAG+tag];        [self addSubview:readNewsLable];

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