CoreText使用

1.如若各項參數無需動态調節則可無視characterSpacing_及linesSpacing_.

MartinCustomLabel.h

#import<Foundation/Foundation.h>
#import<UIKit/UIKit.h>

@interface MartinCustomLabel : UILabel
{
    @private
    CGFloat characterSpacing_;       //字間距
    long    linesSpacing_;           //行間距
}
@property(nonatomic,assign) CGFloat characterSpacing;
@property(nonatomic,assign) long    linesSpacing;

/*
 *繪制前擷取label高度
 */
- (int)getAttributedStringHeightWidthValue:(int)width;

@end

      

2.因為我無需動态調節行,字,段.是以我在代碼中是寫的常量.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
{
    //初始化字間距、行間距
    if(self =[super initWithFrame:frame])
        
    {
        self.characterSpacing = 1.5f;
        self.linesSpacing = 4.0f;
    }
    
    return self;
}

//外部調用設定字間距
-(void)setCharacterSpacing:(CGFloat)characterSpacing
{
    characterSpacing_ = characterSpacing;
    [self setNeedsDisplay];
}

//外部調用設定行間距
-(void)setLinesSpacing:(long)linesSpacing
{
    linesSpacing_ = linesSpacing;
    [self setNeedsDisplay];
}

/*
 *初始化AttributedString并進行相應設定
 */
- (void) initAttributedString
{
    if(attributedString==nil){
        //去掉空行
        NSString *labelString = self.text;
        NSString *myString = [labelString stringByReplacingOccurrencesOfString:@"\r\n" withString:@"\n"];
        
        //建立AttributeString
        attributedString =[[NSMutableAttributedString alloc]initWithString:myString];
        
        //設定字型及大小
        CTFontRef helveticaBold = CTFontCreateWithName((CFStringRef)self.font.fontName,self.font.pointSize,NULL);
        [attributedString addAttribute:(id)kCTFontAttributeName value:(id)helveticaBold range:NSMakeRange(0,[attributedString length])];
        
        //設定字間距
        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);
        }
        */
        
        //設定字型顔色
        [attributedString addAttribute:(id)kCTForegroundColorAttributeName value:(id)(self.textColor.CGColor) range:NSMakeRange(0,[attributedString length])];
        
        //建立文本對齊方式
        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;
        
        //設定文本行間距
        /*
        CGFloat lineSpace = self.linesSpacing;
         */
        CGFloat lineSpace = 4.0f;
        CTParagraphStyleSetting lineSpaceStyle;
        lineSpaceStyle.spec = kCTParagraphStyleSpecifierLineSpacingAdjustment;
        lineSpaceStyle.valueSize = sizeof(lineSpace);
        lineSpaceStyle.value =&lineSpace;
        
        //設定文本段間距
        CGFloat paragraphSpacing = 15.0;
        CTParagraphStyleSetting paragraphSpaceStyle;
        paragraphSpaceStyle.spec = kCTParagraphStyleSpecifierParagraphSpacing;
        paragraphSpaceStyle.valueSize = sizeof(CGFloat);
        paragraphSpaceStyle.value = &paragraphSpacing;
        
        //建立設定數組
        CTParagraphStyleSetting settings[ ] ={alignmentStyle,lineSpaceStyle,paragraphSpaceStyle};
        CTParagraphStyleRef style = CTParagraphStyleCreate(settings ,3);
        
        //給文本添加設定
        [attributedString addAttribute:(id)kCTParagraphStyleAttributeName value:(id)style range:NSMakeRange(0 , [attributedString length])];
        CFRelease(helveticaBold);
    }
}

/*
 *覆寫setText方法
 */
- (void) setText:(NSString *)text
{
    [super setText:text];
    [self initAttributedString];
}

/*
 *開始繪制
 */
-(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);
    
    //翻轉坐标系統（文本原來是倒的要翻轉下）
    
    CGContextRef context = UIGraphicsGetCurrentContext();
    
    CGContextSetTextMatrix(context , CGAffineTransformIdentity);
    
    CGContextTranslateCTM(context , 0 ,self.bounds.size.height);
    
    CGContextScaleCTM(context, 1.0 ,-1.0);
    
    //畫出文本
    
    CTFrameDraw(leftFrame,context);
    
    //釋放
    
    CGPathRelease(leftColumnPath);
    
    CFRelease(framesetter);
    
    UIGraphicsPushContext(context);
}

/*
 *繪制前擷取label高度
 */
- (int)getAttributedStringHeightWidthValue:(int)width
{
    [self initAttributedString];
    
    int total_height = 0;
    
    CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)attributedString);    //string 為要計算高度的NSAttributedString
    CGRect drawingRect = CGRectMake(0, 0, width, 100000);  //這裡的高要設定足夠大
    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;  //最後一行line的原點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為了糾正descent轉換成int小數點後舍去的值
    
    CFRelease(textFrame);
    
    return total_height;
    
}

@end

      

3.建立調用步驟:

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];
        /*設定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];