iOS uses the core text to format the text-go

Original Sticker Address: http://hi.baidu.com/jwq359699768/blog/item/5df305c893413d0a7e3e6f7b.html

Core text This package is not the default, you have to manually add it in.

Several key points for composing text in iOS using the core text are as follows:

Word spacing: kctkernattributename

Line spacing: kctparagraphstylespecifierlinespacingadjustment or kctparagraphstylespecifierlinespacing (deprecated)

Segment spacing: kctparagraphstylespecifierparagraphspacing

Text alignment: Kctparagraphstylespecifieralignment;

The other thing is that the core text shows the word is upside down, when used to flip the following:

Cgcontextref context = Uigraphicsgetcurrentcontext ();

Cgcontextsettextmatrix (context,cgaffinetransformidentity);

CGCONTEXTTRANSLATECTM (Context,0,self.bounds.size.height);

CGCONTEXTSCALECTM (context,1.0,-1.0);

The last point to note is that the carriage return under the MAC is not the same as Windows, the carriage return under Windows is composed of \ r \ n and the Mac has only one \ n, so if it is not removed at the end of each paragraph will have a blank line, the method is removed as follows:

NSString *mystring = [labelstring stringbyreplacingoccurrencesofstring: "\ r \ n" withstring: "\ n"];

The specific code is implemented as follows:

#import <Foundation/Foundation.h>

#import <UIKit/UIKit.h>

@interface Textlayoutlabel:uilabel

{

@private

CGFloat Characterspacing_; Word spacing

@private

Long Linesspacing_; Line spacing

}

@property (nonatomic,assign) cgfloat characterspacing;

@propery (nonatomic,assign) long linesspacing;

@end

#import "TextLayoutLabel.h"

#import <CoreText/CoreText.h>

@implementation Textlayoutlabel

@synthesize characterspacing = characterspacing_;

@synthesize linesspacing = linesspacing_;

-(ID) initWithFrame: (CGRect) frame

{//Initialize word spacing, line spacing

if (self =[super initwithframe:frame])

{

self.characterspacing = 2.0f;

self.linesspacing = 5.0f;

}

return self;

}

-(void) setcharacterspacing: (cgfloat) characterspacing//External call set word spacing

{

Characterspacing_ = characterspacing;

[Self setneedsdisplay];

}

-(void) Setlinesspacing: (long) linesspacing//External call set line spacing

{

Linesspacing_ = linesspacing;

[Self setneedsdisplay];

}

-(void) Drawtextinrect: (CGRect) Requestedrect

{

Remove empty lines

NSString *labelstring = Self.text;

NSString *mystring = [labelstring stringbyreplacingoccurrencesofstring:@ "\ r \ n" withstring: "\ n"];

Create AttributeString

Nsmutableattributedstring *string =[[nsmutableattributedstring Alloc]initwithstring:self.text];

Set font and size

Ctfontref Helveticabold = Ctfontcreatewithname ((cfstringref) self.font.fontname,self.font.pointsize,null);

[String AddAttribute: (ID) kctfontattributename value: (ID) helveticabold range:nsmakerange (0,[string length])];

Set word spacing

if (self.characterspacing)

{

Long number = self.characterspacing;

Cfnumberref num = cfnumbercreate (kcfallocatordefault,kcfnumbersint8type,&number);

[String AddAttribute: (ID) kctkernattributename value: (ID) num rang:nsmakerange (0,[string length])];

Cfrelease (num);

}

Set Font Color

[String AddAttribute: (ID) kctforegroundcolorattributename value: (ID) (self.textColor.CGColor) Range:nsmakerange (0,[ string length]);

Create text alignment

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;

Set Text line spacing

CGFloat linespace = self.linesspacing;

Ctparagraphstylesetting Linespacestyle;

Linespacestyle.spec = kctparagraphstylespecifierlinespacingadjustment;

linespacestyle.valuesize = sizeof (linespace);

Linespacestyle.value =&linespace;

Set Text segment Spacing

CGFloat paragraphspacing = 5.0;

Ctparagraphstylesetting Paragraphspacestyle;

Paragraphspacestyle.spec = kctparagraphstylespecifierparagraphspacing;

paragraphspacestyle.valuesize = sizeof (cgfloat);

Paragraphspacestyle.value = &paragraphSpacing;

Creating an array of settings

Ctparagraphstylesetting settings[] ={alignmentstyle,linespacestyle,paragraphspacestyle};

Ctparagraphstyleref style = ctparagraphstylecreate (settings, sizeof (settings));

Add settings to Text

[String AddAttribute: (ID) kctparagraphstyleattributename value: (ID) style range:nsmakerange (0, [string length])];

Typesetting

Ctframesetterref Framesetter = ctframesettercreatewithattributedstring ((cfattributedstringref) string);

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);

Flip the coordinate system (the text turns upside down)

Cgcontextref context = Uigraphicsgetcurrentcontext ();

Cgcontextsettextmatrix (context, cgaffinetransformidentity);

CGCONTEXTTRANSLATECTM (context, 0, self.bounds.size.height);

CGCONTEXTSCALECTM (Context, 1.0,-1.0);

Draw the text

Ctframedraw (Leftframe,context);

Release

Cgpathrelease (Leftcolumnpath);

Cfreleale (Framesetter);

Cfrelease (Helveticabold);

[String release];

Uigraphicspushcontext (context);

}

@end

iOS uses the core text to format the text-go