iPhone自定义多色彩文本 Layer

http://fei263.blog.163.com/blog/static/9279372420114276519394/

这个自定义多色彩文本 Layer 的代码例子由 CocoaChina 会员 “带睡帽的青蛙” 分享，无需 three20，可以一个一个单词的定义文本颜色，并且可以调整词间距和行间距，根据 layer 的大小自动换行

/**
 *    @file            ColoredTextLayer.h
 *    @author           
 *    @date           
 *    @version        Beta 1.0
 *    @description   
 *    @copyright       
 *    @brief
 */
 
@interface ColoredTextLayer : CALayer{
    NSMutableArray * _textNSArray;
    NSMutableArray * _colorNSArray;
    UIFont * _font;
    NSInteger _lineSpace;
    NSInteger _wordSpace;
}
 
@property (nonatomic, retain) NSMutableArray * textNSArray;
@property (nonatomic, retain) NSMutableArray * colorNSArray;
@property (nonatomic, retain) UIFont * font;
@property (nonatomic, assign) NSInteger lineSpace;
@property (nonatomic, assign) NSInteger wordSpace;
 
/*!
 *  set the layer colored text
 */
- (void)setTexts:(NSArray *)texts inColors:(NSArray *)colors withFont:(UIFont *)font lineSpace:(NSInteger)lSpace wordSpace:(NSInteger)wSpace;
 
/*!
 *  separate the string to words
 */
- (void)initTextsColorsArray:(NSArray *)texts inColors:(NSArray *)colors;
 
@end

/**
 *    @file            ColoredTextLayer.m
 *    @author           
 *    @date           
 *    @version        Beta 1.0
 *    @description   
 *    @copyright       
 *    @brief
 */
 
#import "ColoredTextLayer.h"
#import "ColoredTextLayerDelegate.h"
 
@implementation ColoredTextLayer
 
@synthesize textNSArray = _textNSArray;
@synthesize colorNSArray = _colorNSArray;
@synthesize font = _font;
@synthesize lineSpace = _lineSpace;
@synthesize wordSpace = _wordSpace;
 
/*!
 *  @override
 */
- (id)init
{
    self = [super init];
    if (self) {
        [self.delegate release];
        self.delegate = nil;
        ColoredTextLayerDelegate * delegate = [[ColoredTextLayerDelegate alloc] init];
        self.delegate = delegate;
 
 
        _textNSArray = [[NSMutableArray alloc] initWithCapacity:0];
 
        _colorNSArray = [[NSMutableArray alloc] initWithCapacity:0];
    }
    return self;
}
 
/*!
 *  set the layer colored text
 *  @param texts texts array
 *  @param colors colors array
 *  @param font font
 *  @param lSpace space size between two lines
 *  @param wSpace space size between two words
 *  @return null
 */
- (void)setTexts:(NSArray *)texts inColors:(NSArray *)colors withFont:(UIFont *)font lineSpace:(NSInteger)lSpace wordSpace:(NSInteger)wSpace
{
    [self initTextsColorsArray:texts inColors:colors];
    _font = font;
    _lineSpace = lSpace;
    _wordSpace = wSpace;
    [self setNeedsDisplay];  
}
 
/*!
 *  separate the string to words
 *  @param texts texts array
 *  @param colors colors array
 *  @return null
 */
- (void)initTextsColorsArray:(NSArray *)texts inColors:(NSArray *)colors
{
    for (int i = 0; i < texts.count; i++) {
        NSString * string = [texts objectAtIndex:i];
        UIColor * color = [colors objectAtIndex:i];
        NSArray * array = [string componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
        array = [array filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:@"SELF != ''"]];
        for (int i = 0; i < array.count; i++) {
            [_textNSArray addObject:[array objectAtIndex:i]];
            [_colorNSArray addObject:color];
        }
    }
}
 
/*!
 *  @override
 */
- (void)dealloc
{
    [_textNSArray release];
    [_colorNSArray release];
    [super dealloc];
}
 
@end

/**
 *    @file            ColoredTextLayer.h
 *    @author           
 *    @date           
 *    @version        Beta 1.0
 *    @description   
 *    @copyright       
 *    @brief
 */
 
@interface ColoredTextLayerDelegate : NSObject {
 
    CGPoint _cursor;
}
 
@end

/**
 *    @file            ColoredTextLayer.h
 *    @author           
 *    @date           
 *    @version        Beta 1.0
 *    @description   
 *    @copyright       
 *    @brief
 */
 
#import "ColoredTextLayerDelegate.h"
 
#import "ColoredTextLayer.h"
 
@implementation ColoredTextLayerDelegate
 
/*!
 *  @override
 */
- (id)init
{
    self = [super init];
    if (self) {
        _cursor = CGPointMake(0, 0);
    }
    return self;
}
 
/*!
 *  @override
 */
- (void)drawLayer:(CALayer *)layer inContext:(CGContextRef)ctx
{
    UIGraphicsPushContext(ctx);
    if ([layer isKindOfClass:[ColoredTextLayer class]]) {
        ColoredTextLayer * coloredLayer = (ColoredTextLayer *)layer;
        for (int i = 0; i < coloredLayer.textNSArray.count; i++) {
            NSString * string = [coloredLayer.textNSArray objectAtIndex:i];
            UIColor * color = [coloredLayer.colorNSArray objectAtIndex:i];
            CGSize size = [string sizeWithFont:coloredLayer.font];
            NSInteger restWidth = coloredLayer.frame.size.width - _cursor.x;
            NSInteger restHeight = coloredLayer.frame.size.height - _cursor.y;
 
            [color setFill];
            if (size.width <= restWidth && size.height < restHeight) {      //can draw in current line
                CGSize stringSize = [string drawAtPoint:_cursor withFont:coloredLayer.font];
                _cursor.x = _cursor.x + stringSize.width + coloredLayer.wordSpace;
            } else if (size.width > restWidth && size.height * 2 < restHeight) {    //can draw in next line
                _cursor.x = 0;
                _cursor.y = _cursor.y + size.height + coloredLayer.lineSpace;
                CGSize stringSize = [string drawAtPoint:_cursor withFont:coloredLayer.font];
                _cursor.x = _cursor.x + stringSize.width + coloredLayer.wordSpace;
            } else {
                return;
            }
        }
    }   
    UIGraphicsPopContext();
}
 
@end