ios开发之文字扩散效果

#import <UIKit/UIKit.h>

@interface LightLabel : UILabel{
    float redValue_;
    float greenValue_;
    float blueValue_;
    float size_;
}
@property(assign,nonatomic)float redValue;
@property(assign,nonatomic)float greenValue;
@property(assign,nonatomic)float blueValue;
@property(assign,nonatomic)float size;
@end

 

 

#import "LightLabel.h"

@implementation LightLabel
@synthesize redValue = redValue_, greenValue = greenValue_, blueValue = blueValue_, size = size_;

-(void)awakeFromNib{
    [super awakeFromNib];
//    6 238 238
    redValue_   = 6.0/255.0f;
    greenValue_ = 238.0/255.0f;
    blueValue_  = 238.0/255.0f;
    size_       = 2.0f;
}
- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        // Initialization code
        redValue_   = 6.0/255.0f;
        greenValue_ = 238.0/255.0f;
        blueValue_  = 238.0/255.0f;
        size_       = 2.0f;

    }
    return self;
}

-(void) drawTextInRect: (CGRect)rect{
    //定义阴影区域
    CGSize textShadowOffest = CGSizeMake(0, 0);
    //定义RGB颜色值
    float textColorValues[] = {redValue_, greenValue_, blueValue_, 1.0};
    
    //获取绘制上下文
    CGContextRef ctx = UIGraphicsGetCurrentContext();
    //保存上下文状态
    CGContextSaveGState(ctx);
    
    //为上下文设置阴影
    CGContextSetShadow(ctx, textShadowOffest, size_);
    //设置颜色类型
    CGColorSpaceRef textColorSpace = CGColorSpaceCreateDeviceRGB();
    //根据颜色类型和颜色值创建CGColorRef颜色
    CGColorRef textColor = CGColorCreate(textColorSpace, textColorValues);
    //为上下文阴影设置颜色，阴影颜色，阴影大小
    CGContextSetShadowWithColor(ctx, textShadowOffest, size_, textColor);
    
    [super drawTextInRect:rect];
    
    //释放
    CGColorRelease(textColor);
    CGColorSpaceRelease(textColorSpace);
    
    //重启上下文
    CGContextRestoreGState(ctx);
}

@end