项目中需要实现的效果:
实现方法:自定义CFGradientLabel继承于UILabel,实现 drawRect: 方法,在该方法里面画渐变色。
在 CFGradientLabel.h 里
#import <UIKit/UIKit.h>
@interface CFGradientLabel : UILabel
@property (nonatomic,copy) NSArray *colors;
@end
在CFGradientLabel.m 里
#import "CFGradientLabel.h"
@implementation CFGradientLabel
- (void)drawRect:(CGRect)rect
{
CGSize textSize = [self.text sizeWithAttributes:@{NSFontAttributeName : self.font}];
CGRect textRect = (CGRect){0, 0, textSize};
// 画文字(不做显示用,主要作用是设置layer的mask)
CGContextRef context = UIGraphicsGetCurrentContext();
[self.textColor set];
[self.text drawWithRect:rect options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName : self.font} context:NULL];
// 坐标
CGContextTranslateCTM(context, 0.0f, rect.size.height- (rect.size.height - textSize.height)*0.5);
CGContextScaleCTM(context, 1.0f, -1.0f);
CGImageRef alphaMask = NULL;
alphaMask = CGBitmapContextCreateImage(context);
CGContextClearRect(context, rect);// 清除之前画的文字
// 设置mask
CGContextClipToMask(context, rect, alphaMask);
// 画渐变色
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGGradientRef gradient = CGGradientCreateWithColors(colorSpace, (__bridge CFArrayRef)self.colors, NULL);
CGPoint startPoint = CGPointMake(textRect.origin.x,
textRect.origin.y);
CGPoint endPoint = CGPointMake(textRect.origin.x + textRect.size.width,
textRect.origin.y + textRect.size.height);
CGContextDrawLinearGradient(context, gradient, startPoint, endPoint, kCGGradientDrawsBeforeStartLocation | kCGGradientDrawsAfterEndLocation);
// 释放内存
CGColorSpaceRelease(colorSpace);
CGGradientRelease(gradient);
CFRelease(alphaMask);
}
@end
创建渐变色label:
CFGradientLabel *gradientLbl = [[CFGradientLabel alloc] init];
[self.view addSubview:gradientLbl];
[gradientLbl mas_makeConstraints:^(MASConstraintMaker *make) {
make.left.equalTo(addNumLbl.mas_right).offset(1);
make.centerY.equalTo(addNumLbl.mas_centerY);
}];
gradientLbl.text = @"(确定后无法更改)";
gradientLbl.font = FONT(13);
gradientLbl.colors = @[(id)RGB(254, 42, 61).CGColor,(id)RGB(255, 198, 21).CGColor];
gradientLbl.layer.masksToBounds = YES;