iOS Coding项目片段记录（五）

最新推荐文章于 2022-03-25 11:58:03 发布

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最新推荐文章于 2022-03-25 11:58:03 发布

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原文链接：http://www.cnblogs.com/741162830qq/p/6030896.html

本文介绍如何使用Objective-C为UIButton设置渐变背景颜色，并提供了一个实用的方法来为图片添加白色边框。

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1.设置UIButton UIView 等显示渐变的背景颜色

- (void)setBackgroundColorWithButton:(UIButton *)button  firstColor:(UIColor *)firstColor lastColor:(UIColor *)lastColor{

    CAGradientLayer *gradientLayer = [[CAGradientLayer alloc] init];
    gradientLayer.colors = @[(__bridge id)firstColor.CGColor,(__bridge id)lastColor.CGColor];

    gradientLayer.startPoint = CGPointMake(0, 0);

    gradientLayer.endPoint = CGPointMake(0, 1);

    gradientLayer.frame = CGRectMake(0, 0, CGRectGetWidth(button.frame), CGRectGetHeight(button.frame));

    [button.layer addSublayer:gradientLayer];
}

UIColor *firstColor = [UIColor colorWithRed:(128/256.0) green:(215/256.0) blue:(4/256.0) alpha:1];
    UIColor *lastColor = [UIColor colorWithRed:(41/256.0) green:(129/256.0) blue:(1/256.0) alpha:1];
    [self setBackgroundColorWithButton:_myButton1 firstColor:firstColor lastColor:lastColor];

2.给图片增加一个外围的白色边框

-(UIImage*) circleImage:(UIImage*) image withParam:(CGFloat) inset {
    
    //UIGraphicsBeginImageContext(image.size);
    //解决失真 模糊的问题
    UIGraphicsBeginImageContextWithOptions(image.size, NO, [[UIScreen mainScreen] scale]);
    CGContextRef context =UIGraphicsGetCurrentContext();
    
    //圆的边框宽度为2，颜色为红色
    
    CGContextSetLineWidth(context,2);
    
    CGContextSetStrokeColorWithColor(context, [UIColor whiteColor].CGColor);
    
    CGRect rect = CGRectMake(inset, inset, image.size.width - inset *2.0f, image.size.height - inset *2.0f);
    
    CGContextAddEllipseInRect(context, rect);
    
    CGContextClip(context);
    
    //在圆区域内画出image原图
    
    [image drawInRect:rect];
    
    CGContextAddEllipseInRect(context, rect);
    
    CGContextStrokePath(context);
    
    //生成新的image
    
    UIImage *newimg = UIGraphicsGetImageFromCurrentImageContext();
    
    UIGraphicsEndImageContext();
    
    return newimg;
    
}