动画结束后使layer保持动画后的状态
需要同时设置animation.removedOnCompletion = NO和animation.fillMode = kCAFillModeForwards。
UILabel增加模糊文字阴影
UILabel的shadowOffset和shadowColor可以设置无模糊效果的阴影，如果需要设置模糊效果文字阴影，需要使用NSAttributedString增加NSShadowAttributeName阴影对应的参数。下面是UILabel设置阴影的一个Category方法：
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| // UILabel+Util.m
- (void)setText:(NSString *)text lineSpacing:(CGFloat)lineSpacing shadowColor:(UIColor *)shadowColor{
if (!text) {
self.text = text;
return;
}
NSRange range = NSMakeRange(0, text.length);
NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:text];
// font
[attributedString addAttribute:NSFontAttributeName value:self.font range:range];
// color
[attributedString addAttribute:NSForegroundColorAttributeName value:self.textColor range:range];
// shadow
if (shadowColor) {
NSShadow *shadow = [NSShadow new];
shadow.shadowBlurRadius = 4;
shadow.shadowOffset = CGSizeMake(0, 2);
shadow.shadowColor = shadowColor;
[attributedString addAttribute:NSShadowAttributeName value:shadow range:range];
}
// style
NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
[paragraphStyle setLineBreakMode:self.lineBreakMode];
[paragraphStyle setAlignment:self.textAlignment];
if (lineSpacing > 0) {
[paragraphStyle setLineSpacing:lineSpacing];
}
[attributedString addAttribute:NSParagraphStyleAttributeName
value:paragraphStyle
range:range];
// attributed string
self.attributedText = attributedString;
}
|
UILabel逐行显示动画
增加一个Category方法使UILabel文字逐行显示，需要思想是为UILabel增加一个渐变的maskLayer，并用动画修改渐变的位置。
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| // UILabel+Util.m
- (void)startLineAnimationWithDuration:(CGFloat)duration{
// layout
[self layoutIfNeeded];
// gradient layer
CAGradientLayer *gradientLayer = [CAGradientLayer layer];
gradientLayer.frame = self.bounds;
gradientLayer.locations = @[@0, @0, @0, @1];
gradientLayer.colors = @[(__bridge id)[UIColor whiteColor].CGColor,
(__bridge id)[UIColor whiteColor].CGColor,
(__bridge id)[UIColor clearColor].CGColor,
(__bridge id)[UIColor clearColor].CGColor,
];
gradientLayer.startPoint = CGPointMake(0, 0);
gradientLayer.endPoint = CGPointMake(0, 1);
// set mask
self.layer.mask = gradientLayer;
// animate locations
CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"locations"];
animation.fromValue = @[@0, @(-0.2), @0, @1];
animation.toValue = @[@0, @1, @1.2, @1];
animation.duration = duration;
animation.timingFunction = [CAMediaTimingFunction functionWithName:@"easeInEaseOut"];
animation.removedOnCompletion = NO;
animation.fillMode = kCAFillModeForwards;
// add animation
[gradientLayer addAnimation:animation forKey:@"animation"];
}
|