二、文字漸變實現思路:
1.創建一個顏色漸變層，漸變圖層跟文字控件一樣大。
2.用文字圖層裁剪漸變層，只保留文字部分，就會讓漸變層只保留有文字的部分，相當于間接讓漸變層顯示文字，我們看到的其實是被裁剪過后，漸變層的部分內容。
注意：如果用文字圖層裁剪漸變層，文字圖層就不在擁有顯示功能，這個圖層就被弄來裁剪了，不會顯示,在下面代碼中也會有說明。
2.1 創建一個帶有文字的label，label能顯示文字。
2.2 設置漸變圖層的mask為label圖層，就能用文字裁剪漸變圖層了。
3.mask圖層工作原理:
1.根據透明度進行裁剪，只保留非透明部分，顯示底部內容。
4.詳細代碼+解釋
// 創建UILabel UILabel *label = [[YZLabel alloc] init]; label.text = @"小碼哥,專注于高級iOS開發工程師的培養"; [label sizeToFit]; label.center = CGPointMake(200, 100); // 疑問：label只是用來做文字裁剪，能否不添加到view上。 // 必須要把Label添加到view上，如果不添加到view上，label的圖層就不會調用drawRect方法繪制文字，也就沒有文字裁剪了。 // 如何驗證，自定義Label,重寫drawRect方法，看是否調用,發現不添加上去，就不會調用 [self.view addSubview:label]; // 創建漸變層 CAGradientLayer *gradientLayer = [CAGradientLayer layer]; gradientLayer.frame = label.frame; // 設置漸變層的顏色，隨機顏色漸變 gradientLayer.colors = @[(id)[self randomColor].CGColor, (id)[self randomColor].CGColor,(id)[self randomColor].CGColor]; // 疑問:漸變層能不能加在label上 // 不能，mask原理：默認會顯示mask層底部的內容，如果漸變層放在mask層上，就不會顯示了 // 添加漸變層到控制器的view圖層上 [self.view.layer addSublayer:gradientLayer]; // mask層工作原理:按照透明度裁剪，只保留非透明部分，文字就是非透明的，因此除了文字，其他都被裁剪掉，這樣就只會顯示文字下面漸變層的內容，相當于留了文字的區域，讓漸變層去填充文字的顏色。 // 設置漸變層的裁剪層 gradientLayer.mask = label.layer; // 注意:一旦把label層設置為mask層，label層就不能顯示了,會直接從父層中移除，然后作為漸變層的mask層，且label層的父層會指向漸變層，這樣做的目的：以漸變層為坐標系，方便計算裁剪區域，如果以其他層為坐標系，還需要做點的轉換，需要把別的坐標系上的點，轉換成自己坐標系上點，判斷當前點在不在裁剪范圍內，比較麻煩。 // 父層改了，坐標系也就改了，需要重新設置label的位置，才能正確的設置裁剪區域。 label.frame = gradientLayer.bounds;
#import "LXGradientPRocessView.h"#import "UIView+Extensions.h"#import "UIColor+Extensions.h"static const CGFloat kProcessHeight = 10.f;static const CGFloat kTopSpaces = 5.f;static const CGFloat kNumberMarkWidth = 60.f;static const CGFloat kNumberMarkHeight = 20.f;static const CGFloat kAnimationTime = 3.f;@interface LXGradientProcessView ()@property (nonatomic, strong) CALayer *maskLayer;@property (nonatomic, strong) CAGradientLayer *gradientLayer;@property (nonatomic, strong) UIButton *numberMark; // 數字標示@property (nonatomic, strong) NSTimer *numberChangeTimer;@property (nonatomic, assign) CGFloat numberPercent;@property (nonatomic, strong) NSArray *colorArray;@property (nonatomic, strong) NSArray *colorLocationArray;@end@implementation LXGradientProcessView- (instancetype)initWithFrame:(CGRect)frame{ self = [super initWithFrame:frame]; if (self) { self.backgroundColor = [UIColor whiteColor]; self.colorArray = @[(id)[[UIColor colorWithHex:0xFF6347] CGColor], (id)[[UIColor colorWithHex:0xFFEC8B] CGColor], (id)[[UIColor colorWithHex:0x98FB98] CGColor], (id)[[UIColor colorWithHex:0x00B2EE] CGColor], (id)[[UIColor colorWithHex:0x9400D3] CGColor]]; self.colorLocationArray = @[@0.1, @0.3, @0.5, @0.7, @1]; self.numberMark.frame = CGRectMake(0, kTopSpaces, kNumberMarkWidth, kNumberMarkHeight); [self addSubview:self.numberMark]; [self setNUmberMarkLayer]; [self getGradientLayer]; self.numberPercent = 0; } return self;}- (void)setNUmberMarkLayer { // 提示文字設置漸變色 CAGradientLayer *numberGradientLayer = [CAGradientLayer layer]; numberGradientLayer.frame = CGRectMake(0, kTopSpaces, self.width, kNumberMarkHeight); [numberGradientLayer setColors:self.colorArray]; [numberGradientLayer setLocations:self.colorLocationArray]; [numberGradientLayer setStartPoint:CGPointMake(0, 0)]; [numberGradientLayer setEndPoint:CGPointMake(1, 0)]; [self.layer addSublayer:numberGradientLayer]; [numberGradientLayer setMask:self.numberMark.layer]; self.numberMark.frame = numberGradientLayer.bounds; NSLog(@"numberMark = %@ numberGradientLayer = %@ ",NSStringFromCGRect(self.numberMark.frame),NSStringFromCGRect(numberGradientLayer.frame));}- (void)getGradientLayer{ // 進度條設置漸變色 // 灰色進度條背景 CALayer *bgLayer = [CALayer layer]; bgLayer.frame = CGRectMake(kNumberMarkWidth / 2, self.height - kProcessHeight - kTopSpaces, self.width - kNumberMarkWidth / 2, kProcessHeight); bgLayer.backgroundColor = [UIColor colorWithHex:0xF5F5F5].CGColor; bgLayer.masksToBounds = YES; bgLayer.cornerRadius = kProcessHeight / 2; [self.layer addSublayer:bgLayer]; self.maskLayer = [CALayer layer]; self.maskLayer.frame = CGRectMake(0, 0, (self.width - kNumberMarkWidth / 2) * self.percent / 100.f, kProcessHeight); self.maskLayer.borderWidth = self.height / 2; self.gradientLayer = [CAGradientLayer layer]; self.gradientLayer.frame = CGRectMake(kNumberMarkWidth / 2, self.height - kProcessHeight - kTopSpaces, self.width - kNumberMarkWidth / 2, kProcessHeight); self.gradientLayer.masksToBounds = YES; self.gradientLayer.cornerRadius = kProcessHeight / 2; [self.gradientLayer setColors:self.colorArray]; [self.gradientLayer setLocations:self.colorLocationArray]; [self.gradientLayer setStartPoint:CGPointMake(0, 0)]; [self.gradientLayer setEndPoint:CGPointMake(1, 0)]; [self.gradientLayer setMask:self.maskLayer]; [self.layer addSublayer:self.gradientLayer]; NSLog(@"maskLayer = %@ gradientLayer = %@ bgLayer = %@",NSStringFromCGRect(self.maskLayer.frame),NSStringFromCGRect(self.gradientLayer.frame),NSStringFromCGRect(bgLayer.frame));}- (void)setPercent:(CGFloat)percent { [self setPercent:percent animated:YES];}- (void)setPercent:(CGFloat)percent animated:(BOOL)animated { _percent = percent; [NSTimer scheduledTimerWithTimeInterval:0 target:self selector:@selector(circleAnimation) userInfo:nil repeats:NO]; // 文字動畫 __weak typeof(self)weakSelf = self; [UIView animateWithDuration:kAnimationTime animations:^{ weakSelf.numberMark.frame = CGRectMake((weakSelf.width - kNumberMarkWidth) * percent / 100, 0, kNumberMarkWidth, kNumberMarkHeight); // [weakSelf.numberMark setTitle:[NSString stringWithFormat:@"%.1f分",percent / 20.f] forState:UIControlStateNormal]; }]; self.numberChangeTimer = [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector(changeNumber) userInfo:nil repeats:YES];}- (void)changeNumber { // 每0.1秒改變百分比文字 if (!self.percent) { [self.numberChangeTimer invalidate]; self.numberChangeTimer = nil; } self.numberPercent += (self.percent / (kAnimationTime * 10.f)); if (self.numberPercent > self.percent) { [self.numberChangeTimer invalidate]; self.numberChangeTimer = nil; self.numberPercent = self.percent; } [self.numberMark setTitle:[NSString stringWithFormat:@"%.1f",self.numberPercent] forState:UIControlStateNormal];}- (void)circleAnimation { // 進度條動畫 [CATransaction begin]; [CATransaction setDisableActions:NO]; [CATransaction setAnimationTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaSEOut]]; [CATransaction setAnimationDuration:kAnimationTime]; self.maskLayer.frame = CGRectMake(0, 0, (self.width - kNumberMarkWidth / 2) * _percent / 100.f, kProcessHeight); [CATransaction commit];}- (UIButton *)numberMark { if (nil == _numberMark) { _numberMark = [UIButton buttonWithType:UIButtonTypeCustom]; [_numberMark setTitle:@"0分" forState:UIControlStateNormal]; [_numberMark setTitleColor:[UIColor colorWithHex:0xFF6347] forState:UIControlStateNormal]; [_numberMark setBackgroundImage:[UIImage imageNamed:@"user_score_bubble"] forState:UIControlStateNormal]; _numberMark.titleLabel.font = [UIFont systemFontOfSize:13.f]; _numberMark.enabled = NO; } return _numberMark;}
// 漸變進度條 self.processView = [[LXGradientProcessView alloc] initWithFrame:CGRectMake(20.f, 100.f, SCREEN_WIDTH - 40.f, 45.f)]; self.processView.percent = 0; [self.view addSubview:self.processView]; UIButton *stareButton = [UIButton buttonWithType:UIButtonTypeSystem]; [stareButton setFrame:CGRectMake(20.f, 300.f, SCREEN_WIDTH - 40.f, 38.f)]; [stareButton addTarget:self action:@selector(onStareButtonClick) forControlEvents:UIControlEventTouchUpInside]; [stareButton setTitle:@"Stare" forState:UIControlStateNormal]; stareButton.layer.cornerRadius = 4.f; stareButton.layer.borderWidth = 0.5; stareButton.layer.borderColor = [UIColor lightGrayColor].CGColor; [self.view addSubview:stareButton];//鏤空
- (void)addMask{ UIButton * _maskButton = [[UIButton alloc] init]; [_maskButton setFrame:CGRectMake(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT)]; [_maskButton setBackgroundColor:[UIColor colorWithWhite:0 alpha:0.7]]; [self.view addSubview:_maskButton]; //create path UIBezierPath *path = [UIBezierPath bezierPathWithRect:CGRectMake(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT)]; // MARK: circlePath [path appendPath:[UIBezierPath bezierPathWithArcCenter:CGPointMake(SCREEN_WIDTH / 2, 200) radius:100 startAngle:0 endAngle:2*M_PI clockwise:NO]]; // MARK: roundRectanglePath [path appendPath:[[UIBezierPath bezierPathWithRoundedRect:CGRectMake(20, 400, SCREEN_WIDTH - 22 * 20, 100) cornerRadius:15] bezierPathByReversingPath]]; CAShapeLayer *shapeLayer = [CAShapeLayer layer]; shapeLayer.path = path.CGPath; [_maskButton.layer setMask:shapeLayer]; maskLayer = shapeLayer;}//文字變色
UILabel *_numberMark = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 10, 50)]; _numberMark.textAlignment = NSTextAlignmentLeft; _numberMark.text = @"aa"; textLabel = _numberMark; CAGradientLayer *colorLayer = [CAGradientLayer layer]; colorLayer.frame = CGRectMake(0, 0, 300, 50); // 顏色分配 colorLayer.colors = @[(__bridge id)[UIColor redColor].CGColor, (__bridge id)[UIColor greenColor].CGColor, (__bridge id)[UIColor blueColor].CGColor, (__bridge id)[UIColor redColor].CGColor]; // 顏色分割線 colorLayer.locations = @[@(0.25), @(0.5), @(0.75)]; // 起始點 colorLayer.startPoint = CGPointMake(0, 0); // 結束點 colorLayer.endPoint = CGPointMake(1, 0); [self.view.layer addSublayer:colorLayer]; colorLayer.mask = _numberMark.layer;//繪制wifi圖標
/1?；《绒D角度#define pi 3.14159265359#define RADIANS_TO_DEGREES(radians) ((radians) * (180.0 / M_PI))//2。角度轉弧度// Degrees to radians#define pi 3.14159265359#define DEGREES_TO_RADIANS(degrees) ((pi * degrees)/ 180)@implementation LTWiFiScanView- (id)initWithFrame:(CGRect)frame{ if (self = [super initWithFrame:frame]) { } return self;}// Only override drawRect: if you perform custom drawing.// An empty implementation adversely affects performance during animation.- (void)drawRect:(CGRect)rect { // Drawing code CALayer *superLayer = [CALayer layer]; superLayer.frame = self.frame; CAShapeLayer *layer = [CAShapeLayer layer]; layer.frame = CGRectMake(0, 0, rect.size.width/6, rect.size.height/6); UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:CGPointMake(150,151) radius:2.5f startAngle:DEGREES_TO_RADIANS(220) endAngle:DEGREES_TO_RADIANS(320) clockwise:YES]; layer.path = path.CGPath; layer.lineWidth = 5; layer.strokeColor = [UIColor redColor].CGColor; layer.fillColor = [UIColor blueColor].CGColor; CAKeyframeAnimation *opacityAnimation = [CAKeyframeAnimation animation]; opacityAnimation.keyPath = @"opacity"; opacityAnimation.values = @[@1.0,@0.75,@0.5,@0.25,@0.0]; opacityAnimation.keyTimes = @[@0.0,@0.25,@0.5,@0.75,@1]; opacityAnimation.fillMode = kCAFillModeBoth; opacityAnimation.duration = 1; opacityAnimation.beginTime = CACurrentMediaTime() + (float) 0 * 1.5 / 3; opacityAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear]; opacityAnimation.autoreverses = NO; opacityAnimation.removedOnCompletion = NO; opacityAnimation.repeatCount = HUGE_VALF; // [layer addAnimation:opacityAnimation forKey:@"op"]; [superLayer addSublayer:layer]; CAShapeLayer *layer1 = [CAShapeLayer layer]; layer.frame = CGRectMake(0, 0, rect.size.width/6, rect.size.height/6); UIBezierPath *path1 = [UIBezierPath bezierPathWithArcCenter:CGPointMake(150,150) radius:10 startAngle:DEGREES_TO_RADIANS(220) endAngle:DEGREES_TO_RADIANS(320) clockwise:YES]; layer1.path = path1.CGPath; layer1.lineWidth = 5; layer1.strokeColor = [UIColor blueColor].CGColor; layer1.fillColor = [UIColor clearColor].CGColor; CAKeyframeAnimation *opacityAnimation1 = [CAKeyframeAnimation animation]; opacityAnimation1.keyPath = @"opacity"; opacityAnimation1.values = @[@1.0,@0.75,@0.5,@0.25,@0.0]; opacityAnimation1.keyTimes = @[@0.0,@0.25,@0.5,@0.75,@1]; opacityAnimation1.fillMode = kCAFillModeBoth; opacityAnimation1.duration = 1; opacityAnimation1.beginTime = CACurrentMediaTime() + (float) 1 * 1.5 / 3; opacityAnimation1.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear]; opacityAnimation1.autoreverses = NO; opacityAnimation1.removedOnCompletion = NO; opacityAnimation1.repeatCount = HUGE_VALF;// [layer1 addAnimation:opacityAnimation1 forKey:@"op"]; [superLayer addSublayer:layer1]; CAShapeLayer *layer2 = [CAShapeLayer layer]; layer2.frame = CGRectMake(0, 0, rect.size.width/6, rect.size.height/6); UIBezierPath *path2 = [UIBezierPath bezierPathWithArcCenter:CGPointMake(150,150) radius:20 startAngle:DEGREES_TO_RADIANS(220) endAngle:DEGREES_TO_RADIANS(320) clockwise:YES]; layer2.path = path2.CGPath; layer2.lineWidth = 5; layer2.strokeColor = [UIColor blueColor].CGColor; layer2.fillColor = [UIColor clearColor].CGColor; CAKeyframeAnimation *opacityAnimation2 = [CAKeyframeAnimation animation]; opacityAnimation2.keyPath = @"opacity"; opacityAnimation2.values = @[@1.0,@0.75,@0.5,@0.25,@0.0]; opacityAnimation2.keyTimes = @[@0.0,@0.25,@0.5,@0.75,@1]; opacityAnimation2.fillMode = kCAFillModeBoth; opacityAnimation2.duration = 1; opacityAnimation2.beginTime = CACurrentMediaTime() + (float) 2 * 1.5 / 3; opacityAnimation2.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear]; opacityAnimation2.autoreverses = NO; opacityAnimation2.removedOnCompletion = NO; opacityAnimation2.repeatCount = HUGE_VALF;// [layer2 addAnimation:opacityAnimation2 forKey:@"op"]; [superLayer addSublayer:layer2]; [self.layer addSublayer:superLayer];
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