cdts/xdts-ios 3/TreeHole/CYHResetCode/CYH/QMUIKit/QMUIComponents/QMUIMarqueeLabel.m

/**
 * Tencent is pleased to support the open source community by making QMUI_iOS available.
 * Copyright (C) 2016-2021 THL A29 Limited, a Tencent company. All rights reserved.
 * Licensed under the MIT License (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
 * http://opensource.org/licenses/MIT
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
 */

//
//  QMUIMarqueeLabel.m
//  qmui
//
//  Created by QMUI Team on 2017/5/31.
//

#import "QMUIMarqueeLabel.h"
#import "QMUICore.h"
#import "CALayer+QMUI.h"
#import "NSString+QMUI.h"

@interface QMUIMarqueeLabel ()

@property(nonatomic, strong) CADisplayLink *displayLink;
@property(nonatomic, assign) CGFloat offsetX;
@property(nonatomic, assign) CGSize textSize;
@property(nonatomic, assign) CGFloat fadeStartPercent; // 渐变开始的百分比，默认为0，不建议改
@property(nonatomic, assign) CGFloat fadeEndPercent; // 渐变结束的百分比，例如0.2，则表示 0~20% 是渐变区间

@property(nonatomic, assign) BOOL isFirstDisplay;

@property(nonatomic, strong) CAGradientLayer *fadeLayer;

/// 绘制文本时重复绘制的次数，用于实现首尾连接的滚动效果，1 表示不首尾连接，大于 1 表示首尾连接。
@property(nonatomic, assign) NSInteger textRepeatCount;

/// 记录上一次布局时的 bounds，如果有改变，则需要重置动画
@property(nonatomic, assign) CGRect prevBounds;

@end

@implementation QMUIMarqueeLabel

- (instancetype)initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame];
    if (self) {
        self.lineBreakMode = NSLineBreakByClipping;
        self.clipsToBounds = YES;// 显示非英文字符时，滚动的时候字符会稍微露出两端，所以这里直接裁剪掉
        
        [self didInitialize];
    }
    return self;
}

- (instancetype)initWithCoder:(NSCoder *)aDecoder {
    if (self = [super initWithCoder:aDecoder]) {
        [self didInitialize];
    }
    return self;
}

- (void)didInitialize {
    self.speed = .5;
    self.fadeStartPercent = 0;
    self.fadeEndPercent = .2;
    self.pauseDurationWhenMoveToEdge = 2.5;
    self.spacingBetweenHeadToTail = 40;
    self.automaticallyValidateVisibleFrame = YES;
    self.shouldFadeAtEdge = YES;
    self.textStartAfterFade = NO;
    
    self.isFirstDisplay = YES;
    self.textRepeatCount = 2;
}

- (void)dealloc {
    [self.displayLink invalidate];
    self.displayLink = nil;
}

- (void)didMoveToWindow {
    [super didMoveToWindow];
    if (self.window) {
        self.displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(handleDisplayLink:)];
        [self.displayLink addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes];
    } else {
        [self.displayLink invalidate];
        self.displayLink = nil;
    }
    
    // 需要手动触发一下 setter，否则在 xib 赋值 text 后不生效
    self.attributedText = self.attributedText;
}

- (void)setFadeWidthPercent:(CGFloat)fadeWidthPercent {
    if (!betweenOrEqual(0.0, fadeWidthPercent, 1.0)) {
        return;
    }
    _fadeWidthPercent = fadeWidthPercent;
    
    self.fadeEndPercent = fadeWidthPercent;
}

- (void)setText:(NSString *)text {
    [super setText:text];
    self.offsetX = 0;
    self.textSize = [self sizeThatFits:CGSizeMax];
    self.displayLink.paused = ![self shouldPlayDisplayLink];
    [self checkIfShouldShowGradientLayer];
    [self setNeedsLayout];
}

- (void)setAttributedText:(NSAttributedString *)attributedText {
    [super setAttributedText:attributedText];
    self.offsetX = 0;
    self.textSize = [self sizeThatFits:CGSizeMax];
    self.displayLink.paused = ![self shouldPlayDisplayLink];
    [self checkIfShouldShowGradientLayer];
    [self setNeedsLayout];
}

- (void)drawTextInRect:(CGRect)rect {
    CGFloat textInitialX = 0;
    if (self.textAlignment == NSTextAlignmentLeft) {
        textInitialX = 0;
    } else if (self.textAlignment == NSTextAlignmentCenter) {
        textInitialX = MAX(0, CGFloatGetCenter(CGRectGetWidth(self.bounds), self.textSize.width));
    } else if (self.textAlignment == NSTextAlignmentRight) {
        textInitialX = MAX(0, CGRectGetWidth(self.bounds) - self.textSize.width);
    }
    
    // 考虑渐变遮罩的偏移
    CGFloat textOffsetXByFade = 0;
    BOOL shouldTextStartAfterFade = self.shouldFadeAtEdge && self.textStartAfterFade && self.textSize.width > CGRectGetWidth(self.bounds);
    CGFloat fadeWidth = CGRectGetWidth(self.bounds) * .5 * MAX(0, self.fadeEndPercent - self.fadeStartPercent);
    if (shouldTextStartAfterFade && textInitialX < fadeWidth) {
        textOffsetXByFade = fadeWidth;
    }
    textInitialX += textOffsetXByFade;
    
    for (NSInteger i = 0; i < self.textRepeatCountConsiderTextWidth; i++) {
        [self.attributedText drawInRect:CGRectMake(self.offsetX + (self.textSize.width + self.spacingBetweenHeadToTail) * i + textInitialX, CGRectGetMinY(rect) + CGFloatGetCenter(CGRectGetHeight(rect), self.textSize.height), self.textSize.width, self.textSize.height)];
    }
    
    // 自定义绘制就不需要调用 super
//    [super drawTextInRect:rectToDrawAfterAnimated];
}

- (void)layoutSubviews {
    [super layoutSubviews];
    
    if (self.fadeLayer) {
        self.fadeLayer.frame = self.bounds;
    }
    
    if (!CGSizeEqualToSize(self.prevBounds.size, self.bounds.size)) {
        self.offsetX = 0;
        self.displayLink.paused = ![self shouldPlayDisplayLink];
        self.prevBounds = self.bounds;
        
        [self checkIfShouldShowGradientLayer];
    }
}

- (NSInteger)textRepeatCountConsiderTextWidth {
    if (self.textSize.width < CGRectGetWidth(self.bounds)) {
        return 1;
    }
    return self.textRepeatCount;
}

- (void)handleDisplayLink:(CADisplayLink *)displayLink {
    if (self.offsetX == 0) {
        displayLink.paused = YES;
        [self setNeedsDisplay];
        
        int64_t delay = (self.isFirstDisplay || self.textRepeatCount <= 1) ? self.pauseDurationWhenMoveToEdge : 0;
        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delay * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
            displayLink.paused = ![self shouldPlayDisplayLink];
            if (!displayLink.paused) {
                self.offsetX -= self.speed;
            }
        });
        
        if (delay > 0 && self.textRepeatCount > 1) {
            self.isFirstDisplay = NO;
        }
        
        return;
    }
    
    self.offsetX -= self.speed;
    [self setNeedsDisplay];
    
    if (-self.offsetX >= self.textSize.width + (self.textRepeatCountConsiderTextWidth > 1 ? self.spacingBetweenHeadToTail : 0)) {
        displayLink.paused = YES;
        int64_t delay = self.textRepeatCount > 1 ? self.pauseDurationWhenMoveToEdge : 0;
        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delay * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
            self.offsetX = 0;
            [self handleDisplayLink:displayLink];
        });
    }
}

- (BOOL)shouldPlayDisplayLink {
    BOOL result = self.window && CGRectGetWidth(self.bounds) > 0 && self.textSize.width > CGRectGetWidth(self.bounds);
    
    // 如果 label.frame 在 window 可视区域之外，也视为不可见，暂停掉 displayLink
    if (result && self.automaticallyValidateVisibleFrame) {
        CGRect rectInWindow = [self.window convertRect:self.frame fromView:self.superview];
        if (!CGRectIntersectsRect(self.window.bounds, rectInWindow)) {
            return NO;
        }
    }
    
    return result;
}

- (void)setShouldFadeAtEdge:(BOOL)shouldFadeAtEdge {
    _shouldFadeAtEdge = shouldFadeAtEdge;
    
    [self checkIfShouldShowGradientLayer];
    [self setNeedsLayout];
}

- (void)checkIfShouldShowGradientLayer {
    BOOL shouldShowFadeLayer = self.window && self.shouldFadeAtEdge && CGRectGetWidth(self.bounds) > 0 && self.textSize.width > CGRectGetWidth(self.bounds);
    
    if (shouldShowFadeLayer) {
        _fadeLayer = [CAGradientLayer layer];
        self.fadeLayer.locations = @[@(self.fadeStartPercent), @(self.fadeEndPercent), @(1 - self.fadeEndPercent), @(1 - self.fadeStartPercent)];
        self.fadeLayer.startPoint = CGPointMake(0, .5);
        self.fadeLayer.endPoint = CGPointMake(1, .5);
        self.fadeLayer.colors = @[(id)UIColorMakeWithRGBA(255, 255, 255, 0).CGColor, (id)UIColorMakeWithRGBA(255, 255, 255, 1).CGColor, (id)UIColorMakeWithRGBA(255, 255, 255, 1).CGColor, (id)UIColorMakeWithRGBA(255, 255, 255, 0).CGColor];
        self.layer.mask = self.fadeLayer;
        [self setNeedsLayout];// fadeLayer 作为 layer.mask，它依赖于在 layoutSubviews 里正确布局，否则会因为错误的 size 而导致 label 看不见
    } else {
        if (self.layer.mask == self.fadeLayer) {
            self.layer.mask = nil;
        }
    }
}

#pragma mark - Superclass

- (void)setNumberOfLines:(NSInteger)numberOfLines {
    numberOfLines = 1;
    [super setNumberOfLines:numberOfLines];
}

@end

@implementation QMUIMarqueeLabel (ReusableView)

- (BOOL)requestToStartAnimation {
    self.automaticallyValidateVisibleFrame = NO;
    BOOL shouldPlayDisplayLink = [self shouldPlayDisplayLink];
    if (shouldPlayDisplayLink) {
        self.displayLink.paused = NO;
    }
    return shouldPlayDisplayLink;
}

- (BOOL)requestToStopAnimation {
    self.displayLink.paused = YES;
    return YES;
}

@end

@implementation UILabel (QMUI_Marquee)

- (void)qmui_startNativeMarquee {
    // 系统有 _startMarqueeIfNecessary、_startMarquee，但直接开启的方法其实是 marqueeRunning
    BOOL running = YES;
    self.numberOfLines = 1;
    self.clipsToBounds = YES;
    [self qmui_performSelector:NSSelectorFromString(@"setMarqueeEnabled:") withArguments:&running, nil];
    [self qmui_performSelector:NSSelectorFromString(@"setMarqueeRunning:") withArguments:&running, nil];
    [self qmuimq_removeObserver];
    [NSNotificationCenter.defaultCenter addObserver:self selector:@selector(qmuimq_handleApplicationDidEnterBackground:) name:UIApplicationDidEnterBackgroundNotification object:nil];
    [NSNotificationCenter.defaultCenter addObserver:self selector:@selector(qmuimq_handleApplicationDidBecomeActive:) name:UIApplicationDidBecomeActiveNotification object:nil];
}

- (void)qmui_stopNativeMarquee {
    // 系统有 _stopMarqueeWithRedisplay:，但直接关闭的方法其实是 marqueeRunning
    BOOL running = NO;
    [self qmui_performSelector:NSSelectorFromString(@"setMarqueeRunning:") withArguments:&running, nil];
    [self qmui_performSelector:NSSelectorFromString(@"setMarqueeEnabled:") withArguments:&running, nil];
    [self qmuimq_removeObserver];
}

- (BOOL)qmui_nativeMarqueeRunning {
    BOOL running = NO;
    [self qmui_performSelector:NSSelectorFromString(@"marqueeRunning") withPrimitiveReturnValue:&running];
    return running;
}

- (void)qmuimq_handleApplicationDidEnterBackground:(NSNotification *)notification {
    [self qmui_bindBOOL:self.qmui_nativeMarqueeRunning forKey:@"QMUI_Marquee_Running"];
}

- (void)qmuimq_handleApplicationDidBecomeActive:(NSNotification *)notification {
    if ([self qmui_getBoundBOOLForKey:@"QMUI_Marquee_Running"]) {
        [self qmui_stopNativeMarquee];// 要手动停止一次才能重新 start
        [self qmui_startNativeMarquee];
    }
}

- (void)qmuimq_removeObserver {
    [NSNotificationCenter.defaultCenter removeObserver:self name:UIApplicationDidEnterBackgroundNotification object:nil];
    [NSNotificationCenter.defaultCenter removeObserver:self name:UIApplicationDidBecomeActiveNotification object:nil];
}

@end