[控件] 动态实时设置CAShapeLayer贝塞尔曲线的坐标点

动态实时设置CAShapeLayer贝塞尔曲线的坐标点

效果图:

源码:

PathDirectionView.h 与 PathDirectionView.m

//
//  PathDirectionView.h
//  Path
//
//  Created by XianMingYou on 15/2/27.
//  Copyright (c) 2015年 XianMingYou. All rights reserved.
//

#import <UIKit/UIKit.h>
#import "UIView+SetRect.h"

@interface PathDirectionView : UIView

/**
 *  起始点在右边
 */
@property (nonatomic) BOOL  startPointAtRight;

/**
 *  根据百分比显示
 *
 *  @param percent 百分比
 */
- (void)showPercent:(CGFloat)percent;

@end

//
//  PathDirectionView.m
//  Path
//
//  Created by XianMingYou on 15/2/27.
//  Copyright (c) 2015年 XianMingYou. All rights reserved.
//

#import "PathDirectionView.h"

@interface PathDirectionView () {
    CAShapeLayer  *_shapeLayer;
}

@end

@implementation PathDirectionView

/**
 *  修改当前view的backupLayer为CAGradientLayer
 *
 *  @return CAGradientLayer类名字
 */
+ (Class)layerClass {
    return [CAShapeLayer class];
}

- (instancetype)initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame];
    if (self) {
        _shapeLayer             = (CAShapeLayer *)self.layer;
        _shapeLayer.fillColor   = [[UIColor clearColor] CGColor];
        _shapeLayer.strokeColor = [[UIColor redColor] CGColor];
        _shapeLayer.lineWidth   = 1.f;
        _shapeLayer.strokeEnd   = 0.f;
        _shapeLayer.opacity     = 0.f;
        _shapeLayer.path        = [self createPathWithHeight:0];
    }
    return self;
}

/**
 *  创建出贝塞尔曲线
 *
 *  @param height 高度
 *
 *  @return 贝塞尔曲线
 */
- (CGPathRef)createPathWithHeight:(CGFloat)height {
    UIBezierPath *bezierPath = UIBezierPath.bezierPath;
    
    CGPoint startPoint = CGPointZero;
    CGPoint endPoint   = CGPointZero;
    if (self.startPointAtRight == NO) {
        startPoint = CGPointMake(self.width, height);
        endPoint   = CGPointZero;
    } else {
        startPoint = CGPointMake(0, height);
        endPoint   = CGPointMake(self.width, 0);
    }
    
    [bezierPath moveToPoint:startPoint];
    [bezierPath addLineToPoint:endPoint];
    
    return bezierPath.CGPath;
}


- (void)showPercent:(CGFloat)percent {
    
    if (percent < 0) {
        _shapeLayer.path      = [self createPathWithHeight:0];
        _shapeLayer.strokeEnd = 0;
        _shapeLayer.opacity   = 0;
    } else if (percent >= 0 && percent <= 0.5f) { // [0, 0.5]
        _shapeLayer.path      = [self createPathWithHeight:0];
        _shapeLayer.strokeEnd = percent * 2.f;
        _shapeLayer.opacity   = percent * 2.f;
    } else if (percent <= 1.f) { // (0.5, 1]
        CGFloat currentPercent = percent - 0.5f;
        _shapeLayer.path      = [self createPathWithHeight:currentPercent * self.height * 2];
        _shapeLayer.strokeEnd = 1.f;
        _shapeLayer.opacity   = 1.f;
    } else { // (1, +无穷大)
        _shapeLayer.path      = [self createPathWithHeight:self.height];
        _shapeLayer.strokeEnd = 1.f;
        _shapeLayer.opacity   = 1.f;
    }
}

@end

ShowDownView.h 与 ShowDownView.m

//
//  ShowDownView.h
//  Path
//
//  Created by XianMingYou on 15/2/27.
//  Copyright (c) 2015年 XianMingYou. All rights reserved.
//

#import <UIKit/UIKit.h>
#import "PathDirectionView.h"

@interface ShowDownView : UIView

- (void)showPercent:(CGFloat)percent;

@end

//
//  ShowDownView.m
//  Path
//
//  Created by XianMingYou on 15/2/27.
//  Copyright (c) 2015年 XianMingYou. All rights reserved.
//

#import "ShowDownView.h"

@interface ShowDownView ()

@property (nonatomic, strong) PathDirectionView *leftView;
@property (nonatomic, strong) PathDirectionView *rightView;

@end

@implementation ShowDownView

- (instancetype)initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame];
    if (self) {
        CGFloat width  = frame.size.width / 2.f;
        CGFloat height = frame.size.height;
        
        CGRect leftRect  = CGRectMake(0, 0, width, height);
        CGRect rightRect = CGRectMake(width, 0, width, height);
        
        self.leftView  = [[PathDirectionView alloc] initWithFrame:leftRect];
        self.rightView = [[PathDirectionView alloc] initWithFrame:rightRect];
        self.rightView.startPointAtRight = YES;
        [self addSubview:self.leftView];
        [self addSubview:self.rightView];
    }
    return self;
}

- (void)showPercent:(CGFloat)percent {
    [self.leftView showPercent:percent];
    [self.rightView showPercent:percent];
}

@end

核心原理:

1. 即时的根据值的变化重新生成path值并赋值给CAShapeLayer

2. 即时的根据值得变化设定strokeEnd值