iOS如何簡單實現繪制愛心?

靈感來源於前端CSS畫紅心的原理 參考

自定義愛心View代碼

#import <UIKit/UIKit.h>
/**
    靈感來自於前端CSS畫紅心的原理: 一個正方形 + 兩個圓 + 整體旋轉一定的角度
*/

NS_ASSUME_NONNULL_BEGIN
IB_DESIGNABLE
@interface WGBHeartView : UIView
//❤心有多大?
@property (nonatomic,assign) IBInspectable CGFloat heartSize;
//❤心的顏色?
@property (nonatomic,strong) IBInspectable UIColor *heartColor;
@end
NS_ASSUME_NONNULL_END


#import "WGBHeartView.h"

@interface WGBHeartView()

@property (nonatomic,strong) UIView *bottomView;
@property (nonatomic,strong) UIView *leftView;
@property (nonatomic,strong) UIView *rightView;

@end

@implementation WGBHeartView

- (instancetype)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        [self initConfig];
    }
    return self;
}

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

- (void)initConfig{
        //默認值
    self.heartSize = 150.0;
    self.heartColor = [UIColor redColor];
    [self addSubview: self.bottomView];
    [self addSubview: self.leftView];
    [self addSubview: self.rightView];
    //提前旋轉45度
    self.transform = CGAffineTransformMakeRotation(M_PI_4);
}

//去除設置背景色 
- (void)setBackgroundColor:(UIColor *)backgroundColor{
    backgroundColor = [UIColor clearColor];
    [super setBackgroundColor:backgroundColor];
}

- (void)setHeartSize:(CGFloat)heartSize{
    _heartSize = heartSize;
    CGFloat partSize = heartSize/3.0;
    self.bottomView.frame = CGRectMake(partSize, partSize, partSize*2 , partSize*2);
    self.leftView.frame = CGRectMake(0, partSize, partSize*2 , partSize*2);
    self.rightView.frame = CGRectMake(partSize, 0, partSize*2 , partSize*2);
    
    self.leftView.layer.cornerRadius = partSize;
    self.rightView.layer.cornerRadius = partSize;
}

- (void)setHeartColor:(UIColor *)heartColor{
    _heartColor = heartColor;
    self.bottomView.backgroundColor = heartColor;
    self.leftView.backgroundColor = heartColor;
    self.rightView.backgroundColor = heartColor;
}

    ///MARK:- lazy load
- (UIView *)bottomView{
    if (!_bottomView) {
        _bottomView = [[UIView alloc] initWithFrame:CGRectZero];
        [self addSubview:_bottomView];
    }
    return _bottomView;
}
- (UIView *)leftView{
    if (!_leftView) {
        _leftView = [[UIView alloc] initWithFrame:CGRectZero];
        [self addSubview:_leftView];
    }
    return _leftView;
}

- (UIView *)rightView{
    if (!_rightView) {
        _rightView = [[UIView alloc] initWithFrame:CGRectZero];
        [self addSubview:_rightView];
    }
    return _rightView;
}

@end

簡單調用

    WGBHeartView *heartView = [[WGBHeartView alloc] initWithFrame:CGRectMake(100, 100, 100 , 100)];
    heartView.heartColor = [UIColor blackColor];//默認顏色是紅色
    heartView.heartSize = 100; //這個尺寸最好是設置與視圖寬高一致 生成的愛心❤️比較規則
    [self.view addSubview: heartView];
    
    for (NSInteger i = 0; i < 6; i += 1) {
        CGFloat heartWH = 50.0f;
        CGFloat margin = 15.0f;
        WGBHeartView *heartItemView = [[WGBHeartView alloc] initWithFrame:CGRectMake(20 + (heartWH+margin)*i,   250, heartWH , heartWH)];
        heartItemView.heartColor = [UIColor colorWithRed:arc4random()%256/255.0f green:arc4random()%256/255.0f  blue:arc4random()%256/255.0f alpha:1.0f];
        heartItemView.heartSize = heartWH;
        [self.view addSubview: heartItemView];
    }