一個簡單的繪圖應(yīng)用，模仿蘋果自帶軟件備忘錄里的涂鴉功能

核心代碼

#import "DrawView.h"

#import "DrawPath.h"

@interface DrawView ()

@property (nonatomic, strong) NSMutableArray *paths;


@property (nonatomic, strong) UIBezierPath *path;


@end


@implementation DrawView

- (void)setImage:(UIImage *)image
{
    _image = image;
    
    [self.paths addObject:image];
    

    [self setNeedsDisplay];
}

// 撤銷
- (void)undo
{
    [self.paths removeLastObject];
    
    [self setNeedsDisplay];
}
- (void)clear
{
    // 清除畫板view所有的路徑,并且重繪
    [self.paths removeAllObjects];
    
    [self setNeedsDisplay];
}

- (void)awakeFromNib
{
    _lineWidth = 1;
    _lineColor = [UIColor blackColor];
}

- (NSMutableArray *)paths
{
    if (_paths == nil) {
        _paths = [NSMutableArray array];
    }
    return _paths;
}

// 當(dāng)手指點(diǎn)擊view,就需要記錄下起始點(diǎn)
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    // 獲取UITouch
    UITouch *touch = [touches anyObject];
    
    // 獲取起始點(diǎn)
    CGPoint curP = [touch locationInView:self];
    
    // 只要一開始觸摸控件,設(shè)置起始點(diǎn)
    DrawPath *path = [DrawPath path];
    
    path.lineColor = _lineColor;

    [path moveToPoint:curP];

    
    path.lineWidth = _lineWidth;
    
    // 記錄當(dāng)前正在描述的路徑
    _path = path;
    
    // 保存當(dāng)前的路徑
    [self.paths addObject:path];
}

// 每次手指移動的時候調(diào)用
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{

    // 獲取UITouch
    UITouch *touch = [touches anyObject];
    
    // 獲取當(dāng)前觸摸點(diǎn)
    CGPoint curP = [touch locationInView:self];
    
    [_path addLineToPoint:curP];
    
    // 重繪
    [self setNeedsDisplay];
    
}

// 繪制東西
- (void)drawRect:(CGRect)rect
{
    for (DrawPath *path in self.paths) {
        
        if ([path isKindOfClass:[UIImage class]]) { // 圖片
            UIImage *image = (UIImage *)path;
            
            [image drawAtPoint:CGPointZero];
        }else{
            
            [path.lineColor set];
            
            [path stroke];
        }
    }
}



@end

用法很簡單，導(dǎo)入DrawView.h DrawView.m 文件創(chuàng)建該控件即可

清屏： [_drawView clear];
撤銷： [_drawView undo];
橡皮擦： _drawView.lineColor = [UIColor whiteColor];

github地址：https://github.com/chglog/scrawl

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