知识点：将View上的信息保存到相册

关于绘制图形、路线

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#import <UIKit/UIKit.h>

@interface FFFPaintView : UIView

@PRoperty (nonatomic,strong) UIColor *lineColor;

@property(nonatomic,assign) CGFloat lineWithed;

@property (nonatomic,copy) CGFloat (^lineWithBlock)();

//清屏

-(void)clearScreen;

//回退

-(void)recede;

//橡皮擦

-(void)eraser;

@end

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#import "FFFPaintView.h"

@interface FFFBezierPath : UIBezierPath

@property (nonatomic,strong) UIColor *lineColor;

@end

@implementation FFFBezierPath

@end

@interface FFFPaintView ()

@property (nonatomic,strong) NSMutableArray *paths;

@end

@implementation FFFPaintView

-(NSMutableArray *)paths{

    if(_paths==nil){

        _paths = [NSMutableArray array];

    }

    return _paths;

}

//清屏

-(void)clearScreen{

//    注意这里有时候移除全部的时候会出错，所以为了防止，建议 == nil,即可，然后在重绘

    [self.paths removeAllObjects];

    self.paths = nil;

    //    重绘

    [self setNeedsDisplay];

}

//回退

-(void)recede{

    [self.paths removeLastObject];

    //    重绘

    [self setNeedsDisplay];

}

//橡皮擦

-(void)eraser{

    self.lineColor = self.backgroundColor;

    //    重绘

    [self setNeedsDisplay];

}

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{

//   获取触摸的对象

    UITouch *touch = [touches anyObject];

//    通过触摸对象获取手指的位置

    CGPoint point = [touch locationInView:touch.view];  

//    创建路径对象

    FFFBezierPath *path = [[FFFBezierPath alloc] init];

    [path moveToPoint:point];   

//    设置线的颜色

    path.lineColor = self.lineColor;

    if(self.lineWithBlock){

        path.lineWidth = self.lineWithBlock();

    }

//    下面的方法是无法获取到值的

//    path.lineWidth = self.lineWithed;

//    NSLog(@"%f",self.lineWithed);

//    把path添加到数组中

    [self.paths addObject:path];

}

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{

//    获取触摸的对象

    UITouch *touch = [touches anyObject];

    CGPoint point = [touch locationInView:touch.view];

//    使用数组当中最后一个路径 来连线

    [[self.paths lastObject] addLineToPoint:point];

//    重绘

    [self setNeedsDisplay];

}

-(void)drawRect:(CGRect)rect{

//    遍历所有的路径渲染

    for (FFFBezierPath *path in self.paths) {

        [path.lineColor set];

//        设置样式

        [path setLineCapStyle:kCGLineCapRound];

        [path setLineJoinStyle:kCGLineJoinRound];

    //    渲染

        [path stroke];

//        NSLog(@"%@",path);

    }

}

@end

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#import "ViewController.h"

#import "FFFPaintView.h"

@interface ViewController ()

@property (weak, nonatomic) IBOutlet FFFPaintView *paintView;

@property (weak, nonatomic) IBOutlet UISlider *slider;

@property (weak, nonatomic) IBOutlet UIButton *firstButton;

@end

@implementation ViewController

//- (IBAction)slider:(UISlider *)sender {

//    

//    self.paintView.lineWithed = sender.value;

//    

//}

- (IBAction)savePaint {

//    开启图片类型的上下文

    UIGraphicsBeginImageContextWithOptions(self.paintView.bounds.size, NO, 0);

//    获取当前上下文

    CGContextRef ctx = UIGraphicsGetCurrentContext();

//    把当前view的样式，绘制到上下文当中

    [self.paintView.layer renderInContext:ctx];

//    保存到相册，同时从上下文中获取图片

    UIImageWriteToSavedPhotosAlbum(UIGraphicsGetImageFromCurrentImageContext(), nil, nil, nil);

//    关闭上下文

    UIGraphicsEndImageContext();

}

//清屏

-(IBAction)clearScreen{

    [self.paintView clearScreen];

}

//回退

-(IBAction)recede{

    [self.paintView recede];

}

//橡皮擦

-(IBAction)eraser{

    [self.paintView eraser];

}

- (void)viewDidLoad {

    [super viewDidLoad];

    [self.paintView setLineWithBlock:^CGFloat{

        return self.slider.value;

    }];

    self.paintView.lineColor = self.firstButton.backgroundColor;

}

- (IBAction)setColorSelected:(UIButton *)sender {

    self.paintView.lineColor = sender.backgroundColor;

}

@end

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