iOS_Quartz2D之涂鸦板

响应者对象：继承了UIResponder的对象

触摸事件：一根或多根手指；

开始触摸：

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

移动：每移动一点就会调用一次；

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

触摸结束：

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event;

触摸事件被打断：

- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event;

远程控制事件：

- (void)remoteControlReceivedWithEvent:(UIEvent *)event NS_AVAILABLE_IOS(4_0);

UIToch对象：

触摸时，会为每个手指创建一个相关联的UITouch对象，保存着跟手指相关的信息，触摸的位置、时间等；

手指移动时，系统会更新同一个UITouch对象，一直保存手指触摸的位置；

手指移开时，销毁UITouch；

获取touch对象：UITouch * touch = [touches anyObject];

触摸点所在的view

touch.view

触摸点所在的window

touch.window

获取当前触摸点的位置,相对于哪个view的位置，填nil为相对于window；

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

获取上一个触摸点的位置，可以用于touchesMoved方法中

    CGPoint point2 = [touch previousLocationInView:touch.view];

 效果图：

         画笔笔头根据画笔宽度进行改变:

原理：利用view的触摸事件，使用UIBezierPath对象进行涂鸦，UIBezierPath可以储存线段上的所有点，当成一条路径使用，并且被渲染到视图上；根据触摸点位置变化设置跟踪笔头；

我仅仅实现了效果，封装的不是很好完善，推荐这位大神的博客，封装思想很好点击这里

我有一个继承自UIView的tuyaView来作为白色涂鸦板，一个设置画笔属性的UIViewController，一个用于储存画笔属性的数据manager类；

图片

步骤：

涂鸦板view：

1、自定义一个继承自UIView的view作为涂鸦板，UIView继承自UIResponder，可以接收触摸事件； 声明三个数组属性用于存放线段以及线段属性，并且在懒加载中初始化；

2、在view的touchBegin事件中，新建一个UIBezierPath对象，使用它的moveToPoint方法将当前的触摸点设为这条线段的起点，并且将他存放到我们的线段数组中，从数据管理器中拿出线段的各种属性存放在属性数组中。初始化圆形画笔笔头，添加到涂鸦板上，中心位为触摸点；

4、监控手指的移动，将剩余线段点加入到上面创建的UIBezierPath对象中；从数组中取出贝塞尔对象，使用它的addLineToPoint方法，将移动后得到的当前点储存上；并且调用view的setNeedDisplay方法，重绘view；设置画笔笔头跟踪手指触摸移动。当触摸结束时，将笔头view移除；

5、实现view的drawRect方法：此方法用于绘制view，第四步设置了每当touchmove时都会调用此方法，从数组中拿出每一个贝塞尔对象，将它画到view上，并且取出相应的画笔样式；如果用户选取了照片就将照片绘制上去，这样绘制功能就实现了；

6、实现添加图片、退一步、清空画布、保存图片四个方法；

tuyaView.m

@interface tuyaView ()
保存每条线段
@property (nonatomic, strong) NSMutableArray * linePaths;
保存每条线段的画笔大小
@property (nonatomic, strong) NSMutableArray * penValues;
保存每条线段颜色
@property (nonatomic, strong) NSMutableArray * penColors;
数据管理器
@property (nonatomic, strong) manager * m;
画笔 笔头；
@property (nonatomic, strong) UIView * touchPointView;

@end

@implementation tuyaView
懒加载中初始化各个数组
-(manager *)m
{
    if (!_m)
    {
        _m = [manager shared];
    }
    return _m;
}

-(NSMutableArray *)penValues
{
    if (!_penValues)
    {
        _penValues = [NSMutableArray array];
    }
    return _penValues;
}

- (NSMutableArray *)linePaths
{
    if (!_linePaths) {
        _linePaths = [NSMutableArray array];
    }
    return _linePaths;
}

-(NSMutableArray *)penColors
{
    if (!_penColors) {
        _penColors = [NSMutableArray array];
    }
    return _penColors;
}


触摸事件开始
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch * touch = [touches anyObject];
    CGPoint point = [touch locationInView:touch.view];
    //
    UIBezierPath * linePath = [UIBezierPath bezierPath];
    [linePath moveToPoint:point];
    [self.linePaths addObject:linePath];
    
    //保存线条粗细
    float penValue = self.m.penValue;
    [self.penValues addObject:[NSNumber numberWithFloat:penValue ]];
    //保存线条颜色
    UIColor * penColor = self.m.penColor;
    [self.penColors addObject:penColor];
    
    //创建触控点
    CGFloat touchRadius = self.m.penValue + 10;
    self.touchPointView = [[UIView alloc] initWithFrame:CGRectMake(point.x - touchRadius * 0.5, point.y - touchRadius * 0.5, touchRadius, touchRadius)];
    self.touchPointView.layer.cornerRadius = touchRadius * 0.5;
    self.touchPointView.clipsToBounds = YES;
    self.touchPointView.backgroundColor = [UIColor redColor];
    self.touchPointView.alpha = 0.5;
    [self addSubview:self.touchPointView];
}

手指移动
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{    
    UITouch * touch = [touches anyObject];
    CGPoint touchPoint = [touch locationInView:touch.view];
    
    UIBezierPath * linePath = [self.linePaths lastObject];
    [linePath addLineToPoint:touchPoint];
    
    //触控点移动
    CGPoint current = [touch locationInView:touch.view];
    CGPoint pre = [touch previousLocationInView:touch.view];
    CGPoint center = self.touchPointView.center;
    center.x += current.x - pre.x;
    center.y += current.y - pre.y;
    self.touchPointView.center = center;
    
    [self setNeedsDisplay];
}

触摸结束
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    [self.touchPointView removeFromSuperview];
}


绘制view
-(void)drawRect:(CGRect)rect
{
    [self.tuyaImage drawInRect:CGRectMake(0, 0, rect.size.width, rect.size.height)];

    for (int i = 0; i < self.linePaths.count; i ++)
    {
        UIBezierPath * path = self.linePaths[i];
        //取出线条宽度
        float penValue = [self.penValues[i] floatValue];
        [path setLineWidth:penValue];
        //取出线条颜色
        UIColor * color = self.penColors[i];
        [color setStroke];
        
        [path setLineJoinStyle:kCGLineJoinRound];
        [path setLineCapStyle:kCGLineCapRound];
        [path stroke];
    }
}

选取图片
- (void)fetchPictureWith:(UIImage *)image
{
    self.tuyaImage = image;
    [self setNeedsDisplay];
}

退后一步
- (void)backTheLastTime
{
    [self.linePaths removeLastObject];
    [self.penValues removeLastObject];
    [self.penColors removeLastObject];
    [self setNeedsDisplay];
}

清空画布
- (void)cleanAllPainted
{
    [self.linePaths removeAllObjects];
    [self.penValues removeAllObjects];
    [self.penColors removeAllObjects];
    self.tuyaImage = nil;
    [self setNeedsDisplay];
}

保存图片到手机相册
- (void)savePicture
{
    //1、开启上下文
    UIGraphicsBeginImageContextWithOptions(self.frame.size, YES, 0.0);
    //2、将控制器view的layer渲染到上下文，想要截啥就把哪个图层拿出来渲染
    [self.layer renderInContext:UIGraphicsGetCurrentContext()];
    //3、取出图片
    UIImage * newImage = UIGraphicsGetImageFromCurrentImageContext();
    //保存到手机相册
    UIImageWriteToSavedPhotosAlbum(newImage, nil, nil, nil);
    //关闭上下文
    UIGraphicsEndImageContext();
}

属性控制器：1、从数据管理器中取出数据显示到自身view上。2、当画笔样式被修改时，将数据保存到管理器中。3、和tuyaView通过UINavigationController跳转，各种控件通过Storyboard实现；

PropertyView.m

@interface PropertyView ()

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

@property (nonatomic, strong)manager * m;
@property (weak, nonatomic) IBOutlet UISlider *sliderRed;
@property (weak, nonatomic) IBOutlet UISlider *sliderGreen;
@property (weak, nonatomic) IBOutlet UISlider *sliderBlue;
@property (weak, nonatomic) IBOutlet UISlider *sliderAlpha;

@property (weak, nonatomic) IBOutlet UILabel *lalRed;
@property (weak, nonatomic) IBOutlet UILabel *lalGreen;
@property (weak, nonatomic) IBOutlet UILabel *lalBlue;
@property (weak, nonatomic) IBOutlet UILabel *lalAlpha;

@property (weak, nonatomic) IBOutlet UIView *colorView;

@end

@implementation PropertyView

-(void)viewDidLoad
{
    [super viewDidLoad];
    self.m = [manager shared];
    self.slider.value = self.m.penValue;
    self.lalPen.text = [NSString stringWithFormat:@"画笔宽度：%0.1lf",self.m.penValue];
    
    self.lalRed.text = self.lalRed.text = [NSString stringWithFormat:@"红：%0.0f",self.m.red];
    self.lalGreen.text = [NSString stringWithFormat:@"红：%0.0f",self.m.green];
    self.lalBlue.text = [NSString stringWithFormat:@"红：%0.0f",self.m.blue];
    self.lalAlpha.text = [NSString stringWithFormat:@"透明度：%0.0f",1 - self.m.penAlpha];
    
    self.sliderRed.value = self.m.red;
    self.sliderGreen.value = self.m.green;
    self.sliderBlue.value = self.m.blue;
    self.sliderAlpha.value = 1 - self.m.penAlpha;
    
    self.colorView.backgroundColor = self.m.penColor;
}

- (IBAction)PenSliderValueChanged:(UISlider *)sender
{
    self.lalPen.text = [NSString stringWithFormat:@"画笔宽度：%0.1lf",sender.value];
    self.m.penValue = sender.value;
}

当4slider改变时回调同一个方法；
- (IBAction)ColorChanged:(UISlider *)sender {
    switch (sender.tag) {
        case 1:
            self.lalRed.text = [NSString stringWithFormat:@"红：%0.0f",sender.value];
            self.m.red = sender.value;
            break;
        case 2:
            self.lalGreen.text = [NSString stringWithFormat:@"绿：%0.0f",sender.value];
            self.m.green = sender.value;
            break;
        case 3:
            self.lalBlue.text = [NSString stringWithFormat:@"蓝：%0.0f",sender.value];
            self.m.blue = sender.value;
            break;
        case 4:
            self.lalAlpha.text = [NSString stringWithFormat:@"透明度：%0.1f",sender.value];
            self.m.penAlpha = 1 - sender.value;
            break;
            
        default:
            break;
    }
    self.colorView.backgroundColor = self.m.penColor;
}

@end

数据管理器：储存画笔样式

manager.h

@interface manager : NSObject

@property (nonatomic, assign) CGFloat penValue;

@property (nonatomic, assign) CGFloat red;
@property (nonatomic, assign) CGFloat green;
@property (nonatomic, assign) CGFloat blue;
@property (nonatomic, strong) UIColor * penColor;
@property (nonatomic, assign) CGFloat penAlpha;

+ (instancetype)shared;

@end

manager.m

+ (instancetype)shared
{
    static manager * m = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        m = [[manager alloc] init];
    });
    return m;
}
初始化颜色
-(UIColor *)penColor
{
    _penColor = [UIColor colorWithRed:self.red / 255 green:self.green/ 255 blue:self.blue / 255 alpha:1 - self.penAlpha];
    return _penColor;
}

初始化画笔宽度
-(CGFloat)penValue
{
    if (!_penValue) {
        _penValue = 1.0;
    }
    return _penValue;
}