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 + ;
     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(, , rect.size.width, rect.size.height)];

     for (int i = ; 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", - self.m.penAlpha];

     self.sliderRed.value = self.m.red;
     self.sliderGreen.value = self.m.green;
     self.sliderBlue.value = self.m.blue;
     self.sliderAlpha.value =  - 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 :
             self.lalRed.text = [NSString stringWithFormat:@"红：%0.0f",sender.value];
             self.m.red = sender.value;
             break;
         case :
             self.lalGreen.text = [NSString stringWithFormat:@"绿：%0.0f",sender.value];
             self.m.green = sender.value;
             break;
         case :
             self.lalBlue.text = [NSString stringWithFormat:@"蓝：%0.0f",sender.value];
             self.m.blue = sender.value;
             break;
         case :
             self.lalAlpha.text = [NSString stringWithFormat:@"透明度：%0.1f",sender.value];
             self.m.penAlpha =  - 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 /  green:self.green/  blue:self.blue /  alpha: - self.penAlpha];
     return _penColor;
 }

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