实现代码如下: ①在自定义视图中定义3个属性
//记录线条的路径@property (nonatomic, retain) NSMutableArray *paths;//设置绘图过程中线条的颜色@property (nonatomic, retain) UIColor *pathColor;@property (nonatomic, assign) CGFloat pathWidth;//撤销功能- (void)undo;//清除功能- (void)clear;
②实现效果,需要在手指开始移动即移动过程中处理操作,即需要在下面两个方法中操作.
– (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event;- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event;
方法中实现:
//实现相应时间- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {//获取手指对象UITouch *touch = [touches anyObject];//获取手指当前触摸点CGPoint startPoint = [touch locationInView:touch.view];//创建路径对象UIBezierPath *path = [UIBezierPath bezierPath];//设置路径的起始点[path moveToPoint:startPoint];//配置路径属性//线条宽度path.lineWidth = self.pathWidth; //线条结合处样式path.lineJoinStyle = kCGLineJoinRound;//线条样式path.lineCapStyle = kCGLineCapRound;//将路径添加到路径数组中[self.paths addObject:path];}- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {//获取手指对象UITouch *touch = [touches anyObject];//获取手指当前触摸的位置CGPoint currentPoint = [touch locationInView:touch.view];//获得当前路径UIBezierPath *path = [self.paths lastObject];//设置路径终点[path addLineToPoint:currentPoint];//该方法无需实现,只是通过它自动调用drawRect方法[self setNeedsDisplay];}
③实现视图中自带方法(drawRect),代码如下:
– (void)drawRect:(CGRect)rect {[self.pathColor setStroke];) {path.usesEvenOddFillRule = YES;[self.pathColor setFill];//设置笔画的颜色[self.pathColor setStroke];//和所有的路径相连[path stroke];}}
④属性实现懒加载 即实现消除 和撤销操作
– (NSMutableArray *)paths {if (!_paths) {self.paths = [NSMutableArray arrayWithCapacity:1];}return [[_paths retain] autorelease];}- (CGFloat)pathWidth {if (!_pathWidth) {_pathWidth = 1;}return _pathWidth;}//撤销功能- (void)undo {//删除最后一条数据,路径[self.paths removeLastObject];[self setNeedsDisplay];}//清除功能- (void)clear {//删除所有信息[self.paths removeAllObjects];[self setNeedsDisplay];}
④实现将涂鸦图片保存到系统相册. 1)获取涂鸦图片(UIImage的分类方法),view即当前涂鸦的视图
+ (UIImage *)saveImageFromDrawView:(UIView *)view {//获取图形上下文(上下文在这两个Graphics之间有效或者在DracRect中有效)UIGraphicsBeginImageContext(view.frame.size);//2.将要保存的view的layer绘制到bitmap图形上下文中,完成拍照的功能[view.layer renderInContext:UIGraphicsGetCurrentContext()];//从当前上下文获取图片UIImage *image = UIGraphicsGetImageFromCurrentImageContext();//结束操作UIGraphicsEndImageContext();return image;
2)将图片保存(写在button的触发事件中)
];//保存到相册UIImageWriteToSavedPhotosAlbum(image, self, nil, nil);
⑤滑动最下方的滑竿实现改变线条颜色,即线条的宽度.
//设置颜色- (IBAction)colorAction:(UISlider *)sender {//CGFloat value = sender.value;self.nameView.pathColor = [UIColor colorWithHue:sender.value saturation:sender.value brightness:sender.value alpha:sender.value];}//设置线条的宽度- (IBAction)boldAction:(UISlider *)sender {self}
，勇于接受自己的不完美，认清自己不足的地方，
