iOS---实现在屏幕上实时绘图的简单效果---CAShaperLayer和UIBezierPath的简单运用
2024-10-07 08:20:09
首先,声明几个属性
@property(nonatomic,strong)UIBezierPath * beizer;
@property(nonatomic,assign)CGPoint startPoint;
@property(nonatomic,assign)CGPoint movePoint;
@property(nonatomic,strong)CAShapeLayer * shapelayer;
然后注册屏幕上的拖拽事件,并初始化贝塞尔曲线和CAShapeLayer
- (void)viewDidLoad {
[super viewDidLoad];
UIPanGestureRecognizer * pan = [[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(panTouch:)];
[self.view addGestureRecognizer:pan];
self.beizer = [UIBezierPath bezierPath];
[self initCAShaper]; }
-(void)initCAShaper
{
self.shapelayer = [CAShapeLayer new];
self.shapelayer.frame = CGRectMake(, , self.view.frame.size.width, self.view.frame.size.height);
self.shapelayer.fillColor = nil;
self.shapelayer.lineCap = kCALineCapRound;
self.shapelayer.strokeColor = [UIColor cyanColor].CGColor;
self.shapelayer.lineWidth =;
[self.view.layer addSublayer:self.shapelayer]; }
紧接着处理拖拽事件
-(void)panTouch:(UIPanGestureRecognizer *)pan
{
_startPoint = [pan locationInView:self.view];
if(pan.state == UIGestureRecognizerStateBegan)
{
[self.beizer moveToPoint:_startPoint];
}
if(pan.state == UIGestureRecognizerStateChanged)
{
_movePoint = [pan locationInView:self.view];
[_beizer addLineToPoint:_movePoint];
self.shapelayer.path = _beizer.CGPath;
}
}
大功告成。如图
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