好久没有自己写点东西了，昨天看到前公司的一个小功能，挺感兴趣的，就自己做了个类似于手绘板的功能。废话不多说，上图上代码。

2016-12-23 14_29_37.gif

@property (nonatomic, strong) NSMutableArray *LayerArray;

@property (nonatomic, strong) HBShapLayer *drawLayer;

@property (nonatomic, strong) UIBezierPath *beganPath;
//线宽
@property (nonatomic, assign) CGFloat lineWidth;
//线的颜色
@property (nonatomic, strong) UIColor *lineColor;


- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [touches anyObject];
    CGPoint beganPoint = [touch locationInView:self];
    [self drawBeganPoint:beganPoint];
}
- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [touches anyObject];
    CGPoint currentPoint = [touch locationInView:self];
    //上一个点的坐标
    CGPoint previousPoint = [touch previousLocationInView:self];
    CGPoint middlePoint = midPoint(previousPoint,currentPoint);
    [self drawControlPoint:middlePoint EndPoint:currentPoint];
}
- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [touches anyObject];
    CGPoint currentPoint = [touch locationInView:self];
    CGPoint previousPoint = [touch previousLocationInView:self];
    CGPoint middlePoint = midPoint(previousPoint,currentPoint);
    [self drawControlPoint:middlePoint EndPoint:currentPoint];
}

线条起点位置：

- (void)drawBeganPoint:(CGPoint)point
{
    
    HBShapLayer *drawLayer = [HBShapLayer layer];
    drawLayer.lineWidth = self.lineWidth;
    drawLayer.fillColor = [UIColor clearColor].CGColor;
    drawLayer.strokeColor = self.lineColor.CGColor;
    _drawLayer = drawLayer;
    _drawLayer.isPen = YES;
    [self.layer addSublayer:_drawLayer];
    
    [_LayerArray addObject:drawLayer];
    
    UIBezierPath *beganPath = [UIBezierPath bezierPath];
    [beganPath moveToPoint:point];
    _beganPath = beganPath;
    
}

更新线条的位置：

- (void)drawControlPoint:(CGPoint)controlPoint EndPoint:(CGPoint)point
{
    [_beganPath addQuadCurveToPoint:point controlPoint:controlPoint];
    _drawLayer.path = _beganPath.CGPath;
}
// 计算中间点
CGPoint midPoint(CGPoint p1, CGPoint p2)
{
    return CGPointMake((p1.x + p2.x) * 0.5, (p1.y + p2.y) * 0.5);
}

这个方法是将UIView转为UIImage:

注意UIGraphicsBeginImageContextWithOptions这个方法的第二个和第三个参数，如果将第二个参数设置为yes的话，保存的图片会出现模糊的情况.

//将UIView转成UIImage
-(UIImage *)getImageFromView:(UIView *)theView
{
     // 下面方法，第一个参数表示区域大小。第二个参数表示是否是非透明的。如果需要显示半透明效果，需要传NO，否则传YES。第三个参数就是屏幕密度了
    UIGraphicsBeginImageContextWithOptions(theView.bounds.size, NO, [UIScreen mainScreen].scale);
    [theView.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

有什么错误和疏漏，欢迎指正，附上demo地址。