UIBezierPath用于手指触摸绘制的平滑曲线

Question

我希望在手指触摸绘制线上平滑曲线，我想在UIBezierPath中解决方案只有我的代码不能完全平滑线。我的代码在这里

@implementation MyLineDrawingView
@synthesize undoSteps;

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        // Initialization code

        [super setBackgroundColor:[UIColor whiteColor]];

        pathArray=[[NSMutableArray alloc]init];
        bufferArray=[[NSMutableArray alloc]init];



    }
    return self;
}


// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect
{

    [[UIColor blackColor] setStroke];
    for (UIBezierPath *_path in pathArray) 
    [_path strokeWithBlendMode:kCGBlendModeNormal alpha:1.0];    
}
#pragma mark - Touch Methods
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    [bufferArray removeAllObjects];
    myPath=[[UIBezierPath alloc]init];
    myPath.lineWidth=5;
    myPath.miterLimit=-10;
    myPath.lineCapStyle = kCGLineCapRound;
    myPath.flatness = 0.0;


    UITouch *mytouch=[[touches allObjects] objectAtIndex:0];
    [myPath moveToPoint:[mytouch locationInView:self]];
    [pathArray addObject:myPath];

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

    UITouch *mytouch=[[touches allObjects] objectAtIndex:0];
    [myPath addLineToPoint:[mytouch locationInView:self]];
    [self setNeedsDisplay];

}

-(void)undoButtonClicked
{
    if([pathArray count]>0)
    {
    UIBezierPath *_path=[pathArray lastObject];
    [bufferArray addObject:_path];
    [pathArray removeLastObject];
    [self setNeedsDisplay];
    }

}
-(void)redoButtonClicked
{
    if([bufferArray count]>0){
        UIBezierPath *_path=[bufferArray lastObject];
        [pathArray addObject:_path];
        [bufferArray removeLastObject];
        [self setNeedsDisplay];
    }   
}
- (void)dealloc
{
    [pathArray release];
    [bufferArray release];
    [super dealloc];
}

@end

我正在使用我的代码获得输出，如下面的屏幕截图：

我想要平滑的曲线输出，如下面的屏幕截图：

任何人都可以帮助我！

提前致谢！

Answer 1

问题是您只是使用addLineToPoint:向路径添加点数。这相当于创建一系列直线。您确实需要添加控制点，例如在Illustrator或Sketch中绘制曲线路径时可能拖动的手柄。

您可以使用addCurveToPoint:controlPoint1:controlPoint2:添加这些内容;诀窍在于确定控制点的位置，相对于实际从touches*事件中返回的点数。

为了更好地讨论可能的技巧，我建议使用以下问题：Drawing Smooth Curves - Methods Needed。