UIBezierPath Smooth Curve for finger touch drawing

Question

i want to smooth curve on finger touch draw line and i want solution in UIBezierPath only my code not smoothing line completely.my code here's

@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

and i am getting output using my code like below screen shot:

enter image description here

i want smooth curve output like below screen shot:

enter image description here

can any one help me greatly appreciated!

Thanks in Advance!

score 5 · Answer 1 · edited May 23 '17 at 12:33

The problem is that you're only adding points to the path using addLineToPoint:. That's the equivalent of creating a series of straight lines. You really need to add control points, like the handles you might drag while drawing curved paths in Illustrator or Sketch.

You can use addCurveToPoint:controlPoint1:controlPoint2: to add those; the trick is working out where to put the control points, relative to the points you actually get back from the touches* events.

For a good discussion of possible techniques, I recommend the following question: Drawing Smooth Curves - Methods Needed.

UIBezierPath Smooth Curve for finger touch drawing

1 Answers1