Simple signature capture functionality for iOS. Comes with methods to output as either string of coords or image.

signatureCapture.m

- (void)pan:(UIPanGestureRecognizer *)pan {
    CGPoint currentPoint = [pan locationInView:self];
    CGPoint midPoint = midpoint(previousPoint, currentPoint);

    if (pan.state == UIGestureRecognizerStateBegan) {
        [path moveToPoint:currentPoint];
        currentPath = [NSMutableArray arrayWithObject:[NSValue valueWithCGPoint:currentPoint]];
    } else if (pan.state == UIGestureRecognizerStateChanged) {
        [path addQuadCurveToPoint:midPoint controlPoint:previousPoint];
        [currentPath addObject:[NSValue valueWithCGPoint:midPoint]];
        [currentPath addObject:[NSValue valueWithCGPoint:currentPoint]];
    } else if (pan.state == UIGestureRecognizerStateEnded) {
        if (currentPath != nil) {
            [paths addObject: currentPath];
            hasContent = YES;
        }
    }

    previousPoint = currentPoint;

    [self setNeedsDisplay];
}

- (void)clear {
    path = [UIBezierPath bezierPath];
    paths = [[NSMutableArray alloc] init];
    [self setNeedsDisplay];
}

static CGPoint midpoint(CGPoint p0, CGPoint p1) {
    return (CGPoint) {
        (p0.x + p1.x) / 2.0,
        (p0.y + p1.y) / 2.0
    };
}

- (void)drawRect:(CGRect)rect
{
    [[UIColor blackColor] setStroke];
    [path stroke];
}

- (UIImage*)getImageRepresentation {

    UIGraphicsBeginImageContext(self.bounds.size);

    [self.layer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return viewImage;
}

- (NSString*)getStringRepresentation {

    NSString *retString = @"";
    for (NSArray *pathArray in paths) {
        bool firstPoint = YES;
        for(NSValue *pointValue in pathArray){
            CGPoint point = [pointValue CGPointValue];
            if (firstPoint) {
                firstPoint = NO;
                retString = [retString stringByAppendingFormat:
                             @"s:%f,%f;", point.x, point.y];
            } else {
                retString = [retString stringByAppendingFormat:
                             @"p:%f,%f;", point.x, point.y];
            }
        }
    }
    return retString;

}