blancos blancos - 3 months ago 17
Objective-C Question

Detecting tap inside a bezier path

I have a UIView which is added as a subview to my view controller. I have drawn a bezier path on that view. My drawRect implementation is below

- (void)drawRect:(CGRect)rect
{
CGContextRef context = UIGraphicsGetCurrentContext();
UIBezierPath *bpath = [UIBezierPath bezierPath];

[bpath moveToPoint:CGPointMake(50, 50)];
[bpath addLineToPoint:CGPointMake(100, 50)];
[bpath addLineToPoint:CGPointMake(100, 100)];
[bpath addLineToPoint:CGPointMake(50, 100)];
[bpath closePath];

CGContextAddPath(context, bpath.CGPath);
CGContextSetStrokeColorWithColor(context,[UIColor blackColor].CGColor);
CGContextSetLineWidth(context, 2.5);
CGContextStrokePath(context);
UIColor *fillColor = [UIColor colorWithRed:0.0 green:0.0 blue:0.5 alpha:0.7];
[fillColor setFill];
[bpath fill];
}


I want detect tap inside this bezier path but not the point which is inside the UIView and outside the path. For example in this case if my touch coordinate is (10, 10), it should not be detected. I know about CGContextPathContainsPoint but it does not help when touch is inside the path. Is there a way to detect touch events inside bezier path?

Answer

There is a function CGPathContainsPoint() it may be useful in your case.

Also be careful if you get gesture point from superview, the coordinate may not be correct with your test. You have a method to convertPoint from or to a particular view's coordinate system:

- (CGPoint)convertPoint:(CGPoint)point toView:(UIView *)view
- (CGPoint)convertPoint:(CGPoint)point fromView:(UIView *)view