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copied!<p>iOS doesn't have a public API that directly gives you points spaced along a path. But there is a roundabout way to do it. Suppose you want points along the path spaced a distance of X apart.</p> <p>First, create a <code>CGPathRef</code> containing your path. (You can construct a <code>UIBezierPath</code> if you prefer and then gets its <code>CGPath</code> property.)</p> <p>Then, call <code>CGPathCreateCopyByDashingPath</code>, using a dash pattern of <code>{ X, X }</code>. For example:</p> <pre><code>static CGFloat const kSpace = 10; CGPathRef dashedPath = CGPathCreateCopyByDashingPath(path, NULL, 0, (CGFloat const []){ kSpace, kSpace }, 2); </code></pre> <p>This returns a new path containing multiple subpaths. Each subpath is a length X segment of the original path, and is separated from its neighboring subpaths by a distance of X along the original path. Thus the endpoints of the subpaths are spaced along the original path at an interval of length X.</p> <p>So, finally, enumerate the dashed path using <code>CGPathApply</code>, picking the endpoints and creating buttons there. First, you'll want to wrap it in a function that takes a block:</p> <pre><code>static void applyBlockToPathElement(void *info, const CGPathElement *element) { void (^block)(const CGPathElement *) = (__bridge void (^)(const CGPathElement *))(info); block(element); } void MyCGPathApplyBlock(CGPathRef path, void (^block)(const CGPathElement *element)) { CGPathApply(path, (__bridge void *)(block), applyBlockToPathElement); } </code></pre> <p>Then you can apply a block that finds the each subpath endpoint and creates a button there. Assuming you have a method named <code>createButtonAtPoint:</code>, something like this should work:</p> <pre><code>__block BOOL isInSubpath = NO; __block CGPoint subpathStart = CGPointZero; __block CGPoint currentPoint = CGPointZero; MyCGPathApplyBlock(dashedPath, ^(const CGPathElement *element) { switch (element->type) { case kCGPathElementMoveToPoint: if (isInSubpath) { [self createButtonAtPoint:currentPoint]; isInSubpath = NO; } currentPoint = element->points[0]; break; case kCGPathElementCloseSubpath: // This should not appear in a dashed path. break; case kCGPathElementAddLineToPoint: case kCGPathElementAddQuadCurveToPoint: case kCGPathElementAddCurveToPoint: if (!isInSubpath) { [self createButtonAtPoint:currentPoint]; isInSubpath = YES; } int pointIndex = element->type == kCGPathElementAddLineToPoint ? 0 : element->type == kCGPathElementAddQuadCurveToPoint ? 1 : /* element->type == kCGPathElementAddCurveToPoint ? */ 2; currentPoint = element->points[pointIndex]; break; } }); </code></pre>

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