如何从UIBezierPath获取点列表？ [英] How to get a list of points from a UIBezierPath?

问题描述

我需要提供 UIBezierPath 来自的一个点列表。

I have a UIBezierPath that I need to take a list of points from.

在 Qt 中有一个名为 pointAtPercent的函数这符合我的需求，但我找不到任何等价的 Objective-C 。

In Qt there is a function called pointAtPercent that would fit my needs but I can't find anything equivalent in Objective-C.

有谁知道怎么做？

推荐答案

你可以试试这个：

UIBezierPath *yourPath; // Assume this has some points in it
CGPath yourCGPath = yourPath.CGPath;
NSMutableArray *bezierPoints = [NSMutableArray array];
CGPathApply(yourCGPath, bezierPoints, MyCGPathApplierFunc);

路径应用程序函数将依次传递给每个路径的路径元素。

查看 CGPathApplierFunction 和 CGPathApply 。

The path applier function will be handed each of the path's path elements in turn.
Check out CGPathApplierFunction and CGPathApply.

path applier函数可能看起来像这样

The path applier function might look something like this

void MyCGPathApplierFunc (void *info, const CGPathElement *element) {
    NSMutableArray *bezierPoints = (NSMutableArray *)info;

    CGPoint *points = element->points;
    CGPathElementType type = element->type;

    switch(type) {
        case kCGPathElementMoveToPoint: // contains 1 point
            [bezierPoints addObject:[NSValue valueWithCGPoint:points[0]]];
            break;

        case kCGPathElementAddLineToPoint: // contains 1 point
            [bezierPoints addObject:[NSValue valueWithCGPoint:points[0]]];            
            break;

        case kCGPathElementAddQuadCurveToPoint: // contains 2 points
            [bezierPoints addObject:[NSValue valueWithCGPoint:points[0]]];
            [bezierPoints addObject:[NSValue valueWithCGPoint:points[1]]];            
            break;

        case kCGPathElementAddCurveToPoint: // contains 3 points
            [bezierPoints addObject:[NSValue valueWithCGPoint:points[0]]];
            [bezierPoints addObject:[NSValue valueWithCGPoint:points[1]]];
            [bezierPoints addObject:[NSValue valueWithCGPoint:points[2]]];
            break;

        case kCGPathElementCloseSubpath: // contains no point
            break;
    }
}

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