UIBezierPath 指向路径的一小部分 [英] UIBezierPath point at fraction of path

问题描述

给定一个任意的 UIBezierPath，我正在寻找一种方法来在该路径长度的一小部分处获得一个点.

示例:

UIBezierPath *path = [UIBezierPath bezierPath];[路径 moveToPoint:CGPointMake(200.0, 200.0)];[路径 addLineToPoint:CGPointMake(200.0, 400.0)];CGPoint p = [路径 pointAtFraction:0.5];

在这种情况下，

p 应该是 {x: 200.0, y: 300.0}.

我知道可以计算这个简单的例子，但我正在寻找适合任何UIBezierPath(弧、圆角矩形等)的解决方案

看到 CAShapeLayer，它基本上依赖于 UIBezierPath 和它的属性 strokeEnd，我想信息在路径对象的某个地方.但是，UIBezierPath 和 CGPathRef 接口都没有显示任何方法来实现这一点.

我尝试创建一个 CAShapeLayer，设置 strokeEnd 并从图层中检索 CGPathRef，但路径保持不变.>

有没有办法(公共 API)来实现这一点?

解决方案

抱歉耽搁了时间.我实际上在一年多前解决了这个问题，哇.
我在 UIBezierPath 上创建了一个小类别来完成这项工作.此处的 GitHub 存储库

从 1 年前重新阅读我的代码后，我不得不说，当时我过去的编码方式令人震惊:D 缺乏文档令人不安.如果您需要更多信息，请告诉我，我会更新存储库.

Given an arbitrary UIBezierPath, I'm looking for a way to get a point at a fraction of the length of that path.

Example:

UIBezierPath *path = [UIBezierPath bezierPath];
[path moveToPoint:CGPointMake(200.0, 200.0)];
[path addLineToPoint:CGPointMake(200.0, 400.0)];

CGPoint p = [path pointAtFraction:0.5];

p should be {x: 200.0, y: 300.0} in this case.

I'm aware that this simple example could be calculated, but I'm looking for a solution that fits ANY UIBezierPath (arcs, rounded rects, etc.)

Seeing CAShapeLayer, which basically lives off UIBezierPath, and its property strokeEnd, I suppose the information is somewhere inside the path object. However, neither UIBezierPath nor CGPathRef interfaces show any way to achieve this.

I tried creating a CAShapeLayer, setting the strokeEnd and retrieving the CGPathRef from the layer, but the path stays the same.

Is there any way (public API) to achieve this ?

解决方案

Sorry for the huge delay. I actually solved this more than 1 year ago, wow.
I created a small category on UIBezierPath which does the job. GitHub Repo here

After re-reading my code from 1 year back I have to say it's quite shocking how I used to code back then :D The lack of documentation is disturbing. If you need more info please let me know and I'll update the repo.

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