使用自定义UIBezierPath剪切图像 [英] Clipping an image with a custom UIBezierPath

问题描述

我有一个用户创建的 UIBezierPath



我可以通过使用<$ c $来创建bog标准UIView上的形状c> [myPath fill]; function。

我最想做的是使用路径创建剪贴蒙版UIImage - 也许作为一个 UiImageView ？

我试图将我的UIView更改为 UIImageView 然后将函数更改为 [myPath addClip]; ，但由于某种原因它不工作。

解决方案

您需要创建一个图形上下文，绘制图像，并使用kCGBlendModeDestinationIn绘制掩码。像这样：

  UIGraphicsBeginImageContextWithOptions（size，NO，0.0）; // size是你想要的结果的CGSize 
 [image drawInRect：imageRect]; // image是你想要剪辑的UIImage，imageRect是你想要你的图像的上下文中的rect 
 [mask drawInRect：rect blendMode：kCGBlendModeDestinationIn alpha：1.0]; // mask是一个包含你绘制的掩码的UIImage，rect是你想要的掩码的上下文中的rect  - 可以匹配上面的imageRect 
 UIImage * uiImage = UIGraphicsGetImageFromCurrentImageContext（）; 
  

I was wondering if someone could point me in the right direction with this problem.

I have a user-created UIBezierPath with several points that have come about by user touches.

I can get these to create shapes on a bog-standard UIView by using the [myPath fill]; function.

What I would ideally like to do is to use the path to create a clipping mask for a UIImage - perhaps as a UiImageView?

I tried changing my UIView to a UIImageView and then changing the function to [myPath addClip]; but for some reason it does not work.

解决方案

You need to create a graphics context, draw your image, and draw your mask using kCGBlendModeDestinationIn. Something like this:

UIGraphicsBeginImageContextWithOptions(size, NO, 0.0); // size is a CGSize of the result you want
[image drawInRect:imageRect];  // image is the UIImage you want to clip, imageRect is the rect in the context where you want your image
[mask drawInRect:rect blendMode:kCGBlendModeDestinationIn alpha:1.0];  // mask is a UIImage containing the mask you drew, rect is the rect in the context where you want your mask - could match imageRect above
UIImage* uiImage = UIGraphicsGetImageFromCurrentImageContext();

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