ios – 渲染UIView到没有子视图的图像

2019年7月21日 250次阅读

我想将UIView转换为UI
Image

- (UIImage *)renderToImage:(UIView *)view {
  if(UIGraphicsBeginImageContextWithOptions != NULL) {
    UIGraphicsBeginImageContextWithOptions(view.frame.size, NO, 0.0);
  } else {
    UIGraphicsBeginImageContext(view.frame.size);
  }

  [view.layer renderInContext:UIGraphicsGetCurrentContext()];
  UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
  UIGraphicsEndImageContext();
  return image;
}

两个问题：

>我的观点有子视图.有没有办法在没有任何子视图的情况下创建视图图像？理想情况下,id不必删除它们只是为了稍后再添加它们.
>此外,它不能在视网膜设备上正确渲染图像.我按照这里的建议使用上下文和选项,但它没有帮助. How to capture UIView to UIImage without loss of quality on retina display

最佳答案 您必须隐藏您不希望在视图图像中的子视图.下面是为视网膜设备渲染视图图像的方法.

- (UIImage *)imageOfView:(UIView *)view
{

  // This if-else clause used to check whether the device support retina display or not so that   
  // we can render image for both retina and non retina devices. 

    if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)]) 
       {
               UIGraphicsBeginImageContextWithOptions(view.bounds.size, view.opaque, 0.0);
       } else {
                UIGraphicsBeginImageContext(view.bounds.size);
       }


    [view.layer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage * img = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return img;
}
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