如何仅从顶部获得UIView上的Shadow？ [Objective-c]

Question

我只希望如下图所示从顶部的UIView阴影。

我正在尝试此代码来应用shadow，但是shadow应用于视图的右侧，但我希望从顶部开始。

UIEdgeInsets contentInsets = UIEdgeInsetsMake(10, 0, 0, 0);
CGRect shadowPath = UIEdgeInsetsInsetRect(self.dealMainContentView.bounds, contentInsets);
self.dealMainContentView.layer.shadowPath = [UIBezierPath bezierPathWithRect:shadowPath].CGPath;
self.dealMainContentView.layer.shadowColor = [[UIColor blackColor] CGColor];
self.dealMainContentView.layer.shadowOffset = CGSizeMake(0.0f,0.0f);
self.dealMainContentView.layer.shadowOpacity = 0.4f;
self.dealMainContentView.layer.masksToBounds=NO;

这看起来应该像

Answer 1

我自己解决了这个问题，可以在制作Path之前通过修改帧来获得所需的阴影。

只是hack :)

我没有在这种方法中传递view.frame，而是修改了框架
UIEdgeInsetsInsetRect(viewFrame, contentInsets); 并从顶部产生阴影。

这是下面的代码

UIEdgeInsets contentInsets = UIEdgeInsetsMake(-10, -10, 0, 0);

    CGRect viewFrame=self.dealMainContentView.frame;

    viewFrame.origin.x += 5; // 5 distance from left
    viewFrame.origin.y -= 15;
    viewFrame.size.width -= 1o;  // 5 distance from Right
    viewFrame.size.height -= 20;

   CGRect shadowPathExcludingTop = UIEdgeInsetsInsetRect(viewFrame, contentInsets);

   self.dealMainContentView.layer.shadowPath = [UIBezierPath bezierPathWithRect:shadowPathExcludingTop].CGPath;
    self.dealMainContentView.layer.shadowColor = [[UIColor blackColor] CGColor];
    self.dealMainContentView.layer.shadowOffset = CGSizeMake(0.0,0.0f);
    self.dealMainContentView.layer.shadowOpacity = 0.3f;
    self.dealMainContentView.layer.masksToBounds=NO;