mischa-hildebrand
Vertical Aligment Bug
fileprivate func layoutAttributes(forItemsInLineWith layoutAttributes: UICollectionViewLayoutAttributes) -> [UICollectionViewLayoutAttributes] {
guard let lineWidth = contentWidth else {
return [layoutAttributes]
}
var lineFrame = layoutAttributes.frame
lineFrame.origin.x = sectionInset.left
lineFrame.size.width = lineWidth
// Need to be add
// bug fix for super.layoutAttributesForElements(in:)
// if there are three row (Row1, Row2, Row3), and rows step by step closly, such as
// Row1: (x: 0, y: 0, width: 375, 100)
// Row2: (x: 0, y: 100, width: 375, height: 100)
// Row3: (x: 0, y: 200, width: 375, height: 100)
// then super.layoutAttributesForElements() will reture 3 values(Row1, Row2, Row3), that is incorrect
if lineFrame.height > 2 {
lineFrame.origin.y += 1
lineFrame.size.height -= 2
}
return super.layoutAttributesForElements(in: lineFrame) ?? []
}
That's a good observation! Thanks for reporting this!
I hadn't noticed that it doesn't work with interitem / line spacings of 0.
However, this is not the only place where the frame needs to be adjusted:
More importantly, this function needs adjustment:
fileprivate func isFrame(for firstItemAttributes: UICollectionViewLayoutAttributes, inSameLineAsFrameFor secondItemAttributes: UICollectionViewLayoutAttributes)
Furthermore, x += 1 and height -= 2 won't do it as it will also introduce inaccuracy. Retina screens support 0.5pt intervals, super retina displays 1/3pt intervals and there might be other resolutions in the future. Thus, I'll need to find a solution how to deal with that in a safe way.
Any suggestions are welcome! :)
By the way:
I think, it's a rounding bug because the documentation of the intersects(_:) function itself states:
The first rectangle intersects the second if the intersection of the rectangles is not equal to the null rectangle.
When I define two rectangles as follows:
let rect1 = CGRect(x: 0, y: 0, width: 100, height: 100)
let rect2 = CGRect(x: 0, y: 100, width: 100, height: 100)
the intersection of the rectangles is the null rectangle and thus
rect1.intersects(rect2)
returns false.
