UICollectionView Cell Frame Has Decimal Origin Value - ios

Question

I have a UICollectionView that I created programatically. Each cell in the collection view displays a label, and all the labels have identical properties. Despite this, I noticed that the text contained in each label in the center column of the collection view looked blurry.
A recursive description of the collection view shows that the center cell in the table always has an x origin that is a decimal value:
<UICollectionViewCell: 0xd98c1e0; frame = (242.5 0; 220 45); layer = <CALayer: 0xd98c270>> ...
My questions are: 1) could this be causing the bluriness? and 2) What is the best way to ensure that none of the x and y origins end up having a decimal value? (Aside from manually calculating the layout)
For reference, here is my UICollectionView code:
//subclass UICollectionViewFlowLayout
#implementation LabelLayout
-(BOOL)shouldInvalidateLayoutForBoundsChange:(CGRect)newBounds{
return YES;
}
- (id)init
{
self = [super init];
if (self) {
[self setup];
}
return self;
}
-(void)prepareLayout
{
[super prepareLayout];
_cellCount = [[self collectionView] numberOfItemsInSection:0];
}
- (void)setup
{
self.itemSize = CGSizeMake(220.0f, 45.0f);
self.sectionInset = UIEdgeInsetsMake(0.0f, 0.0f, 0.0f, 0.0f);
self.minimumLineSpacing = 10.0f;
self.minimumInteritemSpacing = 20.0f;
}
#end

Answer 1

This would definitely cause blurring as everything is being anti-aliased across two pixels (Note: On a retina screen, you won't see any blurring because each point is actually two pixels so half points technically exist as a single pixel). To fix it you might have to use CGRectIntegral to force the frame to integer bounds. The best way to do that would be:
- (NSArray *)layoutAttributesForElementsInRect:(CGRect)rect{
NSArray *attributes = [super layoutAttributesForElementsInRect:rect];
for (NSLayoutAttributes *attribute in attributes){
attribute.frame = CGRectIntegral(attribute.frame);
}
}
You should do the same thing for layoutAttributesForItemAtIndexPath:.