怪异合集View frame origin of transform 180 degrees

Question

我通过代码旋转180度

- (UICollectionViewLayoutAttributes *)layoutAttributesForItemAtIndexPath:(NSIndexPath *)indexPath {
    UICollectionViewLayoutAttributes *retAttr = [[super layoutAttributesForItemAtIndexPath:indexPath] copy];

    if (CGAffineTransformIsIdentity(retAttr.transform)) {
        retAttr.transform = CGAffineTransformMakeRotation(M_PI);
    }

    retAttr.frame = CGRectMake(0, retAttr.frame.origin.y, self.collectionView.bounds.size.width, retAttr.frame.size.height);
    return retAttr;
}

由 CGRectMake 制作的框架

(origin = (x = 0, y = 3658), size = (width = 320, height = 1077.5))

但是我得到了

(lldb) po retAttr.frame
(origin = (x = -0.000000000000056843418860808015, y = 3658), size = (width = 320.00000000000011, height = 1077.5))

单元格从屏幕上消失。

如何正确旋转或将框架分配给 x 而不是中断和宽度？

Answer 1

我找到了解决方案 "not use affine transform"，我使用的是 3dTransform

- (UICollectionViewLayoutAttributes *)layoutAttributesForItemAtIndexPath:(NSIndexPath *)indexPath {
    UICollectionViewLayoutAttributes *retAttr = [[super layoutAttributesForItemAtIndexPath:indexPath] copy];

    if (CATransform3DIsIdentity(retAttr.transform3D)) {
        retAttr.transform3D = CATransform3DMakeRotation(M_PI, 0, 0, 1);
    }

    return retAttr;
}

现在，一切正常。

怪异合集View frame origin of transform 180 degrees

Wiered collectionView frame origin if transform 180 degres

ios

uicollectionview

uicollectionviewlayout

cgaffinetransform