top position is wrong when previous item's height is 0.5, on 3x scale screen
hanleylee opened this issue · comments
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- [ x] I have searched existing issues and this is not a duplicate
Issues and Steps to Reproduce
Anyone can reproduce it using below code(YogaKit (for iOS) 2.0.1)
import Foundation
import yoga
final class YogaTestVC: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
initView()
}
}
// MARK: UI
extension YogaTestVC {
private func initView() {
view.backgroundColor = .black
view.configureLayout { layout in
layout.isEnabled = true
layout.flexDirection = .column
layout.alignItems = .stretch
layout.justifyContent = .center
}
let containerView = UIView()
containerView.backgroundColor = .white
containerView.configureLayout { layout in
layout.isEnabled = true
layout.flexDirection = .column
layout.alignItems = .stretch
}
view.addSubview(containerView)
let view1 = UIView()
view1.backgroundColor = .orange
view1.configureLayout { layout in
layout.isEnabled = true
layout.height = YGValue(value: 50, unit: .point)
}
containerView.addSubview(view1)
let view2 = UIView()
view2.backgroundColor = .green
view2.configureLayout { layout in
layout.isEnabled = true
layout.height = 0.5
}
containerView.addSubview(view2)
let view3 = UIView()
view3.backgroundColor = .orange
view3.configureLayout { layout in
layout.isEnabled = true
layout.height = 50
}
containerView.addSubview(view3)
view.yoga.applyLayout(preservingOrigin: true)
}
}
Expected Behavior
The top position of view3
is 50.667 instead of 50.333, because the heights of view1
and view2
are 50, 0.667 respectively
Actual Behavior
The top position of view3 is 50.333
Screenshot
Explore
After check the source code, I found here will convert view3
's top from 50.5
to 50.333
, while textRounding is true
.
yoga/yoga/algorithm/PixelGrid.cpp
Lines 84 to 94 in 7697be5
Other
I suspect this issue is similar to #901, but can't be sure
Yoga assumes every leaf node is YGNodeTypeText
, which triggers ceil instead of round. This assumption is not correct when measure function is used to delegate to different layout system.