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Fix incorrect scroll in media editor's thumbnail strip.

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We need different behaviors for scrolling to the current item in the strip depending on whether the item should be centered or just visible.
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Igor Solomennikov 2026-04-29 14:57:43 -07:00 committed by GitHub
parent 98f52903f9
commit 9b1e3b02f6
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GPG Key ID: B5690EEEBB952194
1 changed files with 15 additions and 7 deletions
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22
SignalUI/Views/GalleryRailView.swift
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@ -325,12 +325,12 @@ public class GalleryRailView: UIView, GalleryRailCellViewDelegate {
}
}
enum ScrollFocusMode {
public enum ScrollFocusMode {
case keepCentered
case keepWithinBounds
}
var scrollFocusMode: ScrollFocusMode = .keepCentered {
public var scrollFocusMode: ScrollFocusMode = .keepCentered {
didSet {
if oldValue != scrollFocusMode {
setNeedsUpdateScrollViewContentInsets()
@ -380,11 +380,19 @@ public class GalleryRailView: UIView, GalleryRailCellViewDelegate {
private func scrollToFocusedCell(animated: Bool) {
guard let focusedCell = cellViews.first(where: { $0.isCellFocused }) else { return }
// Scroll view's "viewport" area size doesn't consider extra padding focused cell might have.
// Adjust content offset accordingly.
let cellFrame = focusedCell.convert(focusedCell.bounds, to: scrollView)
let extraPadding = focusedCell.configuration.focusedItemExtraPadding
let contentOffsetX = cellFrame.minX + extraPadding - scrollView.contentInset.left
scrollView.setContentOffset(.init(x: contentOffsetX, y: 0), animated: animated)
switch scrollFocusMode {
case .keepCentered:
// Scroll view's "viewport" area is very narrow - a width of a single item, centered.
// But that width doesn't take into account an extra padding focused cell might have,
// which is why we have to add it to the content offset.
let extraPadding = focusedCell.configuration.focusedItemExtraPadding
let contentOffsetX = cellFrame.minX + extraPadding - scrollView.contentInset.left
scrollView.setContentOffset(.init(x: contentOffsetX, y: 0), animated: animated)
case .keepWithinBounds:
// Let scroll view handle the position.
scrollView.scrollRectToVisible(cellFrame, animated: animated)
}
}
}