Add extra scroll to the candlesticks

[rturtu]

Pull Request

Summary

Extra scroll to the right.

Mobile PR with testing development builds: https://github.com/elliottech/perps-fe-mobile/pull/1118

Linear ticket: PRO-2155

Author Checklist

• PR tested locally
• PR tested on preview

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The merge-base changed after approval.

[linear]

PRO-2155 Apply patch to lib

The merge-base changed after approval.

[github-actions]

✅ PR Checklist Validation Passed

Status: All 2 checklist items completed
Linear ticket: Valid ✅

🎉 This PR meets all requirements and is ready for review!

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This validation ensures all PR requirements are met before merging.

[github-actions]

🚀 Prerelease Published

Version: 0.7.0-rturtu.1137896.pro-2155-apply-patch-to-lib
Tag: pro-2155-apply-patch-to-lib

Update package.json:

"@elliottech/react-native-kline-view": "0.7.0-rturtu.1137896.pro-2155-apply-patch-to-lib"

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Previous prereleases for this PR have been cleaned up. This prerelease will be automatically cleaned up when the PR is merged.

[devin-ai-integration]

iOS Swift Review

I reviewed the iOS/Swift changes in depth. The minVisibleCandles config addition and the scroll clamping in scrollViewDidScroll / reloadContentOffset look correct on their own. However, there are two critical issues where the auto-scroll-to-end checks weren't updated to match the new content size model, effectively making them dead code.

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Bug 1 (Critical): wasAtEnd in addCandlesticksAtTheEnd is always false

HTKLineContainerView.swift:355

let wasAtEnd = klineView.contentOffset.x >= (klineView.contentSize.width - klineView.frame.width - 10)

With the new reloadContentSize adding + bounds.size.width, the threshold becomes itemWidth * count + paddingRight - 10. But scrollViewDidScroll and reloadContentOffset clamp contentOffset.x to at most itemWidth * (count - minVisibleCandles). For wasAtEnd to be true you'd need 10 >= 5 * itemWidth + paddingRight, which is false for any reasonable values.

Impact: When new candles arrive, the chart will never auto-scroll to keep showing the latest data, even if the user was already at the end. (This was flagged by the earlier automated review comment #9 and marked "Resolved", but the iOS code on the branch hasn't actually been updated.)

Suggested fix:

let allCandlesWidth = configManager.itemWidth * CGFloat(configManager.modelArray.count)
let maxAllowedOffset = max(0, allCandlesWidth - configManager.minVisibleCandles * configManager.itemWidth)
let wasAtEnd = klineView.contentOffset.x >= maxAllowedOffset - 10

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Bug 2 (Critical): isEnd in reloadConfigManager is always false

HTKLineView.swift:138-145

let lastCandlestickOffset = contentSize.width - configManager.paddingRight - configManager.itemWidth / 2

After reloadContentSize(), contentSize.width = itemWidth * count + paddingRight + bounds.width, so lastCandlestickOffset = itemWidth * count + bounds.width - itemWidth/2. This is off by an entire bounds.width from the actual last candle position (itemWidth * count - itemWidth/2), because contentSize.width now includes the extra + bounds.size.width but this formula wasn't adjusted.

For the lower bound of isEnd to be satisfied at max scroll, you'd need 1.5 * itemWidth <= 1 — false for any candle wider than ~0.7pt.

Impact: On config reload with new data, the chart won't auto-scroll to end even when the user was already looking at the latest candles.

Suggested fix — use raw candle width instead of contentSize.width:

let lastCandlestickOffset = configManager.itemWidth * CGFloat(configManager.modelArray.count) - configManager.itemWidth / 2

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Issue 3 (Medium): Inconsistent scroll-to-end target formulas

Three places compute "scroll to end" differently:

• reloadConfigManager (line 152): contentSize.width - 2 * bounds.width
• smoothScrollToEnd (line 207): contentSize.width - 2 * bounds.width
• addCandlesticksAtTheEnd (line 378): contentSize.width - bounds.width

All get clamped by reloadContentOffset so runtime behavior converges, but the inconsistency makes the code harder to reason about. Consider extracting a single computed property.

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Issue 4 (Minor): Debug print() statements

HTKLineContainerView.swift has many print() calls that will spam the console in production. Consider removing or guarding behind #if DEBUG.

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Bottom line: Bugs 1 and 2 mean the auto-scroll-to-end feature is broken on iOS — the checks are dead code. Both need to be fixed before merging.

[devin-ai-integration]

Devin Review found 3 new potential issues.

View 9 additional findings in Devin Review.