feat: improves position of scrollbar

[amir20]

No description provided.

[claude]

PR Review

This PR improves scrollbar positioning in the log view by using actual content and viewport lengths instead of a fixed 100-position scale.

✅ What's Good

1. Correct scrollbar calculation: Using .content_length(num_lines) and .viewport_content_length(state.last_viewport_height) provides accurate scrollbar positioning based on actual log content
2. Simplified logic: Removed the percentage-based workaround in favor of direct position calculation
3. Tests updated: Snapshot tests properly reflect the new scrollbar behavior

⚠️ Potential Issue

Line 145: Scrollbar position calculation may be incorrect

.position(actual_scroll + state.last_viewport_height)

The position should typically represent the top of the viewport, not the bottom. Adding last_viewport_height to actual_scroll places the scrollbar thumb at the bottom of the visible content.

Expected behavior:

• .position(actual_scroll) - represents where the viewport starts in the content

Current behavior:

• .position(actual_scroll + viewport_height) - represents where the viewport ends

This might cause the scrollbar thumb to appear lower than expected, especially when scrolled to the top (actual_scroll = 0 would show position at viewport_height instead of 0).

🧪 Recommendation

Test the scrollbar visually when:

• At the top of logs (actual_scroll = 0) - thumb should be at the top
• At the bottom of logs (actual_scroll = max_scroll) - thumb should be at the bottom
• In the middle - thumb should reflect relative position

If the current behavior is intentional (e.g., Ratatui's Scrollbar expects bottom position), add a comment explaining this.

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Verdict: Approve with suggested verification of scrollbar position calculation.

[github-actions]

Docker Image Built Successfully

docker pull ghcr.io/amir20/dtop:pr-163