RUM-4151 [SR] Support background color for Tab Bars

[mariedm]

What and why?

Session Replay currently does not support custom background colors for tab bars, defaulting to white or black based on the user's trait collection.

How?

This PR:

• Modifies the SR Tab Bar Recorder to support custom background colors.
• Adds new snapshot tests for both static and embedded tab bars.

This work is similar to a previous PR that added support for custom background colors on navigation bars. For more context, see PR #1864.

Notes on deselected items’ Tint Color

TLDR: if no unselectedTintColor is set, icons will be rendered in white.

• Both selected and unselected tint colors for tab bar items can be set using tintColor and unselectedItemTintColor.
• If unselectedItemTintColor is not set, the default is gray, though it appears white in the view debugger and is not accessible via code.
• An item's icon is recorded using the UIImageViewRecorder. The correct tint color for a selected item is obtained through the tintColorProvider.
• It is not possible to detect selection status at the image or imageView level within the UIImageViewRecorder.
  • image.isTinted always returns true if a tintColor is set, regardless of selection status.
  • Without access to the unselected tint color, we cannot determine the rendered color for unselected items.
  • Comparing the recorded image with the withTintColor(_:) effect applied to it does not work.
  • Accessing the Tab Bar and Tab Bar button from the image's superviews is possible, but the button is of type UITabBarButton, a private API, preventing state checks to determine selection status and appropriate tint color.

Snapshot tests screenshots

Static Tab Bar

Embedded Tab Bar

Review checklist

• Feature or bugfix MUST have appropriate tests (unit, integration)
• Make sure each commit and the PR mention the Issue number or JIRA reference
• Add CHANGELOG entry for user facing changes

Custom CI job configuration (optional)

• Run unit tests for Core, RUM, Trace, Logs, CR and WVT
• Run unit tests for Session Replay
• Run integration tests
• Run smoke tests
• Run tests for tools/

[ncreated]

Looks great 🎯. I appreciate the level of details in PR description and snapshot tests - all clear 🚀!

Minor comment on conventions: we usually mention the JIRA ref (RUM-4151 in this case) as part of every commit (prefix) and in the PR title. This way we establish automatic link between GH and JIRA, which helps tracking decisions later. For this PR, let's mention it in the title at least 🙂.

[ncreated]

🎯👌

[maciejburda]

Nice!

I would only suggest defaulting the icon image tint to gray whenever we deal with unselectedItemTintColor == nil.

Also - we probably can drop the bottom border. Seems like native component has only a gray line on top.

[maxep]

Looks great! nice work on the snapshot tests 👏

[mariedm]

Minor comment on conventions: we usually mention the JIRA ref (RUM-4151 in this case) as part of every commit (prefix) and in the PR title. This way we establish automatic link between GH and JIRA, which helps tracking decisions later. For this PR, let's mention it in the title at least 🙂.

Got it! I will follow this pattern next time. In the meantime, I added it to the PR title.

[mariedm]

I would only suggest defaulting the icon image tint to gray whenever we deal with unselectedItemTintColor == nil.

Also - we probably can drop the bottom border. Seems like native component has only a gray line on top.

@maciejburda I can remove the bottom border color. 👍 However, how do you suggest we default the icon to gray when unselectedItemTintColor == nil? We don't have access to this property within the UIImageViewRecorder, and we can't determine if the tab bar item it belongs to is selected or not. Therefore, we don't know whether to apply the tintColor or the unselectedItemTintColor.

[mariedm]

@maciejburda Actually, the current implementation in UITabBarRecorder will also remove the top border, which might not be what we want?

[datadog-datadog-prod-us1]

Datadog Report

Branch report: mariedm/feat/RUM-4151
Commit report: 9a9d00a
Test service: dd-sdk-ios

✅ 0 Failed, 253 Passed, 0 Skipped, 14.05s Total Time

[mariedm]

@maciejburda as discussed in the Daily today, I can merge this PR once I have the required approvals to unblock @ncreated's work. I created a follow-up ticket from your comment.

[maciejburda]

LGTM!

As discussed - we can try to tackle white tint images in a separate PR