Charts: Add legend margin and styling customization props

[annacmc]

Proposed changes:

• Add legendMargin prop to BaseLegendProps interface to allow custom margin spacing around legends
• Add legendStyle prop to BaseLegendProps interface to enable custom CSS styling of legend containers
• Update BaseLegend component to apply both margin and style props to the legend wrapper
• Add Storybook controls for both legendMargin and legendStyle props in legend configuration

Other information:

• Have you written new tests for your changes, if applicable?
• Have you checked the E2E test CI results, and verified that your changes do not break them?
• Have you tested your changes on WordPress.com, if applicable (if so, you'll see a generated comment below with a script to run)?

Does this pull request change what data or activity we track or use?

No, it does not.

Testing instructions:

• Go to Storybook -> Charts -> Legend Configuration
• Use the legendMargin control to test different margin values:
  • Test with number values like 8, 16, 24 for uniform margins
  • Test with object values like {top: 10, right: 15, bottom: 10, left: 15} for custom margins
  • Verify margins are applied correctly around legend containers
• Use the legendStyle control to test custom styling:
  • Test background colors: {backgroundColor: '#f0f0f0'}
  • Test borders: {border: '1px solid #ccc'}
  • Test padding: {padding: '8px'}
  • Test combinations of multiple style properties
• Verify that both props work independently and together
• Test across different chart types (Pie, Bar, Line) to ensure consistent legend styling
• Confirm no TypeScript errors and proper prop type validation
• Ensure backward compatibility - existing charts without these props should render unchanged
• Verify no visual regressions in chart rendering, tooltips, or other legend functionality

[github-actions]

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[github-actions]

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[Copilot]

Pull Request Overview

This PR adds customization options for legend appearance by introducing two new props: legendMargin for controlling margin spacing and legendStyle for custom CSS styling of legend containers.

• Add legendMargin and legendStyle props to BaseLegendProps interface with proper TypeScript definitions
• Update BaseLegend component to apply margin and style props to legend wrapper elements
• Include comprehensive test coverage and Storybook controls for the new functionality

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
types.ts	Adds TypeScript definitions for legendMargin and legendStyle props with JSDoc documentation
base-legend.tsx	Implements the new props by applying margin and style to legend container
legend.test.tsx	Adds comprehensive test cases for margin, styling, and their combination
legend-config.tsx	Adds Storybook controls for legendMargin with descriptive documentation
changelog	Documents the feature addition with minor significance

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[jp-launch-control]

Code Coverage Summary

2 files are newly checked for coverage.

File	Coverage
projects/js-packages/charts/src/components/legend/utils/process-legend-margin.ts	14/14 (100.00%) 💚
projects/js-packages/charts/src/components/legend/types/legend-margin.ts	0/0 (—%) 🤷

Full summary · PHP report · JS report

[Copilot]

Pull Request Overview

Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.

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[Copilot]

Pull Request Overview

Copilot reviewed 13 out of 13 changed files in this pull request and generated 2 comments.

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[Copilot]

Pull Request Overview

Copilot reviewed 14 out of 14 changed files in this pull request and generated 2 comments.

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[kangzj]

Like I commented here before, we probably don't want more props to control legend because there are already a few - Consumers could achieve similar styling by passing in a className.

I'll be more than happy to approve the PR if we allow passing in a legendItemClassName so that consumers have full control of both the legend and the legend items.

As a follow up, this issue CHARTS-36 might be worth looking at to clean things up a bit.

More customization could be achieved with this one CHARTS-119.