Fix for Issue #1430: API to set custom first-line baseline Y in ColumnText

[Copilot]

Fix for Issue #1430: API to set custom first-line baseline Y in ColumnText

Plan:

• Understand the issue: Users want explicit control over first line baseline Y position
• Review ColumnText.java implementation to understand current leading/yLine behavior
• Add new field customFirstLineBaselineY to store custom first line baseline
• Add setter method setFirstLineBaselineY(float baselineY) to set custom baseline
• Modify go() method to use custom baseline when set (instead of yLine - leading)
• Add getter method getFirstLineBaselineY() to retrieve custom baseline
• Add clear method clearFirstLineBaselineY() to reset to default behavior
• Update copy constructor to include custom baseline field
• Create comprehensive test to validate the new functionality
• Run existing tests to ensure no regression
• Create example demonstrating the new API
• Create test for exact issue scenario
• Request code review and security scan
• All checks passed successfully

Implementation Summary:

This PR addresses issue #1430 by adding a new API to ColumnText that allows users to explicitly set the baseline Y position for the first line without needing to manually calculate yLine from the desired baseline and leading.

New API Methods:

• setFirstLineBaselineY(float baselineY) - Sets custom baseline Y for the first line
• getFirstLineBaselineY() - Gets the custom baseline Y (or NaN if not set)
• clearFirstLineBaselineY() - Clears the custom setting

Key Features:

1. Takes precedence over normal yLine - leading calculation
2. Only affects the first line; subsequent lines use normal leading
3. Works with both addText() and addElement() usage
4. Compatible with existing setUseAscender and setAdjustFirstLine flags
5. Validates baseline is within column bounds

Changes Made:

• ColumnText.java: Added customFirstLineBaselineY field and three new methods
• ColumnTextFirstLineBaselineTest.java: Comprehensive test suite (8 tests)
• FirstLineBaselineExample.java: Example demonstrating the new API
• Issue1430Test.java: Test cases matching the exact issue scenario

Test Results:

✅ All 10 new tests passing (8 + 2)
✅ All existing ColumnText tests passing (13 total)
✅ Code review: No issues found
✅ Security scan: No vulnerabilities detected
✅ Generated sample PDFs demonstrating the solution

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[sonarqubecloud]

Quality Gate passed

Issues
16 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud