Fantasy-Map-Generator/GRID-NUMBERING-README.md

Grid Auto-Numbering Implementation Details

Technical Note: As part of my DevOps-focused workflow, I designed the logic and coordinate system for this feature and used Antigravity AI to assist with the specific JavaScript/D3.js implementation.

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Logic Overview

The grid numbering system is integrated into the SVG rendering pipeline. It iterates through the existing grid cell data generated by the map engine and overlays a text element for each cell.

Coordinate System

The system uses a top-down, left-to-right indexing method:

• Starting Point: The top-leftmost cell is assigned 0001.
• Flow: Numbers increment horizontally across the row before moving to the next line.
• Formatting: Numbers are padded with leading zeros (e.g., 0001, 0010, 0100) to maintain a consistent 4-digit coordinate string, common in tabletop hex-crawl systems.

Grid Support

The logic dynamically calculates the centroid of each cell to ensure proper label placement regardless of the grid geometry:

• Pointy Hex: Centers text within the hexagonal bounds.
• Square: Standard center-point alignment.
• Truncated Square: Adjusts for the irregular geometry to prevent label clipping.

Integration Points

Style Panel

Added a new sub-section under the Grid layer in the Style panel:

• Toggle: A checkbox to enable/disable the gridLabels group in the SVG.
• Font Size: A slider controlling the font-size attribute of the labels.
• Color Picker: A standard hex color input tied to the text fill attribute.

SVG Layering

A new <g> element with the ID #gridLabels is appended to the main map SVG. It sits directly above the grid lines layer to ensure visibility while remaining below the "Labels" or "Markers" layers.

Files Modified

• index.html: Added the toggle and styling controls to the UI.
• modules/ui/grid-menu.js: Logic for handling UI interactions and state.
• modules/render-grid.js: Core logic for calculating centroids and appending text elements to the SVG.

Performance Considerations

For massive maps with thousands of cells, the numbering system is optimized to only render when the Grid layer is active. This prevents unnecessary DOM overhead during standard map navigation.