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

Grid Auto-Numbering Feature for Azgaar Fantasy Map Generator

Overview

Added sequential auto-numbering to the grid overlay system, allowing users to reference specific grid cells (e.g., "POI located in grid 0247"). Numbers are displayed centered within each grid cell with customizable size and color.

Features Added

• ✅ Sequential numbering starting from top-left (0001, 0002, 0003...)
• ✅ Works with: Pointy Hex, Square, and Truncated Square grids
• ✅ Customizable font size (1-50px)
• ✅ Customizable color
• ✅ Toggle on/off via checkbox
• ✅ Proper centering in grid cells
• ✅ Full map coverage

Known Limitations

Grid Types Not Yet Supported: The following grid types require additional positioning calculations and are not currently supported:

• ❌ Hex grid (flat)
• ❌ Square 45 degrees grid
• ❌ Tetrakis square grid
• ❌ Triangle grid (horizontal)
• ❌ Triangle grid (vertical)
• ❌ Trihexagonal grid
• ❌ Rhombille grid

The numbering feature will display on these grid types but numbers will not align correctly with cell centers. Each grid type has unique geometry that requires specific positioning logic in the getGridCellCenter() function.

Files Modified

1. index.html

Location: Lines 889-910 (in <tbody id="styleGrid"> section)

Changes: Added UI controls for grid numbering in the Style panel:

<tr data-tip="Enable sequential numbering for grid cells (0001, 0002, etc.)">
  <td colspan="2">
    <input id="styleGridShowNumbers" class="checkbox" type="checkbox" />
    <label for="styleGridShowNumbers" class="checkbox-label">Show grid numbers</label>
  </td>
</tr>

<tr data-tip="Set grid number font size">
  <td>Number size</td>
  <td>
    <input id="styleGridNumberSize" type="number" min="1" max="50" step="0.5" value="8" />
  </td>
</tr>

<tr data-tip="Set grid number color">
  <td>Number color</td>
  <td>
    <input id="styleGridNumberColor" type="color" value="#808080" />
    <output id="styleGridNumberColorOutput">#808080</output>
  </td>
</tr>

2. modules/ui/layers.js

Location: Lines 657-661, 664-754

Changes:

1. Modified drawGrid() function to call drawGridNumbers() when enabled
2. Added three new functions:
   • drawGridNumbers() - Main rendering logic
   • getGridCellDimensions() - Returns cell dimensions for each grid type
   • getGridCellCenter() - Calculates center position for each cell

Key Implementation Details:

// In drawGrid() - Line 657-661
const showNumbers = gridOverlay.attr("data-show-numbers") === "1";
if (showNumbers) {
  drawGridNumbers(maxWidth, maxHeight, scale, dx, dy);
}

3. modules/ui/style.js

Location: Lines 212-215 (initialization), 520-525 (declarations), 543-557 (event handlers)

Changes:

1. Added variable declarations for UI elements
2. Added initialization code to read grid numbering attributes
3. Added event handlers for checkbox, size input, and color picker

// Variable declarations (after styleGridType handler)
const styleGridShowNumbers = byId("styleGridShowNumbers");
const styleGridNumberSize = byId("styleGridNumberSize");
const styleGridNumberColor = byId("styleGridNumberColor");
const styleGridNumberColorOutput = byId("styleGridNumberColorOutput");

// Initialization in selectStyleElement() 
styleGridShowNumbers.checked = el.attr("data-show-numbers") === "1";
styleGridNumberSize.value = el.attr("data-number-size") || 8;
styleGridNumberColor.value = styleGridNumberColorOutput.value = 
  el.attr("data-number-color") || "#808080";

// Event handlers
styleGridShowNumbers.on("change", function () {
  getEl().attr("data-show-numbers", this.checked ? "1" : "0");
  if (layerIsOn("toggleGrid")) drawGrid();
});

styleGridNumberSize.on("input", function () {
  getEl().attr("data-number-size", this.value);
  if (layerIsOn("toggleGrid")) drawGrid();
});

styleGridNumberColor.on("input", function () {
  styleGridNumberColorOutput.value = this.value;
  getEl().attr("data-number-color", this.value);
  if (layerIsOn("toggleGrid")) drawGrid();
});

Position Calculation Math

Pointy Hex Grid Positioning

After extensive testing and calibration, the following values provide perfect alignment:

Row Spacing: cellHeight * 0.5

• This is different from the geometric ideal of 0.75
• Empirically determined through visual alignment with hex centers

Y-Offset (Vertical Center): cellHeight * 0.35

• Positions numbers vertically within hex
• Accounts for hex shape geometry

X-Offset (Horizontal Center): cellWidth / 2

• Standard horizontal centering

Row Offset Pattern: Even rows (0, 2, 4...) are shifted right by cellWidth / 2

• This creates the interlocking hex pattern

Grid Cell Dimensions (Base Size)

From SVG pattern definitions:

• Pointy Hex: width=25, height=43.4
• Flat Hex: width=43.4, height=25
• Square: width=25, height=25
• (Other grid types defined in getGridCellDimensions())

Row/Column Count Calculation

const rowSpacing = cellHeight * 0.5;
const cols = Math.ceil(maxWidth / cellWidth) + 2;
const rows = Math.ceil(maxHeight / rowSpacing) + 2;

Note: Adding +2 ensures full map coverage including edges.

How to Use

For Users:

1. Enable the Grid layer (press G or click Grid toggle)
2. Open Style panel (right sidebar)
3. Select "Grid" from the element dropdown
4. Check "Show grid numbers" checkbox
5. Adjust Number size and Number color as desired

For Developers:

Grid numbering state is stored as attributes on the gridOverlay SVG element:

• data-show-numbers: "1" or "0"
• data-number-size: Number (default 8)
• data-number-color: Hex color (default "#808080")

These can be set programmatically:

gridOverlay.attr("data-show-numbers", "1");
gridOverlay.attr("data-number-size", "12");
gridOverlay.attr("data-number-color", "#000000");
drawGrid();

Testing & Calibration Process

The positioning values were determined through iterative testing:

1. Started with theoretical hex geometry (0.75 row spacing)
2. User placed visual markers at hex centers
3. Adjusted row spacing and Y-offset incrementally
4. Final values: rowSpacing=0.5, Y-offset=0.35

This empirical approach accounts for any rendering quirks or pattern definition nuances.

Performance Considerations

• Numbers are rendered as SVG text elements
• Typical full map: ~3000 grid cells
• Negligible performance impact on modern browsers
• Numbers are part of the gridOverlay group and clear when grid is toggled off

Future Enhancement Ideas

• Save grid numbering preference to localStorage
• Export numbered grid with map export
• Click-to-copy grid number functionality
• Custom numbering patterns (A1, A2... or hex coordinates)
• Grid number search/highlight feature

Technical Notes

Why Not Pure Geometric Spacing?

The theoretical vertical spacing for pointy hex grids is 1.5 × sideLength = 0.75 × height. However, we use 0.5 × height because:

1. SVG pattern rendering may introduce sub-pixel differences
2. The pattern definition includes the full hex perimeter path
3. Visual alignment matters more than mathematical purity
4. The 0.5 value was empirically validated against user-placed markers

Edge Case Handling

• Numbers extend slightly beyond visible map area (+2 buffer)
• Partial hex cells at edges still receive numbers
• Zoom level doesn't affect numbering (numbers don't scale)

Implementation Summary

Total Lines of Code Added: ~150 Files Modified: 3 New Functions Added: 3 UI Controls Added: 3

This implementation integrates cleanly with Azgaar's existing grid system without modifying core rendering logic. All grid numbering code is isolated and can be easily maintained or removed.

Credits

Implementation developed through collaborative debugging session, December 2024. Tested on Azgaar Fantasy Map Generator (latest version as of Dec 2024).

Contact & Contribution

If integrating this into the official Azgaar repository, consider:

• Adding grid numbering to the style presets
• Including in map export metadata
• Adding to the wiki documentation
• Internationalizing the UI labels

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License: Same as Azgaar Fantasy Map Generator (MIT)