bitmap-font-maker: fontc - .font glyph grids -> atlas PNG + metrics JSON + text rendering

- .font format: glyph sections with #/. grids, proportional widths,
  literal unicode glyph names, spacing/space-width/line-height/baseline
- build (atlas white-on-transparent + JSON metrics), render (text -> PNG
  with \n, scale, color), info, preview (terminal half-blocks)
- example tiny5 font: A-Z, ÅÄÖ, 0-9, punctuation (47 glyphs, 3x5)
- go tests: parsing, errors, atlas metrics, text rendering

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MmdG9GqfSWCzts7AkDwRDh

bitmap-font-maker/README.md

@@ -0,0 +1,75 @@
+# bitmap-font-maker (`fontc`)
+
+Turns `.font` text files — pixel glyph grids an agent can read and edit
+directly — into **font atlases (PNG + JSON metrics)** and renders text
+strings to PNG. Proportional widths, unicode glyph names (ÅÄÖ works).
+Go, zero dependencies, single static binary.
+
+## Build
+
+```bash
+# Arch/Garuda: sudo pacman -S go
+cd bitmap-font-maker
+go build -o build/fontc .        # or the VS Code task "build bitmap-font-maker"
+go test ./...
+```
+
+## The `.font` format
+
+```
+# comment
+font: tiny5          optional name
+spacing: 1           px between glyphs (default 1)
+space-width: 3       advance of ' ' (default: width of '0')
+line-height: 7       default: glyph height + 1
+baseline: 5          default: glyph height
+
+glyph A:
+  .#.
+  #.#
+  ###
+  #.#
+  #.#
+
+glyph ::             the char between "glyph " and ":" is literal
+  .
+  #
+  .
+  #
+  .
+```
+
+- `#` = pixel on, `.` = off.
+- **All glyphs share one height; widths may differ** (proportional fonts —
+  `M` can be 5 px wide while `.` is 1 px).
+- Max glyph size 64x64.
+
+## Commands
+
+```bash
+fontc build tiny5.font -o out/tiny5        # -> tiny5.png (atlas) + tiny5.json (metrics)
+fontc render tiny5.font 'HEJ!\nRAD 2' --scale 4 --color '#FFD700' -o title.png
+fontc info tiny5.font                      # validate + list glyphs
+fontc preview tiny5.font 'HELLO'           # draw in the terminal
+```
+
+## Atlas + metrics
+
+The atlas draws glyphs **white on transparent** so game engines can tint
+them. The JSON carries everything a loader needs:
+
+```json
+{
+  "name": "tiny5", "atlas": "tiny5.png",
+  "height": 5, "lineHeight": 6, "baseline": 5,
+  "spacing": 1, "spaceWidth": 3,
+  "glyphs": { "A": {"x": 0, "y": 0, "w": 3, "h": 5, "advance": 4}, ... }
+}
+```
+
+Drawing text in a game: blit `glyphs[c]` from the atlas, advance the
+cursor by `advance`; spaces advance `spaceWidth + spacing`; new lines
+step `lineHeight`.
+
+[`examples/tiny5.font`](examples/tiny5.font) is a complete 3x5 font:
+A-Z, ÅÄÖ, 0-9 and punctuation.