pixel-sprite-maker: spritec - .sprite text format -> png/jpg/svg + sprite sheets

- .sprite format: single-char palette keys (hex/rgb()/CSS names/none), grid
  rows, '.' transparent by default, max 256x256 per sprite
- render/sheet/info/preview subcommands; sheets name themselves
  <base>_<cellW>x<cellH>_<cols>x<rows>.<ext> (row-major)
- SVG output RLE-merges pixel runs; JPG composites over --bg
- go tests for parser, colors, scaling, svg, sheet layout

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

pixel-sprite-maker/README.md

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+# pixel-sprite-maker (`spritec`)
+
+Turns human/agent-readable `.sprite` text files into pixel art (**PNG, JPG, SVG**)
+and combines several sprites into **sprite sheets / animation strips**.
+Written in Go, zero dependencies, single static binary.
+
+## Build
+
+```bash
+# Arch/Garuda: sudo pacman -S go
+cd pixel-sprite-maker
+go build -o build/spritec .        # or run the VS Code task "build pixel-sprite-maker"
+go test ./...
+```
+
+## The `.sprite` format
+
+One file = one sprite. Designed so an agent can *see* the result in the text:
+
+```
+# comment lines start with '#'
+sprite: coin           # optional name
+palette:
+  k = #1A1205    dark outline
+  y = #FFD700    gold
+  Y = gold       CSS names work too — text after the color is a comment
+grid:
+  ..kkkk..
+  .kyyyYk.
+  kyyyYYyk
+  ..kkkk..
+```
+
+Rules:
+
+- **One character = one pixel.** Every grid row must be the same width.
+- Palette keys are exactly one character (any unicode). `#`, `=`, `:` and
+  whitespace are not allowed as keys — so the number of colors is
+  practically unlimited (a-z, A-Z, 0-9, `!@%&*`, unicode…).
+- `.` is **transparent by default**; override it in the palette if you want.
+- Colors: `#RGB`, `#RGBA`, `#RRGGBB`, `#RRGGBBAA`, `rgb(r,g,b)`,
+  `rgba(r,g,b,a)` (alpha 0-255 or 0.0-1.0), all CSS named colors, `none`.
+- Max **256x256** pixels per sprite. Sheets may exceed this; single frames may not.
+
+## Commands
+
+```bash
+spritec render coin.sprite -o coin.png --scale 8      # png/jpg/svg from extension
+spritec render coin.sprite --format svg               # -> coin.svg
+spritec render heart.sprite -o heart.jpg --bg '#222034'  # jpg has no alpha: pick bg
+spritec info coin.sprite                              # validate + palette stats
+spritec preview coin.sprite                           # draw in the terminal (truecolor)
+
+# Sprite sheets / animations — row-major (left→right, then top→bottom):
+spritec sheet walk_1.sprite walk_2.sprite walk_3.sprite walk_4.sprite -o walk           # 1 row
+spritec sheet walk_*.sprite --cols 2 -o walkgrid      # 2D: 2 columns x 2 rows
+```
+
+Flags: `-o` output, `--format png|jpg|svg`, `--scale n` (integer nearest-neighbour
+upscale), `--bg color` + `--quality 1-100` (jpg only), `--cols n` (sheet only).
+
+## Sheet output naming — read the layout from the file name
+
+```
+<name>_<cellW>x<cellH>_<cols>x<rows>.<ext>
+
+walk_8x8_4x1.png   = 8x8 px per frame, 4 columns, 1 row (animation strip)
+tiles_16x16_4x2.png = 16x16 px per frame, 4 columns, 2 rows
+```
+
+Frame order is always **row-major**: index = `row * cols + col`, frame 0 is
+top-left. If the frame count doesn't fill the grid, trailing cells are
+transparent. In game code:
+
+```
+frameX = (index % cols) * cellW
+frameY = (index / cols) * cellH
+```
+
+## Exit codes & errors
+
+`0` on success, `1` on any error, `2` on missing command. Parse errors name
+the exact line/row/column and what was expected, so an agent can fix the
+file without guessing.
+
+Examples live in [`examples/`](examples/); generated output in `examples/out/`.