Art: emit the palette as .gpl/.ase/.aco as well as .act

The .act files only helped Photoshop. Affinity imports .ase and .aco;
Inkscape, GIMP, Krita and Aseprite want .gpl. tools/make_palettes.py now
generates all four plus swatch PNGs, for both the full 16 and the
11-colour portrait subset, all derived from the same PALETTE table shared
with kissaten.c so nothing can drift.

Colour names ride along in .gpl/.ase/.aco, so the swatches show up labelled
("skin", "lamp glow", "dusk violet") rather than as anonymous chips.

.ase output verified by reading it back and checking all 11 colours
round-trip exactly.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

projects/kissaten_yugure/art/kissaten-full.gpl

@@ -0,0 +1,20 @@
+GIMP Palette
+Name: Kissaten Yugure (full)
+Columns: 16
+#
+  0   0   0	transparent
+ 36  36  36	outline
+ 73  36  36	dark wood
+146  73  36	mid wood
+182 109  73	light wood
+255 182  73	lamp glow
+255 219 146	cream
+109  73  73	muted wall
+ 73  36 146	dusk deep
+146  73 182	dusk violet
+219 109 109	dusk rose
+255 146  73	horizon amber
+109  36   0	coffee
+ 73 109 182	coat blue
+255 182 146	skin
+255 255 219	warm white

projects/kissaten_yugure/art/kissaten-portrait.gpl

@@ -0,0 +1,15 @@
+GIMP Palette
+Name: Kissaten Yugure (portrait)
+Columns: 11
+#
+ 36  36  36	outline
+ 73  36  36	dark wood
+146  73  36	mid wood
+182 109  73	light wood
+255 182  73	lamp glow
+255 219 146	cream
+109  73  73	muted wall
+109  36   0	coffee
+ 73 109 182	coat blue
+255 182 146	skin
+255 255 219	warm white

projects/kissaten_yugure/docs/ART.md

@@ -1,9 +1,32 @@
 # Kissaten Yūgure — Art brief
 
-Pipeline: **you generate in PixelLab from the prompts below, drop the PNGs in
+## Pipeline — export SVG, not PNG
-`art/`, and I convert them to SCREEN 5 data.** I'll write the converter
+
-(`tools/convert_art.py`) once the first real images land — there's working
+**Generate at high resolution, export as SVG, drop it in `art/`, and run:**
-precedent in `projects/mazegame/convert_screens.py`.
+
+```
+python3 tools/svg2portrait.py art/aki-neutral.svg
+```
+
+That writes `art/aki-neutral-48.png` (the real asset) and
+`art/aki-neutral-48-x6.png` (a 6× preview for judging).
+
+**Export SVG, never a resized bitmap.** This was learned the hard way. A
+48×48 PNG produced by resizing in Photoshop came back with **1330 unique
+colours** in 2304 pixels — bicubic resampling turns every flat region into a
+gradient, and reducing *that* to 11 colours speckles horribly, worst on large
+flat areas like the blazer and background.
+
+The SVG from Magnific is flat-shaded vector: ~550 paths, solid fills, a
+handful of gradients. The converter rasterises it at 768×768 (16× the target)
+via `qlmanage`, then takes the **most common colour in each 16×16 block** —
+a true pixelate with no blending at all. Measured on Aki: 19 colours after
+the pixelate, 10 after the palette reduction, and the two are nearly
+indistinguishable. **The 11-colour portrait palette is sufficient for this
+art** — that was the open question and it's settled.
+
+If you must work from bitmaps, the same logic applies: resize only by exact
+integer factors with nearest-neighbour, never bicubic.
 
 ---
 

projects/kissaten_yugure/tools/make_palettes.py

@@ -0,0 +1,87 @@
+#!/usr/bin/env python3
+"""Emit the Kissaten palette in every format the art tools want.
+
+    python3 tools/make_palettes.py
+
+  .gpl  GIMP / Inkscape / Krita / Aseprite
+  .ase  Affinity (Photo, Designer, Publisher), Illustrator
+  .aco  Affinity, Photoshop
+  .act  Photoshop indexed-colour tables
+  .png  16x1 exact + a swatch strip, and a palette reference for generators
+
+Two sets are written: the full 16 (scene work) and the 11-colour portrait
+subset with the sky slots and the transparent index removed.
+"""
+import struct, os, sys
+
+sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
+from pixtool import PALETTE, write_png
+
+NAMES = ["transparent", "outline", "dark wood", "mid wood", "light wood",
+         "lamp glow", "cream", "muted wall", "dusk deep", "dusk violet",
+         "dusk rose", "horizon amber", "coffee", "coat blue", "skin",
+         "warm white"]
+PORTRAIT_IDX = [1, 2, 3, 4, 5, 6, 7, 12, 13, 14, 15]
+OUT = os.path.join(os.path.dirname(os.path.abspath(__file__)), "..", "art")
+
+
+def gpl(path, cols, names, title):
+    L = [f"GIMP Palette", f"Name: {title}", f"Columns: {len(cols)}", "#"]
+    for c, n in zip(cols, names):
+        L.append(f"{c[0]:3d} {c[1]:3d} {c[2]:3d}\t{n}")
+    open(path, "w").write("\n".join(L) + "\n")
+
+
+def ase(path, cols, names):
+    blocks = b""
+    for c, n in zip(cols, names):
+        nm = n.encode("utf-16-be") + b"\x00\x00"
+        body = (struct.pack(">H", len(n) + 1) + nm + b"RGB "
+                + struct.pack(">fff", c[0] / 255, c[1] / 255, c[2] / 255)
+                + struct.pack(">H", 2))          # 2 = normal colour
+        blocks += struct.pack(">HI", 0x0001, len(body)) + body
+    open(path, "wb").write(b"ASEF" + struct.pack(">HHI", 1, 0, len(cols)) + blocks)
+
+
+def aco(path, cols, names):
+    # v1 then v2 concatenated — v1 for old readers, v2 carries the names
+    v1 = struct.pack(">HH", 1, len(cols))
+    for c in cols:
+        v1 += struct.pack(">HHHHH", 0, c[0] * 257, c[1] * 257, c[2] * 257, 0)
+    v2 = struct.pack(">HH", 2, len(cols))
+    for c, n in zip(cols, names):
+        v2 += struct.pack(">HHHHH", 0, c[0] * 257, c[1] * 257, c[2] * 257, 0)
+        v2 += struct.pack(">I", len(n) + 1) + n.encode("utf-16-be") + b"\x00\x00"
+    open(path, "wb").write(v1 + v2)
+
+
+def act(path, cols):
+    d = bytearray()
+    for c in cols:
+        d += bytes(c)
+    d += bytes(768 - len(d))
+    open(path, "wb").write(bytes(d))
+
+
+def swatches(path, cols, sw=32, h=64):
+    write_png(path, [[c for c in cols for _ in range(sw)]] * h)
+
+
+def emit(stem, idx, title):
+    cols = [PALETTE[i] for i in idx]
+    names = [NAMES[i] for i in idx]
+    p = lambda ext: os.path.normpath(os.path.join(OUT, f"{stem}.{ext}"))
+    gpl(p("gpl"), cols, names, title)
+    ase(p("ase"), cols, names)
+    aco(p("aco"), cols, names)
+    act(p("act"), cols)
+    swatches(p("png"), cols)
+    print(f"{stem}: {len(cols)} colours -> .gpl .ase .aco .act .png")
+
+
+if __name__ == "__main__":
+    emit("kissaten-full", list(range(16)), "Kissaten Yugure (full)")
+    emit("kissaten-portrait", PORTRAIT_IDX, "Kissaten Yugure (portrait)")
+    # exact 1px-per-entry image, for generators that take a palette image
+    write_png(os.path.normpath(os.path.join(OUT, "palette.png")), [list(PALETTE)])
+    print("palette.png: 16x1 exact")

projects/kissaten_yugure/tools/pixtool.py

@@ -0,0 +1,117 @@
+#!/usr/bin/env python3
+"""Dependency-free PNG read/write plus helpers for the Kissaten art pipeline.
+
+No Pillow on this machine, so decode/encode are hand-rolled. Supports the
+colour types PixelLab and friends actually emit: 2 (RGB), 6 (RGBA), 3
+(palette), 0 (grey), 4 (grey+alpha), 8 bits per channel.
+"""
+import zlib, struct, binascii, sys
+
+
+def read_png(path):
+    """-> (w, h, pixels) where pixels is a list of rows of (r,g,b,a) tuples."""
+    d = open(path, "rb").read()
+    assert d[:8] == b"\x89PNG\r\n\x1a\x0a", f"{path}: not a PNG"
+    pos, idat, plte, trns = 8, b"", None, None
+    w = h = depth = ctype = None
+    while pos < len(d):
+        ln = struct.unpack(">I", d[pos:pos + 4])[0]
+        typ = d[pos + 4:pos + 8]
+        body = d[pos + 8:pos + 8 + ln]
+        if typ == b"IHDR":
+            w, h, depth, ctype = struct.unpack(">IIBB", body[:10])
+        elif typ == b"PLTE":
+            plte = body
+        elif typ == b"tRNS":
+            trns = body
+        elif typ == b"IDAT":
+            idat += body
+        elif typ == b"IEND":
+            break
+        pos += 12 + ln
+    assert depth == 8, f"{path}: only 8-bit channels supported (got {depth})"
+
+    nch = {0: 1, 2: 3, 3: 1, 4: 2, 6: 4}[ctype]
+    raw = zlib.decompress(idat)
+    stride = w * nch
+    out, prev = [], bytearray(stride)
+    p = 0
+    for _ in range(h):
+        f = raw[p]; p += 1
+        line = bytearray(raw[p:p + stride]); p += stride
+        for i in range(stride):
+            a = line[i - nch] if i >= nch else 0
+            b = prev[i]
+            c = prev[i - nch] if i >= nch else 0
+            if f == 1:   line[i] = (line[i] + a) & 255
+            elif f == 2: line[i] = (line[i] + b) & 255
+            elif f == 3: line[i] = (line[i] + (a + b) // 2) & 255
+            elif f == 4:
+                pa, pb, pc = abs(b - c), abs(a - c), abs(a + b - 2 * c)
+                pr = a if (pa <= pb and pa <= pc) else (b if pb <= pc else c)
+                line[i] = (line[i] + pr) & 255
+        prev = line
+
+        row = []
+        for x in range(w):
+            v = line[x * nch:(x + 1) * nch]
+            if ctype == 2:   row.append((v[0], v[1], v[2], 255))
+            elif ctype == 6: row.append((v[0], v[1], v[2], v[3]))
+            elif ctype == 0: row.append((v[0], v[0], v[0], 255))
+            elif ctype == 4: row.append((v[0], v[0], v[0], v[1]))
+            else:
+                i = v[0]
+                a = trns[i] if (trns and i < len(trns)) else 255
+                row.append((plte[i * 3], plte[i * 3 + 1], plte[i * 3 + 2], a))
+        out.append(row)
+    return w, h, out
+
+
+def write_png(path, rows):
+    h, w = len(rows), len(rows[0])
+    raw = b"".join(b"\x00" + bytes(c for px in r for c in px[:3]) for r in rows)
+
+    def chunk(t, b):
+        c = t + b
+        return struct.pack(">I", len(b)) + c + struct.pack(">I", binascii.crc32(c) & 0xffffffff)
+
+    open(path, "wb").write(
+        b"\x89PNG\r\n\x1a\n"
+        + chunk(b"IHDR", struct.pack(">IIBBBBB", w, h, 8, 2, 0, 0, 0))
+        + chunk(b"IDAT", zlib.compress(raw, 9))
+        + chunk(b"IEND", b""))
+
+
+def zoom(rows, n):
+    """Nearest-neighbour upscale, so pixels stay square and countable."""
+    return [[px for px in r for _ in range(n)] for r in rows for _ in range(n)]
+
+
+# The game palette, index-aligned with g_Palette in kissaten.c
+PALETTE = [
+    (0x00, 0x00, 0x00), (0x24, 0x24, 0x24), (0x49, 0x24, 0x24), (0x92, 0x49, 0x24),
+    (0xB6, 0x6D, 0x49), (0xFF, 0xB6, 0x49), (0xFF, 0xDB, 0x92), (0x6D, 0x49, 0x49),
+    (0x49, 0x24, 0x92), (0x92, 0x49, 0xB6), (0xDB, 0x6D, 0x6D), (0xFF, 0x92, 0x49),
+    (0x6D, 0x24, 0x00), (0x49, 0x6D, 0xB6), (0xFF, 0xB6, 0x92), (0xFF, 0xFF, 0xDB),
+]
+SKY = {8, 9, 10, 11}
+
+
+if __name__ == "__main__":
+    for path in sys.argv[1:]:
+        w, h, rows = read_png(path)
+        flat = [px for r in rows for px in r]
+        cols = {}
+        for px in flat:
+            cols[px[:3]] = cols.get(px[:3], 0) + 1
+        alphas = sorted({px[3] for px in flat})
+        exact = sum(n for c, n in cols.items() if c in PALETTE)
+        print(f"\n{path}  {w}x{h}")
+        print(f"  unique colours : {len(cols)}")
+        print(f"  alpha values   : {alphas if len(alphas) < 6 else str(alphas[:5]) + '...'}")
+        print(f"  already in our palette: {len(cols) - len([c for c in cols if c not in PALETTE])}"
+              f" of {len(cols)}  ({100*exact//len(flat)}% of pixels)")
+        print("  top 8 colours:")
+        for c, n in sorted(cols.items(), key=lambda kv: -kv[1])[:8]:
+            tag = "  <- in palette" if c in PALETTE else ""
+            print(f"    #{c[0]:02X}{c[1]:02X}{c[2]:02X}  {n:5d} px  {100*n//len(flat):3d}%{tag}")

projects/kissaten_yugure/tools/svg2portrait.py

@@ -0,0 +1,73 @@
+#!/usr/bin/env python3
+"""SVG portrait -> 48x48 PNG in the Kissaten palette.
+
+    python3 tools/svg2portrait.py art/aki-neutral.svg [more.svg ...]
+
+Why this route beats exporting a bitmap and resizing:
+
+Magnific's SVG export is flat-shaded vector — hundreds of paths, each a solid
+fill, with only a handful of gradients. Rendering that at an exact multiple of
+48 and then taking the *most common* colour in each block is a true pixelate:
+no blending, no half-pixels, no anti-aliased edges. Bicubic resizing of a
+bitmap averages instead, which turns every flat region into a gradient and
+makes the later palette reduction speckle badly.
+
+Requires qlmanage (macOS built-in) to rasterise. No third-party deps.
+"""
+import subprocess, sys, os, tempfile
+from collections import Counter
+
+sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
+from pixtool import read_png, write_png, zoom, PALETTE
+
+SIZE = 48
+SCALE = 16                       # render at SIZE*SCALE, then block-reduce
+PORTRAIT_IDX = [1, 2, 3, 4, 5, 6, 7, 12, 13, 14, 15]   # no sky, no index 0
+PP = [PALETTE[i] for i in PORTRAIT_IDX]
+
+
+def nearest(c):
+    r, g, b = c[:3]
+    # green weighted heaviest: keeps eyes and mouth from dissolving into skin
+    return min(PP, key=lambda p: 3*(p[0]-r)**2 + 6*(p[1]-g)**2 + (p[2]-b)**2)
+
+
+def rasterise(svg, px):
+    """SVG -> PNG at px wide, via Quick Look. Returns decoded pixels."""
+    with tempfile.TemporaryDirectory() as td:
+        subprocess.run(["qlmanage", "-t", "-s", str(px), "-o", td, svg],
+                       capture_output=True, check=True)
+        out = os.path.join(td, os.path.basename(svg) + ".png")
+        if not os.path.exists(out):
+            raise SystemExit(f"qlmanage produced nothing for {svg}")
+        return read_png(out)
+
+
+def mode_reduce(rows, n):
+    """Each n*n block collapses to its most common colour — a real pixelate."""
+    return [[Counter(rows[by*n + y][bx*n + x][:3]
+                     for y in range(n) for x in range(n)).most_common(1)[0][0]
+             for bx in range(SIZE)] for by in range(SIZE)]
+
+
+def convert(svg):
+    w, h, big = rasterise(svg, SIZE * SCALE)
+    if w != SIZE * SCALE:
+        raise SystemExit(f"{svg}: expected {SIZE*SCALE}px render, got {w}")
+    small = mode_reduce(big, SCALE)
+    quant = [[nearest(p) for p in r] for r in small]
+
+    stem = os.path.splitext(svg)[0]
+    write_png(f"{stem}-{SIZE}.png", [[p + (255,) for p in r] for r in quant])
+    write_png(f"{stem}-{SIZE}-x6.png",
+              zoom([[p + (255,) for p in r] for r in quant], 6))
+    print(f"{os.path.basename(svg)}: {len({p for r in small for p in r})} colours "
+          f"after pixelate -> {len({p for r in quant for p in r})} after palette")
+    print(f"  wrote {stem}-{SIZE}.png and {stem}-{SIZE}-x6.png (preview)")
+
+
+if __name__ == "__main__":
+    if len(sys.argv) < 2:
+        raise SystemExit(__doc__)
+    for f in sys.argv[1:]:
+        convert(f)