Gemini に @Canva が住みついた日 ― MCP コネクタ連携で「会話するデザイン制作」を 1 週間まわした実践メモ

# tools/canva_prompt.py — Brand Kit 指定と安全領域を機械的に埋める
import json, sys
 
MEDIA = {
    # key: (幅, 高さ, 可読領域から外す上下の割合, ロゴ位置)
    "ig_post":    (1080, 1350, 0.08, "右下 80px 角"),
    "ig_story":   (1080, 1920, 0.12, "中央下 96px 角"),
    "threads":    (1080, 1350, 0.08, "右下 80px 角"),
    "x_header":   (1500,  500, 0.20, "左下 64px 角"),
    "note_cover": (1280,  670, 0.10, "右下 72px 角"),
}
 
 
def load_kit(path="brand_kit.json"):
    kit = json.load(open(path, encoding="utf-8"))
    for key in ("name", "colors", "fonts"):
        if key not in kit:
            raise ValueError(f"brand_kit.json に {key} がありません")
    return kit
 
 
def color_ref(kit, name):
    """色名を必ず『名前 (#HEX)』に展開する。未定義ならここで落とす。"""
    if name not in kit["colors"]:
        known = ", ".join(sorted(kit["colors"]))
        raise KeyError(f"未定義の色名: {name}（定義済み: {known}）")
    return f'{name} ({kit["colors"][name]})'
 
 
def build(kit, media_key, title, subtitle, bg, fg):
    if media_key not in MEDIA:
        raise KeyError(f"未定義の媒体: {media_key}")
    w, h, margin, logo = MEDIA[media_key]
    return (
        f'@Canva Brand Kit 「{kit["name"]}」を参照して、{w}×{h} の表紙を作ってください。\n'
        f'タイトル「{title}」/ サブタイトル「{subtitle}」。\n'
        f'見出しフォントは {kit["fonts"]["heading"]}、'
        f'背景は {color_ref(kit, bg)}、文字は {color_ref(kit, fg)}。\n'
        f'可読領域は上下 {int(margin * 100)}% を外し、ロゴは {logo} に固定してください。'
    )
 
 
if __name__ == "__main__":
    kit = load_kit()
    print(build(kit, sys.argv[1], sys.argv[2], sys.argv[3],
                bg=sys.argv[4], fg=sys.argv[5]))

{
  "name": "dolice-design-2026",
  "colors": {
    "primary":   "#1B2A4A",
    "accent":    "#E0553B",
    "ink-black": "#14161A",
    "off-white": "#F4F1EA"
  },
  "fonts": { "heading": "Zen Old Mincho", "body": "Noto Sans JP" }
}

# tools/worklog.py — 工程別の中央値と、前週比の短縮幅を出す
import json, sys
from collections import defaultdict
from statistics import median, mean
 
PHASES = ["ideate", "first_draft", "revise", "export"]
 
 
def load(path):
    rows = []
    with open(path, encoding="utf-8") as f:
        for line in f:
            line = line.strip()
            if not line:
                continue
            r = json.loads(line)
            if r.get("phase") not in PHASES:
                raise ValueError(f"未知の phase: {r.get('phase')}")
            rows.append(r)
    return rows
 
 
def by_phase(rows, week):
    acc = defaultdict(list)
    for r in rows:
        if r["week"] == week:
            acc[r["phase"]].append(float(r["minutes"]))
    return acc
 
 
def per_post_total(rows, week):
    acc = defaultdict(float)
    for r in rows:
        if r["week"] == week:
            acc[r["post_id"]] += float(r["minutes"])
    return list(acc.values())
 
 
if __name__ == "__main__":
    rows = load(sys.argv[1])
    before, after = sys.argv[2], sys.argv[3]
    b, a = by_phase(rows, before), by_phase(rows, after)
    print(f"{'phase':12s} {'before':>7s} {'after':>7s} {'diff':>7s}")
    for p in PHASES:
        if not b[p] or not a[p]:
            print(f"{p:12s} {'-':>7s} {'-':>7s}   欠測")
            continue
        mb, ma = median(b[p]), median(a[p])
        print(f"{p:12s} {mb:7.1f} {ma:7.1f} {ma - mb:+7.1f}")
    tb, ta = per_post_total(rows, before), per_post_total(rows, after)
    print(f"\n合計 中央値 {median(tb):.1f} → {median(ta):.1f} 分 "
          f"(平均 {mean(tb):.1f} → {mean(ta):.1f} / n={len(tb)}→{len(ta)})")

# tools/brand_drift.py — 書き出し画像とパレットの色差(ΔE76)を測る
# 事前準備: pip install pillow
import json, sys, glob
from PIL import Image
 
THRESHOLD = 5.0          # これを超えたら要確認
QUANTIZE_COLORS = 12     # 支配的な色だけを見る
MIN_SHARE = 0.02         # 面積 2% 未満の色は無視（アンチエイリアス除去）
 
 
def hex_to_rgb(h):
    h = h.lstrip("#")
    return tuple(int(h[i:i + 2], 16) for i in (0, 2, 4))
 
 
def srgb_to_lab(rgb):
    def lin(c):
        c /= 255.0
        return c / 12.92 if c <= 0.04045 else ((c + 0.055) / 1.055) ** 2.4
    r, g, b = (lin(v) for v in rgb)
    x = (0.4124 * r + 0.3576 * g + 0.1805 * b) / 0.95047
    y = (0.2126 * r + 0.7152 * g + 0.0722 * b) / 1.00000
    z = (0.0193 * r + 0.1192 * g + 0.9505 * b) / 1.08883
 
    def f(t):
        return t ** (1 / 3) if t > 0.008856 else 7.787 * t + 16 / 116
    fx, fy, fz = f(x), f(y), f(z)
    return (116 * fy - 16, 500 * (fx - fy), 200 * (fy - fz))
 
 
def delta_e(a, b):
    la, lb = srgb_to_lab(a), srgb_to_lab(b)
    return sum((x - y) ** 2 for x, y in zip(la, lb)) ** 0.5
 
 
def dominant(path):
    """支配的な色を (rgb, 面積比) で返す。"""
    img = Image.open(path).convert("RGB")
    q = img.quantize(colors=QUANTIZE_COLORS, method=Image.MEDIANCUT)
    pal = q.getpalette()
    total = img.width * img.height
    out = []
    for count, idx in q.convert("P").getcolors(total):
        share = count / total
        if share >= MIN_SHARE:
            out.append((tuple(pal[idx * 3:idx * 3 + 3]), share))
    return out
 
 
if __name__ == "__main__":
    palette = json.load(open("brand_kit.json", encoding="utf-8"))["colors"]
    flagged = 0
    for path in sorted(glob.glob(sys.argv[1])):
        for rgb, share in dominant(path):
            name, d = min(
                ((n, delta_e(rgb, hex_to_rgb(h))) for n, h in palette.items()),
                key=lambda t: t[1],
            )
            if d > THRESHOLD:
                flagged += 1
                print(f"{path}: {name} から ΔE={d:.1f} "
                      f"(面積 {share * 100:.0f}% / RGB{rgb})")
    print(f"\n要確認 {flagged} 件 / しきい値 ΔE>{THRESHOLD}")