72 lines
2.4 KiB
Python
72 lines
2.4 KiB
Python
# -*- coding: utf-8 -*-
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"""
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生成深色站反白版 logo（logo-light.png）：
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1. flood-fill 镂空深蓝底（容差 84 = v1 验证成功参数，能吃掉 #000020 底色）
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2. 不透明内容亮度反转 L' = 1 - L（黑字→白字，红/青/绿提亮，色相保留）
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深色页黑字看不清、白底块又突兀，反白是深色站标准解法。
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用法: uv run --with pillow python3 tools/make_logo_light.py
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"""
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import colorsys
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from collections import deque
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from PIL import Image
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SRC = 'assets/img/logo.png'
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OUT = 'assets/img/logo-light.png'
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TOL = 84 # 曼哈顿距离容差（v1 实测：清除 83%、红色主体完整保留）
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im = Image.open(SRC).convert('RGBA')
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w, h = im.size
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px = im.load()
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# --- flood-fill 清底 ---
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corners = [px[0, 0], px[w-1, 0], px[0, h-1], px[w-1, h-1]]
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bg = tuple(sum(c[i] for c in corners) // 4 for i in range(3))
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def is_bg(p):
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if p[3] < 10:
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return True
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return abs(p[0]-bg[0]) + abs(p[1]-bg[1]) + abs(p[2]-bg[2]) <= TOL
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seen = [[False]*w for _ in range(h)]
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q = deque()
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for x in range(w):
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q.extend(((x, 0), (x, h-1)))
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for y in range(h):
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q.extend(((0, y), (w-1, y)))
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cleared = 0
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while q:
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x, y = q.popleft()
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if x < 0 or x >= w or y < 0 or y >= h or seen[y][x]:
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continue
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seen[y][x] = True
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p = px[x, y]
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if not is_bg(p):
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continue
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px[x, y] = (0, 0, 0, 0)
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cleared += 1
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q.extend(((x+1, y), (x-1, y), (x, y+1), (x, y-1)))
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ratio = cleared / (w * h)
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assert 0.10 < ratio < 0.92, f'镂空异常: 清除 {ratio:.0%}'
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# --- 暗部提亮、亮部保留（logo 含 ~20% 浅色元素，全量反转会把它们变黑） ---
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# L' = max(L, 1-L)：暗像素翻到亮侧（黑→白），亮像素不动，色相全保留
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opaque = [px[x, y] for y in range(h) for x in range(w) if px[x, y][3] > 128]
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assert opaque, '镂空后内容为空'
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for y in range(h):
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for x in range(w):
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r, g, b, a = px[x, y]
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if a == 0:
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continue
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hh, ll, ss = colorsys.rgb_to_hls(r / 255, g / 255, b / 255)
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r2, g2, b2 = colorsys.hls_to_rgb(hh, max(ll, 1 - ll), ss)
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px[x, y] = (round(r2 * 255), round(g2 * 255), round(b2 * 255), a)
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im.save(OUT, 'PNG', optimize=True)
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# 验证：反白后所有不透明像素亮度下限
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final = [px[x, y] for y in range(h) for x in range(w) if px[x, y][3] > 128]
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dark = sum(1 for p in final if 0.299*p[0]+0.587*p[1]+0.114*p[2] < 90) / len(final)
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print(f'完成: {OUT} 镂空 {ratio:.0%}，暗部像素剩 {dark:.1%}（应为 0）')
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