#!/usr/bin/env python3 # gen-cjk-font.py — dev-time generator for the kernel's 16x16 CJK bitmap font. # # Why generated, not hand-authored: a 16x16 Chinese glyph is 32 bytes of bit # data; hand-encoding even a dozen characters is error-prone and unverifiable. # This rasterizes a *curated* charset from a real font (Noto Sans CJK SC) into # kernel/src/cjk_font16.h. The kernel stays self-contained (no runtime font # parsing); regenerate by re-running this on any host with PIL + the font. # # The charset is intentionally small (only what the Chinese desktop renders) to # keep the kernel image tiny — this is a *minimal* landing, not full Unicode. # Add characters to CHARSET below and re-run to extend coverage. # # Usage: # python3 kernel/tools/gen-cjk-font.py # writes kernel/src/cjk_font16.h # python3 kernel/tools/gen-cjk-font.py --font /path/to/font.ttc --index 0 # # Output contract (consumed by framebuffer.c fb_draw_utf8): # - cjk_glyph16[N][32] : N glyphs, 32 bytes each (16 rows x 2 bytes, MSB=left) # - cjk_codepoints[N] : ascending Unicode code points, parallel to glyphs # - CJK_GLYPH_COUNT : N # - cjk_lookup(uint32_t) : binary search -> glyph index or -1 import argparse import os import sys # Curated charset for the minimal Chinese desktop. Grouped for readability; the # generator sorts/dedupes by code point. Keep this the single source of which # Chinese characters the kernel can render. CHARSET = ( # Desktop / window chrome "欢迎使用桌面终端系统信息关于设置文件管理器" # Kernel / arch vocabulary shown in System Info window "混合内核架构格式端口就绪运行中状态版本" # Common shell / help words "命令帮助输入查看清屏列表进程内存磁盘网络时间" # Generic high-frequency characters "你好我是的了在有和不这中人上来个到大小开关打" # Desktop UI extras (graphics / interface vocabulary) "图形界已就绪点阅读写画始应用程序桌秒" # Punctuation (fullwidth) commonly mixed into Chinese UI "，。：；！？、（）" ) def build_codepoints(): seen = {} for ch in CHARSET: cp = ord(ch) if cp < 0x80: continue # ASCII handled by the existing 8x16 font seen[cp] = ch return sorted(seen.keys()), seen SUPERSAMPLE = 4 # render at 4x then downsample for antialiased edges CELL = 16 # glyph cell size in px GLYPH_PT = (CELL - 1) * SUPERSAMPLE # font point size on the supersampled canvas def rasterize(font, ch, size=CELL, ss=SUPERSAMPLE): """Render a glyph as 8-bit grayscale alpha (0=bg, 255=full ink). `font` must already be sized for the supersampled canvas (size*ss). We draw big, then box-downsample to `size` so the kernel can blend these alphas over the background — Chinese strokes look crisp instead of jagged 1bpp.""" from PIL import Image, ImageDraw big = size * ss img = Image.new("L", (big, big), 0) draw = ImageDraw.Draw(img) # Center the glyph in the supersampled cell using its bounding box. try: bbox = draw.textbbox((0, 0), ch, font=font) gw = bbox[2] - bbox[0] gh = bbox[3] - bbox[1] ox = (big - gw) // 2 - bbox[0] oy = (big - gh) // 2 - bbox[1] except Exception: ox, oy = 0, 0 draw.text((ox, oy), ch, fill=255, font=font) img = img.resize((size, size), Image.BILINEAR) out = [] px = img.load() for y in range(size): for x in range(size): out.append(px[x, y]) # one alpha byte per pixel, row-major return out # size*size bytes def find_font(): candidates = [ "/usr/share/fonts/opentype/noto/NotoSansCJK-Regular.ttc", "/usr/share/fonts/opentype/noto/NotoSansCJK-Black.ttc", "/usr/share/fonts/truetype/arphic/uming.ttc", ] for c in candidates: if os.path.exists(c): return c return None def main(): ap = argparse.ArgumentParser() ap.add_argument("--font", default=None, help="TTF/TTC path (CJK)") ap.add_argument("--index", type=int, default=0, help="face index in a TTC") ap.add_argument( "--out", default=os.path.join( os.path.dirname(os.path.abspath(__file__)), "..", "src", "cjk_font16.h" ), ) args = ap.parse_args() try: from PIL import ImageFont except ImportError: print("ERROR: Pillow (PIL) required: pip install Pillow", file=sys.stderr) return 1 font_path = args.font or find_font() if not font_path or not os.path.exists(font_path): print( "ERROR: no CJK font found. Pass --font /path/to/NotoSansCJK-Regular.ttc", file=sys.stderr, ) return 1 # The font is sized for the supersampled canvas (GLYPH_PT = (CELL-1)*ss); # rasterize() draws big then box-downsamples, smoothing edges into alpha. font = ImageFont.truetype(font_path, GLYPH_PT, index=args.index) cps, table = build_codepoints() glyphs = [(cp, rasterize(font, table[cp])) for cp in cps] lines = [] lines.append("/* cjk_font16.h — 16x16 grayscale CJK font (GENERATED, do not edit). */") lines.append("/* Source: %s (face %d). Regenerate via kernel/tools/gen-cjk-font.py. */" % (os.path.basename(font_path), args.index)) lines.append("/* Each glyph: 256 bytes = 16x16 8-bit alpha (row-major, 0=bg 255=ink). */") lines.append("#ifndef CJK_FONT16_H") lines.append("#define CJK_FONT16_H") lines.append("") lines.append("#include ") lines.append("") lines.append("#define CJK_GLYPH_WIDTH 16") lines.append("#define CJK_GLYPH_HEIGHT 16") lines.append("#define CJK_GLYPH_BYTES 256") lines.append("#define CJK_GLYPH_COUNT %d" % len(glyphs)) lines.append("") lines.append("static const uint32_t cjk_codepoints[CJK_GLYPH_COUNT] = {") for i in range(0, len(cps), 8): chunk = ", ".join("0x%04X" % cp for cp in cps[i:i + 8]) lines.append(" %s," % chunk) lines.append("};") lines.append("") lines.append("/* Alpha coverage per pixel; kernel blends ink over background. */") lines.append("static const uint8_t cjk_glyph16[CJK_GLYPH_COUNT][CJK_GLYPH_BYTES] = {") for cp, data in glyphs: try: ch = chr(cp) except ValueError: ch = "?" lines.append(" /* U+%04X %s */ {" % (cp, ch)) for r in range(16): row = data[r * 16:(r + 1) * 16] lines.append(" %s," % ",".join("0x%02X" % b for b in row)) lines.append(" },") lines.append("};") lines.append("") lines.append("/* Binary search the ascending code-point table. Returns glyph index or -1. */") lines.append("static inline int cjk_lookup(uint32_t cp) {") lines.append(" int lo = 0, hi = CJK_GLYPH_COUNT - 1;") lines.append(" while (lo <= hi) {") lines.append(" int mid = (lo + hi) / 2;") lines.append(" uint32_t v = cjk_codepoints[mid];") lines.append(" if (v == cp) return mid;") lines.append(" if (v < cp) lo = mid + 1; else hi = mid - 1;") lines.append(" }") lines.append(" return -1;") lines.append("}") lines.append("") lines.append("#endif /* CJK_FONT16_H */") out_path = os.path.abspath(args.out) with open(out_path, "w", encoding="utf-8") as f: f.write("\n".join(lines) + "\n") print("Wrote %d CJK glyphs -> %s" % (len(glyphs), out_path)) return 0 if __name__ == "__main__": sys.exit(main())