"""svg_preview.py: 把 SVG 页渲成 PNG 的可选预览工具(chromium 优先,cairosvg 兜底)。 SVG-first 管线里 SVG 就是视觉真相(导出的 pptx 与之 1:1),想直观看一眼版面时 渲 SVG 最忠实 —— 比渲最终 pptx 更早、更准地暴露观感问题。 注意:本脚本是**可选工具**,不再是交付管线的强制环节。页面正确性(越界 / 压字 / 错位 / 网格漂移)由 svg_quality_checker.py 的几何检测保证,并在导出 边界自动复跑 —— 交付不依赖渲图,渲图只服务"人想看效果"。 用法: python svg_preview.py # 渲 全部页 python svg_preview.py --pages 1,3,5 # 只渲第 1/3/5 页(按文件排序) python svg_preview.py -o # 指定 PNG 输出目录(默认 .build/preview) python svg_preview.py # 直接渲某个目录/单文件 约定:优先渲 /.build/svg_final(图标/配图已内嵌);没有则渲 svg_output(图标占位符会由 cairosvg 路径就地展开)。 渲染器:找得到 Chrome/Edge/Chromium 就用无头浏览器(保真度最高);找不到、 或浏览器对某页渲染失败,自动回退 cairosvg(装了的话)。产物默认 2x 超采样。 """ from __future__ import annotations import argparse import re import subprocess import sys try: # zcbot: Windows GBK 控制台兼容，避免 emoji/© 等触发 UnicodeEncodeError sys.stdout.reconfigure(encoding="utf-8", errors="replace") sys.stderr.reconfigure(encoding="utf-8", errors="replace") except Exception: pass import tempfile import os import shutil from pathlib import Path _CHROME_CANDIDATES = [ r"C:\Program Files\Google\Chrome\Application\chrome.exe", r"C:\Program Files (x86)\Google\Chrome\Application\chrome.exe", r"C:\Program Files\Microsoft\Edge\Application\msedge.exe", r"C:\Program Files (x86)\Microsoft\Edge\Application\msedge.exe", ] # Linux / zcbot sandbox: the image ships chromium at /usr/bin/chromium (installed # for mermaid-cli). The original ppt-master discovery only knew Windows # chrome/edge, so SVG preview always failed inside the container. Mirror the # discovery zcbot already uses in rendering/pdf.py so it resolves the bundled # chromium instead. _LINUX_CANDIDATES = [ "/usr/bin/chromium", "/usr/bin/chromium-browser", "/usr/bin/google-chrome", "/usr/bin/google-chrome-stable", ] _WHICH_NAMES = ( "chrome", "chrome.exe", "msedge", "msedge.exe", "chromium", "chromium-browser", "google-chrome", "google-chrome-stable", ) def find_browser() -> str | None: """Return a chromium/chrome/edge executable path, or None if none found. Returns None (not raise) so the caller can fall back to the cairosvg renderer when no browser exists (e.g. a sandbox image built without the chromium layer). """ # Explicit override first (matches rendering/pdf.py's CHROMIUM/CHROME env). env = os.environ.get("CHROMIUM") or os.environ.get("CHROME") if env and (shutil.which(env) or Path(env).exists()): return shutil.which(env) or env for c in _CHROME_CANDIDATES + _LINUX_CANDIDATES: if Path(c).exists(): return c for name in _WHICH_NAMES: p = shutil.which(name) if p: return p return None def find_cairosvg(): """Return the cairosvg module, or None if not importable.""" try: import cairosvg return cairosvg except Exception: return None _VIEWBOX_RE = re.compile(r'viewBox\s*=\s*["\']\s*([\d.]+)\s+([\d.]+)\s+([\d.]+)\s+([\d.]+)\s*["\']') _WH_RE = re.compile(r'\b(width|height)\s*=\s*["\']\s*([\d.]+)') def _dims(svg_text: str) -> tuple[float, float]: m = _VIEWBOX_RE.search(svg_text) if m: return float(m.group(3)), float(m.group(4)) w = h = None for name, val in _WH_RE.findall(svg_text): if name == "width": w = float(val) elif name == "height": h = float(val) return (w or 1280.0), (h or 720.0) def _wrap_html(svg_path: Path, w: float, h: float) -> str: # 内联引用本地 svg,固定画布尺寸、去边距,Chrome 截图即得整页 uri = svg_path.resolve().as_uri() return ( "" f"" "" ) def render(browser: str, svg_path: Path, out_png: Path, scale: float = 2.0) -> bool: """Render one SVG to PNG via headless chromium. Returns True on success. On failure prints a concise warning with the chromium stderr tail (the original code silenced stderr, so a broken render looked identical to a missing browser — impossible to diagnose). The caller keeps going so one bad page doesn't abort the whole batch. """ svg_text = svg_path.read_text(encoding="utf-8", errors="ignore") w, h = _dims(svg_text) html = _wrap_html(svg_path, w, h) # chromium resolves --screenshot against its own cwd, not ours; a relative # path silently fails to write ("系统找不到指定的路径"). Always pass absolute. out_png = out_png.resolve() out_png.parent.mkdir(parents=True, exist_ok=True) # TemporaryDirectory holds both the wrapper HTML and a throwaway # --user-data-dir; auto-cleaned on exit. with tempfile.TemporaryDirectory(prefix="svgprev-") as tmp: html_path = Path(tmp) / "page.html" html_path.write_text(html, encoding="utf-8") proc = subprocess.run( [ browser, "--headless", "--disable-gpu", "--no-sandbox", # Required in the cap-dropped sandbox: chromium's own setuid # sandbox can't start (--no-sandbox), and the container's 64MB # /dev/shm is too small (--disable-dev-shm-usage), else chromium # crashes mid-render. Same flags rendering/pdf.py uses. "--disable-dev-shm-usage", "--user-data-dir=%s" % (Path(tmp) / "cr"), "--hide-scrollbars", "--force-device-scale-factor=%s" % scale, "--window-size=%d,%d" % (round(w), round(h)), "--default-background-color=FFFFFFFF", "--screenshot=%s" % str(out_png), html_path.as_uri(), ], stdout=subprocess.DEVNULL, stderr=subprocess.PIPE, timeout=120, check=False, ) if out_png.exists() and out_png.stat().st_size > 0: return True tail = (proc.stderr or b"").decode("utf-8", "replace").strip()[-400:] print(f" [warn] chromium 渲染失败 {svg_path.name}(rc={proc.returncode})" + (f": {tail}" if tail else "")) return False def _collect(target: Path) -> tuple[list[Path], Path]: """返回 (svg 文件列表, 默认输出目录)。""" from project_utils import svg_final_dir, preview_dir if target.is_file() and target.suffix.lower() == ".svg": return [target], preview_dir(target.parent) # 目录:优先 .build/svg_final(finalize 后图标/配图已内嵌,渲出来最忠实); # 没有就退而渲 svg_output(cairosvg 兜底会就地展开图标,chromium 直接渲则 # 图标仍是占位符不显示)。 sf = svg_final_dir(target) if sf.is_dir() and any(sf.glob("*.svg")): svg_dir = sf elif (target / "svg_output").is_dir(): svg_dir = target / "svg_output" else: svg_dir = target return sorted(svg_dir.glob("*.svg")), preview_dir(target) def _select(files: list[Path], pages: str | None) -> list[Path]: if not pages: return files idxs = [] for tok in pages.split(","): tok = tok.strip() if tok.isdigit(): idxs.append(int(tok) - 1) return [files[i] for i in idxs if 0 <= i < len(files)] def _expand_icons_for_cairo(svg_text: str) -> str: """Expand `` placeholders to real `` in-memory. cairosvg does not understand the `data-icon` placeholder and errors on the href-less `` (observed: CAIRO_STATUS_INVALID_MATRIX on every icon-bearing page). Reuse finalize's exact regex embedder so the fallback rasterizes the same icons the native exporter draws. No-op when the SVG carries no placeholders (e.g. already-finalized svg_final/). """ if 'data-icon' not in svg_text: return svg_text try: from svg_finalize.embed_icons import process_svg_file, DEFAULT_ICONS_DIR except Exception: return svg_text # can't expand — let cairosvg try as-is try: import contextlib import io as _io with tempfile.TemporaryDirectory(prefix="svgprev-ico-") as tmp: f = Path(tmp) / "x.svg" f.write_text(svg_text, encoding="utf-8") # Silence the embedder's per-file "[OK] x.svg (N icons)" chatter — # the temp name is meaningless in preview output. with contextlib.redirect_stdout(_io.StringIO()): process_svg_file(f, DEFAULT_ICONS_DIR, dry_run=False, verbose=False, fallback_dir=DEFAULT_ICONS_DIR) return f.read_text(encoding="utf-8") except Exception: return svg_text def render_cairosvg(cairosvg, svg_path: Path, out_png: Path, scale: float = 2.0) -> bool: """Rasterize one SVG via cairosvg (browser-free fallback). Returns True on success. Icons are pre-expanded so cairosvg doesn't choke on ``. Fidelity is slightly below chromium (no JS, limited filter support), but it lets preview run in a sandbox image built without chromium — or one whose chromium crashes at runtime. """ svg_text = _expand_icons_for_cairo( svg_path.read_text(encoding="utf-8", errors="ignore")) out_png = out_png.resolve() out_png.parent.mkdir(parents=True, exist_ok=True) try: cairosvg.svg2png(bytestring=svg_text.encode("utf-8"), write_to=str(out_png), scale=scale) except Exception as e: print(f" [warn] cairosvg 渲染失败 {svg_path.name}: {e}") return False return out_png.exists() and out_png.stat().st_size > 0 def main() -> None: ap = argparse.ArgumentParser(description="把 SVG 页渲成 PNG(可选预览工具)") ap.add_argument("target", type=Path, help="project_dir / svg 目录 / 单个 .svg 文件") ap.add_argument("--pages", default=None, help="只渲指定页,如 1,3,5(按文件排序)") ap.add_argument("-o", "--out", type=Path, default=None, help="PNG 输出目录") ap.add_argument("--scale", type=float, default=2.0, help="超采样倍数,默认 2") args = ap.parse_args() files, default_out = _collect(args.target) if not files: raise SystemExit(f"[fatal] 没找到 SVG:{args.target}") all_count = len(files) files = _select(files, args.pages) if not files: raise SystemExit(f"[fatal] --pages {args.pages} 没选中任何页(共 {all_count} 页)") out_dir = args.out or default_out # Renderer: prefer a real browser (chromium — highest fidelity, matches the # native pptx); cairosvg covers both "no browser at all" and "browser found # but crashes at render time" (seen with the sandbox chromium) — a found # browser that can't render must not be a dead end. browser = find_browser() cairo = find_cairosvg() if browser: print(f"[svg_preview] browser={browser}" + ("" if cairo else " (无 cairosvg 兜底)")) elif cairo: print("[svg_preview] 未找到 chromium → 用 cairosvg 渲染(图标已预展开;" "保真度略低于 chromium。装 chromium 或设 CHROMIUM 可用浏览器渲染)") else: raise SystemExit( "[fatal] 未找到 Chrome / Edge / Chromium,也无 cairosvg。这是环境/镜像" "问题:沙箱镜像应自带 /usr/bin/chromium(需 rebuild sandbox 镜像)," "本机可设 CHROMIUM 环境变量指向浏览器。渲图只是可选预览,不阻塞" "质检与导出 —— 请把本报错如实告知用户,不要在会话内安装渲染依赖。") ok = 0 fell_back = 0 for svg in files: png = out_dir / (svg.stem + ".png") done = render(browser, svg, png, scale=args.scale) if browser else False if not done and cairo: if browser: fell_back += 1 done = render_cairosvg(cairo, svg, png, scale=args.scale) if done: ok += 1 print(f" [ok] {svg.name} -> {png}") else: print(f" [FAIL] {svg.name} 未生成 PNG") if fell_back: print(f"[svg_preview] {fell_back} 页浏览器渲染失败,已回退 cairosvg") print(f"[svg_preview] {ok}/{len(files)} 页渲好,输出目录:{out_dir}") if ok < len(files): raise SystemExit(1) if __name__ == "__main__": main()