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