d8461076b8
- layout: _PAD_BOTTOM 100→160, _PAD_LEFT 120→160 to prevent label clipping - axes: fix _format_tick float-comparison bug (1.1→"1.1" not "1.10"); add auto-rotation for categorical x-axis labels when they overflow slot width - engine: tick guard (>20 ticks falls back to nice_ticks); stacked_bar falls back to bar instead of crashing; extend _find_date_column keywords - series: bar width uses 25th-percentile gap instead of min to avoid invisible bars - legend: line series use line swatch with dash pattern; proportional square size - export: @font-face injected in HTML <head> for PDF to prevent T3Font in InDesign - prompts: add categorical bar chart few-shot example; ban stacked_bar; improve tick_interval guidance; add bar chart refine examples Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
115 lines
4.1 KiB
Python
115 lines
4.1 KiB
Python
"""Playwright-based SVG export to PNG and PDF.
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Headless Chromium honours @font-face with base64 data URIs, so Roboto Condensed
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renders correctly in all exports — no CairoFont-0-0 fallback, no outlined glyphs.
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For PDF: @font-face is duplicated in the HTML <head> (not just SVG <defs>) so
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Chromium's PDF engine embeds TrueType subsets (CIDFont) rather than Type 3 fonts,
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which prevents InDesign from substituting T3Font.
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"""
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from __future__ import annotations
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import base64
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from pathlib import Path
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_playwright = None
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_browser = None
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# Resolve fonts directory relative to this file: app/renderer/ → app/static/fonts/
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_FONTS_DIR = Path(__file__).parent.parent / "static" / "fonts"
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_FONT_ENTRIES = [
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("Roboto Condensed", "RobotoCondensed-Light.ttf", "300"),
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("Roboto Condensed", "RobotoCondensed-Regular.ttf", "normal"),
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("Roboto Condensed", "RobotoCondensed-Bold.ttf", "bold"),
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]
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def _build_font_css() -> str:
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"""Build @font-face CSS for Roboto Condensed from the bundled TTF files."""
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css = ""
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for family, filename, weight in _FONT_ENTRIES:
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font_path = _FONTS_DIR / filename
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if font_path.exists():
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b64 = base64.b64encode(font_path.read_bytes()).decode("ascii")
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css += (
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f"@font-face{{"
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f"font-family:'{family}';"
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f"src:url('data:font/truetype;base64,{b64}') format('truetype');"
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f"font-weight:{weight};font-style:normal;"
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f"}}"
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)
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return css
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async def init_browser() -> None:
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"""Start persistent Playwright/Chromium instance. Call once at app startup."""
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global _playwright, _browser
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from playwright.async_api import async_playwright
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_playwright = await async_playwright().start()
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_browser = await _playwright.chromium.launch(headless=True)
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async def close_browser() -> None:
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"""Shut down browser gracefully. Call at app shutdown."""
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global _playwright, _browser
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if _browser:
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await _browser.close()
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_browser = None
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if _playwright:
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await _playwright.stop()
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_playwright = None
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def _html_wrapper(svg_str: str, width: int, height: int, font_css: str = "") -> str:
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return (
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f"<!DOCTYPE html><html><head>"
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f"<style>*{{margin:0;padding:0;overflow:hidden}}"
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f"@page{{size:{width}px {height}px;margin:0}}"
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f"{font_css}"
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f"</style></head>"
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f"<body style='width:{width}px;height:{height}px'>"
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f"{svg_str}"
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f"</body></html>"
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)
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async def svg_to_png(svg_str: str, width: int, height: int) -> bytes:
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"""Render SVG to PNG via headless Chromium. Returns raw PNG bytes."""
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page = await _browser.new_page(viewport={"width": width, "height": height})
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try:
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await page.set_content(_html_wrapper(svg_str, width, height), wait_until="load")
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# Brief wait for @font-face to finish loading
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await page.wait_for_timeout(200)
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png_bytes = await page.screenshot(
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type="png",
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clip={"x": 0, "y": 0, "width": width, "height": height},
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)
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finally:
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await page.close()
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return png_bytes
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async def svg_to_pdf(svg_str: str, width: int, height: int) -> bytes:
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"""Render SVG to PDF via headless Chromium.
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The resulting PDF contains embedded TTF subsets and real text operators,
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making text fully selectable and editable in InDesign and Illustrator.
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Stroke weights match the SVG preview exactly (1px SVG = 0.75pt PDF).
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Font CSS is injected into the HTML <head> (not just SVG defs) so Chromium
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embeds TrueType subsets as CIDFont rather than Type 3, preventing InDesign
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T3Font substitution.
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"""
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font_css = _build_font_css()
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page = await _browser.new_page(viewport={"width": width, "height": height})
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try:
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await page.set_content(_html_wrapper(svg_str, width, height, font_css), wait_until="load")
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await page.wait_for_timeout(200)
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pdf_bytes = await page.pdf(
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width=f"{width}px",
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height=f"{height}px",
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print_background=True,
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)
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finally:
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await page.close()
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return pdf_bytes
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