Function _inline_latex_svg

SLiCAP/schematic/export.py:447–495

Inline LaTeX SVG content as a positioned, scaled element. Glyph are hoisted to the output SVG's top-level so that QSvgRenderer renders them as vector paths rather than rasterising them. IDs are prefixed with a unique token to avoid collisions when multiple exp

(parent, defs, svg_bytes, x, y, w, h)

def _inline_latex_svg(parent, defs, svg_bytes, x, y, w, h):
    """
    Inline LaTeX SVG content as a positioned, scaled <g> element.

    Glyph <defs> are hoisted to the output SVG&#x27;s top-level <defs> so that
    QSvgRenderer renders them as vector paths rather than rasterising them.
    IDs are prefixed with a unique token to avoid collisions when multiple
    expressions are inlined into the same document.
    """
    global _latex_uid
    try:
        sym = ET.fromstring(svg_bytes.decode("utf-8", errors="replace"))
    except ET.ParseError:
        return

    vb_str = sym.get("viewBox", "")
    parts  = vb_str.split() if vb_str else []
    if len(parts) == 4:
        vb_x, vb_y, vb_w, vb_h = (float(p) for p in parts)
    else:
        vb_x, vb_y, vb_w, vb_h = 0.0, 0.0, w, h
    if vb_w <= 0 or vb_h <= 0:
        return

    pfx = f"lt{_latex_uid}-"
    _latex_uid += 1
    _rename_svg_ids(sym, pfx)

    defs_tag = f"{{{_SVG_NS}}}defs"
    content  = []
    for child in list(sym):
        if child.tag == defs_tag:
            for grandchild in list(child):
                defs.append(grandchild)
        else:
            content.append(child)

    sx = w / vb_w
    sy = h / vb_h
    # y is the SVG bottom (bottom-aligned at label origin, matching text baseline).
    # QSvgRenderer renders _svg_rect from y-h to y in canvas space.
    transform = f"translate({x:.3f},{y - h:.3f}) scale({sx:.6f},{sy:.6f})"
    if vb_x or vb_y:
        transform += f" translate({-vb_x:.3f},{-vb_y:.3f})"

    g = ET.SubElement(parent, f"{{{_SVG_NS}}}g")
    g.set("transform", transform)
    for child in content:
        g.append(child)


def _rename_svg_ids(element, prefix: str) -> None: