pdf/rendering/annotate_method.py

"""Metodo E — PDF annotato non distruttivo (testo conservato)."""

from __future__ import annotations

import io

from pdf.rendering.base import MethodInfo, RenderKind, RenderMethod, RenderOutput, RenderParams
from pdf.rendering.styles import fit_fontsize, severity_rgb


class AnnotatePdfMethod(RenderMethod):
    info = MethodInfo(
        key="annotate",
        label="E · PDF annotato",
        kind=RenderKind.DOWNLOAD,
        media_type="application/pdf",
        styles=("fill", "outline", "label"),
        default_style="fill",
        description=(
            "PDF scaricabile con box cosmetici: il testo resta nel file "
            "(solo anteprima, NON adatto alla consegna)."
        ),
        destructive=False,
    )

    def render(self, params: RenderParams) -> RenderOutput:
        import fitz

        doc = fitz.open(stream=params.pdf_bytes, filetype="pdf")
        n = 0
        for b in params.boxes:
            page = doc.load_page(b.get("page", 0))
            rect = fitz.Rect(b["x0"], b["y0"], b["x1"], b["y1"])
            color = severity_rgb(b.get("severity", "media"))
            if params.style == "outline":
                page.draw_rect(rect, color=color, width=1.2)
            elif params.style == "label":
                page.draw_rect(rect, color=color, fill=color, fill_opacity=params.opacity)
                text = str(b.get("label", ""))
                page.insert_textbox(
                    rect, text, fontsize=fit_fontsize(text, rect),
                    color=(1, 1, 1), align=fitz.TEXT_ALIGN_CENTER,
                )
            else:  # fill
                page.draw_rect(rect, color=color, fill=color, fill_opacity=params.opacity)
            n += 1

        buf = io.BytesIO()
        doc.save(buf, garbage=4, deflate=True)
        doc.close()
        return RenderOutput(
            data=buf.getvalue(),
            media_type=self.info.media_type,
            filename="anteprima.pdf",
            headers={"X-Entities-Annotated": str(n)},
        )