Create app.py

app.py

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+"""Gradio app wrapping the official `commonforms` package to convert PDFs
+into fillable forms using jbarrow's FFDNet-L object detector (CPU ONNX).
+
+- Paper: <https://arxiv.org/abs/2509.16506>
+- Model: <https://huggingface.co/jbarrow/FFDNet-L-cpu>
+- Package: <https://pypi.org/project/commonforms/>
+
+Detecta 3 classes de campos: text boxes, checkboxes (choice buttons) e signatures.
+"""
+from __future__ import annotations
+
+import tempfile
+from pathlib import Path
+
+import gradio as gr
+from commonforms import prepare_form
+
+
+def detect_fields(
+    pdf_path: str | None,
+    image_size: int,
+    use_signature_fields: bool,
+    keep_existing_fields: bool,
+) -> str:
+    if not pdf_path:
+        raise gr.Error("Envie um PDF.")
+
+    src = Path(pdf_path)
+    if not src.exists():
+        raise gr.Error(f"Arquivo não encontrado: {src}")
+
+    fd, out_str = tempfile.mkstemp(suffix="_fillable.pdf")
+    out = Path(out_str)
+
+    try:
+        prepare_form(
+            path_to_input_pdf=str(src),
+            path_to_output_pdf=str(out),
+            image_size=int(image_size),
+            use_signature_fields=bool(use_signature_fields),
+            keep_existing_fields=bool(keep_existing_fields),
+        )
+    except Exception as exc:
+        raise gr.Error(f"Falha ao processar PDF: {exc}") from exc
+
+    return str(out)
+
+
+with gr.Blocks(title="CommonForms — Form Field Detector") as demo:
+    gr.Markdown(
+        "# CommonForms — Form Field Detector\n"
+        "Converte um PDF em formulário preenchível usando **FFDNet-L** "
+        "(`jbarrow/FFDNet-L-cpu`, Object Detection ONNX em CPU). "
+        "Detecta *text boxes*, *checkboxes* e *signature fields*.\n\n"
+        "Paper: [arxiv 2509.16506](<https://arxiv.org/abs/2509.16506>)  ·  "
+        "Modelo: [jbarrow/FFDNet-L-cpu](<https://huggingface.co/jbarrow/FFDNet-L-cpu>)"
+    )
+    with gr.Row():
+        with gr.Column():
+            pdf_in = gr.File(
+                label="PDF de entrada",
+                file_types=[".pdf"],
+                type="filepath",
+            )
+            image_size = gr.Slider(
+                minimum=512,
+                maximum=2048,
+                value=1600,
+                step=32,
+                label="Image size (px)",
+                info="Tamanho usado na inferência. Maior = mais preciso, mais lento.",
+            )
+            use_sig = gr.Checkbox(
+                value=False,
+                label="Incluir signature fields",
+                info="Detecta áreas de assinatura além de text/checkbox.",
+            )
+            keep = gr.Checkbox(
+                value=False,
+                label="Manter campos já existentes",
+                info="Preserva widgets AcroForm que já estavam no PDF.",
+            )
+            btn = gr.Button("Detectar campos", variant="primary")
+        with gr.Column():
+            pdf_out = gr.File(label="PDF preenchível")
+
+    btn.click(
+        fn=detect_fields,
+        inputs=[pdf_in, image_size, use_sig, keep],
+        outputs=pdf_out,
+        api_name="detect",
+    )
+
+
+if __name__ == "__main__":
+    demo.queue(max_size=4).launch()